Comparative study of self compacting concrete using recycled coarse aggregate.

Comparative study of self compacting concrete using recycled coarse aggregate. Types of recycled coarse aggregate. Concrete Mix Design. Segregation resistance. Concrete strength evaluation. Shrinkage

1. Comparative Study of Self Compacting Concrete using Recycled Coarse Aggregate Group Members: Salman Ali Jawwad Naeem Bhatti Asim Sultan Sarmad Rashid 1 Project Supervisor: Prof. Dr-Ing Syed Ali Rizwan

2. Problem Statement The growth in construction industry poses a looming and inevitable threat of scarcity of natural sources of aggregate. Furthermore construction wastes occupy about 25 of space in landfills. 2 Research Objective To recommend the use of recycled coarse aggregate in production of structural concrete by a comparative study of SCC Systems using recycled coarse aggregate with natural coarse aggregate. Recycling of Construction Waste

3. Why RCA? Sustainability: Conservation of Energy Environmental Protection Preservation of resources Land saving Reducing Carbon footprint 3 Recycled Coarse Aggregate is the aggregate containing the original aggregate and residual cement mortar adhered to its surface. It has lower density and higher porosity. It has lower specific gravity and higher water absorption . Recycled Coarse Aggregate (RCA) http://ascelibrary.org/cms/attachment/78911/1702527/figure1.gif http://www.business.mmu.ac.uk/seeg/images/images/diagram.png

4. Materials Margalla Crush as Natural Coarse Aggregate Same sourced Recycled Coarse Aggregate extracted by manual crushing of concrete cylinders Lawrencepur Sand as Fine Aggregate Bestway Grade 53 Cement. Glenium ® 51 as superplasticizer 4 Natural Coarse Aggregate Recycled Coarse Aggregate  Glenium ® 51 Acquisition of Recycled Coarse Aggregate

5. Materials: Gradation Natural Coarse Aggregate Recycled Coarse Aggregate Fine Aggregate 5 Gradation of natural coarse aggregate Gradation of recycled coarse aggregate Gradation of fine aggregate

6. Materials: Properties 6 Properties of Cement ASTM Standard Results Water Demand ASTM C187 26.5% Initial Setting Time ASTM C191 170 min Final Setting Time ASTM C191 220 min Specific gravity ASTM C188 3.15 Properties of Coarse Aggregate Standards Natural Coarse Aggregate Recycled Coarse Aggregate Fineness Modulus ASTM C 136 6.47 6.56 Specific gravity (Oven Dried) ASTM C127 2.72 2.44 Specific gravity (SSD) ASTM C127 2.75 2.53 Absorption Capacity ASTM C127 1.10 % 3.81 % Dry Rodded Bulk Density ( Compacted) (Kg/m 3 )   ASTM C29   1476   1419 Porosity ASTM C29 41.73% 47.65% Impact Value BS 812 20.79 % 22.4 % Crushing Value BS 812 23.86 % 25.97 % 10% Fine Value (tons) BS 812 20.1 18.68 Los Angeles Abrasion Value ASTM C 535 15.34 % 20.62 % Properties of Fine Aggregate Standards Fine Aggregates Fineness Modulus ASTM C 136 2.04 Bulk specific gravity ( oven dried) ASTM C128-07a 2.67 Bulk specific gravity (SSD) ASTM C128-07a 2.69 Absorption Capacity ASTM C128-07a 0.81% Dry Rodded Bulk Density (Compacted) Kg/m3   ASTM C29   1596 Percent of Silt and Clay ASTM C117 1.67% Glenium ® 51 Structure of the Material Polycarboxylic ether based Color Amber Density 1.082-1.142 kg/litre Chlorine content % < 0.1 Alkaline content % <3 Properties of Fine Aggregate Properties of Cement Technical data for Glenium ® 51 Properties of Coarse Aggregate All the test for materials were carried out by following the standards in controlled lab conditions of temperature and humidity. Sample Name Bestway G -53 SiO 2 19.19 TiO 0.29 Al 2 O 3 4.97 3.27 MnO 0.04 MgO 2.23 CaO 65.00 Na 2 O 0.58 K 2 O 0.51 P 2 O 5 0.08 LOI 3.84 Fe 2 O 3 XRF of Cement

