3 May 2023

INFLUENCE OF MINERAL ADDITIONS ON THE PERFORMANCE OF GREEN

RECYCLED AGGREGATE CONCRETE

DAYAL KURIAN VARGHESE

1

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2 OVERVIEW

Introduction Green recycled aggregate concrete (GRAC) Recycled concrete aggregate (RCA) Case study-1 Case study-2 Conclusion References

Mobile Recycling Unit

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3 INTRODUCTION

By the end of the 20th century, sustainable development and environmental protection became key goals of modern society

Main problems that industry of construction materials faces were:

natural aggregate depletion

high consumption of Portland cement and associated high emission of carbon dioxide

large amount of generated construction and demolition (C&D) waste

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4 GREEN RECYCLED AGGREGATE CONCRETE (GRAC)

GRAC made with recycled concrete aggregate, low cement content and high content of different mineral supplements

Such concretes belong to ‘‘green’’ or ‘‘eco’’ concretes

Here GRAC produced with

fine river aggregate

coarse recycled aggregate

Portland Cement

Silica fume (SF), fly ash (FA), Metakaolin (MK), GGBS

Enterprise Park

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5RECYCLED CONCRETE

AGGREGATE (RCA)

Collection of C&D wastes Screening Vibrating

feederPlant

crusher

Jaw crusher

Magnetic separatorcone crusher

vibratory screens

storage compartment

Recycled aggregate

Sampling & Testing

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6 CASE STUDY-1

“Comparisons of natural and recycled aggregates concretes prepared with the addition of different mineral admixtures”

Kou et al. (2011) conducted studies on GRAC prepared with different mineral admixtures such as SF (10%),MK (15%),FA (35%), GGBS (55%)

The coarse aggregates were replaced with 50% and 100% of RCA

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7 MATERIALS USED

Portland cement (PC) Metakaolin (MK) Silica fume (SF) Fly ash (FA) Ground granulated blast slag (GGBS) Natural fine aggregate Recycled coarse aggregate

GGBS

Fly ash

Recycled concrete material

Silica fume Metakaolin

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8

Contents Cement

Fly ash

Silica fume

Metakaolin

GGBS

SiO2 21 56.79 85-86 53.2 44.6Al2O3 5.9 28.21 - 43.9 13.3Fe2O3 3.4 5.31 - 0.38 0.9CaO 64.7 <3 - 0.02 33.8MgO 0.9 5.21 - 0.05 4.8Na2O - - - 0.17 1.0K2O - - - 0.10 -TiO2 - - - 1.68 -SO3 2.6 0.68 0.3-.7 - 1.3Specific gravity (g/cm3) 3.15 2.31 2.22 2.62 2.98Specific surface (cm2/g) 3520 3960 1865

012680 5350

Physical and chemical properties of cement, fly ash, silica fume, GGBS and metakaolin

(Source: Shi-cong Kou et al. (2011))

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9 SPECIMEN PREPARATION AND CURING

Three series of concrete mixtures were prepared in the laboratory using a Pan mixer

SF, MK, FA and GGBS were used as cement replacements on a weight basis

A constant water/binder ratio at 0.50 was used Series I concrete mixtures used natural aggregate

as the coarse aggregate C (control, natural aggregate with 100% OPC),

C-SF10 (natural aggregate with 10% SF),C-MK15,C-FA35,C-GGBS55

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10 Contd…….

In Series II mixes, recycled aggregates were used to replace 50% of natural coarse aggregate

R50,R50-SF10,R50-MK15,R50-FA35,R50-GGBS55

In Series III mixes, recycled aggregates were used to replace 100% of natural coarse aggregate

R100,R100-SF10,R100-MK15,R100-FA35,R100-GGBS55

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11

Constitution (kg/m3)

Composite of binder

Sand

Series I Series II Series III

Water Cement Mineral admixtures

Coarse natural agg.

Coarse natural agg.

Coarse recycled agg.

Coarse recycled agg.

