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7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
1/26
3D Volume Analysis of Inuence of SAP Content andCuring Age on Air Void Distribution of High
Performance Concrete
Babatunde J. Olawuyi* and William P. Boshoff*
* Department of Civil Engineering, Stellenbosch University, Private Bag X1, Matielan !"##,
Stellenbosch, $estern Cape, So%th &frica
e'mail( babs)amess%n+ac+a
Abstract: The use of superabsorbent polymers (SAP) is one internal curing method being adopted for
the mitigation of autogenous shrinkage in concrete especially high strength/performance concrete(HSC/HPC) SAP absorbs !ater and releases the !ater internally !hen cement hydrates "t ho!e#er
lea#es micro #oids in this process and this can negati#ely influence the mechanical properties of
concrete This paper reports on three dimensional ($%) #olume analysis of the influence of SAP
content and curing age on air #oids distribution in HPC &our HPC mi'tures !ith different binder
constituents and !ater/binder (/) ratios +,and +,%(-.) +.(-.0) and +$(-$) !ere tested !ith
t!o grain si1es of SAP ( -## .m /ith pro%ct label 02SE3 CS 4! an "## .m, labelle 02SE3
CC 4!) The SAP contents !ere also #aried (-23 -.23 -$23 and -42) by !eight of binder
Concrete cylinders (0- mm in diameter and ,-- mm high) !ere cast and cured in !ater for different
ages (.5 06 and 7- days) before the dry hardened HPC !as sub8ected to 9:ray computed
tomography (CT) scanning for determination of the air #oid distribution The $% 9:ray images !ere
then e'amined and analysed using A#i1o &ire image analysis soft!are ; #ersion 5- to filter and
classify the indi#idual #oids for determination of the si1es distribution and #olume analysis of #oid
created by SAP in the HPC !ith the respecti#e influence of binder type !ater/binder ratio and curing
age assessed The CT scanning !as also used to affirm the grain si1es and distribution of the dry
SAP particles
Keywords: Computed tomography (CT) scanning $% : #oid analysis high : performance concrete
air #oid distribution superabsorbent polymers (SAP) SAP content binder type curing age
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1 INTRODUCTION
Concrete is a #ersatile material for construction !orks but it ho!e#er re for better output The concrete samples used for the image analysis !ere also made to appropriate
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si1es to gi#es a true reflection of the actual pore and #oid states "t further e'amines the influence of
hydration period SAP type SAP content and binder type on the air #oid si1e sphericity and
distribution
2 EXPERIMENTAL INVETI!ATION
2"1 Mater#a$s
T!o si1es of SAP ( -## .m /ith pro%ct label 02SE3 CS 4! an "## .m labelled 02SE3 CC
4!) !ere used at different SAP content -2 -.2 -$2 and -42 by !eight of binder The SAP are
thermoset polymers specifically co#alently cross:linked polymers of acrylic acid and accrylamide
neutralised by alkali hydro'ide !hich according to Schrofl +echtcherine Dorges =,4> ha#e been
pro#en efficient as internal curing agents in concrete The absorption capacity of the SAP is sho!n in
pre#ious !ork =,0> to be .0- g/g in distilled !ater and .0 g/g (ie .0-- 2) in cement pore solution
(CPS) for both SAP grain si1es
A natural sand !ith minimum particle si1e of $-- Em (ie all the particles smaller than $-- Em !as
remo#ed using the sie#ing method) ha#ing the follo!ing physical property &ineness +odulus (&+ F
.B7) coefficient of uniformity (Cu F .4$) coefficient of gradation (Cc F ,-.) and dust content (-$2)
of medium sand classification =,6> as obser#ed in the preliminary sie#e analysis reported in Gla!uyi
oshoff =,B> !as used as fine aggregate ,$ mm crushed grey!acke stone !as used as the coarse
aggregate GPC C+ " 0.0 I conforming to S I ,7B =,5> !as the binder !ith silica fume core'
slag and fly ash added as cement e'tender !hile Premia $,- (a PC) supplied by Chryso !as added
as superplastici1er The composition of the reference HPC mi'tures is sho!n in Table ,
Tab$e 1 +i' constituents of HPC mi'tures
Constituents
Jeference +i'es (kg/m$)
+,+,%
+. +$
ater ,.0 ,.0 ,$4 ,00
Cement (C+ " 0.0 I) 0$- 0$- 04- 0--
Coarse Aggregate (,$ mm ma'imum) ,-0- ,-0- ,-0- ,-0-
Sand (Jetained on $-- Em sie#e) 07- 07- B,- B--
&ly Ash ,..0 - - -
Core' Slag - ,..0 - -
Silica &ume 0.0 0.0 4- 4-
Super:plastici1er (Chryso Premia $,-) ., ., ,6 04
ater/binder ratio -. -. -.0 -$
2"2 Met%ods
&our reference HPC mi'tures of different binder combination types (cement silica fume fly ash and
core' slag)3 / (+, +,% (-.)3 +.(-.0) and +$(-$)) and .5:day characteristic strength (fck cube)
of B- +Pa minimum (ie C6-/CB0 ; C7-/C,-0 HSC) !ere made using the method described in AKtcin=,7> for HPC !ith other mi'es ha#ing #aried SAP contents (-.2 3 -$2 and -42) for the t!o SAP
