Abu Kammash Marine Jetty

7/28/2019 Abu Kammash Marine Jetty

http://slidepdf.com/reader/full/abu-kammash-marine-jetty 1/78

STUDYIS IN

no. (1) 23/0lJ2007, in Arabie:

P r e S t ~ J ] t sS ( ~ h e m e s

report entitled

me no, (2)



L

2. l Temporary Supporting Systern .... , .

RCHiOVa! Reconstruction

2.2.1 Precast Concrcte Slabs., . . . . . . . . . . .

Concrete Slabs Supporting thè Wall<

4·

2.3.1 Precast Capping 7

2.3.3 Concrete Abuttnent ...... .... 16•• > ....... .. ,. > . . . . . " • , ••

15

Renaît'

2 shotcrete................. , .......... ", .. > ••• > .

. . lusm g specHl con crete, .... .,."." .. ", ... , . > > "' > > , •• > > > ........ ..

Surfaœ finishing ImH'taL. > • > > > ......... > . . . . . . . . . . . . . • •• •• > • , • > .. .

2.5 19

.2. l mprcssed

ofDamaged Steel Structures. ... > . ' >

Repairs for some Damaged

2.7.1 Piles.. > , • > > ., • • • > " " • " .......... •• • > > •• • , • •• • ". " . . . . . .

'[rus::> .. > •• > " ••• > > ........ > > • • • • • " " > •• > •• " • • .. . .'

2

Guide l I U ' [ UU ' , " ofjeHy

4

18

18

20



3.1

lards with! therut rubber

Control , . , , .. , ...... , ..... , .. .

3.2 Quality ')

4, 'Rcpai:rs . . . . . . " . . . . . . ,. ••• '" , ••• " " • • •• • •• ., •• " •• • , ••••••• , •• " •• ",

5. to 25

( ~ o n d i t i o n s .. , .... " ,......... , ..... , , .... , ..... , .. .

7. SpcI:ific Conditions.. . , , .. , ..... , ..... , . . . . . . . .. ,. , . . . . . . . . . , .. 2ï

8, of

9,



Kammashfollows

guidance

Reinfi.Hced

specifications schcmes prcsented

report are both çonsidercd as

LIBYAN AN])

Repair

L INTRODUCTION

repaJr

suftkicnl guidance on

of

contractor

to the

HPatch R.epair

lI], a copy of which is

tl1at the

uu

recornmcndations,

Marine

H is important to state

concrete tomOlmt

works rI].

considered

to

unfbrcsecn

bill

- 1



1. Supporting of ail were

60 mm.

1.2 Supporting piles rnovemenlSrcpair of the precast concrete beams.

2.1.3 tn!ss as

screws, nuts .....cet.

and

states

concrete

is considered necessary,

mainly on

The

execlition:

2, 1 Precast Concrete

Humber of Precast

detcrioration

reduction

addition to

to 0),

Fixing new

to the

- :2





------- ----------- - - - - - - - ~ - - - - - - - - - - - -

c

report, subjed

foUO\ving

Ali f1xing steel

b- supporting of the walk

to the

supporting shaHand approvt:d by SE.

2.

in cross-sectional reduction of up tn

this '\-'lm

hoHow

of the saül

sprayed

rein forcement

corrosion,

signs of

eieroents,

efer.nent;:.;

elements

abmrnent



General view t h ( ~ofthe

arro','vs refer to sever

Red 81ïOWS l'cier to the stcel



~ ~ ~ ~ _ . _ _ ._---- - - ~ . _ . _ ~ - ~ _ . _ -_ . _ - - . _--_ . -

Hol!m',' part of the bcams

- ~ , ~ . _ ~ , . ~ . , _ . - . ~ ~ ~ . ,.

,

Sied Piles



Provision for temporary support

before starting the cb'-,

1 and h<:nce be rernoved upon

and the

Due to

provisionand approvcd by

Prinr to chipping an area

sounding survey of

location of

l ->

(l - Capping Beams

to a distance Hot

and corners of

as possible.

contractor is to give

in axes nos. l,

precautions during the

Upon compktition of

contractor is

adhering COl1crete

appears sound.



a u!ppmg Bearn

r - - - - - - - - - ~ - - --,

a

1),;;mol ished

ConGrete

m- - _ . ~ - - - - -

!L __

;:,ectwn ~ l - ~ ll

r_ •. _", . ,_"" .. __ _ >< <._". ,•• ,1.

>60mm 20mmApparcm Concrete

> 6()mm" lhick!less of concrete cover to be chipped.

20mm = Chipping depdl reinJorcement

Sec a-a shows the extent of ( m c n ~ t e removalRepair the

-8



Fig. (5): Typical detedoutnon of the S€«h. vfater intake support e h ; ~ m i e v l l t sblue anows refcr to th(;;; con-osion deteriorations spread over the extemal faces

of the lOOmm thickness slabs.

red arrows point at the corrosion deteriorations of the extemal f2ces li""capping beams.

-9



- ~ - _ ..--,,---- ---_. ~ - ~ - - ~

.Reinibn::Îng bars must beexamined

Rebars experiencingare retained,

foHovving [3]:

A.s shown in (6), the contractor is to en:;<:l ne'\-\'omlitudinal reinforcement of 16 mfn

tn the

connectors 10

the

"nIe •.::onneetürs is 1.0

coyer rI!;;:'W is not to

than 50 mm.

Bcams are reprofiled

those

shotcrete according

to

,- Concrete must be fully

- Beams a n ; ~ to

ihicknes$

- Repaired beams are f(I

(7)

- lJpper surface the beams axe tn

concrete as d(;scribed item no.

- iO



Additional Grid z , ~ i . l l t o r c e m c n t 0Similar to ~ , " 0 " " U , ' "'-J""\l!J lIC

New Stinups (0 Hlmm

Apparent Concrcw

Beam

i ~ e i n f « r ç è n J 0 n t

70mm 40mm 180mm20mm

", ",

40mm"

40mm "oc. Anchorage of

2Umm Depth of CllrVllt:u concrete behütdRcinJofççmenr

70mm Distance betwcen new rcinfbrcemem ilnd c;dsîingm21.i"1) jçjnforCClilent

Stimrp

Fig. (6):

180mm Di<;tance

-11



Special Concrete

Concrete (Shotcrete)

S u r j ~ I { ; 0 Fillishing t.:Jortar

lOmm l40mm

new reiniorcemcnL

of shotcrete layer.

1 'fhickl1ess of Hnishing InOliar

.' ,

.Fig, (7)::beams



- Bond

Hnishing mortar is ln

an

- Concrete coyer of repaired

60 mm.

a!6 Choice of repair method

intakewill main!y

concrete

mm depth will he repaired by a

of 10 Inm,

is ln not

ce.mentitious mortar to bc

cxceeding thickn.css by

Repair ofPrecast Ca,oping Bearns

as tür .

above. Chipping of

facesof

a depth morevievy' of one of the beams

are some points to

these

contractor is to

repaîr of anchor

pipes to pi.!es,

Anchor

new

"", '

1"





only:

e!crnents sufter from corrosion type

fOp sidt: only, The extent. of chipping

CX!)C1cre:(1 10 reach dcpths beyond 60 Bun

surface area of the slabs,clements are to bl::' aecording to thc

aIl Ail deteriorated cüncretc tü bi,:

con crete

appears sound,

loosely adhering

concrete

in these elernents shaH

not less than 20 nun,corners of chipped areas must

This

ternnon'!fV support

the chipping

must be supportee!

slabs carrying

wil 1 be removee!

required

Upon the cmnpletion

tbe çontractor 13

concrele

to

andconcrete appears sound,

bars must be cleaned by

reduction,

concrete Lü

be a

\ '

- l5 •



arc tü

original shape and leveL

r,:,epaired slabs are to be

days watcr or other

instruction

h- Rq7air

bottOfrt

!lOS.si;)llowed

bl2 Rians are

the foHowing procedure:

Con crete surfaces must be ln a

condition.

Repaîrin Fig (9),

entrapment of

- Repaired

days

instruction

water or

chernical

23.3 Reinjbrced concrete abutrnent

These clements are ta be

1'br

than

using Shotcrete

to must n o ~ ; s e : i S

Type of "'''"uv"", or l{)r

enviromnent

.. ( \ ~ m e n t - Addition

Dot

(6.5 '" j.

". Maximum w/c

16 -



Apparent

deteriorated concrete remova!

of

view of con crete

sec b-b method of casting

of



envimnmenL

to

to the

superplasucizers [8,- Coarse shaH

to AG 506.

IS to of

rnerre

.. Continuously alc"v concrete must(7) days

.. Cube comnI

thanat

2.4,2 using ,)peciaI

SpeciaÎ to- Type of cement:

fbr

- Cement content ( 3 6 ( ) ' ~w/c 0.45

lS tosuperplasticizers 9},

condition vibrator(s) 1 be { ~ O n l r K l C t of

concrete,- Continuously c.uring of new

least (7)- Cube compressive at

40 MPa.

2.4.3 Repair using Expanding [6].material shall be and abutment as an

above. It i5

d;:;pth exceeding 60 mm and is ta

al

not

2.4.4 l

. 8



Marine . contaminated

hrnits to a depth

'1"1 ü t ? : r l f ~ l " ' > 1. I!.. OV1. . . . . . . .uL ,

fùrmation of

surfaces.

('athndic

system he

"-Ji:' ' ~ > l",,),1 ûacrr/,Clü,

the rnarlne

in this report, in

and help in prolonging

fJ [ '}t i"d ' l ' 'If' S.;V < ' ' ' " ' ' ' - V l ' '.Jt-"..-J.t ,,-,l' .\. . . ~ > . t .

Protection [3, l !.l l,

is an dectrochemkal

anodes at different

") li' 7'L1J U, j /.1

This systemstructure from

manufacturer

l)rolong the service

10" 20 depending

used. The main idea

on introducîng more

in the

cementitious mortar

rein forcemen t

,/ '.

. -9·



2.5.2 fmpressed current ~ r s t e m {3, 10, ! 1/ln impressed enrrent system a I1l0re reactive rnatcrlaI the

reinl'orœment is intmducccL, the anode Hm,terial. itsclf he inclt

but is maintained in an <mocHe statc relative to the stnJCt.UH: by

bdng connccted to the correctpoIe of a direct currenl! power

supply :::;: 10 mA. 'rhis system requires a frequcnt monitoring and

inspection program in order to achieve il prolonged tife,

2.6 5 : t ; n J Q , Y , ~ , l , . Q f " g < . ! r r i l l g , ~ ç L g ~ : . e J " . , t n l § ~ , , ? t n ! ç J m : ç ~Due tü the severe corrosion damage observed on sorne steel truss

structures, plates and most of the connecting bolts and nuL:; marine

jetty, which lcd to il rernarkable loss in cross section and heaviJy

effecting the structural performance n:quimd to withsümd existing

loads, 'l'lwse heaviIy darnaged sections must he rernoved rep.!p,ced bynev\! as buih sections as described in the recolTlrnendcd bill qunntitie:;,

Based on the structural. analyses discussed in the Jll,ain report and fromq " ' l '>"u ,; ,. !'" ! 't "" .0 t, d tt, î r " " < " " ~ l, > l, ,. () ..,',,, , ' t!, o ' j"h1C C,.Sl b !1 p L O ! \ l ev \ , 1. \" lS rc,\C.1le, . l Ia , no """,,1..,1\(. , )dUH1 . l , ;ü)" .O)

existed in ail steel sections, Bence., although the structure je; considered

sah:, any los5 or reduction in the clement sections cmù be aHo\vcd.

