Performance of recycled aggregate concrete: Strength and

Performance of recycled aggregate concrete:

Strength and stiffness

Jorge de Brito

Recycled Aggregate Concrete in South East Asia 1/3106-03-2021



Jorge de Brito

• CERIS is a research unit that operates in the Built and Natural Environment sector and is registered with the Portuguese Foundation for Science and Technology (FCT).

• MISSION - The mission of CERIS is to create and disseminate scientific knowledge and to promote innovation in the Built and Natural Environment sector through the active involvement in fundamental and applied research, at both national and international levels, and to enhance higher education and research training.

Recycled Aggregate Concrete in South East Asia

Cooperation

More information in: http://ceris.pt/

06-03-2021 2/31

1. Introduction: CERIS R&D Unit

http://ceris.pt/



Jorge de Brito

The study of the mechanical and durability-related performance of recycled aggregate

concrete (RAC) is made by comparing it with a conventional natural aggregate concrete

(NAC), whilst maintaining the same effective water to cement ratio.

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Replacement

of natural with

recycled

aggregates

Water

Cement

Recycled Aggregate Concrete in South East Asia06-03-2021

1. Introduction: What is recycled aggregate concrete?



Jorge de Brito

2. Recycled aggregates from CDW recycling plants

06-03-2021 4/31

According to the Portuguese Environmental Agency (APA),

there are 400+ licensed operators that recycle wastes from

construction and demolition activities.

The analysis to the properties and composition of the

output of some of these recycling plants has shown that

there is still a significant degree of variability, which

decreases the confidence of some of the construction

industry's professionals.

Recycled Aggregate Concrete in South East Asia

Source: Rodrigues et al. (2013)



Jorge de Brito

06-03-2021 5/31Recycled Aggregate Concrete in South East Asia

Apart from the differing materials coming from

different construction and demolition sites, the

application of different processing stages (or even

the inexistence of some) leads to a significant

variation of physical properties as well as

chemical composition of the resulting aggregates,

making it difficult to certify them and facilitate their

wider use in new construction applications.




Jorge de Brito

06-03-2021 6/31Recycled Aggregate Concrete in South East Asia

Source: Rodrigues et al. (2013)

Summary of the processing procedures and final output of each plant

The final size of processed CDW varies from plant to plant

The type of crushing, which has obvious influence on the properties of the recycled aggregate, either varies from

plant to plant or does not consider enough processing stages of aggregates for some applications.

It is clear that most CDW recycling plants still operate without regarding the potential usability of the

output material, but for the sole purpose of processing. Future standards and specifications must

include CDW recycling plants so that they operate in a way that maximizes the materials’ performance

with minimum contaminant content.




Jorge de Brito


Reduce size of individual fragments to a maximum size

between 400 and 700 mm

Separate storage of RCA, RMA, MRA and CDRA (heavily

contaminated)

Manual or mechanical pre-crushingseparation (removal of large pieces of wood, iron, paper, plastics, etc.)

Primary screening (removal of all materials finer than 10 mm such

as soil, gypsum, etc.)

Primary crushing(normally, a jaw crusher)

Electromagnetic removal of ferrous materials

Secondary screening

Manual or mechanical removal ofcontaminants

Secondary crushing(impact or cone crusher)

Washing or air sifting (removal of lightweight contaminants)

Final screening and storage of various size fractions conforming with the costumer's requirements

Bypa

ss o

f mat

eria

lwith

siz

e10

mm

< d

< 4

0 m

m

Bypa

ss o

f mat

eria

lwith

siz

ed

< 40

mm

RCA RMA MRA

Asphalt Gypsum Glass

Soil Wood Plastic




Jorge de Brito


Effect of recycled aggregates from valorised CDW on the compressive strength

0

10

20

30

40

50

60

0 10 20 30 40 50 60 70 80 90 100

28

-DA

Y C

OM

PR

ES

SIV

ES

TR

EN

GT

H(M

Pa

)

REPLACEMENT RATIO (%)

AR Grossos ValnorAR Grossos VimajasAR Finos VimajasAR Grossos AmbileiAR Finos AmbileiAR Grossos Europontal

• The 28-day compressive

strength of the control

concrete was of 53.9

MPa.

•This property varied

significantly depending

on the origin of RA.

•Fine RA from Vimajas

and Europontal led to the

lowest compressive

strength values.