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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si1es (Sp,and Sp.) orkability and cohesion of the fresh HPC mi'tures !as determined using the
Slump flo! table to ensure consistent !orkability for all the mi'ture irrespecti#e of SAP content The
concrete !as cast in 0- mm ' ,-- mm cylindrical moulds and cured in !ater at .$ L $ oC for
different hydration periods (ie .5 06 and 7- days respecti#ely) in accordance to rele#ant S
Standards ; =. .- ., .. .$> The hardened HPC specimens !ere then placed in the o#en at 4-o
Cfor $- minutes after remo#al from curing tank at respecti#e hydration period to make it totally dry
before taken to the CT scanner for analysis +i' +, and +,%are both of the same / (-.)3 mi'ture
+, contains fly ash !hereas +,%has core' slag as cement e'tender The dry hardened HPC !as
sub8ected to 9:ray CT scanning for the determination of the air #oid distribution The $% 9:ray images
!ere then e'amined and analysed using A#i1o &ire #ersion 5- =.4> and MD Studio +a' .. =.0> (both
being commercial computer programmes) to filter and classify the indi#idual #oids for determination of
the si1es distribution and #olume analysis of #oid created by SAP in the HPC !ith the respecti#e
influence of binder type !ater/binder ratio SAP content and curing age The CT scanning !as also
used to affirm the grain si1es and distribution of the dry SAP particles
The $% 9:ray images !ere obtained using a Deneral lectric Phoeni' MTome9 .4- 9:ray micro
computed tomography scanner (micro:CT) ach concrete specimen !as mounted in a less dense
cardboard tube to reduce e'ternal influences on the samples during the scan Jeconstruction !as
performed !ith system supplied %atos Jeconstruction soft!are and analysis !as conducted The
#o'el si1e !as set to ,-- Em !ith settings at ,B- kM and ,0- EA for ':ray generation and image
ac
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The outcome of the analysis !as then plotted using histogram chart for the respecti#e HPC mi'tures
tested after .5 days of curing and is sho!n in &igure 6 to 7
a CT scan of HPC cylinder !ith $% #isuali1ation of porosity in blue b Thresholding applied to sliced .% image
'(re 1,-- Em scan of concrete cylinder !ith $% #isuali1ation of porosity in blue
%etermination of the dry SAP particle si1e distribution !as carried out by scanning the t!o SAP types
separately in a transparent cylindrical container Jeconstruction !as performed as e'plained abo#e
!ith system supplied %atos Jeconstruction soft!are and analysis conducted !ith the A#i1o &ire 5-
follo!ing the steps stated pre#iously The scanning !as ho!e#er done at . Em #o'el si1e to be able
to capture the actual si1e of the SAP particles !hile a crop of 5- mm ' 4- mm ' 4- mm !as made
centrally from the MD" file !hen loaded before thresholding The analysis ho!e#er e'amined a
complete particle distribution of the dry SAP samples rather than indi#idual particle e'amination as
earlier reported =$-> &igure .a sho!s a $% image of separated SAP particles !ith different colours
depicting #arious si1e categories !hile &igure .b gi#es the .% image of centrally cropped dry SAP
specimen being analysed !ith the separated SAP particles in blue colour !ith spaces in bet!een
them
(a) (b)
'(re 2 $% "mage of separated dry SAP particles !ith colour indicating si1es classification (a) and(b) Centrally cropped CT image of dry SAP particles obtained from $% MD" file
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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) REULT AND DICUION
)"1 AP #*es a+d ,or-%o$o'y
The SAP particles !ere obser#ed to be of #aried si1es and shapes3 they are mostly angular and
irregular in shape and not totally spherical The grain si1es are noted to be in the range of-/$-- Em (Sp,) and -/0-- Em (Sp.) !hen e'amined under CT scanning ($%) image analysis (&igure
.) These #alues agree #ery !ell !ith the manufacturer?s specification of
$-- Em (Sp,) and
6-- Em (Sp.) respecti#ely Table . sho!s the fre This ga#e a clearer detailed and more reliable assessment than the
approach adopted in an earlier study =$-> !hich in#ol#ed only random e'amination of indi#idual SAP
particle !ith a resultant si1e range of B0 Em to $0- Em (dry SAP) and ..0 Em to ,-0- Em (s!ollen
SAP)
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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Tab$e 2&re
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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'(re ): 2 cumulati#e #olume present of #arious particle si1es for Sp,and Sp.
'(re /:CT image of e'amination of indi#idual SAP particles obtained from a $% MD" file
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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)"2 )D 0o#d A+a$ys#s o PC s-ec#,e+s
&igure 6 to 7 for the #arious HPC mi'tures after .5 days of hydration re#eals that air #oids e'ists in all