Fur!hennore, tcmporary supports shaH

rcmovaJ phase and mounting of the nev/ clements

proposed lIy the eontractor and approved by the SE.

coated as pe r coating specification presented in item 2/7

_ . ~ . __ ~ , , _ . ~ ~ ___ ,__ ~ ~ ___ ______,______ ~ _ . _ ~ ~ __ , _ ~ , , _ , .._'___ ""__ ,_n _____.__ _,7 Limitee! Ref)airs for some darnaged steel structuresl" · ' i , ~ , l " " '1 ,.,", .',,., t ~ ~ , . . , . l , . . , , , , , , \ · , , · , t ' , !I,urn JAl. ...:orrOSlOn {amàh,C WdS Ot1St,I\CU "lB scrnt ;, CL

' l ' ~ et>"f',:l tr'1"3'" ' l ~ ' < ' { ' r r l i ' l l " "nid s , t " c ~ 1 p'!p,< "\{Jj'l!'l 11" r ' ' ' ' ' F , · ! , , , j , . ~ ) h i , , i ( l ; , ' k l ' l e ' ~ " . o. '-'%.. '" . -h " ~ : , . > " , .. .J .. L .J (.,t, , "-........ ,Ll'l,,/ ...., ' l ,", _ , ~ ~ . J: h;i \ 1 \ "< . . .. h . , t . " , '" "j,3

1,1;;',;, " ~ " ' l î " " r ! " ' I : ' ( ) J " " "'(}'l'C'Ctl'\"" fr" ' l ' l i ' r o>('t i ()f1 1111'St' l)l"- ' P 1q (" n 1 f 'p tcd :" . tjf:( ttw:. '\.. . ', .. . " \"" .J ,,' {Y . '-'J. "- . ",.l i.", v 1 . . ~ . ~ . ' i . \...... " l . . " " . " ~ . ,,,',.' ....;<"1. . . . .,... ..

folkrwing details:

"/·.f.,, . . . . .

2,7.1 Steel Piles

Recommendcd repairs can be das:51{1ed hascd CUl CWü l'nain

categories:

Cl. Atrno.spheric zones or areas no! covered by wa[er

envlronmental conditions.

New proper coating shaH he applied including aH l'ft/visions

f",(',,,S";,> "'" ti ) n r ' : ~ I " " l t · · " 'tl'1" ' ' ' l ' '(Q(',,, '''l')(j ,'P"""!,;';! Il''1' ''''j:'l'{) l ' - ' fc,(!n , ' " < ' w ' , ~ . u . ~ . . . 7 '",. .t" "" .fL." "-, ~ . . . . . : : ' } t .1. .lt ... ,,,", U , ! t ~ , t vLc.P.... C... 1 ~ , : \ / ,"t..,," \., ct"l-\......

t:")'Xt;'1g' l'n ""I(')S't 'H' ' ' ' "! " 'l'l'le ·"lll'jivJ·[''',') "',.,Ij 1-),,,'\. u . U. , lE .. . '-u"","' , ) ~ . . . . l\ , , l ~ !t. " lS ~ . l ' l l o , j " " t . , . .

') ,! f ' ) \".J j .",H,J.l Rem(}vai of old coating by blast d;;:;aning to (

insure removal of aU C01TOsionj2wshl,Ç!::,:, etc as the

- 20

beim.pkIllcnted the

heshaH be

to

!" -

http://slidepdf.com/reader/full/stnJCt.UH

http://slidepdf.com/reader/full/stnJCt.UH



112 orstandard.

a3 he applied

international standard l

In addition to above, the for Iowing

coating shall adhered to:

l-ligh abrasioncurîng.

to arnbient T''''''''''':»"O'

equivalent

b. SplŒI;h Zones areas.

nr. ',n,c',- coating

coating and

b. 1 prepared

2/7/1. Areas to

above

Ctass

2. 2 T'russ

Proper protective

preparation sections fbrming

be1o\v main marine

/

a. as

,. (, ,

·2 1 .,



induding

and applying the nevi

b,

..n , , . ' rH ' as weil as s ~ e e l elements

west walk ways, ladders, cablefoHo\ving:

replaccd

2.8.2 Guide Boards

Steel

2.8.1 Flour panels on walk 1vays

lJamaged Flour on wall<

2.8.3 Bollards with/ without

of

zemc areas as



(IO,c): Bollard mbber fender

Fig (1 k1,,,,,,,,"tt:! canying the



- - - - ~ - - ~ - - - - ~ - . _-_._-

:t CONTROL

3.0 Routine

H is al.so important to state that

implernented durin g

of testing is· to be "'''''-'''-·'-<''''U

SE \:vhich tS a

to

equipm.cntssource,

Quality Control tests

n:pair materials

undertakcn

No, 340/97, or

1980

- Compressive strength of the hardened rnortar

he tcstcd to 188]: 1

-, T ~ : s t i n g of reinfürcemcnt bars

bars in 10

special concrct.e grout and

testing of o m : T e t t ~ workability

testing compressIve

concrett::, mortar grout [4,

- T'he contractor i5 to submit method of

coatîng lninternational

be

w o r k ~ L



- The contractor not

conditions e,g. rain fi:dL

v"·,,,-.u,,-, Cores for

Unùertaking pul l

the

RIB3PAIRS:

[22}_

including the

undCl1akcn

requîred sta.ndards

by coutractor [ 1J.

S, RF;PAlR I M P L E M } ~ N T A 1 ' l O NREPAIRS):Repai r irnplcmcntation sequence

cOlltractor obligated to assemble a

personal possessing good cxperience

addition to a programmcd QC/QA throughoutproject

Tu darit); the

repair

fix imp!ernentation,

(.,

·25

10



presentcd this report, the eontract

arc consideree!

contractor is

doemnents

compared with ...."- ...".n"'....client to assign a weB

the saicl repairs. H is

""'n.. ,.·'.> supcrvising

whole perind of the said O V ( ~ 1 t c()me any

that rnay occur or ailer !h;; hnplernentlttionto put

10 the fact

process in \vhich

BQ prescntcd in

the listed

rnixîng

tn achievc up to

:3

a

slated abovc,

dassi.fied as rH",.,.."", ! v J l a ~ ; ~ I ' i . , , ( l . lthe faet that it is 1,0 aceurately quanl.ily

to he repaired befüre actual executron of

% 15 for additional works normally spedl1cd

cover the md{m;seen work::; caused by any

from those table (1) o1'tlüs

"1 i i .Ù. ",1 ",;

works

( l l " " r l ! ' ; j ~ , f t i ' , ~ ' ' ' ' P ' ' '

to coyer

l'he contractor

slrm:,tural clements

based on the

The

relevant

said

6.6 The cont.ractor lS obligated tü

rcpaired the approval



personne! t()r control of <",""",-"",,"'C"''Y,p,nh'

the as well a,') to rend cr

with perfonnam:e of

whah;oever.

!l1aintain a

meters fuHy

machine, c o m p u t e f S ~ colored printers,

al,1 office a c ( : e 7 - : ~ , o n

msurance and

costs in

be bome by

a

shall flot

contract

origin\-vhcn i n s l . r u c t t ~ d . s u t ~ j e c t to the

·27·



. _ - _ . ~ ~ ~ . ~ . - - . . . . - _ . _ ~ ~ , ~ . _ ~ - - - _ . _ - - - - - -, __ ~ ~ ~ ~ , ~ - - - - - - - ~ ~ - ~ ~ - , - " ' - " ' - ~

table !) are bascd

l'nentioned

partîcularly

considercd as useilt! starter for

mobilization 'l'he exact

evaluated afJer

13 of BQ an of 11 % Cluantitv ro'\t"P<".I)';.f.>.t'\ "o.u'ü-1zc . . r " ' ( ~ n C > < l ~ f ~ f-'f.'f.t any increases

il l

1/3

''l''"'

211

') J,-, ! ,

prepared hy

blasting as per item 392

1392

1392

",

- 28 ·



HE 200 A profileln 4700

p; HE 160 A profilem

2240

C, LLIOO*lO ln 4000

D, m168

E 182

L 70*7 5700

C, IPl:: !80 profilem

1120

1sections carrying

walk way Ilomm

840

panels

coatcd as

pei item in

A. HE 20() A profile

B. HE 160 A profîlerri

2240

C. LU 00* 10 proi!le1'n

4000

D, IlC 200 B profileln

168

LL 70*7tH

182

F, 70*7III

5700

G. IFE 180 profile:III

1120

H. 1sections carrying

wall< way flomIII 340

to be finally

as peT 2!7i2 clause (b) in

this report

Profi!es as 1'ollow:

"r"1) , L , A, HE 200.Ani 4700

B. HE 160 A pronlem

2240

C. LU 00* 10 profileln 4000

D, HE 200 Bni

168

- 29 "



F. L 70*7 profîlern

Jf':l G. IPE 180 profil eHI I l

IL 1 sections carryîng

waik way no mrn

840

·30·



- 3 J •



a., Rernove guide boardtubes in heavily corrodedamas and new

bar tubes as170

described in item 2/8!2 in 111

5/1 this reportdisposaI of emOVCG

items.

!-l.. Repaît and maintain ailboards tubing as

described in item Hl ni 5250this report.

Ladders

Rerlloval of ladders in dam<1ged

amas and mounüng of new5/2 ladders, using of proper

Il !40

pel' instructionÎnduding ofold

WaJkway unde, mlltÎn

Rernovai of damaged floorand of ne\'! Boor

5/3 ilS desçrib'.::d in item 2/8/l Hl t h i ~ rH

inc:luding disposa i of olt!1100!" panels

Remnval of destroyedS!4 i support and m 1760

Ifenders

lT'realment,' and maintenance of

, as describeJ in ilern515

i :.18/3 i Il this

- 32-



6/1

6/3

inc Imling

supports to pl'cvcnt

rnovement of ste!;!i as sÜlted in c![îllSe (2/1)

including disposai of n;tnoved

ofremoved

provision

supports and disposal of

rcmoved items as

Capping beams with no

anchor plates, as

in item no.) dause (a),

Capping heams with

anc!Jor

no.

.,

m"

90

90

1200

140



713

7i4

and a c c e s ~ , o r i e s .b- Slabs \vith no cClI)so!e

Rt:construction of removed in

\0 original p r ( ~ i e c tdetai1s

itern;:; as fi)llows:a·, Slabs with console

with no console

b-

console

induding provision ofc" "wV , , " , 1 ' . . I ~ ) r

sJabs from büttom side

only ilS dcscrihed in itemclause ir:clwJingremoved Îtems HS follows:

lI- Shlbs with "on<:, ' ' '{ '

provision of

for thepipes and accessories.

b- Slabs \Vith console

pcs

pcs

Pcs

95

106

95

532

·34 ..



9/1

9/3

9/4

10l!

f ' ,wrr , , , ;nn deteriorated

as foHows:

using shotcretc

using specialCOlluete

l- Rcpair usÎng modificdmortar

of deteriorated concretethiclŒ©S5locatcdinduding disposal

removed items

ReconstructÎon of removcdconcreie sh b În accordancc to, :1 '!proJ'::ct ( eli:l!iS as

described in item no. (2/3/2)clause

m"nt"

!11

mi

nl'

97

200

200

Lump Sum

125

., .cc

.1, ;

40

0/2

Jon



Due to the fact that

dift1cult to

total

concrete to

bcfüre actual

worÎ<s ! l},th!s item

is

increase in quantity to coyer

any un foreseen work:>caused any inereases in

J-epair works,

mnnbers

AND TOTAL in iette:t's

36 -





. _ - - - - - - - _ . ~ - - _ . - . --_._-_ . _ ~ - - ...

organization,-")k •f structun::s bv

. "

1998.

Specification

Standards lnstitution, 882: n " ~ ~ f ' " tc,r 992.