Control 195 390 0 678 1107 527 539 1078

SF10 195 351 39 664 1107 527 539 1078

MK15 195 331.5 58.5 669 1107 527 539 1078

FA35 195 253.5 136.5 640 1107 527 539 1078

GGBS55 195 175.5 214.5 658 1107 527 539 1078

Concrete mix proportion

(Source: Shi-cong Kou et al. (2011))

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12 Contd……. Workability measured using the slump cone test Concrete cubes of size 100 mm casted for

determining compressive strength 100mm x 200mm concrete cylinders casted to

determine the tensile splitting strength 100mm x 50mm concrete cylinders casted to

determine the chloride ion penetration 75mm x 75mm x 285mm prisms were casted for

determining drying shrinkage

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13 RESULTS

Slump of concrete mixtures

Slump value

(Source: Shi-cong Kou et al. (2011))

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14 Compressive strength

Development of compressive strength of concrete mixtures in Series I

C-FA35 : 66.2%C-GGBS55 : 66.5%C-SF10 : 41.7%C-MK15 : 43.3%

Compressive strength gain

(Source: Shi-cong Kou et al. (2011))

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15 Compressive strength

Development of compressive strength of concrete mixtures in Series II

RA50-FA35 : 68.6%RA50-GGBS55 : 67.2%RA50-SF10 : 49.8%RA50-MK15 : 52.2%

Compressive strength gain

(Source: Shi-cong Kou et al. (2011))

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16 Compressive strength

Development of compressive strength of concrete mixtures in Series III

RA-FA35 : 70.9%RA-GGBS55 : 69.1%RA-SF10 : 55.7%RA-MK15 : 56.8%

Compressive strength gain

(Source: Shi-cong Kou et al. (2011))

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17 Tensile strength

Tensile splitting strength of concrete mixturesTensile strength gain

C:17.2%,C-SF10:23.1,C-MK15:26.4,C-FA35:35.3,C-GGBS55:33

R50:23.9%,R50-SF10:34.9,R50-MK15:36.9,R50-FA35:40.5,R50-GGBS55:38.8

R100:24.6%,R100-SF10:46.2,R100-MK15:40.8,R100-FA35:48,R100-GGBS55:44.9

(Source: Shi-cong Kou et al. (2011))

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18 Drying shrinkage

Drying shrinkage of concrete mixtures at 112 days(Source: Shi-cong Kou et al. (2011))

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19 Chloride ion penetration The total charge passed increased with the use of RA.

Total charge passed in coulombs of concrete mixtures

(Source: Shi-cong Kou et al. (2011))

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20 DISCUSSION The compressive strength of RAC was lower than

that of the control specimen, but could be compensated by the use of 10% SF or 15% MK

However 35% FA or 55% GGBS lowered the compressive strength

The tensile strength of natural and RAC made with SF and MK was higher than that of the corresponding control concrete at all test ages

FA and GGBS decreased the tensile strength

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21 Contd……. The drying shrinkage values of the natural and RAC

made with SF and MK was higher than that of control

The chloride ion penetration test indicated that the concrete containing recycled aggregate had a more open pore structure, compared to the control concrete

The test results show that SF and MK can improve both strength and durability properties of RAC

FA and GGBS significantly improved the durability performance of the recycled aggregate concrete

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22 CASE STUDY-2

“Experimental analysis of properties of recycled coarse aggregate (RCA) concrete with mineral additives”

Ö. Çakır (2014) observed compressive strength and splitting tensile strength of GRAC prepared with incorporation of SF and GGBFS

The RAC was prepared by using 5%, 10% of SF and 30% ,60% of GGBFS whereas coarse aggregates were replaced with 50% and 100% of RCA

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23 MATERIALS USED

Portland cement (PC) Silica fume (SF) Ground granulated blast slag (GGBS) Natural fine aggregate Recycled coarse aggregate

GGBS

Recycled concrete material

Silica fume

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24 SPECIMEN PREPARATION AND CURING

Three series of concrete mixtures were prepared in the laboratory using a Pan mixer