the HPC samples irrespecti#e of the SAP content and concrete mi'ture The peak of the histogram
!ere noted to be around the same #alues (ie ..0 Em ; $-- Em diameter air #oids F --6 ; -,4,
mm$pore #olume si1es) !hereas only a reference mi' + ,%has a peak at $B0 Em These can be seen
to refer to air #oids created by SAP dry particles of si1es - to ,-- Em3 the range !ithin !hich bulk of
the particle si1es of SAP belong as seen in Table . A critical study of histograms further re#eals that
the air #oids distribution are more and of !ider spread in HPC specimen containing SAP Presence of
micro:air #oids in the reference mi'es also sho! that the high concentration of superplastici1er
resulted in air bubbles !hich could not be totally eliminated by #ibration of concrete SAP addition
ho!e#er created more air #oids in the HPC and these air #oids !ere obser#ed to be !ell distributed
!ithin the concrete
(a)
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0.60
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M1!"D
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2.04
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0200040006000
M1S'1()!!"D
Volume #mm3$
%re&uency
(c)
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Volume #mm3$
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(d)
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0200040006000
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7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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(e)
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0
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Volume #mm3$
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(f)
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2.04
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0200040006000
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Volume #mm3$
%re&uency
(g)
0.00
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3.05
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0200040006000
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Volume #mm3$
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'(re 3:Histogram Plot of Air Moid %istribution of (.0 ' .0 ' 0- mm $) +,; HPC Samples
(a)
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Volume #mm3$
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7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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(e)
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Volume #mm3$
%re&uency
'(re 4:Histogram Plot of Air Moid %istribution of (.0 ' .0 ' 0- mm $) +,%; HPC Samples
(a)
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00
0.11
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0
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4000
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Volume #mm3$
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(b)
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4000
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(c)
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01000200030004000
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%re&uency
'(re 5:Histogram Plot of Air Moid %istribution of (.0 ' .0 ' 0- mm $) +.; HPC Samples
(a)
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(c)
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'(re 6:Histogram Plot of Air Moid %istribution of (.0 ' .0 ' 0- mm $) +$; HPC Samples)") I+$(e+ce o AP co+te+ts o+ A#r Vo#d D#str#b(t#o+
The general trend is that SAP #oid 2 and total #oid 2 (ie percentage porosity) increased as the SAP
content increased and also as / increased !ith little #ariations (&igures 0 to 5) &igure 7 sho!s that
the SAP #oid 2 increased !ith increase in SAP contents for all HPC mi'tures at .5 days irrespecti#e
of the SAP si1e e'cept for the outliers The higher the binder (ie fines) content the lo!er the porosity
and hence the better the HPC produced The reason for the obser#ed #ariation could be due to the
fact that only single sample of each specimen !as used for the CT scanning analysis further !orks
using triplicate samples is thereby recommended
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A study of the ma'imum and the minimum #oid si1es re#eals neither a particular trend nor
consistency "n all the HPC mi'tures the reference mi' at .5 days ga#e ma'imum #oid si1es amongst
the largest #alues (+,(0B5- mm$)3 +,%($74, mm
$)3 +.(,... mm$) and +$(0--4 mm
$) : Tables $
to 6) This can possibly e'plain the #ariations obser#ed in the percentage porosity as recorded Some
e'cess !ater !as trapped !ithin the concrete hence creating large air #oids !hich are not #oidcreated by SAP These large air #oids form part of !hat !as used to calculate total #oid but !ere