3 l

Standards Institution, i;

strength of concrete

Institutioll,

üx assessment

1

21-

Intemationa[ standard''';!,

,w"",,,.:/,,,, protection steel structuresby " -

[ ; . ~ ç l , ; u t m u and supervision of 1998,

.. 3B .



1





UO!Sü1JO:J îu.:mr<lJJo}UFIl

-- , ) ~ J J J U O : ) p i ) ; H { ) J u ~ ; : ' ! H JO



.. on tM ; Rh BQ:

PART3-METHOD OFMEASUREMENT

INTRODUCTION

l. GENERAL ITEMS

2. SURFACE CLEANING AND INSPECTION AND TESTING

3. REPAIR

4. PROTECTION

PART 4 - BILL OF QUANTITIES

PREAMBLE TO THE MEASUREMENT OF PATCH REPAIR OFREINFORCED CONCRETE

BILL 1 General

BILL 2 - Surface Cleaning, Inspection and Testing

BILL 3 - Repair

BILL 4 - Protection

Page Number

47

49

50

53

56

59

60

62

69

83

. -i



tm t

tt"H ** ••

PART 1 - INTRODUCTION



hM mMtrttttM! ''t!,

GENERAL INTRODUCTION

Concrete has long been renowned for Hs stren gth and durability. There are many examples of good

practice which have stood the test of Ume. Unfortunately there have also been too many examples ofearly deterioration in recent yearsand the image of concrete, particularly reinforced concrete, has becometarnished. Tt is fair to point out that the vast majority of concrete structures have had and continue tohave excellent records of trouble-free service.

The performance of a structure, in durability terms, is dependant both on its condition of exposure and

on the "quality" achieved in design, detailing and construction. There are wide variations in theexpectations of structure owners and these lead to different judgements of what is considered to be

acceptable performance. As an example industrial structures may have a usefull ife of only ten or twenty

years because of changes in processes or markets whereas churches and other public buildings are

expected to last for generations.

There are many causes of untimely deterioration. In sorne cases the causes can be traced back to failureto achieve "qua lity" because of constraints on finance or time. Qualit y and durability may have been

compromised by the more immediate needs of economy and expediency. Another cause may be that thelocal environment to which the structure 1S subjectcd has changed. An example of this is the increaseduse of de-icing saIts on highway structures. In other cases the use of a building may continue long af terthe period originally intended as with the case of pre-cast houses constructed in the late 1940s and early1950s. In other cases there may have been failure to appreciate the consequences of a particular localenvironment. '

The deterioration experienced by sorne concrete structures has generated much activity and interest inthe field of repair. This interest was recognised by the Society in the publica tion of its Technical ReportNo 26 -Re pairofconcrete damaged by reinforcement corrosion -and the publication ofBS 6270 Cleanin gand surface repa ir of buildings, Part 2 Concrete and pre-cast concrete masonry. Technical Report No 26

gives general guidance on many aspects of concrcte repair. Since Hspublica tion there has been continued

interest in the topic and the Materials Group of the Society has become aware of a necd for uniforrnityin approach to specifications Jq r repair contracts. The extensive range of repair materials which isavailable has also given rise, to a need for guidance on properties, testing and use.

With these factors in mind, the Materials Group set up a working party with the objective of producing

a specification for patch repair which could become a standard and model for the industry. Thedocument which has been produced relates specifically to the repair of concrete which has suffereddamage because of reinforcement corrosion. The working party was able ta draw on a wide range of

expertise and included representatives from contractors, consultants, materials suppliers and the PSA.Representatives from FeRFA and late.r the Concrete Repair Association were includcd. The resul tingdocument attempts to coyer most:aspects of the specification of repair contracts including access,processes, materials and testing. . .

These last two topics are particularly difficult to address because of the lack of national standards forrepair materials. It is hoped that the situation with regard to test methods may improve within the near

future because of the moves towards standard isati on in Europe and there may be a need to revise certainclauses or to add new clauses. Il is feH that the need for the specification is so urgent t hat it is better topublish in the present form rather than delay until new information becomes available.

As far as the method of specifying materials is concerned, at the present time it is feH that a suitableapproach is for the specifier to name one material manufacturer in the document or give a list of severalmanufacturers whos e products have been found to be suitable in similar situations in the past. Thiscould be taken as a guide to the standa rd of material required. Specifiers may also wish to consider theadvantages of the use of those materials wh ich have British Board of Agrémen t certificates.

As work on the specification progressed the working party became aware of the urgent need to provide

guidance on means of drawing up bills of quantities for repair contracts. The task of drawing up asuitable method of measurement was, therefore, added.

The document which has been produced relates specifically to repair of damage caused by corrosion in

reinforced concrete elements or structures. Although the processes could be applied, for instance, to

secondary reinforcement in prestressed members, a much more carefuI overall approach would be

appropri a le in this Case.

G



44 •

APPROACHTOREPAIRS

It is worth repeating sorne of the aàvice given in Technical Report No 26. The approach to repairsrecomrnenàed in TR26 was sumrnarised as follows:

a) Carry out sufficient investigations so that the rea$Ons for and the extent of the problemare identified and understood.

b} Considercarefully thewayinwhich structural and opera tional conside rations will affectthe choice of repair me thod.

c) Prepare a full specification for the work.

It is anticipated that the following document will assist greatly in the last named task. It is hoped thatmost sections of this specification can be used without change and that the specification can become astan dard for the industry, as far as this is possible.

The necessity for the pre-tender investigation cannot be over emphasis ed and, again, it 1S pertinent toquote TR26:

"I t is important to distinguish between chloride-induced corrosion and that simply following fromcarb onat ionof the concrete. Whilst the repair methods will usually be similar in the two cases, the detailsmay be different and, most importantly, the likely future performance will be different."

Patch repair cannot be considered to be a reliable long term method of preventing continued deterioration in concrete st ructures cont aining high chloride concentrations.

Another point which needs to be borne in mind when considering repair options is that patch repairsmay be visually obtrusive. It may be difficult to ob ain a good colour matéh with the existing concrete.The repairs may have a different surface textureand rnay weather differently to the rest of the structure.Protective or decorative renders or coatings may go some way to m ~ n i m i s i n g these problems.

THE MODEL SPECIFICATION

Technical Report No 26 includes four different repair options as follows:

(i ) Re-casting.

(ii) Spraycd concrete and mortar.

(Hi) Hand-applied cementitious mortar.

(iv) Hand -appl ied resin-based mortars.

The Society has an existing specification and code of practice for sprayed concrete and it was realisedthat a similar document for hand-applied mortars would be useful to consultants, repair contractors andothers. The greatmajority of con crete repair work is carried out on relatively small areas using polymermodified cementitious mortars but proprietary pre-bagged fine aggregate concretes, generally placedusing a letter box technique, are used in some instances especially for deeper repairs. Sprayed concretecan also be used for patch repairs if a sufficient number of patches can be made ready at the same timewithin a convenient area. Sprayed concrete may also be the most appropr ia te technique for repairinglarge areas of $Offits, for instance, following fire damage.

For the pu rposes of this specification, patch repairs are generally consi dered to be hand applied and tohave an area of less than 0.5m2 and a depth less than 100 mm. The repairs rnay assist in reinsta ting load

carry ing ca pacity in sorne instancesbut their usual function is to reinstate protection to the reinforcementlocally rather than to act structurally. Patch repairs are frequently ernployed in the effort to prolong thelife of structures where carbonation has caused corrosion of reinforcement.

The mode! specification is in thirteen sections. Each section has acco mpanyin g user notes which givegeneral guidance on the topie of the section or guidance relevant to a particular clause. In Appendix Bthere isa general checklist whichmaybeofassistance whenc omple ting the specification on eachoccasionon which it is issued.

'7,



4C$iMi@ WW ' #Ai;' i .M e

Two alternatives are given for Section 4 Survey and Location of Defects. The standard form specifiestha t the Contra ctor will undertake the survey work du ring the Contract and also locateand mark up thedefects to be repaired and the Engineer monitors these activities. An alternative form is given in

Appendi x A to coyer the case when the Engineer undertakes the bulk of the sur vey work and marks up

the areas to be repaired.

THE METHOD OF MEASUREMENT

The section on method of measurement is in two parts:

a) General principles

b) Specimen bill of quantities

The method of measurement is compatible with that drawn up by a working pa rty of the Concrete RepairAssociation which has already been publis hed.

It has to be understood that at tender stage, bills of quantities for repair work can never be considered

as more than a guide to the amount of work required. The number of repairs, the area of individualrepairs an d the depth of individual repairs cannot be established until close access is provided. Thedocumentation, therefore, needs ta provide a mechanism for the inevitable changes in quantities thatwill occur as work progresses. The fact that quantiti es and costs are uncertain should be made clear to

the client 50 that he can make suitable budgetary arrangements.

8



- *P Sijio H f F*bilMMtêfMt'f 4

PART 2 MODEL SPECIFICATION

. 1'



9' 1ssWkiUê%#li iE •

NOTES ON THE USE OF THE SPECIFICATION

a) It is suggested that the specifica tion should be reproduc ed in full each timethat it is used rather than merely listing amendments

b) When clauses are not used the original numbering system should be

maintained by including the clause number and inserting the word

"Deleted"

c) Where additional clauses are required they should be, if possible, placed

at the end of the appropriate section using the next number in sequencewith an "A" to show that itis an additional clausee.g. 2.1OA. The wording

of the clause should be underlined. Where it is not appropriate to placethe additional clause at the end of the section, it should be placed in the

most suitable position and the numbering system exteded e.g. 8.4.1 A. The

wording of the clause should be underlined.

d) When a clause is replaced in its entirety the numbering system should be

retained but an S placed after the number e.g. 5.45. The wording of the

new clause should be underlined. This proced ure (the underlining of thewhole clause and the use of an "5" after the clause number) should be

followed even if only one or two words are substituted or added.

e) The specification refers to "the Engineer" throughout. For some forms ofcontract il may be necessary to substitute "Architect" or "Supervising

Officer". This can be done without following the mie on underlining

changes above.



S JI AW&

1. GENERAL

1.1 General description of structure

.1.2 Details of problem

1.3 Details of any restriction on or phasing of access

1.4 The general sequence of operations and events will be as follows:

a) Work areamade

available to Contractor. b) Contractor provides access. c) Carryout trial sample:repairs. d) Acceptance of trial sarriple repairs. e) Surface c1eaningby Contractor. f) Contractor surveys and marks out areas for repair. g) Engineer inspects and agrees. h) Contractor removes conaete in repair areas. i) Engineer inspects and agrees or indicates

requirements for; additional concrete removal,additiona l reinforcement, and movement ofexisting rein forcement.

j) Engineer agrees measurement of work. k) Cleaning of rein forcement. 1) Engineer inspects. m) Completion of repair. n) Carry out pull-off testing. 0) Preparation of concrete surface for protective treatment.

p) Acceptance of area for protective treatment. q) Application of protective treatment. r) Acceptance of protective treatment. s) Removal of access.

This clause should give ageneral descrip

tion of the structure and the form ofcon

struction. If repairs are being carried out

to occupied structures then the Specifica

tion should clearly state this and define

the points of access and the areas which

will continue ta be in use during the

works and which will require special pro

tective measures .

This clause shauld describe the defeds in

general terms. A pre-tender investiga

tion must have been carried out. Refer ence shauld be made ta any relevant

information in the form of survey or in spection reports or results of tests. The

results of surveys, inspections and tests

should be made available ta Tenderers in report form. The reports should clearly

ident ify thearea of the survey, location of defects and results of tests. It shouid also

be noted that changes in condition could

have occurred if there is an extended peri

ad between the lime of the survey and the

repair contract.

This clause should be used ta infarm the

Contractor of any phasing requirements, restrictions on warking hours, access ta

the structureetc, naisy working and pro

duction of dust etc.

