Compressive Strength of Recycled Suraya Hani Adnan

8/10/2019 Compressive Strength of Recycled Suraya Hani Adnan

1/10

COM PRESSIVE STRENGTH OF RECYCLE D

GG REG TE TO CONCR ETE WITH V R IOUS

PERCENT G E OF RECYCL ED GG REG TE

SUR Y H NI DN N

LEE YEE L OON

ISM IL B DUL R HM N

H MID H MOHD S M N

MI VIM L SOEJ OSO


2/10

C O M P R E S S I V E S T R E N G T H O F R E C Y C L E D A G G R E G A T E C O N C R E T E W I T H

V A R I O U S P E R C E N T A G E O F R E C Y C L E D A G G R E G A T E

Suraya Hani Adnan, Lee Yee Loon, Ismai l Abdul Rahman,

Hamidah Mohd Saman, Mia Wimala Soe joso

Fakul t i Kejuruteraan Awam dan Alam Seki tar

Univers i t i Tun Hussein Onn Malays ia (UTHM)

E-mai l : [email protected] .my

A B S T R A C T : C o m p r e s s i v e s t r e n g t h i s t h e b a s i c m e c h a n i c a l p r o p e r t i e s a n d o n e o f t h e i n d i c a t o r s t o d e t e r m i n e t h e

p e r f o r m a n c e o f a c o n c r e t e . I n t h i s p a p e r , t h e e f f e c t s o f v a r i o u s p e r c e n t a g e s ( 0 % , 2 5 % , 5 0 % , 7 5 % , 1 0 0 % ) o f R e c y c l e d

A g g r e g a t e ( R A ) o n c o m p r e s s i v e s t r e n g t h o f R e c y c l e d A g g r e g a t e C o n c r e t e ( R A C ) w e r e i n v e s t i g a t e d . R A i s u s e d t o

r e p l a c e n a t u r a l a g g r e g a t e ( N A ) a s c o a r s e a g g r e g a t e i n c o n c r e t e m i x e s . T h i s r e s e a r c h a l s o c o v e r e d R A C m i x t u r e s a t

d i f f e r e n t w a t e r - c e m e n t r a t i o (0 . 4 , 0 .5 , 0 . 6 ) . I t w a s f o u n d t h a t R A C h a d l o w e r c o m p r e s s i v e s t r e n g t h c o m p a r e d t o N a t u r a l

A g g r e g a t e C o n c r e t e ( N A C ) . A t th e a g e o f 2 8 d a y s , R A C w i t h w a t e r - c e m e n t r a t i o 0 . 4 h a d t h e h i g h e s t s t r e n g t h .

K e y w o r d s : c o m p r e s s i v e s t r e n g t h , r e c y c l e d a g g r e g a t e , r e c y c l e d a g g r e g a t e c o n c r e t e , n a t u r a l a g g r e g a t e , n a t u r a l a g g r e g a t e

c o n c r e t e , r e p l a c e m e n t , w a t e r c e m e n t r a t i o

1 0 I N T R O D U C T I O N

Recycled Aggregate Concrete (RAC) is concrete that us ing Recycled Aggregate (RA) as par t ial ly or

fully replacement in coarse and fine aggregate. I t is believed RA have been used from 1945 in

concrete producing and started when World War II damaged a large quantity of concrete structures

and the high demand of aggregate to rebui ld the s t ructures (Kheder and Al-Windawi, 2005) . They

recognised the factors l ike depletion of natural aggregates, t ightly environmental law and waste

disposal problems which inf luenced the appl icat ion of RA.

RA ha d such a pos sible ap plication in certain area and M aso od et. al . (2002 ) have

summarised i t . They have conducted some exper imental inves t igat ions and found that RA had a

potent ial funct ioning as aggregate that can be appl ied in concrete roads , drainage work, shal low

storage tanks , culver ts and sewa ge or t reatment plants .

Recently Malaysia is not yet practising RA in i ts construction industry. No depletion of

natural aggregate sources are the main factor why RA is not been using. But according to Masood et.

al . (2002), Asia country should think seriously about the application of RA due to the increasing of

discharge concrete for each year . Hong Kong, Japan and China have become pioneer count ies in

Asia which are act ively conducted s tudy on RA appl icat ion in cons truct ion indus try. They can be

seen in some research by Poon and Chan, (2006), Eguchi et . al . , (2006) and Huang et. al . ,(2002).