e'cluded in the calculation of SAP #oids 2 The minimum #oid si1e in all the concrete samples !ere
ho!e#er same #alue (---,$ mm$) This is because the CT scanning on the HPC !as carried out at
,-- Em3 hence the lo!est air #oids that can be detected are those abo#e ,-- Em The a#erage #oid
si1e too did not gi#e a particular trend or consistency This is because of the presence of some
arbitrary large #oid si1es !hich thereby influenced the #alue of a#erage #oid si1e calculated A study
of the triplicate samples !ill surely gi#e a better conclusion on the influence of SAP contents and /
or mi'ture type on the air #oid distribution of HPC
The optimum SAP content for the HPC mi'tures can ho!e#er be taken as -$ (since the outliers as
obser#ed on &igure 7 are mainly noticed at SAP contents higher than -$ 2) The presence of a high
number of large air #oids ( ,0-- mm $) in HPC of higher SAP contents can therefore be responsible
for obser#ed loss in strength and relati#e lo! mechanical properties pointed out in pre#ious studies
=.B .5 .7 ,0> HPC made of high / definitely has a lesser need for internal curing and hence the
less the demand for SAP as "C:agent SAP air #oids cannot ho!e#er be said to be detrimental to the
porosity of HPC as SAP #oids for all SAP containing HPC mi'tures studied lies belo! . : 02 !ith the
a#erage porosity #alues all belo! $2 This is belo! the e'pected SAP #oids calculated based on
additional !ater pro#ided for SAP and also the de:moulded concrete porosity for the HPC mi'tures
The reference mi' for the HPC !ith -$ / (ie +$) ga#e a total porosity #alue similar to same
mi'tures containing SAP This can be due to e'cess air bubbles created by superplastici1er since
concrete at higher / has less need for !ater reducing agents The mi'tures containing &ly Ash and
Core' Slag as cement e'tenders (+,and +,%3 at / of -.) ho!e#er sho!ed a good trend of the
influence of SAP on HPC !ith the SAP air #oids been about 0- 2 of e'pected SAP pore content
The SAP type can be ad8udge to influence the air #oid content in all HPC specimens as the #oid
#olumes for Sp. is taken as about double the #oid #olumes in Sp, This is because as obser#ed in $,
abo#e Sp. (-/0-- Em) is double Sp, (-/$-- Em) in si1e
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0 0.1 0.2 0.3 0.4 0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
M1Sp1 M1DSp1 M2Sp1 M3Sp1
SAP content (%)
Void (%)
(a) Sp, Moid series after .5 days curing
0 0.1 0.2 0.3 0.4 0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
M1Sp2 M1DSp2 M2Sp2 M3Sp2
SAP content (%)
Void (%)
(b) Sp.Moid series after .5 days curing
'(re 7:SAP #oid 2 against SAP content 2
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Tab$e ) Summary of "nfluence of SAP contents and curing age on #oid distribution for + ,; HPC
Curing Age Influence Ref SAP1 SAP2
M1-28D Series M1 M1Sp10.2 M1Sp10.3 M1Sp10.4 M1Sp20.2 M1Sp20.3 M1Sp20.4
SAP pore epec!e"# 0.00 3.40 $.01 6.$6 3.40 $.01 6.$6
De-%oul"e" Porosi!# 0.$8 4.3' 6.$6 6.66 2.43 $.6( 6.1(
)o of *oi"s 1$00 +% 3$ 4$ 48 $2 3$ $( (0
SAP Voi" , 0.00 1.2$ 1.$1 2.(( 2.1' 3.0$ 4.40
o!l Porosi!& , 1.4( 2.03 2.'1 4.42 2.$3 3.$3 $.06
M Voi" Si/e %%3 $(.80$3 23.1448 6$.$331 4'.$11' 14.(461 11.2816 $$.'81'
Min. Voi" Si/e %%3 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013
A*. Voi" Si/e %%3 0.1$3$ 0.0$8$ 0.08(8 0.0(0( 0.0$$4 0.10(0 0.0$$6
M1-$6D Series M1 M1Sp10.2 M1Sp10.3 M1Sp10.4 M1Sp20.2 M1Sp20.3 M1Sp20.4
)o of *oi"s 1$00 +% 3( 3( 3( 64 42 6( 36
SAP Voi" , 0.00 1.30 1.8( 2.60 1.68 3.'1 2.23
o!l Porosi!& , 1.68 2.22 2.68 4.02 2.0( 4.4' 2.$6
M Voi" Si/e %%3 $$.0342 2$.$84$ $(.4$26 1$.(61( 46.'3(( 32.86$1 121.80$0
Min. Voi" Si/e %%3 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013
A*. Voi" Si/e %%3
0.028( 0.10(' 0.06$6 0.0$(0 0.063( 0.1161 0.0604M1-'0D Series M1 M1Sp10.2 M1Sp10.3 M1Sp10.4 M1Sp20.2 M1Sp20.3 M1Sp20.4
)o of *oi"s 1$00 +% 2' 4$ $3 $$ 3' 1$2 $1
SAP Voi" , 0.00 1.3$ 2.21 2.$( 1.63 3.88 2.6'
o!l Porosi!& , 1.48 2.21 3.31 4.40 2.00 $.31 3.1(
M Voi" Si/e %%3 60.6$63 ((.'44( $$.6$84 38.8080 30.221( 31.2426 61.04(6
Min. Voi" Si/e %%3 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013
A*. Voi" Si/e %%3 0.0861 0.0('4 0.0888 0.08(8 0.0$34 0.1664 0.0$60
Tab$e /:Summary of "nfluence of SAP contents and curing age on #oid distribution for + ,%; HPC
Curing Age Influence Ref SAP1 SAP2
M1D-28D Series M1D M1DSp10.2 M1DSp10.3 M1DSp10.4 M1DSp20.2 M1DSp20.3 M1DSp20.4
SAP pore epec!e"# 0.00 3.40 $.01 6.$6 3.40 $.01 6.$6
De-%oul"e" Porosi!# 0.20 3.'' 4.4( 6.38 3.$2 4.'6 6.3'
)o of *oi"s 1$00 +% 13 32 26 1( 3' 2' 4$
SAP Voi" , 0.00 1.60 1.'2 0.(3 2.(1 1.(0 2.6$
o!l Porosi!& , 0.82 2.31 2.60 1.08 3.0$ 1.'8 3.03
M Voi" Si/e %%3 3'.406' 41.(4$$ 1(.23'1 26.40'( 22.1(18 23.41$0 14.$('8
Min. Voi" Si/e %%3 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013
A*. Voi" Si/e %%3 0.108$ 0.06$6 0.0$1( 0.03'1 0.081$ 0.1003 0.0'34