Amend sequence of operations if pull-off

lests are not specified.

Amend sequence of operations ifstandard version of Section 4 is not being used e.g.

fJ Engineer undertakes inspection, sur

vey and testing work.

g) Engineer mIlrks out area for repair.

The period required lJy the Engineer ta

undertake theseactivities shouldbe stated keeping in mind the time required ta ob

tain the results of any laboratory testing.

11



• 4iheW.'

2. ACCESS

General Notes

Abseiling is not considered ta be a suitable rneans of access for undertaking patch repairs. ft is considered ta be a useful and economic means of access for suroeys and inspection but ils use may be restricted in poor weather conditions. Use of abseiling could pose problems ofaccess for the Engineer.

A useful guide to safety regulations is given in the Building Advisory Seroices publication Construction Safety. This publication is available from Building Advisory Services or the Building Employers Confederation.

The Contractor should normally be allowed freedom in the choice of means of access with agreement from the Engineer. The specification should clearly state any limitations that would restrict choiœ or if any one form ofaccef!s is mandatory. The documents shouldaIso indicate in Section 1 of the Specification any phasing requirements if free access is not granted to

al/ areas for the duration of the Contract.

Should there be any imposed or physical restraints upon the means of access to and from the structure then these should be clearly stated.

If, forenvironmental reasons, it is reqrûred that working areas are enclosed, then th!s should be slated in the specification so that

the Contractor can make adequate provisions and ensure lhat scaffolds and platforms are appropriately designed for the extra loads imposed (including wind loads).

Where additionalloads imposed upon the structure by scaffolds or platforms are expected to be significant, the Engineer should require that temporary works details are submitted in order that the effect upon the permanent structure can be assessed. Any known limitations should be indicated in the Contract.

If there is a requirernent for separate hoists for personnel and goods this should be made clear in the specification.

General

2.1 The Contractor sJiaU pro vide suitable an d safe meansof gaining access to ail repair areas to enable the worksdescribed in theContract to becarried out and the Engineer

ta carry ou t the necessary inspections. Abseiling tech-niques shall not be used. The means of access shaH be tothe approval of the Engineer and to the current safetyregulationsand appropria e British Standards .

2.2 Scaffolds, platforms and. cradles shall be designed,erected, operated, maintaine:d.ànd dismantled so as to

ensure that safe working conditions are provid ed for aIl

site personne l. In addition , complete protection shaH be

provided to the structure, its occupants and the generalpublic.

2.3 Scaffolds, platforms and cradles shall be erected, a\-tered and dismantled by experienced operatives who shaH

be under competent supervision.

2.4 Before any access provision is used, and at least every7 days thereafter, the access provision shaH be inspected.and appropr iately certified by a suitably experienced andqualified person.

2.5 Where temporary fixings and attachmen ts are made to If there are restrictions on the locations of

the fabric of the structu re their locations shan be subjectto

ties and fixings to the building theseagreement with the Engineer and they shaH be removed should be indicated in the relevant clause

when the work is complete and holes made good to the and/or the drawings.

satisfaction of the Engineer.

2.6 Where ties are required to pass through window open-

ings the glazing shaH be carefully removed and replaced

by plywood. The opening shaH be seaïed against the ef-



M rl&w 4 P' n F!Wfdl

fects of weathe r and to prevent du st and dirt from entering

the building. The glazing shaD be reinstated after removalof the scaffold.

2.7 Scaffolds shaH be boarded out to the face of the struc-ture in working areas to prevent material or equipmentfalling to lower levels or the ground.

2.8 Boarded lifts or scaffolds shall be positioned 50 as to

allow practical access to the working areas and at suchheights in relation to the working areas that operat ives cansafely and efficiently use mechanical hand held tools andequipmen t. Where the full height of the scaffold is notboarded out then an agreed number of lifts and sequenceof movement down the face of the structure shaH be im-plemented to provide adequate access at aIl times to theworking areas.

2.9 The Contractor shaIl provide access facilities for in-

spection and testing by the Engineer incIuding the end ofmaintenance period inspection.

2.10 The Con tracto r shaIl provide suitable access facilitiesto enable trial samp le repairs to be carried out, tested andinspected.

Should it be necessary to provide access

for testing and sampling in advance oftherepairs then this should be clearly stated.

Any particular form ofaccess facility re-

quired for the end of maintenance period

inspection should be stated.

13



3. SURFACECLEANING

General Note

Guidance on the c1eaning of the facades of buildings is given in BS 6270.

3.1 Before cleaning work begiT1s the Contractor shaHremove aU surface attachments (signs, notices, electricalfittings etc) from the areas to be repaired or from positionsthat obstruct access or which may be damaged, Unlessotherwise directed a11 inserts and fixings which have beencast in or mortared in o pockets or otherwise a ttached tothe concrete shaH be removed from the area to be repaired.The method of removal shaH be such as to avoid unnecess-ary damage and shaH be subject to the approval of theEngineer. An electrical supplies to surface attachmentsshaH be sealed off and the mains suppl Y shaH be discon-nected. AIl surface attachment s shaH be carefully stored

during the course of the works and refixed, includingelectrical connections, when aIl other work is complete.

3.2 The cleaning operation shall remove aIl dirt or othercontaminants, p revious coatings, laitance, paint, algae, moss,lichens, plant growth etc.

3.3 Before any repairs are carried out on any area thesurface shaH be prepared by:-

a) Grit blasting (wet, dry or vacuum blasting) and orb) High pressure water jetting, steam cIeaning

employing wax free detergents or biocides togetherwith power scrubbing as required.

The Contractor's proposed method shaH be such that no damage is caused to sound concrete. Trial areas shall be carried out on typicallocations on the site for the appro-val of the Engineer before the main cleaning operation commences.

The Engineer may instruct a change in the method of sur-

face preparation if the Contractor's proposed method causes damag e to the concrete or is otherwise unsui table.

3.4 AH necessary measures shaH be taken to provide pro-tection to the general public, occupants of the building,furniture, fixtures, fi ttings and fabricof the buildingdu ringcleaning operations. The Contractor shaH make good or

rectify any dama ge caused.

3.5 The Contractor shall provide protection to windows,window frames, do ors, door frames and similar built in

items. Windows shaH be kept clean.

N'Cei51"""f M'MN 5'F'Yf''W''!f..OJi:!mfl:ti fi54ŒWCt "x«r&r

The requirement for and method ofclean-ing may have to be specified if there areparticular constmints imposed by thesite. If the cleaning method is specified itshould be tested prior ta tender.

ln gencral it is anticipated that the Con-tractor will visit site during the Tenderperiod ta assess the cleaning method(s)required and will be given the option tastate the proposed cleaning method(s) in

his Tender. High pressure water }etting

may not be appropriate on heavy depositsas t I " d ~ p r e s s u r e m a y have ta beso highthatthe con crete substmte is damaged.

There may be sorne situations where fu.ll .cleaning ofsurfaces is not required. Those 'are considered ta be the exception rather than the rule as often the full extent of defects cannat be apprecù<ted until after

cleaning. Adequate cleaning is also considered ta be essential if coatings are ta be applied but manufacturers' requirements

may vary. If full cleaning is not required Clauses 3.2 and 3.3 should be amendtid.

Any partÎeu/ar requirements or restric-

tions under Clause 3.4 should be indi-

cated on the drawings or in the

Specification.



es M-4. SURVEY AND LOCATION OF DEFECTS

(STANDARD FORM WHERE SURVEY AND LOCATION OF DEFECTS ARE CARRIED OUT BY

AND ARE THE RESPONSIBILITY OF THE CONTRACTOR).

General Notes

The need for patch repair will have been established before Tender by initial surveys and investigations carried out by or onbehalf of the structure owner or tenant or lessee. The area covered by the initial survey will often be considerably less than thetotal surface area of the structure, particularly where it can be seen that the nature of the defects and results of investigationsappear ta be similar throughout. The results of the initial surveys and investigations should be made available ta Tenderers inreport form as indicated in Section 1 of this specification. Quantities for repair work cannat in most cases be drawn up withany degree of accuracy prior to the Contract. They will often only reflect the nature and extent of defeets in the area of the initialsurvey and the Bills of Quantities may be drawn up on apro-rata basis.

During the repair contract if is necessary ta survey aU exposed concrete surfaces and carry out appropriate in situ and laboratorytests in arder ta locale and assess the nature, position and exient of individual defeds and ta determine the appropria te remedialwork. The Contract programme must allow for the survey work ta be carried out ahead of repairs.

Ilis necessary ta define c/early where the responsibility lies for making decisions on the exlent and location of individual repairareas. The standard form of this Specification is written on the basis that the Contractor undertakes this work and the Engineer

adopts a monitoring role. It is felt that this is the most usual procedure at present. However an alternative Sedion 4 fias beendrafted toallow for the situationwhere the Engineer undertakes the survey and inspection work and marks up the areas requiringrepair. This version of Section 4 is given in Appendix A. Other alternatives are possible and can be achieved by modifying thewording but il is necessary that the responsibilities are clearly indicated and Clause 1.4 amended.

The activities carried out in the survey and described in Clauses 4.5 ta 4.11 can be added ta or adjusted as necessary to takeaccount of CÎrcumstances for a particular project. Other surveys or tests could be inc/uded such as dimensional surreys, featuresurveysand resistivity testing.

The requirement for documentary records of the survey results should be stated.

Caution needs ta be exercised in arder that the stability and strength of the building or structure is not jeopardised by' surveyand investigation aetivities.

4.1 The location number and extentof defccts shown in theContract are indicative only. The true location number andextent of defects requiring repair can only be assessed

properly by close inspection and other testing once access

has been provided and deaning has been completed.

4.2 Prior to breaking out an area the Contractor shaH carry Adddescriptions which give the basis for ::"

out a survey of ail exposed concrete surfaces to dete rmine decision making on locations ta be rethe location of defects requiring repair. This survey will paired. As pointed out in the introduc-

include visua! inspection, a soundi ngsurvey, a covermeter tion, this document relates specifically tasurvey and testing of carbonation depth, chio ride content repair of damage caused by corrosion in

reinforced concrete. The limitations andand where indicated cement content. Addition al sur-cautions in the situation where corrosionveying shaH be carried out during the course of the Con-has been caused by high chloride concentract as agreed by the Engineer. The limits of each repairtrations should also be kept in mind. AshaH be marked by the Contractor as a series of straighttypicallist might include:lines on the surface. The limits of each repa ir shaH bea) Cracked areas

subject to agreeme nt by the Engineer.b) Spalled areasc) HolIow-sounding areas

Areas to be repaired may inc1ude:d) Areas where the existing cover to reinforcement is less than xx mm.

a)e) Areas where the carbonation depth is

b)within yy mm of the reinforcement

c) f) Areas with clùoride content in excessetc) ofzz%.

The specifier will have ta add the mini-

mum caver depth in d) (possibly related ta carbonation depth) where repairwill be required, the distance between the carbo nation front and reinforcement in e) and

also the critical chIoride concentration in

f) if these conditions are used.



ee w 'm

4.3 Where the acccss r e q u i r < : ~ d under the Contract forcarrying ou t the works Is not in position the Contractorshall provide temporary access required to facilitate sur-vey work. The temporary access shall be in a form which

allows close inspection of ail concret e surfaces and whichprovides a suitable platfo rm for aIl testing and sampling.

4.4 The personnel to be employed in surveying, samplingwork and marking up of repairs shall be suitably trainedand competent. Operatives found to beunsatisfactory shaH

be debarred From the work of surveying, sampling and

markingup.

4.5 During the course of the survey work photographs

shaH be taken at locations agreed by the Engineer. One setof negatives and two sets of prints shaH be provided for theEngineer. Prints shaH be of approxima te size 150mm x100mm. Prints shan be mounted on plain looseleaf A4

sheets with Htles by typewriter or simiJar means.