SF, GGBFS were used as cement replacements on a weight basis

A constant water/binder ratio at 0.50 was used Series I concrete mixtures used natural aggregate

as the coarse aggregate NA (control, natural aggregate with 100%

OPC), NA-SF5 (natural aggregate with 5% SF),NA-SF10,NA-GGBS30,NA-GGBS60

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25 Contd……. In Series II mixes, recycled aggregates were used to

replace 50% of natural coarse aggregate RA50,RA50-SF5,R50-SF10,RA50-GGBS30,RA50

GGBS60 In Series III mixes, recycled aggregates were used to

replace 100% of natural coarse aggregate RA100,RA100-SF5,RA100-SF10,RA100

GGBS30,RA100-GGBS60 100mm x 200mm concrete cylinders casted to determine

the tensile splitting strength 150 mm concrete cubes casted for the determination of the

compressive strength

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26RESULTS

Notation Compressive strength(Mpa) Splitting tensile strength(Mpa)

NA 42.40 3.30NA-SF5 42.90 3.30NA-SF10 46.10 3.50NA-GGBS30 34.50 3.20NA-GGBS60 32.10 3.20RA50 34.70 3.20RA50-SF5 35.50 3.30RA50-SF10 35.80 3.30RA50-GGBS30 30.10 2.90RA50-GGBS60 26.60 2.70RA100 32.10 3.00RA100-SF5 32.00 3.20RA100-SF10 35.60 3.30RA100-GGBS30 25.30 2.60RA100-GGBS60 21.90 2.50

Compressive and splitting tensile strength at 28 day

(Source: Ö. Çakır (2014))

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27 DISCUSSION

The compressive strength of the GRAC gradually decreases as the amount of RCA increases.

At 100% of the replacement level, the compressive strength decreases about 24% at 28 days. At over 50% of the replacement level, the strength reduction is more significant.

GRAC containing 5% and 10% SF increases the compressive strength. However, the use of 30% and 60% GGBFS lowered the compressive strength.

GRAC containing 5% and 10% SF increases the tensile strength. However, the use of 30% and 60% GGBFS lowered the tensile strength.

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28 Examples of Structural Application of GRAC

BRE Office Building

Enter prise park

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29 CONCLUDING REMARKS SF and MK improve both strength and durability properties

of green recycled aggregate concrete. Use of FA and GGBS improved the durability performance

of the recycled aggregate concrete. Stricter quality control of recycled concrete aggregate is

required. The resistance to chloride penetration decreases as the

percentage of recycled aggregate in concrete increases. Use of mineral admixtures enhances the resistance to

chloride attack .

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30 Contd……. Mineral admixtures contribute more to the strength

properties RAC than that of natural aggregate concrete.

In GRAC, it was finally concluded that the recycled aggregates may be used up to 50% and silica fume may be used up to 10% for obtaining best results.

Overall economy of GRAC is comparable with that of natural aggregate concrete.

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31 REFERENCES Kou S.C, Poon C.S, Agrela F (2011), “Comparisons of natural and

recycled aggregates concretes prepared with the addition of different mineral admixtures.” Cement and Concrete Composites, Vol. 33, pp. 788-795.

Ö. Çakır (2014), “Experimental analysis of properties of recycled coarse aggregate (RCA) concrete with mineral additives.” Construction and Building Materials Vol. 68, pp 17–25.

Marinkovic´ S, Radonjanin V, Malešev M, Ignjatovic´ I (2010), “Comparative environmental assessment of natural and recycled aggregate concrete.” Waste Manage Vol. 30, pp 2255–2264.

Radonjanin V, Malesev M, Marinkovic S, Al Malty A.E.S (2013), “Green recycled aggregate concrete.” Construction and Building Materials Vol. 47, pp 1503-1511.

Corinaldesi V, Moriconi G. (2009), “Influence of mineral additions on the performance of 100% recycled aggregate concrete.” Constr Build Mater Vol. 23, pp 2869–2876.

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THANK YOU FOR YOUR KIND ATTENTION!!!

Any Questions???