M1D-$6D Series M1D M1DSp10.2 M1DSp10.3 M1DSp10.4 M1DSp20.2 M1DSp20.3 M1DSp20.4
)o of *oi"s 1$00 +% 2$ 21 2$ 32 21 1$4 21
SAP Voi" , 0.00 0.64 1.18 1.8' 1.(3 3.46 1.4(
o!l Porosi!& , 1.32 1.03 1.62 2.(( 1.'1 4.'2 1.68M Voi" Si/e %%3 3'.$014 42.2$3' 66.'(1' 31.13(4 13.1822 6(.111( 31.02$6
Min. Voi" Si/e %%3 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013
A*. Voi" Si/e %%3 0.06'$ 0.0($2 0.0(16 0.0602 0.0818 0.1'(( 0.0'$(
M1D-'0D Series M1D M1DSp10.2 M1DSp10.3 M1DSp10.4 M1DSp20.2 M1DSp20.3 M1DSp20.4
)o of *oi"s 1$00 +% 2( 2' 4$ 22 4( 22 26
SAP Voi" , 0.00 1.$$ 1.(3 1.86 2.1$ 2.40 2.4$
o!l Porosi!& , 0.86 2.2' 2.6$ 2.63 2.$$ 2.61 2.6'
M Voi" Si/e %%3 28.21$' 1$.2320 3$.8$(1 21.'362 23.82(6 1(.2884 1$.4103
Min. Voi" Si/e %%3 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013
A*. Voi" Si/e %%3 0.14(( 0.0608 0.081( 0.0$'3 0.0641 0.0(84 0.10$1
N'pected pore content by #olume based on the .0 g/g pore absorption used for pro#ision of additional !ater
calculated taking the s!ollen SAP as a spherical substanceNNPorosity calculated #olumetrically using %e:moulded density in comparison to designed density
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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Tab$e 3:Summary of "nfluence of SAP contents and curing age on #oid distribution for + .; HPC
Curing Age Influence Ref SAP1 SAP2
M2-28D Series M2 M2Sp10.2 M2Sp10.3 M2Sp10.4 M2Sp20.2 M2Sp20.3 M2Sp20.4
SAP pore epec!e"# 0.00 2.8$ 4.21 $.$3 2.8$ 4.21 $.$3
De-%oul"e" Porosi!# 0.1( 2.3( 3.'8 $.4( 1.88 4.06 $.38
)o of *oi"s 1$00 +% 63 $0 63 4( '8 118 1$(
SAP Voi" , 0.00 2.01 1.'1 1.1' 2.$1 3.12 3.12
o!l Porosi!& , 2.33 3.0$ 3.6$ 2.22 3.3' 4.1' 4.6$
M Voi" Si/e %%3 122.1'$0 101.0430 $2.((68 8(.1312 43.'62' 8(.0(6( $3.$381
Min. Voi" Si/e %%3 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013
A*. Voi" Si/e %%3 0.124( 0.0640 0.1244 0.11'' 0.146' 0.1'0( 0.24(4
M2-$6D Series M2 M2Sp10.2 M2Sp10.3 M2Sp10.4 M2Sp20.2 M2Sp20.3 M2Sp20.4
)o of *oi"s 1$00 +% 4' $0 (0 44 43 36 1'$
SAP Voi" , 0.00 0.'3 1.3( 1.14 1.86 2.00 2.84
o!l Porosi!& , 2.2' 1.(1 3.02 2.03 2.23 2.3$ 4.(2
M Voi" Si/e %%3 28.63$1 '3.'300 84.8632 34.1$48 $2.4$60 4'.'$$1 (2.2334
Min. Voi" Si/e %%3 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013
A*. Voi" Si/e %%3
0.0((0 0.0(0( 0.1161 0.0881 0.12'3 0.0'0' 0.3(34M2-'0D Series M2 M2Sp10.2 M2Sp10.3 M2Sp10.4 M2Sp20.2 M2Sp20.3 M2Sp20.4
)o of *oi"s 1$00 +% 33 4( 36 6( 8$ 40 10(
SAP Voi" , 0.00 1.44 1.(( 2.0$ 2.1' 1.'8 2.8'
o!l Porosi!& , 1.(8 2.44 2.60 3.1' 2.'$ 2.3( 3.88
M Voi" Si/e %%3 (8.'6'6 46.86(2 41.0228 14.31(6 24.(034 34.($'1 28.$$'3
Min. Voi" Si/e %%3 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013
A*. Voi" Si/e %%3 0.0'13 0.0680 0.0648 0.0(33 0.2126 0.102' 0.1(('
Tab$e 4:Summary of "nfluence of SAP contents and curing age on #oid distribution for + $; HPC
Curing Age Influence Ref SAP1 SAP2
M3-28D Series M3 M3Sp10.2 M3Sp10.3 M3Sp10.4 M3Sp20.2 M3Sp20.3 M3Sp20.4
SAP pore epec!e" 0.00 2.64 3.'1 $.14 2.64 3.'1 $.14
De-%oul"e" Porosi!& 1.$8 3.2$ 6.00 6.00 3.'2 3.$6 4.$4
)o of *oi"s 1$00 +% 6$ $0 $( 1'1 1(1 11' 1''
SAP Voi" , 0.00 2.2( 2.32 1.'4 4.04 4.0' 3.33
o!l Porosi!& , 3.$4 3.8$ 4.12 $.(3 $.63 $.26 $.23
M Voi" Si/e %%3 $0.0416 14.261( 20.4162 103.''10 86.8118 $3.210( 48.4244
Min. Voi" Si/e %%3 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013
A*. Voi" Si/e %%3 0.11$6 0.0821 0.0'30 0.2443 0.1(42 0.1$(6 0.21(0
M3-$6D Series M3 M3Sp10.2 M3Sp10.3 M3Sp10.4 M3Sp20.2 M3Sp20.3 M3Sp20.4
)o of *oi"s 1$00 +% $3 43 42 1'6 84 14' 113
SAP Voi" , 0.00 1.($ 1.3' 2.23 3.0$ 3.34 3.($
o!l Porosi!& , 2.10 2.84 2.33 6.0$ 3.86 4.(1 4.83
M Voi" Si/e %%3 22.0$4( 38.$81( 46.$664 3'.6((1 $$.8621 60.343$ 2$.2$84
Min. Voi" Si/e %%3 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013
A*. Voi" Si/e %%3 0.118$ 0.0((' 0.0'1$ 0.1'(3 0.18$' 0.1('0 0.1$08
M3-'0D Series M3 M3Sp10.2 M3Sp10.3 M3Sp10.4 M3Sp20.2 M3Sp20.3 M3Sp20.4
)o of *oi"s 1$00 +% 34 3$ 64 (0 $1 $2 104
SAP Voi" , 0.00 1.04 1.'8 2.06 2.44 2.44 3.1'
o!l Porosi!& , 1.'8 2.41 3.4' 3.8$ 2.'$ 2.'2 4.1$
M Voi" Si/e %%3 31.(1$1 28.(1(( 12.1826 (1.184$ 4$.''14 100.'($0 26.2220
Min. Voi" Si/e %%3 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013 0.0013
A*. Voi" Si/e %%3 0.06(' 0.1026 0.1134 0.1008 0.1$33 0.1634 0.146$
N'pected pore content by #olume based on the .0 g/g pore absorption used for pro#ision of additional !atercalculated taking the s!ollen SAP as a spherical substanceNNPorosity calculated #olumetrically using %e:moulded density in comparison to designed density
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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)"/ I+$(e+ce o c(r#+' a'e o+ a#r 0o#d d#str#b(t#o+
Tables $ to 6 present summary of the result of influence of curing age SAP type and SAP contents on
the SAP air #oid distribution of the #arious HPC specimens &igures ,- to ,$ on the other hand sho!