4.6 A sounding survey shall be carried out by striking theconcrete surface with a club hammer of 200 grammes

nominal mass and recording the loca tion of hollow sound-ing a f ( ~ a s . On plane a n ~ a s of concrete the surface shaH besounded at approximately 300mm centres in each direc-tion. On columns, beams or othe!' similar members vdthfacesless than300mm wideeach face shan be sounded neareach edge or corner at approximately 300mm centresalong

the member. Where a hollow sound ing area is detectecl ils

ltis difficult ta give general guidance onthe values to be inserted in dl, e) and f) as

they depend OI"i exposure conditions, predictions of performance and future liferequirements for the structure. Values of

5-lOmm are thought ta be common forcondition d) and 5mm for condition el.Guidance on critical chloride concentra

tions is given in BRE Digest 264. Thecomments in Concrete Society TechnicalReport No 26, quoted in the introduction

ta this document ,expressing reseruat ions

about the perfarTrfance of repaired

chloride-affected s t ~ c t u r e s should beborne in mind.

ft should be emphasised lhat carbonatedconcrete in ilself is not damaging or deletenous and does not need to be broken out

and reinstated as a mattcr ofcourse. lt isthe breakdown in the passivating effectwhich is important. In a sitU1Àtion whercuncorroded reinforcement is surrounded

by carbonated concrete the specifier may

make a judgement in certain drcumstan

ces that corrosion is unlikely sa long asthe concrete can be kept dry.

Advice on repair of cracked areas wherepatch repair is not appropriate is given inConcrete Society Tech nica1Report l'{o .22 ."Non-structural cracks in concretc." .

: ".,



I I#&iMM *HiM_ M' 8

extentsha1l

be determined by local sounding and its pe-riphery marked on the surface of the member and thelocation and extent recorded on drawings.

4.7 A covermeter survey shall be carried out using meth-ods and equipment as described in B5 1881 Part 204. Onplane members the direction of reinforcement with leastco ver shaH be determined. The covermeter head shall bemoved arross the surface of the cancre e along a line in adirection perpendicular ta the direction of reinforcementwith least caver and with the head oriented in the directionwhich enables the caver ta that reinforcement ta bemeasured. The Unes along which the covermeter head ismoved shaIl traverse the full width of the member andshaH be approximately 500mm apart. On columns, beamsor other similar members the cover ta longitudinal barsshaH be determined and recorded at 1m centres along themember. The cover to each stirrup or binder shaH be

determined and recorded on eachface

of the member. Thelocation and caver of any bar with a caver less than xx mm

shall be marked on the surface and recorded on dra wings.Where a bar is detected as having less than xx mm coverthe length having less than this caver shaH be determined,the location and extent shall be recorded on drawings andthe location marked on the con crete surface.

4.8 Carbonation depth shaH be determined and recordedat locations agreed by the Engineer. Carbonation depth

shaH be determined by breakin g off a picce of concrete or

taking a smaH ~ i a , m e t c r core in a sound area and sprayingthe fresh fracture surface with phenolphthalein solutionusing a suitable spraying bottle. The perpendicular depthof the interface betwecn the magenta coloration and theuncoloured concrete from the surface shalI be measured.Phenolphthalein solution shall be prepared by dissolving19 of phenolphthalein powder in 50mI ethyl alcohoI and

making up to l00ml with water. The location of the testand the average and maximum depth of carbonation at

each location shaH be teC0rded on drawings.: :.,

Add lhe crilical cover depth (xx) in the

last two sentences.

Taking small diameter cores for carbona-

tian tests may cause less damage than

breaking off a piece of concrete. The

sample area will have ta be reinstated and

could be unsightly if a surface coating is

not inc/uded in the Contract. Il shouldbe remembered that carbonation depth

will probably be greatest at corners.

The phenolphthalein method can give

misleading resuIts on produds such as

cast stone where areas with unhydratedcement may be exposed by breaking off

test areas. Petrographie examination is

preferred for these products.

Details of the phenolphthalein test are

given in BRE Information Sheet IS

14/78. The phenolphthalein solution

should be only lightly sprayed on the

surface otherwise transport of dissolved

alk,ûis may obscure the location of the

true carbonation front.

17



JH*PWi 'e tl ; ~ 4 ' i i i ' M # W 8 W M t A w&tl'i§

4,9 Dust sampl es of con crete for testing shall be taken atthe locations agreed by the Engineer, The area s:'1all besurveyed by covermeter and the sample obtained at alocation away from reinforcement. The sample shall beobtained using a rota ry percussion drill with a bit of 12mmdiameter. The concrete surface surroundi ng the test areashall be thoroughly cleaned and four holes in a squarepatte rn drilled. Samples from dep th increments 0-25mm,25-50mm, 50-75mm and 75-100mm shall becollected. Thedust from the four holes in each depth increment shaH be

carefullycollected and combined and placed immediatelyin a robust plastic bag which shall be immediately sealed.The sample bag shaH be marked indelibly with a discretesample number on an adhesive label on its outside. Thelocation and sample number shall be recorded on drawings. Chloride determina tions shall be carried out in accordance with BS 1881 Part 124 at a NAMAS accreditedlaboratory. Results shaH be stated as percentage chloride

ion by weight of sample.4.10 Concrete cores of xx mm diameter shaH be drilled inlocations and to depths agreed by the Engineer. Unlessspecifically requested by the Engineer, it is to be assumedthat the cores are to be drilled away from reinforcementand before drilling commences a covermeter survey is to

be carried out and the locations of reinforcing bars rna rkcdon the surface. The cores shall be drilled at positionschosen by the Contractor 50 as to avoid reinforcement.Unless otherwise directed by the Enginccr cores shaH be

cut perpendicular to the concrete surface. The coringequi pment shàll bef ixed firml y in posi tion to allow smoothbarrelled cores'to be obtained. If steel is struck coring shaH

be discontinued and the core position moved or abandoned as directed by the Engineer. Cores shaH be \\'ashedoff in c1ean water the surface dried and the core indeliblymarked wit h a discrete number, The core shall be Îmme

diately wrapped in two layers of ding film and placed in astrong plastic bag. Th.e plastic bag shall be marked indelibly on Hs exterior \vith the core number on an adhesivclabel. The location frOTh which the core is taken shaH berecorded on drawings.

4.11 Haif-cell surveys shall be carried out in the areasagreed by the Engineer generally in accordance with

ASTM C876-80. Conti nuity of reinforcement shaH be

checked before commencing the survey by breaking ou ta s

necessary and measuring the resistance between bars in

locations remote from each other across the area or structure. Readings shaH be taken on the surface over reinforcement positions preferably on an .orthogonal grid at amaximum spacing of 300mm. Equipotential contoursshaH be plotted on drawings of the structure from therecordcd data.

Sorne authorities suggest that the drill

diameter should be similar ta the nominal

maximum aggregate size in the concrete.

Drill sample depths will have ta be as

signed in re/ation ta the particular struc

ture under repair. For example some

water retaining structures are thin

walled and dri/ling ta a depth of l00mm

may not be appropriate.

Add the required core diarneter (xx) de

pending on structure dimensions, bar

spacing and intended testing.

ASTM C876-BO procedures for imple

menting half-œll surveys should be fol

lowed but the document should not be

followed blindly when interpreting re

sulls. Specialist advice should be ob

tained as ta the need for and the

Interpretation of l'esults of half-œll sur

veys. A forthcoming Concrete Society

Technical Report prepared in con junc

tian with the Institute of Corrosion will

give additional guidance on the specifica

tion and Interpretation of half-œlI poten

tiai surveys.

4.12 Any areas broken out, cored or drilled for the purposes of testing or sampling shall be made good using therepair methods described in this specification.

18



5

+ Mt ,em RffiW't!îff'fB§iW**fti§M5##S#itom'Mj Fe *F'M"1

CONCRETE REMOVAL

5.1 Any temporary propping described in the ContractshaJl be securely in place before any concrete is removed.Where additional propping is required duringremoval theContractar shall ensure that such propping is securely inplace before the extent of remaval exceeds the limits de-scribed in the Contract. Temporary prapping shaH remainin place until the member has been fully repaired and therepair mortar has gained the required strength.

5.2 The power and size of the equipmen t used for conereteremoval shaH be appropr ia e to the scale of the individualrepairs and shan be subject to the approval of th e Engineer.Where percussive equipment is used particular care shaH

be taken that damage is not caused to concrete substrateand reinforcement which is to remain in place.

5.3 The amount of concrete removed From a member atany time shaH be subjeet to the restrictions deseribed in theContract and to the approv al of the Engineer.

5.4 The limits of each repair area shall be eut as a series ofstraight lines at right angles to the surface to a depth ofapproxima tely lOmm (5mm for repairs using epoxy mor-tar) using a dise cutter or similar. The dise eut surfacesshaH beroughened prior to reinstatement. Feather edgingshall not be perIIÙtted.

5.5 Concrete in repair areas shaH be removed ta the depthindicated in the Contract or as required by the Engineer.

The Engineer should specify the degree ofpropping that will be necessary in carrying out repair work. ln addition, thespecification or drawings should indicatethe amount of concrete remova/ lhat will

be permissible al any one time.

Where there are environmental eon-

stmints it may be neeessary to specîfypartieular methods of removal such aswater jetting.

In describing the removal of concrete,care should be exercised in the description., For example, "defeetive" concrete

suggests that the material is in a redu.cedphysical condition and henee relatively

easy ta remove. Alternatively "contaminated" concrete will require repair but inail probability may be physiClÙly soundand involve considerable effort for ils

removal.

The restrictions may be deseribed in theContract by drawings ,notes on drawings

or a written statement. Examples of restrictions inc/ude:a) Limitations on reduction ofcross-sectionb) Limitations on length of break out ona memberc) Limitations on breaking out adjacentmembers at the same time

Where the cover is low, dise cutting willhave la be omi!!ed or limited in order taavoid damage ta reinforcement. Careneeds ta be exercised when rougheningthe disc-cut surfaces to prevent damageta the edges. It is probably best achievedby gritblasting al the same time as cleaning the reinforcement.

The depth of concrete removal must bespecified in the Contrad (e.g. on thedrawings). If concrete is removed behindthe bars this will help to lock the repaîrinto the member and al/ow the full circumference of the bars to be cleaned provided sufficient clear distance is brokenout behind them (say 20mm). Whereconcrete is notbroken out behind the bars

and also where the repaîr is ta be built outfrom the existing surface it may be considered necessary ta provide aphysical tieby the use of resin anchored slainless steelfixings into the parent concrete. A sug-

gested clause is given al the end of theGeneral Notes in Section 6.

19



5.6 Additional concrete removal shan be carried ou t alongactively corroding expo sed bars until a cantinuous lengthof 50mm of bar free from active corrosion is exposed. Thelimit of active corrosion shaH be assessed on a visu al basis.The edges of any additional areas removed shall be eutsquare as specified above. The extent of concrete removaIshaH be agreed by the Engineer before any reinstatementcommences.

5.7 AIl necessary precautions shaH be taken to ensure thatdust or falling debris does not constitute a hazard to per-sonnel, equipment, the structure, Hs occupants and thegeneral public. Effective means of clearing dust and debrisaway from the working area shaH be continuauslyplemented. '

5.8 The extent and depth of cancrete removal requiredshan be measured and recorded on drawings by the Con-tractor and agreed with the Engineer as the work proceeds.

The degree of removal of carbonated con-

crete needs to be defined. If the carbona-

lion front is close to or has not yet reached

the reinforcement and corrosion has not

commenced asurface coatingmay suffice.

The Engineer may have to decide the ap-

propriate course of action in conjunction

with the structure owner after expiai ning

the risks and economies of the alterna-

tives.

