Design and Performance Evaluation of Dry-Mixed Cement Recycled Aggregate Pile

Abstract

In this paper, dry-mixed recycled cement concrete gravel (CCG) piles and dry-mixed cement macadam gravel (CMG) piles were analyzed. CCG and CMG were prepared by using recycled concrete aggregate (RCA) with different substitution rates, recycled macadam aggregate (RMA) from waste bricks and tiles, and fly ash, respectively. Mechanical properties, hydration heat release performance, and frost resistance were used as evaluation factors. The compressive strength, hydration heat, relative dynamic elastic modulus, and mass loss rate were tested. Based on the requirements of subgrade reinforcement on the material strength, hydration heat release, and frost resistance of dry-mixed CRA piles, TOPSIS analysis method was used to conduct a comprehensive evaluation. The results show that the mechanical properties and frost resistance of CCG and CMG gradually deteriorate with the increase of RCA and RMA replacement rates. At the same time, the hydration heat release of CCG and CMG increases with the increase of the replacement rate. The fly ash instead of cement can improve the compressive strength and frost resistance of CCG and CMG and reduce the hydration heat and material cost. When the CCG replacement rate reaches 20%, the CCG composite score of 20% fly ash is higher than that of traditional dry-mixed cement gravel pile and has better comprehensive performance.