Jorge de Brito

Recycled Aggregate Concrete in South East Asia 9/31

Undisputed “truth”

“Concrete made with recycled aggregates

cannot exhibit high compressive strength.”

06-03-2021



Jorge de Brito

3. High performance recycled aggregate concrete


Replacement ratio (%)

A maximum decrease of 5% was observed when 100% RCA (fine and coarse) were incorporated.

Concrete mixes in phase 1, in which silica fume replaced the part of the

cement, compressive strength decreased. However, it increased for phase 2 mixes, where it was used as

addition to cement. The reason behind this discrepancy in comparison

to that normally observed in the literature may be due to the relatively greater particle size of the addition,

which may not have reacted properly with the calcium hydroxide.

06-03-2021



Jorge de Brito

Primary plus secondary crushing


Jaw crusher Impact hammer

06-03-2021




Jorge de Brito


Jaw

crusher

Primary

crushing

Impact hammer

or cone crusher

Secondary

crushing

- Size decreases

- Old mortar content decreases

- Surfaces become more regular

- Fine content increases (more dumping and energy)

Better quality

coarse RCA

Higher compressive

strength

06-03-2021




Jorge de Brito

Influence of the crushing procedure on the compressive strength of concrete


The application of a primary + secondary crushing, which produced rounder aggregates and with less adhered mortar content, allowed the production of concrete mixes with slightly

higher compressive strength values. This was also noticeable for natural aggregates.

Primary crushing Primary + secondary crushing

06-03-2021




Jorge de Brito

Modulus of elasticity of high-performance recycled aggregate concrete


Replacement ratio (%)

As expected the modulus of elasticity decreased with

increasing RCA content. This is due to the greater deformability of the adhered mortar of RCA in

comparison the to natural counterparts.

06-03-2021




Jorge de Brito

The characteristics of the original materials

are often difficult to obtain by the time that

they are made into aggregates.

To overcome this barrier, a performance-

based classification is proposed, which

provides a means to “measure” the quality

of RA based on easily accessible data.

A meta-analysis to ~600 different

aggregates from over 100 publications

showed a clear relationship between water

absorption and oven-dried density.

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0.0

5.0

10.0

15.0

20.0

25.0

30.0

1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700

Wa

ter

ab

sorp

tio

n (

%)

Oven-dried density (kg/m3)

Agrela et al. (2012) Akbarnezhad et al. (2011) Amorim et al. (2011)

Barbudo et al. (2012) Barra and Vázquez (1998) Butler et al. (2011)

Buyle-Bodin and Zaharieva (2002) Cachim (2009) Chandra (2004)

Chen et al. (2003) Corinaldesi (2009) Corinaldesi (2010)

Corinaldesi and Moriconi (2004) Corinaldesi and Moriconi (2007) Corinaldesi and Moriconi (2009a)

Corinaldesi and Moriconi (2009b) Corinaldesi and Moriconi (2011) Corinaldesi et al. (2002)

Corinaldesi et al. (2007) Correia et al. (2006) Debieb and Kenai (2008)

Debieb et al. (2010) Dhir and Paine (2007) Dhir et al. (1999)

Dhir et al. (2003) Dhir et al. (2008) Dillmann (1998)

Etxeberria et al. (2007) Evangelista and de Brito (2010) Ferreira et al. (2011)

Fonseca et al. (2011) Gokce et al. (2011) Gomes and de Brito (2009)

Gómez-Soberón (2002) Gonçalves et al. (2004) González and Martínez (2004)

González and Martínez (2005) Henry et al. (2011) Higashiyama et al. (2011)

Jiménez et al. (2012) Katz (2004) Khalaf and DeVenny (2004)

Khalaf and DeVenny (2005) Khatib (2005) Kikuchi et al. (1998)

Knights (1998) Kou and Poon (2006) Kou and Poon (2009)

Kou and Poon (2009) Kou et al.(2011) Koulouris et al. (2004)

Lee (2009) Limbachiya et al. (2000) Limbachiya et al. (2004)

Limbachiya et al. (2012) Lin et al. (2004) Meddah and Sato (2010)

Mills-Beale and You (2010) Moon et al. (2002) Nagataki and Lida (2001)

Nagataki et al. (2004) Otsuki et al. (2003) Padmini et al. (2009)

Paine et al. (2009) Park (1999) Park (2003)

Pereira et al. (2012) Poon and Chan (2006) Poon and Kou (2010)

Poon et al. (2002) Poon et al. (2004) Poon et al. (2006)

