Material performance evaluation of recycled construction and demolition waste as aggregate alternative of precast piles in soft soil treatment

Abstract

In this paper, the performance and feasibility of recycled construction and demolition waste (C&DW) using as aggregates of precast concrete piles in soft soil treatment scenario are evaluated. Firstly, the compressive strength, splitting tensile strength, elastic modulus and slump of recycled aggregate concrete (RAC) with different replacement rates of C&DW aggregates are studied at different water-cement ratios (w/c). Then, the durability of C&DW concrete piles is evaluated by the compressive strength, splitting tensile strength and mass changes with the time of RAC standard specimens respectively immersed in clean water, sulfate and fulvic acid solutions simulating different attack environments of soft soil foundation. Based on the experimental results, a Recurrent Neural Network (RNN) prediction model optimized by Particle Swarm Optimization (PSO) was developed. Its accuracy was subsequently verified by compared with that of Long Short-Term Memory (LSTM) neural networks and Support Vector Machine (SVM) algorithms, and the corresponding testing set. The deterioration mechanism is further investigated using scanning electron microscopy (SEM). The results show that the C&DW piles can meet the basic material performance requirements of precast concrete piles in the soft soil treatment, which extends the application range of C&DW and has significant potential of economic and environmental benefits.