the trend of the cumulati#e small air #oid #olume (ie all air #oids belo! ,0-- Em in si1e) present in
the #arious HPC This !as to in#estigate influence of curing age SAP type and contents on the
pattern of air #oid distribution in the respecti#e HPC mi'tures Although a single sample of each
specimen !ere analysed a total of 54 HPC specimens !ere studied using the CT scanner
The results in Tables $ and 4 re#eal a trend that for +,and +,%(/ F -. in reference mi') the total
#oids 2 decreased as the hydration period increased The SAP #oids !ere also noted to increase as
the SAP si1e and contents increased at all the respecti#e hydration periods for both HPC mi'es A
closer e'amination of the number of air #oids larger than ,0-- Em (diameter) as presented in the
tables gi#es a consistent #alue range of $- ; B- !ith some fe! outliers (pink colour highlights in the
tables) !hile the ma'imum #oid si1es !as also obser#ed to be of similar #alue range of .- ; B- mm $
but for t!o e'tremes : ,, mm$and ,., mm$(blue colour highlights) The pattern of the cumulati#e
small #oids 2 present in the respecti#e HPC (&igure 7) also ga#e similar trends !ith de#iation
obser#ed in the specimens marked as outliers (eg +,Sp.-$:06% in &igure ,-(d)3 +,%Sp,-4:06% and
+,%Sp.-4:06% in &igure ,, (c d)) ffect of large air #oids ( ,0-- Em) !as also noted to be glaring
in the total #oid calculated for these samples "t can thereby be inferred ho!e#er from this study that
for #ery lo! / mi'es SAP addition made additional internal !ater a#ailable for longer period of
cement hydration leading to possible increase in structure of the cement hydration products and
hence reduction in the #oids present
The HPC !ith Core' Slag as cement e'tender (+,%) !as ho!e#er noted to e'hibit the lo!est number
of large air #oids present for all hydration periods This implies that Core' Slag as a cement e'tender
enhanced better dispersal of the cement and other fine particles and good utilisation of mi'ing !ater
and thereby a possible good early age strength de#elopment3 a complimentary role to silica fume in
HPC A study of the particle si1e distribution particle structure of the #arious fine materials and the
general strength de#elopment of the HPC mi'tures !ill surely offer good ans!ers to this assertion
&igures ,. and ,$ sho! similar trends as abo#e in the cumulati#e small #oids present in + .and +$
(/ F -.0 and -$) specimens but !ith large numbers of #oid si1es abo#e ,0-- Em (ie large air
#oids) and great #ariation in the #alue of ma'imum #oid si1e present in these HPC mi'tures (pink and
blue colour highlights respecti#ely on the Tables 0 and 6) Moid #olume #alues abo#e B- mm $ !ere
noted to be more in these HPC samples !ith the specimens at .5 %ays hydration e'hibiting greater
proportion of them !hile some reference mi'es also contain #ery large air #oid such as ,.. mm $ in
#olume (+. :.5% in Table 0) The numbers of large #oids !ere consistently #ery high (5- ; .--) in the
+$mi'tures3 implying that the additional !ater pro#ided for the SAP addition got collated to amount to
these large air #oids The SAP #oids can ho!e#er still generally be ad8udged to decrease as the
curing age increases despite the higher number of outliers reported for these HPC mi'tures A better
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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inference on this !ill emerge if triplicate samples of these specimens are analysed as there are
possibilities that some single specimen e'amined might be the poor specimen of the particular batch
The presence of large numbers of air #oid #olumes abo#e ,0-- Em in these HPC mi'tures especially
+$mi'tures e#en after 7- days of curing (Table 6) is a confirmation that at this / ratios addition of
SAP for internal curing purposes might not be re
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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0
500
1000
1500
2000
0.0
1.0
2.0
3.0
4.0
5.0
M1-28D
M1Sp10.2-28D
M1Sp10.3-28D
M1Sp10.4-28D
Void Diameter #+m$
Void Content #,$
0
500
1000
1500
2000
0.0
1.0
2.0
3.0
4.0
5.0
M1-28D
M1Sp20.2-28D
M1Sp20.3-28D
M1Sp20.4-28D
Void Diameter #+m$
Void Content #,$
(a) +,; HPC !ith SP,at .5 %ays (b) +,; HPC !ith SP.at .5 %ays
0
500
1000
1500
2000
0.0
1.0
2.0
3.0
4.0
5.0
M1-56D
M1Sp10.2-56D
M1Sp10.3-56D
M1Sp10.4-56D
Void Diameter #+m$
Void Content #,$
0
500
1000
1500
2000
0.0
1.0
2.0
3.0
4.0
5.0
M1-56D
M1Sp20.2-56D
M1Sp20.3-56D
M1Sp20.4-56DVoid Diameter #+m$
Void Content #,$
(c) +,; HPC !ith SP,at 06 %ays (d) +,; HPC !ith SP.at 06 %ays
0
1000
2000
0.00
1.00
2.00
3.00
4.00
5.00
M1-90D
M1Sp10.2-90D
M1Sp10.3-90D
M1Sp10.4-90D
Void Diameter #+m$
Void Content #,$
0
1000
2000
0.00
1.00
2.00
3.00
4.00
5.00
M1-90D
M1Sp20.2-90D
M1Sp20.3-90D
M1Sp20.4-90D
Void Diameter #+m$
Void Content #,$