Ifcondition e) in the user note for Clause

4.2 has been inc1uded. the following sen-tence should be added immediately afler

the second sentence:

"Additional concrete shall also be broken

out if it is found that carbonation has

reached within yymm of the reinforee-

ment".

An additional length of uncorroded bar

(up to 200mm) will have to be broken out

if couplers are to be used for replacement

reinforeement.

; :"

1.0



1 MU f t # bd r=rr

6 PREP ARATION OF REINFORCEMENT

General Notes

Replacing or Supplementing Reinforeement

The effective replacement or supplementing of corrosion damaged reinforcement is a complex tapie and it is doubtful whetherthe subject has been adequately addressed ta date.

In arriving at adecision on the adequacy of the reinforeement the [irst step is ta assess the extent and type of stress in the affectedbar or bars. As avery broad general rule, if a structural appraisal indicates lhat the bar was nearly fully stressed before corrosionand has lost 10% or more of ils Cross sectional area therr it may be Expedient ta strengthen the member. This broad general ruleapplies ta individual bars as most patch repairs will include only one main reinforcing bar. &pairs which include a number ofbars will have ta be eonsidered individually on their merits.

Methods of rep/acing or supplementing reinforeement are described below but it should be emphasised that no significant cutting. out of either reinforeement or concrete should be eontemplated without a reasonable understanding of the effect this may have

on the member or the structure.

Before cutting out corroded reinforeement the Engineer must check that the structure is made safe by temporary propping orother suitable means.

Provision of extra reinforeement using straight laps

Where existing eoncrete remains bonded ta stressed main bars, no breaking out should take plaee ta provide lap lengths forsupplementary reinforeement unless applied loads are relieved by temporary propping. If propping is Not feasible then othermethods of strengthening the member should be eonsidered. Lap lengths should be a minimum of 40d and be greater if the repairmortar does not provide a bond strength equivalent ta that of the substraie concrete.

Provision of extra reinforeement which is anchored

Extra reinforcement may be instal/ed with reduccd laps by anchoring the ends at 9Cf ta the concrete face. The ends should beembedded using resin or cementitious mortars. Care must be taken ta avoid damaging adjacent areas wJiere' (he existingreinforcement ta concrete bond remains intact, unless the structure or member can be temporarily propped. Bond and bearingstresses of the anchors would need ta be calculated.

Provisioll of extra reinforcement using cotmeetors

This method of supplementing reinforeement may require greater access around the bar in arder ta make the connection. Thefinished connections will in some cases signi[icantly reduce the caver ta the reinforeement.

The connector should be capable of transferring ail the forees in the bar and the properties of the joined bars should correspondas c/osely as possible ta those of a continuous

bar.:::..

Fçr details of reinforeement connectors reference may be made to, "Reinforcement con necto rand anchorage methods", by W S

Paterson and KR Ravenhill, CIRIA Report 92.

Provision of extra reinforcement usi?lg welding

The site wdding of reinforcement should be avoided if alternative methods of repair are available. Doubts rernain as ta whetherthewelded sections can restore the strength properties of the original undamaged bar. The introduction of preheating may inducethermal stresses on cooling and could damage the bond between the existing reinforeement and concrete substrate.

If site welding is ta be carried out there are several essentlal features ta be inc/uded in every programme of work.

1) A written procedure should be agreed before work commences, covering methods of work, etc" for each type of joint ta bemade.

2) Qualification tests ta certify ail welders should be carried out bath before beginning a project and at intervals during thework.

3) A quality control programme should be instituted which should include lensile testing and radiographic inspection or othernon-destructive testing.

Referenee should be maae ta the following publications Whel1 preparing a specification.

a) BS 7123 - Specification for metal arc welding of steel for concrete reinforeement.

b) Thewelding ofReinforcing Steels - A guide ta design and proeedures, published by the Reinforcement Steel Services Divisionof the British Steel Corporation.

YI



, 1

c) CIRIA Report 92, "Reinforcemcnl conneclor and anchorage methods", by W 5 Paterson an4 KR Ravenhill,

In some cases il may be necessary ta dowel in additional reinforcemenl of small dÎilmeter bars la anchor back repairs ta cornersand arrises, If adequate caver cannat be obtained these should be of stainless steel. A suitable clause might be:

"Where shawn on the drawings or as directed by the Engineer, additional xx mm dÎilmeter stainless steel bars shall be groutedinto hales drilled in the existing concrete ta anchor repairs, The method of grouting shall be approved by the Engineer."

6.1 Rust scale corrosion products and other deposits shaH

be removed irom reinforcement exposed within the areaof repair by grit blasting or other method approved by theEngineer to achieve SA 21 / 2 quality to BS 7079 : Part ALThe means of removal shaH comply with health and safetylegislation.

Uncantained dry sand blasting is notpermitted as it is a health hazard. Con-tained dry sand blasting may be usedsubject ta approval of the device or equip-

ment by the Health and Safety Executive.

Wet san4 blasting may be uSed subject taapproval for use of the equipment by theHealth an4 Safety Executive.

Dry grit blasling may be used but con-sideration should be given ta the protec-tion of the general public and the

Immediate environs from grit an4 dust.

Wet grit blasting may be used and this

process removes dust and reduces thespread of used grit.

Needle guns are unlikely ta clean adequ-ate/y behind the reinforeement when ( lC-

cess for the equipment is limited by other

reinforeement or lhe concrete substrate.

Water jetting is eonsidered by the work-ingparty ta bepermissibleand.is effective

in mast situations including teinforee-

ment junctions. Surfaee preparation bywater jetting may not be good enough forsome epoxy reinforeement protection sys-

tems because of incomplete removal ofany localised areas of remainingpassivat-

ing layer. Care and protection of thegeneral public and the Immediate envi-

rons against the foree of the wateT jetneeds ta be pravided. :'.

Mechanical reinforcement cleaners

should be lested on site before approval isgiven for use. These tools can reach be-hind bars but are not very effective atreinforcement junetions. Care is re-quired ta avoid polishing rather thancleaning steel and when rotating serratededges are used there is a risk of cutting

into sound steel if tao much pressure is

applied.

Chemical rust removers are also availableand there are differing opinions on their

benefits or otherwise. Their use needscareful control as they would have ta betotally removed before application of re-inforcement p1'Otective system and caTewould have ta be taken that they do notconlaminate or damage the concrete.

Theil' use is not recommended here.



6.2 Ali necessary measures shall be taken to provide pro-

tection to the general public, occupants of the building,furniture, fixtures, fittings and fabricof the build ing during

cleaning operations. The work shall be damped down asnecessary to reduce the spread of dust. The Contractor

shaH make good or rectify any damag e caused. Windowsshall be kept clean.

6.3 Grit blasting shaH be carried out in such a way as to

include the hidden faces at the backs of bars and at inter-sections of bars.

6.4 Abrasives shaH be new, c1ean and dry and of a grade

suitable for the preparation of steel to the standard indi-cated above. Abrasives shaH he of a type approved by theHeaIth and Safety Executive. Exhausted abrasive shaH bebagged up and removed from site after single use.

6.5 Equipment shaH be capable of delivering abrasives at

a nozzle pressure sufficient to achieve the standard ofc1eaning specified above and the air supply shall be free ofentrained oil and water.

6.6 If directed by the Engineer the exposed reinforcementshaH be thoroughly washed down wit h cleanwater as partof the preparation operations.

6.7 If directed by the Enginecr the existing reinforcementshall be moved or supplemen ted or replaced by new bars

in accordaI1ce with BS 4449 welded or spliced to existingbars. Bprs tobe removed shaH be eut by dise.

6.8 Replacement bars shaH be cleancd if required by the

Engineer to the British Standard specified above. Where

bars are lapped a minimum lap of fort y times the bardiameter shaH be provided.

6.9 AIl r e i n f o r ~ m e n t shaH be adequately fixed and tied in

position such tQat'u will not be displaced during reinstate-ment. "

There may be an advantage, particularly

where epoxy barrier coat reinforeement

protective systems are ta be used, in in-

c/uding an inhibitor in the wash water



. if . îR* iî'Sî!lffl#*i' $§@eMèW.W&JiEH "eSdM"

7. REINFORCEMENTPROTECTIVE SYSTEM

General Notes

Protective coatings applied to reinforcement in patch repairs înclUJie the following:

Cement slurry orp olyme r madified cement based slurI-Y, This serves as a repassivation coating which res/ores the a/kalineenvironment around the reinforcement.

Epoxy resin based coatings. These form a physical barrier between the rebar and the repair moTtar.

Zinc rich primers. Il is submitted by the proponents of these primers that when a hostîle environment exists within thesubsfrate the zinc will provide a sacrificial anode thereby protecting the reinforcement. ,_

Otherprimer treatments.

High standards of surface preparation are essential when using epoxy based materials.

Research 1S currently in progress comparing the different coating systems for bars and results of this are awaîted before anyfurther guidance can be given. At present it is suspected that if chloride ions migrate into the repaîr, the cement slurry m.ay

offer less resistance than a barrier or sacrifîcial coating provided. the barrier coating is defect free. However a reinforcement bar

barrier coating may be vulnerable[rom the presence of discontinuities, and at the ends of the repair. At these points pîtting andunderfîlm corrosion may Occur.

When carbonation is the prime cause of damage it is considered that there is little benefit in providing abarrier coatingand thatthe cement 51urry in conjunction with the new alkaline material in the repaîr will provide a protective environ ment.

Reference may be made to the CIRIA book "Corrosion Damaged Concrete - Assessment and Repair" published by ButterwoTthand BRE Information Paper IP 18189.

7.1 After cleaning the surface of the bars shaH be coated with a protective system if such a treatment is part of the specified e p ~ i r system.

7.2 The exposed area of the reinforcement shaH be com The 3 hour period in this clause may have

pletely covered with the protective system. The first coat to be modified in sorne drcumstances.

shaH be applied within 3 hours of cleaning. Any rein force Where wark is being carried out in highly

ment remaining uncoated at the end of a 3 hour period humid or chloride rich atmospheres, cor

shaH be recleaned in accordance with the Specification rosion maY take place an the cleaned sur-

face within 3 haurs. Epoxy based systemsprior to applica tion of the reinforcement protective system.requiregood surface cleanliness and some

manufacturers refer to application "im·

mediately" after blasting.

7.3 Number of coats, time between coats, mixing and

application of the reinforcemen t protective system shall ail

be in accordance with the manufacturer's instructions.



MhEii MM

8. REINST A TEMENT

General Note

Delele Clauses 8.16 to 8.21 if repairs with resin-based mortars are not required.

8.1 Before the application of repair comp ounds begins theContractor shall satisfy himself that the condition of thesurface to be repaired and the weather are suc h as to allowthe work to proceed. Repairs shaH not proceed if the airtemperature or con crete sub strate temperature lS SoC or

less an d shaH cease if the air temperatu re reaches SOC on afalling thermometer unless the planned procedures specified below are implemented. A higher or Iower temperature than SoC shaH be substituted above if required by theinstructions of the manufactur er of repair compounds.

8.2 Repairs may proceed at low temperatures if specifieplanned procedu res are implemented. These include:

i) Provision of heated tenting which envelops the repair area and w hich pro ducesan environment with a sustainable airtemperature in excess of SoC

ii ) Warming materials and the substrate to atemperature above soc. The method of

warming the substrate shaH be such thatthe substrate is not damaged and is notcaused to dry out in the case of cernentbased repair materials.

iii) Insulatin g the completed orpaitiallycompleted repairs in accordance with goodpractice for winter concreting

A higher or lower tempcrature than SoC shaH be sub

stituted above if required by the instructions of the manufacturer of repair compounds.