7. Formulations SCC mix composition were designed in accordance with the guidelines of EFNARC 2005 and ACI 237R-07 . Successful trail mixes satisfying the workability requirements were selected. 7 Concrete Mix Designs Mix Designation SCC System Formulations NCASCC 1:1.58:1.58:0:0.45:1.3% (C1:FA:NCA:RCA:W:S.P ) RCASCC-25 1:1.58:1.20:0.36:0.45:1.6% (C1:FA:NCA:RCA:W:S.P ) RCASCC-50 1:1.58:0.79:0.72:0.45:1.9% (C1:FA:NCA:RCA:W:S.P ) RCASCC-100 1:1.58:0:1.45:0.45:2.2% (C1:FA:NCA:RCA:W:S.P ) % of RCA Mix Designation Cement Kg/m 3 Fine aggregate Kg/m 3 Coarse aggregate Kg/m 3 Water Kg/m 3 SP Kg/m 3 NCA RCA NCASCC 520 820 820 ___ 234 1.3% = 6.76 25 RCASCC-25 520 820 620 186 234 1.6%= 8.32 50 RCASCC-50 520 820 408 374 234 1.9% = 9.88 100 RCASCC-100 520 820 ___ 750 234 2.2 %=11.44 Mixing Regime The four formulations based on different replacement percentages of RCA and superplasticizer demand were studied.   Time   Mixing Regime   1 minute   Dry mixing of constituents at 180 rpm (slow rate ).   2 Minutes   Add 80% of water in the dry constituents and mix again at 180 rpm (Slow Mixing ).   3 Minutes   Add SP and / or Viscosity Enhancing Agent (VEA) in remaining 20% water; mix again thoroughly at 360 rpm (Fast Mixing ). % of RCA Mix Designation Cement Kg/m 3 Fine aggregate Kg/m 3 Coarse aggregate Kg/m 3 Water Kg/m 3 SP Kg/m 3 NCA RCA NCASCC 520 820 820 ___ 234 1.3% = 6.76 25 RCASCC-25 520 820 620 186 234 1.6%= 8.32 50 RCASCC-50 520 820 408 374 234 1.9% = 9.88 100 RCASCC-100 520 820 ___ 750 234 2.2 %=11.44 % of RCA Mix Designation Cement Kg/m 3 Fine aggregate Kg/m 3 Coarse aggregate Kg/m 3 Water Kg/m 3 SP Kg/m 3 NCA RCA NCASCC 520 820 820 ___ 234 1.3% = 6.76 25 RCASCC-25 520 820 620 186 234 1.6%= 8.32 50 RCASCC-50 520 820 408 374 234 1.9% = 9.88 100 RCASCC-100 520 820 ___ 750 234 2.2 %=11.44 % of RCA Mix Designation Cement Kg/m 3 Fine aggregate Kg/m 3 Coarse aggregate Kg/m 3 Water Kg/m 3 SP Kg/m 3 NCA RCA NCASCC 520 820 820 ___ 234 1.3% = 6.76 25 RCASCC-25 520 820 620 186 234 1.6%= 8.32 50 RCASCC-50 520 820 408 374 234 1.9% = 9.88 100 RCASCC-100 520 820 ___ 750 234 2.2 %=11.44 % of RCA Mix Designation Cement Kg/m 3 Fine aggregate Kg/m 3 Coarse aggregate Kg/m 3 Water Kg/m 3 SP Kg/m 3 NCA RCA NCASCC 520 820 820 ___ 234 1.3% = 6.76 25 RCASCC-25 520 820 620 186 234 1.6%= 8.32 50 RCASCC-50 520 820 408 374 234 1.9% = 9.88 100 RCASCC-100 520 820 ___ 750 234 2.2 %=11.44

8. Fresh Properties: Tests Flow test V-funnel test L-Box test J-ring test Sieve Stability test Density and Air Content 8 All the fresh properties tests of Self-Compacting Concrete were performed as per EFNARC 2005 guidelines. Tests were carried out in following sequence. Flow test V-funnel Test L-Box Test J-ring Test Air content Apparatus