Poon et al. (2009) Rahal (2007) Ravindrarajah and Tam (1987)

Razaqpur et al. (2010) Ridzuan et al. (2005) Rodrigues (2011)

Ryu (2002) Sadek (2011) Sani et al. (2005)

Sarhat (2007) Sato et al. (2007) Soutsos et al. (2011)

Soutsos et al. (2011) Takavoli and Soroushian (1996) Tam and Tam (2009)

Tang et al. (2007) Teranishi et al. (1998) Thanaya (2009)

Tsujino et al. (2007) Tu et al. (2006) Vegas et al. (2009)

Vieira et al. (2011) Waleed and Canisius (2007) Wang et al. (2011)

Yanagibashi et al. (2002) Yang et al. (2008) Yang et al. (2011)

Zega and Di Maio (2006) Zega et al. (2010) Behiry (2013)

Choi and Yun (2012) Corinaldesi and Moriconi (2011) Dong et al. (2013)

Higashiyama et al. (2013) Ismail and Ramli (2013) Jiménez et al. (2013)

Kim et al. (2013) Kim and Yun (2013) Manzi et al. (2013)

Matias et al. (2013) Pérez et al. (2013) Sata et al. (2013)

Sheen et al. (2013) Silvestre et al. (2013) Thomas et al. (2013)

y = 2.9373E-09x3 - 9.4014E-06x2 - 1.8977E-02x + 62.745

R² = 0.8779

4. Performance-based classification of recycled aggregates




Jorge de Brito

16/31

0

5

10

15

20

25

30

1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900

Wat

er a

bso

rpti

on

(%

)


A

B

C

D

A

B

C

D

IIII II IIII II IIII II0

5

10

15

20

25

30

1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900

Wa

ter

ab

sorp

tio

n (

%)


NA RCA RMA MRA CDRA

Aggregate classA B C

DI II III I II III I II III

Minimum oven-dried density

(kg/m3)2600 2500 2400 2300 2200 2100 2000 1900 1800

No

limit

Maximum water absorption

(%)1.5 2.5 3.5 5 6.5 8.5 10.5 13 15

Maximum LA abrasion mass loss

(%)40 45 50


4. Performance-based classification of recycled aggregates



Jorge de Brito

17/31

Normally, compressive strength

decreases with increasing RA

content.

The upper and lower limits of the

95% confidence interval shows

that there is a probability of 95%

that RAC with 100% coarse or fine

RA content may exhibit a

compressive strength value of

between 1.14 and 0.56 times that

of the control concrete.

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

0 10 20 30 40 50 60 70 80 90 100

f cm

-RA

C/

f cm

-Co

ntr

ol

RA content (%)

Akbarnezhad et al. (2011) Amorim et al. (2011) Barra and Vázquez (1998)Butler et al. (2011) Buyle-Bodin and Zaharieva (2002) Cachim (2009)Casuccio et al. (2008) Chen et al. (2003) Choi and Yun (2012)Corinaldesi (2010) Corinaldesi and Moriconi (2007) Correia et al. (2006)Dapena et al. (2011) Debieb and Kenai (2008) Dhir and Paine (2007)Dhir et al. (1999) Dhir et al. (2003) Domingo et al. (2009)Dosho (2007) Etxeberria et al. (2007) Evangelista and de Brito (2007)Evangelista and de Brito (2010) Ferreira et al. (2011) Gómez-Soberón (2002)Gonçalves et al. (2004) González and Martínez (2004) Jau et al. (2004)Juan and Gutiérrez (2004) Kenai et al. (2002) Khalaf and DeVenny (2004)Khalaf and DeVenny (2005) Khatib (2005) Kim and Yun (2013)Kim et al. (2013) Knights (1998) Kou and Poon (2009)Kou et al. (2007) Koulouris et al. (2004) Limbachiya et al. (2012)Manzi et al. (2013) Matias et al. (2013) Nagataki et al. (2004)Olorunsogo (1999) Otsuki et al. (2003) Park (1999)Pereira et al. (2012) Poon and Kou (2010) Poon et al. (2004a)Poon et al. (2004b) Rahal (2007) Rao et al. (2010)Ravindrarajah and Tam (1987) Razaqpur et al. (2010) Ridzuan et al. (2005)Salem et al. (2003) Sarhat (2007) Shayan and Xu (2003)Tang et al. (2007) Teranishi et al. (1998) Thomas et al. (2013)Vieira et al. (2011) Waleed and Canisius (2007) Wang et al. (2011)Yang et al. (2008) Yang et al. (2011)

y = 0.0014x + 1

y = -0.0044x + 1

38%

50%


5. Effect of recycled aggregates on strength and stifness



Jorge de Brito

18/31

0

0.2

0.4

0.6

0.8

1

1.2

0 25 50 75 100

f cm

-RA

C/

f cm

-Con

trol

Replacement level (%)

y = -0.0038x + 1

y = -0.0021x + 1

y = -0.0065x + 1

y = -0.0054x + 1

A

B

C

D

Maximum

strength loss

(%)

