A strength-based mix design method for recycled aggregate concrete and consequent durability performance

摘要

This paper puts forward a strength-based mix design method for recycled aggregate concrete using a modified empirical formula. A total of 30 mixes, the amount of cement varies from 300 kg/m(3) to 500 kg/m(3) and the proportion of recycled coarse aggregate ranges from 0% to 100%, were prepared for the regression analysis of relationships between multiple parameters. Then for a defined workability and specified value of recycled coarse aggregate replacement ratio, and known natural water absorption of recycled coarse aggregate to be used in a mixture, two mixture design parameters, cement-water ratio and cement content, are generated from the proposed method after determining the water consumption. Moreover, the confirmatory experiments show that the test results of 26 validation mixes, designed strength ranges from 30 MPa to 50 MPa and recycled coarse aggregate replacement ratio varied from 20% to 100%, were in satisfactory agreement with the target compressive strength. Recycled aggregate concrete durability performances corresponding to this method were also evaluated, and results show that the increasing of recycled coarse aggregate, degrades the freeze-thaw resistance, drying shrinkage, chloride penetration and carbonization. (C) 2021 Elsevier Ltd. All rights reserved.