Abstract

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Title:: Long-term Strength, Shrinkage and Creep Properties of Recycled Aggregate Concrete

Author(s):: XIAO Jian-zhuang; ZHENG Shi-tong; WANG Jing; Department of Building Engineering, Tongji University

Keywords:: recycled aggregate concrete; air-entraining agent; mineral admixture; long-term strength; shrinkage and creep; fitted curve

Abstract:: The effects of the recycled coarse aggregate（RCA）replacement ratio and air-entraining agent on cube compressive strength and shrinkage of recycled aggregate concrete(RAC) were experimentally investigated. The creep of RAC with 50% RCA replacement ratio was also studied by varying the loading time. Meanwhile, the calculation formula for the compressive strength of RAC at various ages was established. The experimental results reveal that the longterm strength increasing rule of RAC is similar to that of natural aggregate concrete. The cube compressive strength of RAC at 28 d reduces whereas the shrinkage increases with the increase of RCA replacement ratio. In addition, adding reasonable amount of slag and fly ash can reduce the shrinkage of RAC. The loading time has an effect on the creep of RAC as the creep is greater when the specimens are loaded at an earlier age. The compressive strength values calculated by the proposed formula are in good agreement with the experiment results and more accurate than the outcomes deprived from the suggested formula in CEB-FIP Model Code 1990.