Poon and Chan, (2006) has reported the application of 14,300 m

3

RA fo r Hon g Kong W etland Park

cons truct ion. Meanwhile in Taiwan, the Construct ion and Demoli t ion (C & D) waste is handl ing

proper ly s ince 1999 (Huang et . a l , 2002) and Japan have commit ted in appl icat ion of RA by

publ ishing 'Standard for Usage of Concrete wi th Recycled Aggregate ' in 1996 (Eguchi et . a l . , 2006) .

Uni ted Kingdom is one good example of wes tern countr ies which pract is ing RA in i t s

cons truct ion indus try. In DOE 1996, the '1995 UK Government White Paper Making Waste Work '

had targets to increase the using of waste and recycled materials as aggregates to 30 million tonnes

per year by 2006. In UK, Construct ion and Demoli t ion (C&D) waste has been ident i f ied were had

value in engineering materials for construction industry (Lawson et. al . , 2001). Lawson et. al . (2001)

also reported that 51.1% or 27.4 million tonnes of (C& D) waste were disposed directly to landfil l ,
mailto:[email protected]:[email protected]


3/10

39.6 % or 21.2 mil l ion tonnes were except ing f rom l icensed disposal and were pr imar i ly used for

land modelling during the construction projects and 9.2 % or 5 million tonnes were either crushed to

produce a graded product or di rect ly recovered. Recycl ing and reuse (C&D) waste and produced as

RA is expected to improve on supplying of construction material and also can solve the disposal of

waste construction material (Masood et. al . , 2001).

RAC has at t racted many researchers to s tudy i ts performance. Previous researchers have

conducted s tudy on appl icat ion of RA and found that RAC have lower compress ive s t rength

compared to Natural Aggregate Concrete (NAC), ( Ismai l , Suraya and Mia, 2007) . Table 1.0 shows

the resul ts of previous s tudies which were us ing RA as replacement coarse aggregate in concrete

mixes at di f ferent water-ce me nt rat io .

Table 1.0 Summ arisation Result of Com pressive Strength from Previous Studies

N o .

N a m e o f R e s e a r c h e r S o u r c e o f A g g r e g a t e s w / c r a t io

P e r c e n t a g e

C o m p r e s s i v e

R e p l a c e m e n t o f

R A S t r e n g t h ( M p a )

1

R a h a l K .

N a t u r a l A g g r e g a t e f r o m 0 . 6 5

0 %

22.7

G a b b r o c r u s h e d r o c k 0 . 5

0 %

32.3

i m p o r t e d f r o m U n i t e d

0 . 4 8 0 %

3 6

A r a b E m i r a t e s

0 . 4 3 0 %

4 6

0.4

0 %

53.5

R e c y c l e d A g g r e g a t e f r o m 0 . 6 5

1 0 0 %

20.3

t w o b u i l d i n g s u n d e r d e m o l i t i o n

0.5

1 0 0 %

29.2

i n t h e H a w a l l y a r e a i n K u w a i t

0 . 4 8 1 0 0 % 3 2 . 2

0 . 4 3 1 0 0 % 39.4

0 .4

1 0 0 % 4 6 . 5

2

T o p c u a n d S e n g e l N a t u r a l A g g r e g a t e i s G r a v e l 0 . 6 3 9