Maximum replacement level (%)

Class A Class B Class C Class D

5 23.8 13.2 9.3 7.7

10 47.6 26.3 18.5 15.4

15 71.4 39.5 27.8 23.1

20 95.2 52.6 37.0 30.8

Using the performance-based

classification, it is possible to

easily predict the compressive

strength loss of concrete for a

given replacement level, with

a probability of 95% that the

actual value will be greater

than predicted.





Jorge de Brito

19/31

𝑓𝑐𝑡𝑘;0.05 = 0.7 ∙ 𝑓𝑐𝑡𝑚

𝑓𝑐𝑡𝑘;0.95 = 1.3 ∙ 𝑓𝑐𝑡𝑚

𝑓𝑐𝑡𝑚 = 0.30 ∙ 𝑓𝑐𝑘23

For strength classes ≤ C50/60

𝑓𝑐𝑡𝑚 = 2.12 ∙ 𝑙𝑛 1 +𝑓𝑐𝑚10

For strength classes > C50/60

0

1

2

3

4

5

6

7

8

0 20 40 60 80 100

f ctm

(MP

a)

fck (MPa)

fctk,0.95fctk,0.05EC2 - fctm

Tensile strength behaviour of recycled aggregate concrete


It is concluded that the EC2

formulas for NAC can be used

for RAC, regardless of

replacement ratio, type and

size of the RA.

Results from 630 mixes from

41 publications.




Jorge de Brito

20/31

0

10

20

30

40

50

60

70

0 10 20 30 40 50 60 70 80 90 100

E cm

(GP

a)

fcm (MPa)

EC2 - Basalt aggregates EC2 - Quartzite aggregatesEC2 - Limestone aggregates EC2 - Sandstone aggregatesACI Committee 318 (2002) EHE-08 (2010)Ravindrarajah and Tam (1987) Dillmann (1998)Kakizaki et al. (1988) Dhir et al. (1999)Zilch and Roos (2001) Mellmann (1999)Cabral et al. (2010) Xiao et al. (2006)

0

10

20

30

40

50

60

0 10 20 30 40 50 60 70 80 90 100

E cm

(GP

a)

fcm (MPa)

EC2 - Basalt aggregates EC2 - Sandstone aggregates Akbarnezhad et al. (2011)Amorim et al. (2011) Cachim (2009) Chen et al. (2003)Corinaldesi (2010) Corinaldesi and Moriconi (2009) Dhir and Paine (2007)Etxeberria et al. (2007) Evangelista and de Brito (2010) Ferreira et al. (2011)Gómez-Soberón (2002) Khatib (2005) Koulouris et al. (2004)Park (1999) Pereira et al. (2012) Rao et al. (2010)Ravindrarajah and Tam (1987) Razaqpur et al. (2010) Teranishi et al. (1998)Vieira et al. (2011) Waleed and Canisius (2007) Yang et al. (2008)Zega and Di Maio (2006) Limbachiya et al. (2012) Casuccio et al. (2008)Dapena et al. (2011) Dosho (2007) Juan and Gutiérrez (2004)Kou et al. (2007) Poon and Kou (2010) Salem et al. (2003)Yanagi et al. (1998) Dolara et al. (1998) Evangelista and de Brito (2007)Choi and Yun (2012) Manzi et al. (2013) Thomas et al. (2013)Rao et al. (2011) Kou et al. (2008) Tam et al. (2007)Kou and Poon (2008) Bravo (2014) González and Etxeberria (2014)

Over 95% of all RAC

mixes are above the

EC2 relationship

corresponding to

sandstone aggregates

Results from 588 mixes

from 43 publications.