9. Fresh Properties: Results All the key fresh properties of self-compacting concrete (filling ability, passing ability and segregation resistance) are satisfactory and within the acceptable limits as per EFNARC 2005 guidelines. Typical acceptance criteria for fresh properties of SCC: 9 Filling ability: Method Unit Typical range of values Minimum Maximum Slump flow by Abrams cone mm 650 800 T50cm slump flow sec 2 5 J-ring mm 10 V-funnel sec 6 12 L-box H2/H1 0.8 1.0 GTM Screen Stability test % 15

10. Passing Ability: 10

11. Segregation Resistance: 11 Correlation among Fresh Properties:

12. Hardened Properties: Tests Following Tests were performed for different formulations to determine the hardened properties of SCC. Cylinders of 100x200 mm 2 for Compressive Strength Test. Beams of 100x100x400 mm 3 for Flexural Strength Test. SCM was prepared by passing freshly mixed SCC through Sieve No.10 (2mm ). Prisms of 40x40x160 mm 3 for Flexural and Compressive Strength Test. 12 Compression testing of Cylinder Flexural testing of SCM Prism Flexural testing of Beam Broken SCM Prism Compression testing of SCM Cubes

13. Strength Evaluation of SCC and SCM systems: 13 T he compressive strength of cylinders and flexural strength of beams for RCASCC-100 is 70% and 85 % of NCASCC respectively.

14. Comparison of SCC with SCM 14 It shows that compressive strength of SCM is higher and increases with the increase in replacement of RCA. Cracking Pattern of Specimens NCASCC-28D RCASCC-100 28D

15. Shrinkage Response of SCM Formulations German classical “Schwindrinne” apparatus measuring 4x6x25 cm at 25-30 ᵒC and RH of 35-40 % was used. Freshly prepared SCC mix passing through 2 mm sieve used for all formulations. Samples kept uncovered for 24 hours in shrinkage apparatus. 15 Shrinkage Apparatus Shrinkage Response vs Time

16. XRD and SEM: NCASCC-7D and RCA SCC-100-7D were selected to observe the microstructure and growth of hydration products. 16 NCASCC-7D RCASCC-100-7D

17. 17 NCASCC-7D RCASCC-100 7D

18. The compressive and flexural strength of SCC are reduced by increasing the replacement percentage of RCA. The maximum decrease in compressive and flexural strength of RCASCC-100 is 30% and 15% of NCASCC respectively. Contrary to SCC, SCM compressive and flexural strength increases with increase in replacement percentage of RCA. The maximum increase in compressive and flexural strength of RCASCC-100 is 12% and 20% of NCASCC respectively. Despite the deterioration of physical properties of RCA as compared to NCA, the fresh and hardened properties of self compacting concrete prepared by using RCA are satisfactory for structural use. 18 Conclusions:

19. Recommendations: The durability properties of the concrete such as (creep, drying shrinkage, sulphate attack, oxygen permeability and resistance to acid attack) should be observed. The hardened properties of recycled coarse aggregate concrete should be observed for greater time periods to ascertain the long-term strength evolution of concrete containing recycled coarse aggregate. SRMs such as fly ash and silica fume can be used to further enhance the properties of SCC prepared from recycled coarse aggregates . 19

20. References: European Guidelines for Self-Compacting Concrete,. s.l. : EFNARC , 2005 . Syed Ali Rizwan. PhD Thesis. (2006). “High Performance Mortars and Concretes using Secondary Raw Materials”. Technischen Universtat Bergakademie Freiberg. Safiuddin , M. D., Salam, M. A., & Jumaat , M. Z. (2011). Effects of recycled concrete aggregate on the fresh properties of self-consolidating concrete.  Archives of Civil and Mechanical Engineering ,  11 (4), 1023-1041. Grdic Z.J., Toplicic-Curcic G.A., Despotovic I.M., Ristic N.S.: Properties of self-compacting concrete prepared with coarse recycled concrete aggregate, Construction and Building Materials, Vol. 24, No. 7, 2010, pp. 1129-1133 . Poon, C. S., Shui , Z. H., & Lam, L. (2004). Effect of microstructure of ITZ on compressive strength of concrete prepared with recycled aggregates.  Construction and Building Materials ,  18 (6), 461-468. 20

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