Abstract
This research investigates the effect of using recycled concrete aggregate (RCA) as a partial replacement of natural aggregate (NA) on the mechanical and durability-related properties of a cement-stabilized recycled concrete aggregate (CSR) mixture. In this case, mixtures were prepared with 0%, 40%, 70%, and 100% (by weight) RCA to replace NA, and cement contents of 4%, 5%, and 6% were used in this study. Test parameters included the replacement ratio, cement content, and curing time. Tests were carried out to establish the unconfined compressive strength (UCS), indirect tensile strength (ITS), drying shrinkage, and water loss ratio of each mix proportion. The preliminary results of UCS and ITS tests indicated that the incorporation of RCA resulted in a decrease of strength compared with a cement-stabilized macadam (CSM) mixture, but the seven-day strength of the CSR mixture met the related requirements of road bases. The increase in cement content and curing time had an obvious effect on strength improvement. The drying shrinkage test showed that the drying shrinkage properties of the CSR mixture were obviously reduced with a high replacement ratio. It is evident that the CSM mixture presented a better drying shrinkage performance than that of the CSR mixture.
Highlights
Semi-rigid bases are widely used in highway bases and sub-base systems due to their higher strength, greater rigidity, better uniformity, and water stability [1]
Road construction has a high demand of aggregates, it would be profitable to use waste concrete to manufacture recycled aggregate and apply it in a cement-stabilized macadam (CSM) mixture, which can be an effective way to significantly alleviate the shortage of natural aggregate resources while contributing to minimizing environmental burdens caused by the disposal of waste concrete and energy consumption
The purpose of this paper is to systematically evaluate the performance of CSR mixtures incorporated with a different replacement ratio and cement content under various curing times from the aspect of strength and shrinkage; results are compared with those of a CSM mixture
Summary
Semi-rigid bases are widely used in highway bases and sub-base systems due to their higher strength, greater rigidity, better uniformity, and water stability [1]. Road construction has a high demand of aggregates, it would be profitable to use waste concrete to manufacture recycled aggregate and apply it in a CSM mixture, which can be an effective way to significantly alleviate the shortage of natural aggregate resources while contributing to minimizing environmental burdens caused by the disposal of waste concrete and energy consumption. A literature review indicated that the research on variables that affect RCA pavement performance mainly focused on discussing the influence of either replacement ratio [18,19,20,21] or particle size [22,23] By analyzing their experiment results, it was found that the compressive strength of RACs is lower than that of parent concrete. This paper could be helpful in providing a theoretical foundation and reference for the design and performance assessment of CSR mixtures
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