Basalt

Sandstone

𝑬𝒄𝒎 = α×𝟐𝟐𝒇𝒄𝒎𝟏𝟎

𝟎.𝟑

[𝑮𝑷𝒂]

Modulus of elasticity vs. compressive strength of recycled aggregate concrete





Jorge de Brito

21/31

Simply supported beam and one-way slab;

Incorporation of 20%, 50% and 100% RA of classes A, B and C;

Accepted strength loss vs. no strength loss;

Conservative vs. average scenarios.

Target strength class C30/37

Type of cement CEM I 42.5

Aggregate maximum size (mm) 25.4

Slump class S3

Environmental exposure XC3 + XS1


ϕ10//0.125

6ϕ20

300 mm

220 mm

480 mm

Extreme scenario with elements exposed to very aggressive CO2- and chloride-enriched environments

6. Implications on structural design of RAC elements



Jorge de Brito

22/31

0

0.2

0.4

0.6

0.8

1

1.2

0 25 50 75 100

f cm

-RA

C/

f cm

-Co

ntr

ol

Replacement level (%)

y = -0.0038x + 1

y = -0.0021x + 1

y = -0.0065x + 1

y = -0.0054x + 1

A

B

C

D

𝑓𝑐𝑡𝑚 = 0.30 ∙ 𝑓𝑐𝑘23

For strength classes ≤ C50/60

𝑓𝑐𝑡𝑚 = 2.12 ∙ 𝑙𝑛 1 +𝑓𝑐𝑚10

For strength classes > C50/60

Effect of RA on the strength of RAC


0

1

2

3

4

5

620%

50%

100%

-4

-3

-2

-1

0

A B C A B C

RA class

Str

ength

cla

ss v

aria

tion

P5 - No strength loss P50 - No strength loss

P50 - Strength lossP5 - Strength loss

0

Greater change required

to mix design with

increasing incorporation of

RA of lower quality.

Only one variation in

strength class when

considering average

conditions

Estimation of strength loss/target

strength class increase




Jorge de Brito

ϕ10//0.125

6ϕ20

300 mm

210 mm

470 mm

6ϕ20

300 mm

ϕ10//0.125

220 mm

500 mm

23/31

• NAC

Variation in the beam-slab cross-section


30 mm• 100% RA of class B or C

10 mm and 30 mm increases were needed to the slab and beam, respectively.

P50 scenario considering constant target strength

10 mm




Jorge de Brito

Laboratory

characterization

06-03-2021 Recycled Aggregate Concrete in South East Asia 24/31

Dynamic characterization tests:

• Accelerometers and triaxial seismometer

• Horizontal and vertical natural frequencies

Accelerometer

Seismometer

6. Performance of a simple RAC structure



Jorge de Brito

Vertical load testing

• Water (γ = 9,8 kN/m3)

• Rulers

• Elastic behaviour (horizontal testing)

• Deflectometers (midspan of beams

and slabs).

Data analysis and modelling:

• Consideration of real geometry

• Modelling of masonry walls





Jorge de Brito

Horizontal destructive testing:

• Non-linear response

• Step-by-step controlled test with successive applied loading

Displacement Cracking





Jorge de Brito

Comparison between force/deformation curves

Plastic hinge formation and

collapse mechanismSome operations during one test





Jorge de Brito


Structure collapse




Jorge de Brito

29/31

7. Conclusions

CDW recycling plants lack consistent and comprehensive processing

techniques capable of producing high quality recycled aggregates and

thus these cannot be easily certified nor widely used in concrete

production.

Provided that a selective demolition approach was used and that correct

beneficiation procedures were applied in CDW, it is probable that the resulting

recycled aggregates can be used in the manufacture of high performance

concrete.

Since the quality of the recycled aggregates rules over the performance

loss of the resulting recycled aggregate concrete, special considerations

must be taken in order to ensure that the correct type of aggregates are

used in their most suitable application.




Jorge de Brito

30/31

7. Conclusions

The use of recycled concrete aggregates on the production of high

performance recycled aggregate concrete is perfectly feasible from

mechanical and durability viewpoints. However, some aspects need to be

taken into account in order to minimize the almost always present

performance decrease.

The structural behaviour of recycled aggregate concrete showed that there

was marginal impact of the recycled aggregate’s incorporation. The steel

reinforcements were highly effective at reducing any possible detrimental

effect of recycled aggregate incorporation in terms of cracking and, if code

regulations are followed and a proper design is made, the incorporation of

high quality recycled aggregates will not influence the structure’s good

seismic behaviour.




Jorge de Brito


Documents

Performance of recycled aggregate concrete: Strength and