0

18.8

0 . 6 3 9

3 0 %

15.2

0 . 6 3 5

5 0 %

15

0 . 6 3 8

7 0 %

14.2

0 . 6 3 7

1 0 0 %

13.8

R e c y c l e d A g g r e g a t e i s c r u s h i n g 0 . 5 7 1

0 %

2 0

n a t u r a l c o n c r e t e ( 2 8 - d a y 0 . 5 7 3 0 % 18.2

c y l i n d r i c a l c o m p r e s i i v e s t r e n g t h 0 . 5 6 9

5 0 %

17.8

o f 1 4 M P a ) 0 . 5 7 1 7 0 %

16.6

0 . 5 7

1 0 0 %

14

3

T . Y . T u , Y . Y . C h e n R e c y c l e d A g g r e g a t e f r o m 0 . 3 2

1 0 0 %

3 2

a n d C . L H w a n g

d e m o l i s h e d - c o n s t r u c t i o n w a s t e s 0 . 3 6

1 0 0 %

2 7


4/10

g e n e r a t e d d u r i n g 9 2 1 C h i - C h i

0 . 4 1 0 0 %

2 8

e a r t h q u a k e

4 H . J . C h e n , T . Y .

N a t u r a l A g g r e g a t e i s f r o m 0 . 3 8

0 %

5 5

a n d K . H . C h e n c r u s h e d r o c k

0 . 4 6 0 % 4 2

0 . 5 8 0 %

2 9

0 . 6 7 0 %

2 5

0.8

0 %

2 0

R e c y c l e d A g g r e g a t e is f r o m

0 . 3 8 1 0 0 % 3 8

b u i l d i n g r u b b l e c o l l e c t e d f r o m

0 . 4 6

1 0 0 %

3 2

d a m a g e d s t r u c t u r e s t h a t 0 . 5 8 1 0 0 % 2 7

c o n t a i n i n g w a s t e c o n c r e t e , t i l e s ,

0 . 6 7

1 0 0 %

2 2

b r i c k s a n d o t h e r i m p u r i t i e s s u c h 0 . 8 1 0 0 % 1 9

a s g y p s u m a n d c l a y .

5 K o u , P o o n a n d C h a n

N a t u r a l a g g r e g a t e i s c r u s h e d

0 . 4 5

0 % 6 6 . 8

G r a n i t e

2 0 % 6 2 . 4

5 0 % 5 5 . 8

1 0 0 % 4 2

R e c y c l e d A g g r e g a t e i s f r o m 0 . 5 5 0 % 4 8 . 6

R e c y c l i n g f a c i l i t y i n H o n g 2 0 % 4 5 . 3

K o n g

5 0 %

4 2 . 5

1 0 0 %

38.1

From Table 1.0. , can be seen in Topcu and Sengel (2004) and Kou, Poon and Chan (2007) s tudy,

that compress ive s t rength of RAC is lowered when replacement of RA as coarse aggregate in

concrete mix is increased. According to Olorunsogo (1999) , the factors l ike RA had smoother

surface and rounder com pared to NA which lead to this mat ter . Otherw ise, Otsuki et . a l . (2003) and

Tam et . a l . (2005) had proposed modif ied mixing procedure to enhance compress ive s t rength of

RAC.

Different sources of RA also played an impor tant role in determining compress ive s t rength of

RAC. Although those concrete had same w/c rat io , but i t ' s compress ive s t rength seemed qui te

dif ferent to each other . For examp le, in Rahal K. (2007 ) and T.Y T.Y . Tu, Y.Y.Chen and

C.L.Hwang (2005) s tudy, al though their w/c rat io for concrete mixture is 0 .4 and used RA at 100%

replacemen t , but they obtained a di f feren t resul t in com press ive s t rength which is 46.5 and 28 M Pa.

Cements content in the mixture also be a factor which lead to this different result .


5/10

In T.Y. Tu, Y.Y.Chen and C.L.Hwang (2005) s tudy also, i t found that water content in

concrete mix es mu st be suff icient when RA is used in concrete mixe s . This can be viewed in thei r

s tudy which R A C with same w/c rat io but had a di f ferent wate r content that 150, 160 and 170 kg/m

3

.

Supposedly, lower water content wi l l lead to greater compress ive s t rength, but in this s tudy, RAC

with water content 160 kg/m

3

obtained higher compress ive s t rength than that of 150 and 170 kg/m

3

.

Al though they fou nd a di f ferent resul t f rom expec ted, they have conclud ed that RA need suff icient

water to ful f i l the abso rpt ion capaci ty nee ds . Strength wi l l decrease w hen w ater content i s

insuff icient and poor hydrat ion process occurred. But excess ive amount of pas te also leading to

weak inter face-zone and low dens i ty concrete wi l l deal to poor compress ive s t rength.

In H.J . Chen, T.Y. and K.H. Chen (2003) s tudy, washed RA is used as coarse aggregate.

They found that washed RA comprised higher s t rength than that of unwashed RA. Greater bond

effects were produ ced whe n im pur i t ies , powde r and harmfu l mater ials on aggregate surface in RA

are washed away. They also identif ied that at low w/c ratio, the compressive strength ratio of

recycled concretes to normal concretes are decreased. Main factor which lead to this result is

strength of the paste is increase at low w/c ratio. Based on composite material theory, they revealed

that RA wil l become a weak mater ial and i ts bear ing capaci ty become smal ler which inf luenced to

decrease in strength.