Preparation

8.3 Immediately before reinstatement aH dust, debris and

loose materia l shaH be removed from the area of the repair

by air blasting with oil-free air, vacuuming or vigorouswirebrushing. Waterjettingorbrushingmaybepermitted

subject to compatibility with the repair medium.

8.4 When using cernent based repair mortars the concretesubstrate shaH be thoroughly soaked with water to obtaina saturated surface dry condition. Any surplus water shaH

be removed before reinstatement begins.

Priming

8.5 Concrete surfaces within the repair area shaH be treated

with a bonding aid or primer in accordance with the manufacturer' s instruction.

8.6 Priming coats or bonding aids shaH be thoroughlyworked into all hollows and crevices in the prepared sur

face and around the reinforcement if required.

TheMeteological Office can provide local

forecasts.



H@ l!ift*!WW" ,'tlH M1M" MiNi; .M""

8.7 Repair morta r shall be applied "wet on wet" when using a bonding aid or primer unless the manufacturer of

the repair system specifies that the bonding aid or primer must dry out before the repair mortar is applied.

8.8 If at any time the primer or bonding aid completely dries out before over-layingexcept as permitted above the repair surface shaH be re-prepared generally by complete removal of the dried primer or bond ing aid or as specified by the manufacturer of the repair materials.

Filling - Cementitious Mortar

8.9 The repair mortar shaH be applied in layers not exceeding the thickness specified by the manufacturer of the mortar.

8.10 Each layer shaH be thoroughly worked and com

pacted into the repair zone and aroundor

between reinforcing bars. The technique employed shaIJ ensure that no air is entrapped and that full contact with the primed substrate is achieved.

8.11 Successive layers shaH be applied as soon as the preceding coat has become sufficiently stiff to support the weight of the additional build-up layer bu t is still adequately tacky to pro vide bonding. The time be tween layers shaH bein accordance \vith themanufactu rer's recommendations. If sagging occurs the material shaH be completely

removed and reapplied at a reduced thickness.. .

8.12 If at any time the last layer applied completely dries In the situation where aprevious layer of

out before over-Iaying the surface shall be prepared ac cement based mortar MS been allowed ta

cording to the manufacturer's recommendations. dry out the manufadurer's stated proce-

dures should be followed. These proce-

dures are often along the /ines of:

i) Roughen the surface of the previous

layerii) Thoroughly soak the surface

iii) Apply bonding aid or priming coat

iv) Proceed with next layer

8.13 The final build-up layer within a re pair shaH not be less than 10mm thick and shaH be levelled off or profiled usi ng trowelling techniques to produce a finish as specified below.

8.14 Curing to retain moi sture shaH be implemented immediately on completion of the repair. The surface of the

mortar shaH be protected from strong sunligh t and drying winds.

8.15 The repair shaH be cured by the method and for the The Working Party was of the opinion

period recommended by the manufacturer of the repair that there is a good case for specifying

system. During this period the tempera ture of the ma terial curing by sealed polythene sheets over the

shaH not be allowed to drop below SoC and the repair shaH repairs for 72 hours as a minimumbe shaded from direct sunlight. Curing membranes shall notwithstanding the manufacturer's

not be permitted. stated recommcndations. The curin.g

period will have ta be adjusted accordingto elimate. hl win ter there will be a

necessity to protect from frost. Good pro-

tection and curing in exposed windy con-

ditions is particularly important.

26



; iIiiiiif ? +PW*kM' e t "t5tkfH*iHEw; '" j Mi.: ,.raI' ! . - ~ - g

The specification prohibi/s the ux, ' ": :

ing membranes because they -.'••.

the adhesion of any applied coa:-:·'.: fcoating is not 10 be applied this .:-.: ..:

•• _ "1 -

tian may be removed. Sorne eur!r.: ' .branes may be specifically fonm•. : , · , 1receive a subsequent coatirlg.

The importance of effective curin:, :.,",-.d

be overemphasized. Inadequal.c." "'S

can lead to cracking or delJondir.;:.' .1e

repair.

Filling - Resin M ortar

8.16 Surfaces shall be c\ean ar.d sound prior to the use of resin repair mortar. Surfaces s ; ~ l a l l be dry unless a primer specifically designed for damF surfaces is used.

8.17 Primer shaH be applied te the substrate ensuring that If the primer is absorbed b"j the $ ) . , " - : . " ~ t ewithin say 30 minutes theYi a e ( ' ; , : ; · , ~ tit is weIl br ushed into the prepared surface taking care toshould be applied in accor::lanœ ;..: : : .1eavoid "puddIing" in depressk-,ns. Where, due to the namanufacturer'5 instruct r.. YI s.ture of the substrate, the primer is absorbed by the con

crete, a second application of :-1rimer shaH be made. The second coat shaH be applied ' ..:ithin 16 hours of the first coat.

8.18 The resin mortar shaH applied whilst the primer has adequ ate surface tack.

8.19 The mixed material s h a l ~ be applied to the primed surface in layers not x c e e d i n ~ the manufacturer's recommended thickness using a tech:lique to prevent entrapped air.

8.20 If subse quent layers are t0 be applied the surface shaH

be thoroughly scratched to pr0\'ide a good mechanical key.

The time between layers shaH be in accordance with the manufactu rer's recommendations. Primer shall be applied betwee n each layeras required in the manufacturer' s

. : .instructions.

8.21 Intermediate stages and the completed repair shaIl be Resins de-oelop full strer :tth Il "-- _ , : : :

protected From rain until at ](>,lst 24 hours after the repair characteristics within 48 ".ours ,;.. '

theperioJ will belongera: :O'Wer ~ . ' . , : < . ' : l -has been completed. The temperature of the repair shaH not be allowed to drop belo\\' SoC and the repair shaH be tures.

shaded from direct sunlight during reinstatement and until at least 48 hours after completion of the repair.

Surface Finish

8.22 The final layer of aIl repairs shaH be finished to

provide a close textured accurate level surface which matches theappearance of the surroundingconcrete including arrises and which accords with the standard achieved in

the successful trial sample repairs.



1.....& & "lB ",t. ml " .M 'H I pw'w,i@i&H'ftM' i 'f"eW*Wt tiM'$t4}Wt*&fIfb

9.SURFACE PREPARATIONFOR P ROTECTIVETREATMENT

General Notes

Fairing coats are supplied as a part of sorne repair systems. They will also be required on rough areas to provide a suitable basefor coating. However fairing coats can only be applied to limited thickness typically 2or3mm. Where the surface profile requiresa layer thicker than this a repair mor/ar or other suitable material will have to be used.

There may be an option be/ween using a fairing coat with a low-build coating system and no fairing coat with a high-buildcoating system. A surface fil/er would still be required with the high-build coating system. The high-build coating option maybe cheaper but may not achieve comparable Ilesthetic results as cracks and repairs may show through.

9.1 The surface shaH be prepared by blast cleaning, steam Equiprnent used for surface preparation

cleaning, wate r jettingorneedle gunning to remove alldirt, should reflect constraints existing al sile

salt deposits, grease, paint or other contaminants and any when the work is being carried out e.g.

surface scaling, weak surface layers or lai tance and to open problems of ingress of water and dust,

nuisance ta the generai public.up blowholes. Unless otherwise directed or approved the

final cleaning down operation or treatmentto

the whole Surface texture of prepared concrete. surface shall be carr ied ou t as a single continuous oper-shciuld be that specified by the manufacation.turer of the subsequent treatment.

9.2 Items such as glazing and door and window frames shaH be adequately protected during the preparation pro-cess and the appl ication of protective treatment.

9.3 Nibs or ridges on the surface or within repairs or at the joints between repa ir and original concrete shaH be ground smooth prior to the appli cation of protective treatment.

9.4 Surface filler shall be applie d to blowholes and other The use of surface fillers is important

isolated surface ble mishes or defects in order to provide a where a coating system is ta be used ta

surface suitable to receive subsequent treatment. reduce carbonation. Pinholes in coatingover pores can leati to rapid local carbo

nation.

9.5 The fairing coat shaH be applied to the whole of the Delete ifno fairing coat is required. If thisexposed concrete element or structure, unless otherwise clause is included the thickness shouid be

directed by the Engineer. stated in the Bill of Quantitles. Any re

quirement for re-profiling members

should be stated.

9.6 For cementitious fairing coats and surface fillers the substrate shaH be treated as required by the application instructions of the manufactur er of the fairing coat.

9.7 Fairing coats and surface fillers shall be mixed, applied and cured strictly in accordance with the manufacturers

recommenda tions.

9.8 Before applica tion of fairing coa t or surface filler begins the Contractor shaH satisfy himself that the condition of the surface to which the materials are to be applied and the weather are such as to allow the work to proceed. Fairing

coa t or surface filler shall not be a pplied if the air tempera-ture or concrete substrate temperature is SOC or less and

shaH cease if the air temperature reaches SoC on a falling thermometer unless the planned procedures specified in Clause 8.2 are implemented. A higher temperature than SoC shaH be substituted above if required by the instruc-tions of the manufacturer of the fairing coat or pore filler.

78



.4 av @'Mi • M*tA4WUUW"#'PMWIi tt mi iI@

9.9 Fairing coats and surface fillers shaH be fini shed to give

a smooth level surface. Arrises shall be formed as necess-ary.

9.10 Trial sample panels of fairing coat shaH be preparedin the works forapproval. No other fairingcoat applicationshall be carried out until a trial sample panel has beenapproved. The trial sample panel shaH be used as a stand-ard against wh ich the rest of the work will be judged.

; :..

i;

Deiete if no fairing coat is required.

:29



±HW'H*W&&&&

10. PROTECTIVE TREATMENT FOR CONCRETE SURFACES

General Notes

The owner of the building should be made aware of the ongoing maintenance implications of using protee/ive coatings.

Required temperatures, relative humidifies and surface moisture condition should be clearly specified and facilities should be

provided on site ta check these parameters.

ln generaJ it is difficu/t ta measure wet or dry film thickness on concrete. The application rates can be used as a guide ta the

film thickness likely to have been achieved providing temperature and melhod ofapplication remain constant.

The selection ofapplication equipment requires care in lhat it should take account of the r.ature of the tt!,ea to be trealed andshould be compatible with the products ta be employed. Operating pressures, output etc. need ta be considered and themanufacturer consulted.

Mixing limes,working life and overcoating times should be checked with the manufacturer taking into account the temperatureal the time of use.

Where exlernal application is ta take place the imminent weather conditions should be checked by reference ta the local weather

office and by local observation. Arrangements should be made to protect the surface [rom water or contaminants [rom othersources.

Trials ofmaterial compatibility should reflect the true site circumstances of use i.e. the method ofapplication of the coating.

Records of application rates should incorporate temperatures and details of site circumstanees such as weather conditions.

The Specification or drawings should state colour requirements for surface treatmenl. The use of different coloured primer/lstcoatj2nd coat makes is easier ta check that ail coats have been applied.

Useful information on protective treatmenfs for concrete surfaces is given in CIRIA Technical Report 130, "Protection ofreinforced concrete by surface treatmentsN

•

,

10.1' Protective treatment shaH be applied to the whole of The words "as described in the con tract "

the exposed concrete surface and repairs as described in should be deleted if ail of the exposed

the mntract. concrete is ta be trealed. Otherwisedraw-

ings which indicate the locations to be

treated should be included.

10.2 Protective treatments shall be mixed and applied strict lyin accordancewith the manufac turer' s instructions.

,- Thinning.ordiluting in excess of the manufacturer's rec-ommendàtions shaH not be permitted.

10.3 AB surfaces shaH be dry before and during the appli- Instruments which indicatesurface mois-

cation of protective treatment. Ambient and surface tem- lure condition, though not on an abso-

peratures/ ambient relative humidity and the surface lu!e seale, are available and values are

moisture condition shaH be measure d and recorded by the quo!ed in sorne coating manufacturer's

specifications.Contractor on each day before coating commences and during coating. No coating shaH be applied unless the conditions meet the coating manufacturer'5 specification.