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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(e) +,; HPC !ith SP,at 7- %ays (f) +,; HPC !ith SP.at 7- %ays
'(re 18:"nfluence of Curing Age on Moid Content of (.0 ' .0 ' 0- mm $) +, ; HPC Samples
0
500
1000
1500
2000
0.0
0.5
1.0
1.5
2.0
2.5
3.03.5
4.0
M1D-28D
M1DSp10.2-28D
M1DSp10.3-28D
M1DSp10.4-28D
Void Diameter #+m$
Void Content #,$
0500
10001500
2000
0.0
0.5
1.0
1.5
2.0
2.5
3.03.5
4.0
M1D-28D
M1DSp20.2-28D
M1DSp20.3-28D
M1DSp20.4-28DVoid Diameter #+m$
Void Content #,$
(a) +,%; HPC !ith SP,at .5 %ays (b) +,%; HPC !ith SP.at .5 %ays
0
500
1000
1500
2000
0.0
0.51.0
1.5
2.0
2.5
3.0
3.5
4.0
M1D-56D
M1DSp10.2-56D
M1DSp10.3-56D
M1DSp10.4-56D
Void Diameter #+m$
Void Content #,$
0
500
1000
1500
2000
0.0
0.51.0
1.5
2.0
2.5
3.0
3.5
4.0
M1D-56D
M1DSp20.2-56D
M1DSp20.3-56D
M1DSp20.4-56D
Void Diameter #+m$
Void Content #,$
(c) +,%; HPC !ith SP,at 06 %ays (d) +,%; HPC !ith SP.at 06 %ays
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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0
500
1000
1500
2000
0.0
0.5
1.01.5
2.0
2.5
3.0
3.5
4.0
M1D-90D
M1DSp10.2-90D
M1DSp10.3-90D
M1DSp10.4-90D
Void Diameter #+m$
Void Content #,$
0
500
1000
1500
2000
0.0
0.5
1.01.5
2.0
2.5
3.0
3.5
4.0
M1D-90D
M1DSp20.2-90D
M1DSp20.3-90D
M1DSp20.4-90D
Void Diameter #+m$
Void Content #,$
(e) +,%; HPC !ith SP,at 7- %ays (f) +,%; HPC !ith SP.at 7- %ays
'(re 11:"nfluence of Curing Age on Moid Content of (.0 ' .0 ' 0- mm $) +,% ; HPC Samples
0
500
1000
1500
2000
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
M2-28D
M2Sp10.2-28D
M2Sp10.3-28D
M2Sp10.4-28D
Void Diameter #+m$
Void Content #,$
0500
10001500
2000
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
M2-28D
M2Sp20.2-28D
M2Sp20.3-28D
M2Sp20.4-28DVoid Diameter #+m$
Void Content #,$
(a) +.; HPC !ith SP, at .5 %ays (b) +.; HPC !ith SP.at .5 %ays
0
500
1000
1500
2000
0.0
0.5
1.0
1.5
2.0
2.53.0
3.5
4.0
M2-56D
M2Sp10.2-56D
M2Sp10.3-56D
M2Sp10.4-56D
Void Diameter #+m$
Void Content #,$
0
500
1000
1500
2000
0.0
0.5
1.0
1.5
2.0
2.53.0
3.5
4.0
M2-56D
M2Sp20.2-56D
M2Sp20.3-56D
M2Sp20.4-56D
Void Diameter #+m$
Void Content #,$
(c) +.; HPC !ith SP,at 06 %ays (d) +.; HPC !ith SP.at 06 %ays
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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0
500
1000
1500
2000
0.0
0.5
1.01.5
2.0
2.5
3.0
3.5
4.0
M2-90D
M2Sp10.2-90D
M2Sp10.3-90D
M2Sp10.4-90D
Void Diameter #+m$
Void Content #,$
0
500
1000
1500
2000
0.0
0.5
1.01.5
2.0
2.5
3.0
3.5
4.0
M2-90D
M2Sp20.2-90D
M2Sp20.3-90D
M2Sp20.4-90D
Void Diameter #+m$
Void Content #,$
(e) +.; HPC !ith SP,at 7- %ays (f) +.; HPC !ith SP.at 7- %ays
'(re 12:"nfluence of Curing Age on Moid Content of (.0 ' .0 ' 0- mm $) +. ; HPC Samples
010
0020
00
0.00
1.00
2.00
3.00
4.00
5.00
M3-28D
M3Sp10.2-28D
M3Sp10.3-28D
M3Sp10.4-28D
Void Diameter #+m$
Void Content #,$
010
0020
00
0.00
1.00
2.00
3.00
4.00
5.00
M3-28D
M3Sp20.2-28D
M3Sp20.3-28D
M3Sp20.4-28D
Void Diameter #+m$
Void Content #,$
(a) +$; HPC !ith SAP, at .5 %ays (b) +$; HPC !ith SAP. at .5 %ays
0
1000
2000
0.00
1.00
2.00
3.00
4.00
5.00
M3-56D
M3Sp10.2-56D
M3Sp10.3-56D
M3Sp10.4-56D
Void Diameter #+m$
Void Content #,$
0
1000
2000
0.00
0.50
1.00
1.50
2.002.50
3.00
3.50
4.00
M3-56D
M3Sp20.2-56D
M3Sp20.3-56D
M3Sp20.4-56DVoid Diameter #+m$
Void Content #,$
(c) +$; HPC !ith SAP, at 06 %ays (d) +$; HPC !ith SAP. at 06 %ays
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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0
1000
2000
0.00
0.50
1.001.50
2.00
2.50
3.00
3.50
M3-90D
M3Sp10.2-90D
M3Sp10.3-90D
M3Sp10.4-90D
Void Diameter #+m$
Void Content #,$
0
1000
2000
0.00
0.50
1.001.50
2.00
2.50
3.00
3.50
M3-90D
M3Sp20.2-90D
M3Sp20.3-90D
M3Sp20.4-90D
Void Diameter #+m$
Void Content #,$
(e) +$; HPC !ith SAP, at 7- %ays (f) +$; HPC !ith SAP. at 7- %ays
'(re 1):"nfluence of Curing Age on Moid Content of (.0 ' .0 ' 0- mm $) +$ ; HPC Samples
/ CONCLUION AND RECOMMENDATION
"nfluence of SAP addition and curing age on the air #oids distribution in HPC ha#e been e'amined #ia
a $% #olume analysis using computed tomography (CT) scanner for HPC mi'tures of different !ater/
binder binder types and SAP types Also studied !ith the CT scanner is the dry SAP particles si1e
distribution shape and sphericity The result re#eals that
a CT scanning is a good tool for studying the air #oids in concrete cement pastes and HPC Afast approach and representati#e concrete specimen (0- mm ' ,-- mm cylinder) enhanced
clear e'amination of the HPC !ith little or no modification to the cast specimenb The SAP particles are of #aried si1es mostly angular and irregular in shape and not totally
spherical The dry SAP particle si1e distribution analysed using CT scanner (SP,: -/$-- Em3
SP.: -/0-- Em) agrees !ith the manufacturers specification (SP, $-- Em3 SP . 6-- Em)c All the HPC?s mi'tures had micro:air #oids present irrespecti#e of SAP contents SAP created