General conclus ion is made based f rom this table that compress ive s t rength of RAC is lower

than that of NAC. It is also showed that when w/c ratio of concrete mix is lower, compressive

s t rength for RA C a nd NA C is higher . Acco rdingly, this paper wi l l s tudy the ef fect of var ious

replaceme nt of RA on i ts compre ss ive s t rength for di f feren t wa ter-cem ent rat io .

2.0 E X P E R I M E N T A L W O R K

2 1 M aterials

The mater ials used in this exper iment were:

1. Ordinary Por t land C em ent (O PC)

2. Sand

3. Natural gravel wi th maxim um s ize 20 mm (NA )

4. Superplas t icizer

5. Recycled Aggregate (RA) - used as coarse aggregate

The recycled coarse aggregates were produced by crushing the was te concrete cubes at outer UTHM

Mater ial Laboratory that had compress ive s t rength between 20 to 25 MPa. These waste cubes were

broken into smal ler pieces and crushed us ing a jaw crusher . Then the RA produce d is s ieved with

max s ize 20 mm. Table 2.1 showed the phys ical proper t ies of NA and RA.

Table 2.1 Physical Properties of Aggreg ate

Type of Proper t ies

Normal Aggrega te

Recyc led Aggrega te

Specif ic

Gravity

SSD

2.48

2.39

pecif ic

Gravity

Oven Dried

2.46 2.31

Specif ic

Gravity

Apparen t

2.51 2.5

Aggrega te Impac t Value

17.6

36.3


6/10

( )

Aggrega te Crush ing Value

( )

17.25

35.86

Absorpt ion (%)

0.83

3.34

2 2 Concr ete mixes

Two groups of concrete mixes , NAC and RAC were produced us ing natural sand as f ine aggregate.

NA C m ixes were used ful ly Natural A ggregate as coarse aggreg ate in concrete mix. Mea nwh ile

RA C mixes w ere used Recycled Agg regate as par t ially or ful ly replace me nt of Natural Agg regate as

coarse aggregate. These mixes were des igned according to DOE mix des ign. The concrete mixtures

were prepared with a water-cement (w/c) rat io 0.4, 0 .5 and 0.6. The s lump target i s between 60 mm

to 180 mm for N A C and R AC mixes . Skim Q uick Set (SQS) is used as superplas ticizer . The

com binat ion in concrete mix es af ter this wi l l be called as RA 00, RA25 , RA 50, RA7 5 and R A10 0.

Table 2.2 showed the detai ls of concrete mixes .

Table 2.2 Series of mix proportion

Series

Natural Aggregate (%)

Recycled Aggregate (%)

R A 0 0

100

0

RA25 75

25

RA50 50

50

RA75 25

75

RA100 0

100

2 3 Test ing of Con crete

Slump and compress ive tes t i s conducted to determine concrete 's workabi l i ty and compress ion

s trength. Slump tes t i s conducted fol lowing ASTM C 143-90a. Meanwhile , compress ive tes t i s

conducted by fol lowing BS 1881: Par t 108:1983 and three cubes of 100mm x 100mm x 100mm

were tested at 7, 14 and 28 days.

3.0 R E S U L T S A N D D I S C U S S IO N

3 1 Slum p Test Result

The slump results are presented in Table 3.1. I t can be observed in Figure 3.1 that concrete mixes at

0.4 had a lower s lump compared to 0.5 and 0.6 concrete mixes . On the other hand, when

replacement of RA is increased in concrete mixes , the s lump of concrete mixes is decreased. I t was

expected because recycled aggregate is high in water absorpt ion. Poon C.S. et . a l . (2006) revealed

that mortar over RA is lead to low s lump of RAC.