10.4 Where repair mortars or fairing mats or surface fillers and mating systems are supplied by different manufac-turers, the repair mortar shaH be subjected to trials by the coating manufacturer and repaîr material manufacturer to

ensure compatibility between the various elements and evidenœ shall be provided of acceptable performanceelse-where on simiJar structures under similar conditions.

10.5 Records of application rates shall be submitted by the Contractor to the Engineer on a dail y basis indîca ting batch numbers, the area covered by each coat and the amount of coating material used.

30



w Mff'GRDMh a •

10.6 Items or areaS which are not to be coated shall besuitably protected or masked before application of theprotective treatment.

10.7 Trial sample panels of protective treatment shaH beprepared in the works for approval by the Engineer. Pro-tective treatment application shaH not be carried out untila trial sample panel has been approved by the Engineer.The trial sample shan be used as a standard against whichthe rest of the work will be judged.

.: :-.



MH E Q%& F PMM'<,.tiW_lWif'f

11. TRIAL SAMPLEREPAIRS

General Notes

The need for sample repairs will depend ta acertain extent on the size of the contract and the avallable time. If possible the size

and location should be shown on the drawings or described in the Specification.

Pull-off testing could be specified for the cores and used as a basis for assessing pull off values achieved in the works.

11.1 Trial sample repairs for approval shaH be undertaken

for each type ofdesigna ted repair not less than three weeks before the related work is schedu led to start. Trial sample repairs shaH be carried out using materials of the same

formulation as that to be used in the works. If the formulation of materials is changed during the course of the works, additional trial sample repairs shan be carried out.

11.2 Trial repa irs shaHbe assessed by the Engineer to check that the required standard will be achieved by the materi

aIs an d methods proposed by the Contractor. Trial repair areas shall be used as a standard against which subsequent

work shaH be judged.

11.3 Trial sample repairs shaH be chosen, as far as it 1S

reasonably possible to encompass the majority of the positions an d orientations of the surfaces to be repaired.

11.4 During the trial repairs six cubes for each type of mortar shaH be made and three tested at 7 and three at 28

days. Cubes shaH be made cured and ·tested. gener ally in accordance with BS 6319 Part 2 and lor the manufacturer's recommendations.

11.5 After reinstatemen t six number 50mm diameter cores Coring should not be undertaken until 3

shaH be cut through each trial repair area to a depth such days after repair for resin mor/arS and 14

that each core penetra tes the substrate by approximately days after repaîr for cementitious mor-

25mm. The cores shaH be visuaHy examine d by the Engin fars. These periods may have ta be ex

eer to de termine the degree of compaction and ~ n : t e r - l a y e r tended in periods ofcold weather.

adhesion achieved. '. : .

The cores could be used used for pull-oft

tests as described in Clause 12.8.

11.6 On completion of the coring a section of the trial

samplerepairs shaH becarefull y broken ou t in the presence of the Engineer to demonstrate that adequate compaction and adhesion have been achieved.

11.7 Approv al for trial repairs shaH be based on the fol Acceptance criteria may have ta be ad-

lowing: justed in the light ofexperience.i) Cube results shaH demonstrate an average If necessary add ta 11.7:

strength which exceeds 90% of the iv) Colour match and surface texture

manufacturer's stated strength with no single match with adjacent concrete.

result less than 75% of the manufacturer's Where the repair material is required to

reach aparticular strength for structuralstated strength.ii) reasons il will be necessary to use thisVisual inspection of the trial area shaH indicate

strength as the acceptance criterionthat the area is free from excess voidage and hasrather than the manufacturer's quoted

good bond to the substrate/reinforcement.strength.Iii) Cores are weIl compac ted and free from entrappedIf a characteristic strength has been spe-

air with good inter-layer adhesiDn.cified in 13.3add ta 11.7a reference to thecharacteristic strength and the amountby which the result shall exceed the spe-cified characteristic strength.

32



12 MMMM 1N,., ,aa' Ahfi

12. TESTING

General Notes

Clauses 12.8. la 12.12 ta be omitted if pull-off testing is not specified. Also amend sequence of operations in Clause 1.4.

Alternative forms of testing could be substituled or added.

A European Standard on testing of repair ma terials is in the early course of preparation but may not be available for several

years.

12.1 One sample of mortar for repairs shaH be taken for every three days on which repair mortar is used unless otherwise specified by the Engineer. The strength result from the sample shaH represent mortar placed on the previous day, the day on which the sample was taken and the following day. Three cubes shall be made and tested from each sample. For cement based mortar, the cubes shaH be tested at 28 days. The average of the three 28 day values

shall be taken as a strength result. For resin based mortar the cubes shaH be tested at an age agreed by the Engineer and the average value for those cubes shaH be taken as a strength result.

12.2 Sampling and testing of repair mortars shall be in accordance with BS 6319 Part 2 unless otherwise specified by the Engineer

12.3 AlI testing shan be carried ou t by a NAMAS accredited labo ra tory.

12.4 Test cubes sha1l be stored and cured in a manner Cubes oJpa/ymer modified morlar should

appropr ia te ta the materials under test in accordance with be placed in sealed polylhene bags imme

the manufacturer's instructions but generally in accord diately after making and struck from Iheir

ance with BS6319. They shalI be delivered properly ident mould at an age of l day. Thereafter they

should he air cured al a tempe rature ofified to the approved laboratory.approximately 2fYC until they are tested.

12.5 Cube results shaH be judged for compliance against Where the repair material is required ta

the manufacturer's quoted strength. Each strength result comply with a "char.acteristic" slrength

shall exceed 80% of the manufacturer's stated typical for slructural reasqns it will be necessary

strength. la use Ihis strerigth as the acceptance

c r i t ~ r i a n .

12.6 The repairs at risk due to non compliance shaH in Adjust this clause ta clearly identify

dude aIl repairs executed on days represented by any which repairs are at risk if a "charac-

strength resu lt which fails to achieve compIiance. leristic" strength luis been specified in

13.3. The repairs at risk will depend an

the form af the acceptance criteria speci-

fied in 12.5.

12.7 As a consequence of non-compliance in the tenns of the above, the Contractor shaH be directed to take such remedial action as the Engineer may consider necessary. This action may include removal of material in repairs at

risk as described above and/or further testing required to

establish the acceptability or o therwise of the repair mortar. The Contractor shall.bear: the cast of any such additional testing and removal and reinstatement of repàirs.

33



H H ~ W i ' r i*ee

-

12.8 During the course of the wo rks the Engineer will carryout approximately x No pull-off tests on repaired areas.The tests wiII be carried out fourteen days after reinstatement of the area under test. The Contractor shaH cu t 50mmdiameter cores through the repair and 50mm into theoriginal concrete at locations directed by the Engineer. TheContractor shaH make goo d the core hoIes after completionof the test using the repair methods and materials described in this specification.

12.9 Three No. pull-off tests shaH be carried out on eachselected area. The average of the three values shaIl be takenas a pull-off strength result.

12.10 Each pull-off strength result on an area shaH be atleast 0.8 N/mm2 unless failure occurs within the parentconcrete at a lower value.

12.11The mode of failure shaH be recorded i.e. withinsubstrate, within repair material.

12.12 As a consequence of non-compliance with the puIIoff strength requirement, the Contractor shaH be directedto take such remedial action as the Engineer may considernecessary.

Add number of pull-off tests. Pull-off testlocations have to avoid reinforeement.

Sorne authorities advocale using a disc

cutler to cut a 50mm square rather thancoring prior to the pu/l-off test. The ac-

cep/ance value ofO.8Nfmm2 may have to

be revised (upwards or downwards) in

the light ofexperience.

34



·J•• ' • Aseem_

13. MATERIALS

General Notes

Alternative clauses could be drafled to allaw site batching of repaîr mortar using po/ymer latex or the use of flowîng concrete.These are felt to be applicable only ta larger contracts. The clauses shauld inc/ude requirements for strict quality cantrol and theEngineer should consider modifications to the testing regime. The Contractor should be required ta demonstrate that he can

exert effective co.ntrol over the sile batchingoperation.

The properties of repaiT materials need to match those of the concrete in the structure under repaîr. Hîgh shrinkage valuesldifferenees in elastic m odulus and thermal coefficient can lead ta high stresses in the patch and the surrounding concrete whichcould cause debonding and premature failure.

At present there are few national standards which are directly applicable ta repaîr materiais. Many manufacturers have carried

out comprehensive test programmes but il is nol possible ta compare materials because different test methods may have beenused. Work is at present being undertaken by CEN ta produce European Standards for test rnethods and eventually repairmateriais. At present it is considered that the best approach is ta include the narnes ofl say, three repair system manufacturersbased on Experience of past sa tisfact ory performance in similar conditions.

A schedule of proposed repair materials, ta be completed by tenderers, is given in Appendix C.

13.1 AlI materials for repair an d protection of concrete Add narnes and addresses of manufac-

structures shaH be obtained from a single manufacturer turers.

from the list given below. Alternative manufacturers may be proposed by the Contractor prior to commencement of Repair systems are available from a large

work at site but their materials shaH not be used without number of manufacturers of widely va-

rying resourees and track record. Mem-the prior approval of the Engineer.bers of the Working Party were stronglya)of the opinion that where circumstaneesb)permit this Clause should be amended tac)inc/ude referenee ta FeRF A or other such. etc)body. Sorne materials have British Board

of Agrément Certification.

ft is recommended that aIl elements of a

repair and protection system (reinforee-

ment protective system, bonding aid or

primer, repair mortar, surface filler, fair-ing coat and protection system) are ob-

tained from a single manufacturer.

O/herwise there can be divided responsi-: :.. bilities ifproblemsarise. Ifuseof products

from more than one manufacturer is un-

avoidable then the combination should be

the subject of trials by bath manufac-

turers ta check compatibility. Evidence

of previous successful use of the materials

in combination would also be useful.

13.2 AlI materia ls shaH be used strictly in accordance with

the manufacturers' instructions and this Specification.

Manufacturers' instructions shall be available to ail operatives at site.

13.3 R epair mortars, fairing coats and pore fillers shaH be Add any strength or other requirements

factory pre-batched materials. Th e chloride ion content of for the repair mortar. If he term "charac-

cement based mater ials shaH not exceed 0.1 % by weight of tenstic strength" is used this would have

cement. The ingredients and their proportioning shan be ta be defined as say "that strength below

such that disruptive alkali aggregate reaction does not which only 5% ofsamples are expected ta

occur. fall". Add ta the clause if colaur and

surface lex/ure match VJith tlu::: existing

concrete are required.

25



13.4 Mixing and application of repair and protection ma-

terials shaH be carried out strictly in accordance with themanufactu rer' s instructions. Mixing of part bags or othercontainers of components shall be allowed only with theprior permiss ion of the Engineer and the manufacturer.

13.5 Ail materials and the manner in which they are usedshaH conform to the relevant Health and Safety and Con-trol of Substances Hazardous to Health Regulations.

13.6 Mater ials shall be stored in an environment whichconforms with the requirements of the manufactu rer. Ma-

terials shaH not be removed from store until immediatelyprior to mixing or use. Matenal from damaged containers

shaH be discar ded.

Storage facilities are required ta be stated

in the information provided by the Con-

Iractor with his tender.



* MG HM ....?

APPENDIXA

SURVEY AND LOCATION OF DEFECTS

(ALTERNA TIVE FORM WHERE SURVEY 15 CARRI ED OUT BY THE ENG1NEER

DURING THE CONTRACT)

: ;.

Documents

Abu Kammash Marine Jetty