#oids are ho!e#er more and follo!s same pattern as the distribution of the dry SAP particlesd The HPC mi'tures had large #olume air #oids present possibly being a result of high
concentration of superplastici1er in the HPC The fre
7/21/2019 3D Volume Analysis of Influence of SAP Contents and Curing Age on Air Void Distribution in High
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ACKNO9LED!EMENT
e ackno!ledge the follo!ing +r Duillaume Oeanson (Construction Product +anager) SI& &loerger
: AC de +ilieu' 4.,6$ AI%J"@9 Cede' ; &JAIC3 %a#y Penhard &" Misualisation Science
Droup3 %r Anton du Plessis and Stephan le Jou' CT Scanner @nit Central Analytical &acilities
(CA&) Stellenbosch @ni#ersity South Africa for the assistance recei#ed in materials procurement use
of facilities soft!ares and time input in the analysis
RE&ERENCE
=,> AC" $-5J ; -, (.--5) QDuide to curing concrete : AC" Committee JeportR!!!concreteorg
=.> S I ,.$7- ; . (.---) QTesting of hardened concrete : making and curing specimen forstrength testsR S" ondon
=$> AC" THPC/TAC (,777) QAC" %efines High Performance Concrete ; the Technical Acti#itiesCommittee Jeport (Chairman : HD Jussell)R !!!concreteorg
=4> T C Po!ers Copeland H +ann QCappilary continuity or discontinuity in cementpastes Capillary Continuity Gr %iscontinuity in Cement PastesR ulleting M (,707 ,,- ,,:,.
=0> AC" ($-5 : .,$) J,$ QJeport on internally cured concrete using pre!etted absorpti#elight!eight aggregateR !!!concreteorg
=6> G + Oensen P ura QTechni ol#er G Oensen (eds) Q"nternal curing of concrete State:of:the:art report of the J"+technical committee ,76:"CCR J"+ Jeport 4, .--B "SI 7B5:.:$0,05:-5.:- e:"SI 7B5:.:$0,05:-5.:-
=5> S austsen % P ents + T Hasholt G + Oensen QCT measurement of Small #oids inconcreteR in G + Oensen +T Hasholt S austsen (eds) @se of Superabsorbent Polymersand Gther Ie! Additi#es in Concrete PJ-B4 J"+ Publications Technical @ni#ersity of%enmark yngby %enmark .-,- p,0$:,6.
=7> M +echtcherine H Jeinhardt (eds) QApplication of superabsorbent polymers in concreteconstruction State:of:the:art report of the J"+ TC ..0:SAPR Springer Heidelberg/Dermany.-,. "SI 7B5:74:--B:.B$.:5
=,-> +aire P O ithers Quantitati#e 9:ray tomographyR "nternational materials re#ie!s Mol07Io, .-,4 Pp ,:4$ doi,-,,B7/,B4$.5-4,$U--------.$
=,,> S I 45- : ,, VAdmi'tures for concrete mortar and grout : Test methods for determination ofair:#oids characteristics in hardened concreteV S" ondon
=,.> AST+ C40B ; ,-a QStandard test method for microscopical determination of parameters of theair:#oid systems in hardened concreteR @SA !!!astmorg
=,$> % P ent1 P + Halleck A S Drader O Joberts Q&our:dimensional 9:ray
microtomography study of !ater mo#ement during internal curingR in G+ Oensen P ura o#ler (eds) Molume Changes of Hardening Concrete Testing and +itigation PJ-0. J"+Publications Technical @ni#ersity of %enmark yngby %enmark .--6 p ,,:.-
=,4> C SchrWfl M +echtcherine + Dorges QJelation bet!een the molecular structure and theefficiency of superabsorbent polymers (SAP) as concrete admi'tures to mitigate autogenousshrinkageR Cement and Concrete Jesearch 4. (6) (.-,.) 560:5B$
=,0> O Gla!uyi P oshoff QCompressi#e strength of high:performance concrete !ithabsorption capacity of super:absorbing:polymers (SAP)R in Jesearch and Applications inStructural ngineering +echanics and Computation ; ingoni (d) X .-,$ Taylor &rancisDroup ondon .-,$ "SI 7B5:,:,$5:---6,:. Pp ,6B7:,65$
=,6> + S Shetty QConcrete technology : theory and practiceR Ie! %elhi "ndia S Chand andCompany imited (.--4)
=,B> O Gla!uyi P oshoff Q"nfluence of particle si1e distribution on compressi#e strength andelastic modulus of high performance concreteR in "nternational Conference on Ad#ances in
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Cement and Concrete Technology in Africa (ACCTA) Oohannesburg South Africa .-,$ Pp5.0:5$$
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=,7> P C AKtcin QHigh:performance concreteR Taylor &rancis (,775)
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=.0> Molume Draphics QMDStudio +a' ..: Application soft!are for analysis and #isualisation ofindustrial computed tomography/ #o'el dataR (.-,$) !!!#olumegraphicscom
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publication) (.-,4)
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=.7> + T Hasholt G + Oensen ol#er S huto#sky3 QCan superabsorbent polymers mitigateautogenous shrinkage of internally cured concrete !ithout compromising the strengthYRConstruction and uilding +aterials $, (.-,.) ..6:: .$-
=$-> O Gla!uyi P oshoff Q$% #oid analysis of high performance concrete containingsuperabsorbent polymersR submitted for presentation at "nternational Conference onApplication of Superabsorbent Polymers and Admi'ture in Concrete Construction Technical@ni#ersity %resden Dermany September .-,4
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