7/10

Table 3.1 Slump for Different w/c Ratio

Concrete Mixes

S E R I E S

W / C R A T I O S L U M P ( m m )

R AOO 0 . 4 135

0 . 5 173

0 . 6 1 7 9

R A 2 5 0 . 4 1 2 8

0 . 5 165

0 . 6

170

R A 5 0 0 . 4 9 0

0 . 5 165

0 . 6 165

R A 7 5 0 . 4 6 0

0 . 5 160

0 . 6 159

R A 1 0 0 0 . 4 5 0

0 . 5 153

0 . 6 156

SLUMP

R A O O R A 0 2 5 R A 0 5 0 R A 0 7 5 R A 1 0 0

P e r c e n t a g e o f R A { )

0 . 4

0 . 5

0 6

Fig. 3.1 Slump for Concrete Mixes

3 2 Com pressive Test

The compress ive s t rength resul ts are presented in Table 3.2. Each presented value is the average of

three measurements . I t i s shown in Fig. 3 .2.1 that compress ive s t rength of RAC is lowered compared

to Natural Aggregate Concrete (NAC). For w/c rat io 0.4 and 0.5, the concrete mixtures prepared

with 25, 50, 75 and 100 % replacement of RA had a decrease of 21.9, 23.7, 43.3, 32.7 % and 13.2,

7.7, 19.1,13.2 % in the compress ive s t rength at 28-day com pared to N AC . Then , the concrete

mixtures wi th w/c rat io 0.6 that prepared with 25, 50, 75 and 100% replacement of RA had a

decrease of 11.85, 17.1, 31.3, 22.3 % in compressive strength than that of NAC. In these figure, i t

a lso found that RA 10 0 obtained higher compress ive s t rength than that of RA 075. Norm al ly as RA

replacement increased, compress ive s t rength wi l l decrease (Topcu and Sengel (2004) and Kou, Poon

and Chan (2007)) . The higher compress ive s t rength may be at t r ibuted to the greater bonding force

and s t rength when same type of aggregates was used. Otherwise, RAC s t i l l obtained lower

compress ive s t rength compared to NAC.

Table 3.2 Result o C ompressive Strength for Different W/C Ratio

S E R I E S

W / C R A T I O

7 - d a y 1 4 - d a y

2 8 - d a y

R A O O

0. 4

0 . 5

0 . 6

34.4 38.6

56.6

A O O

0. 4

0 . 5

0 . 6

20.3 22.0

30.2

R A O O

0. 4

0 . 5

0 . 6

15.9 18.4 21 .1

R A O O

0. 4

0 . 5

0 . 6

R A 0 2 5

0 . 4

0 . 5

0 . 6

29.9

37.5 44.2

A 0 2 5

0 . 4

0 . 5

0 . 6

19.2 21.7

26.2

R A 0 2 5

0 . 4

0 . 5

0 . 6

13.4 16.4

18.6

R A 0 2 5

0 . 4

0 . 5

0 . 6


8/10

R A 0 5 0

0.4

0 .5

0 .6

27.1

36.3 43.2

A 0 5 0

0.4

0 .5

0 .6

15.5

21.9

25.1

R A 0 5 0

0.4

0 .5

0 .6

12.3

15.8

17.5

R A 0 5 0

0.4

0 .5

0 .6

R A 0 7 5 0.4

0.5

0 .6

23.2 31.3 32.1

A 0 7 5 0.4

0.5

0 .6

16.1

18.6

22.0

R A 0 7 5 0.4

0.5

0 .6

11.4

12.9

14.5

R A 0 7 5 0.4

0.5

0 .6

R A 1 0 0

0.4

0 .5

0 .6

21.8

30.2

38.1

A 1 0 0

0.4

0 .5

0 .6

16.5

18.9

23.6

R A 1 0 0

0.4

0 .5

0 .6

10.3

11.9

16.4

R A 1 0 0

0.4

0 .5

0 .6

Fig. 3.2.1 Com pressive Strength for Fig. 3.2.2 Com pressive Strength for

w/c ratio 0.4 w/c ratio 0.5


9/10

C O M P R E S S I V E S T R E N G T H R A C W IT H W / C R A T I O 0 .6

R A OO R A 2 5 R A 5 0 R A 7 5 R A 1 0 0

SERIES K)

7 D A Y

1 4

D A Y

0 2 8 D A Y

Fig. 3.2.3 Compressive Strength for w/c ratio 0.6

5 0 C O N C L U S I O N

The fol lowing conc lus ions have been made based on the resul ts of this s tudy:

1. With the same w/c ra t io , the s lump va lue decreases i f percentage of RA is increased.

2. The compress ive s t rength of Recyc led Aggrega te Concre te was lower than tha t of Natura l

Aggre ga te Conc re te .

3 . Lower wate r-cement ra t io of Recyc led Aggrega te Concre te lead to higher in compress ive s t rength.

