Abstract

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Title:: Experiment on Effect of Several Measures by Modifying Recycled Coarse Aggregate on Improving Compressive Strength of Concrete

Author(s):: WANG Jiang-hao; GENG Ou; LI Fu-min; Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering, China University of Mining and Technology

Keywords:: waste concrete; recycled coarse aggregate; modification; compressive strength

Abstract:: In order to compare the effect of several measures by modifying recycled coarse aggregate on improving compressive strength of concrete, the HCl solution with different concentrations, H₂C₂O₄ solution with concentration of 8%, waterproofing mortar solution with concentration of 25% and PVA solution with concentration of 2% were used to treat the recycled coarse aggregate samples by chemical immersion or physical filling, respectively. By using the treated recycled coarse aggregate，some cubic concrete samples with the dimension of 100 mm×100 mm×100 mm were fabricated for testing the compressive strength. The results show that different treatments may achieve an increase in the compressive strength of the mixed concrete to some different extents. Comparing with the untreated recycled coarse aggregate, the aggregates treated respectively with the above-mentioned HCl solution with concentration of 2% (closing to the best effect), H₂C₂O₄ solution with concentration of 8%, waterproofing mortar solution with concentration of 25%, and PVA solution with concentration of 2% contribute to an increase in the compressive strength of the mixed concrete for 11.84%, 7%, 4.37% and 11.31%, respectively. The increased compressive strength achieves a good level as high as 96.63%, 92.44%, 90.18% and 96.17% of the concrete mixed with the natural coarse aggregate, which has the same grain composition with the recycled coarse aggregate.