RAC could increase i ts compress ive s t rength by reduc ing the wate r-cement ra t io of concre te .

4 . The re la t ionship of w/c ra t io and compress ive s t rength of RAC is inverse ly propor t iona l .

6 0 R E F E R E N C E

Chen, H.J . , Yen, T . and Chen, K.H. , U s e of Building Rubbles as Recycled Aggregates,''' Ce m e nt a nd

Concre te Research 33, (2003) , pp. 125-132.

E guc h i , K . , T e ra n ish i , K . , Na k a gom e , A . , K ish imo to , H . , Sh inoz a k i , K . a nd Na r ika w a , M . ,

Application of Recycled Coarse Aggregate by Mixture to Concrete Construction , , Con struc t ion

a nd Bui ld ing Ma te r ia l s , 2006 .

Huang, W.L. , L in, D.H. , Chang, N.B. , L in,K.S. ,

R ec yc li ng of Construction and Demolition Waste

via A Mechan ical Sorting Process

. Reso urces Con serva t io n & Recyc l in g, Vol . 37, Issue 1 , Dec

2 0 0 2


10/10

Ismai l , A.R. , Suraya, HA ., Mia, W.M .S. , Po ssi bi lit y of Using Recycled Aggregate as an

Alternative to Natural A ggregate in Ma laysia

Proceedings of A W A M 200 7 held at Un iversit i

Sains Malays ia, 2007.

Kheder , G.F. , Al-Windawi, S .A. , Va ria tio n in Mechanical Properties of Natural and Recycled

Aggreg ate Concrete as Related to the Strength of Their Binding Mo rtar, M aterials and Structures

38 (August-September 2005) , pp. 701-709.

Kou, S.C. , Poon, C.S. and Chan, D. ,

Influence of Fly Ash as Cemen t R eplacement on the Properties

of Recycled Aggrega te Concrete . Journal of Ma ter ials in Civi l Engin eer ing, Septemb er 2007.

Lawson, N. , Douglas , I . , Garvin, S . , McGrath, C. , Manning, D. and Vet ter lein, J . ,

Recycling Construction and Dem olition Wa stes- A UK Perspective,

, Envi ronmenta l Managem ent

and Hea lth, Vol. 12, N o. 2, (2001) .

Masood, A. , Ahmad, T. , Ar i f , M. and Mahdi , F . ,

W a st e Managem ent Strategies for Concrete, ,

Environ Eng Pol icy (2002) .

Olorunsogo, F.T. , E a rl y Age Properties of Recycled Aggregate Concrete . Proceedings of the

Internat ional S emina r on Exploi t ing W astes in Conc rete held at the Univers i ty of Dun dee,

Scot land,U K on 7 Septem ber 1999,pp. 163-170.

Otsuk i ,N. , Miyaza to ,S . ,Yodsud ja i ,W. ,

In fl u en ce of Recycled Aggregate on Interfacial Transition

Zone, Strength, Chloride Pen etration and Carbo nation of Concrete

. Journ al of Ma terials in Civil

Engineer ing, Sept /Oct 2003, pp.443-451.

Poon, C.S. and Chan, D. , The Use of Recycled Aggregate in Concrete in Hong Ko ng, , Resources

Conservat ion & Recycl ing, 2006.

Poon, C.S. , Kou, S.C. , Lam, L. ,

Influence of Recycled Ag gregate on Slump and Bleeding of Fresh

Concrete, Ma ter ials and Structure, 2006.

Rahal, K., M ec ha ni ca l Properties of Concrete with Recycled Coarse Aggregate, Building and

Environment 42, (2007) , pp. 407-415.

Tam,V.W.Y. , Gao , X.F . ,Tam, C .M. , Ca rb on ati on around near aggregate regions of old hardened

concrete cement paste . Cem ent and Con crete Research, Vol 35, Issue 6, June 2005, pp. 1180-1186.

Topcu, I . B., Sengel, S., Pr op er tie s of Concretes Produced with Waste Concrete Aggregate,

Cement and Concrete Research 34, (2004) , pp. 1307-1312.

Tu, T.Y. , Chen, Y.Y. and Hwang, C.L. ,

Pr op er tie s ofHPCwith Recycled Aggregates,

Cement and

Concrete Research 36, (2006) , pp. 943-950.

Documents

Compressive Strength of Recycled Suraya Hani Adnan