A Study on the Durability of Solidification Materials Based on Multi-Source Solid Waste Using Recycled Aggregates in Chemical Environments

Against the backdrop of global green and low-carbon development, recycling industrial solid waste for building-material applications attracts increasing attention. In this work, a composite solidifier (SGPC) was prepared using soda residue (SR), ground-granulated blast-furnace slag (GGBS), phosphogypsum (PG) and Portland cement. Fluidized solidified soil was produced by incorporating 15% recycled concrete aggregate (RCA). Chemical-erosion tests including strong-acid, strong-alkaline and neutral-sulfate corrosion were carried out. Mass-loss-rate and unconfined-compressive-strength-loss-rate measurements at different exposure ages, combined with X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterisation, were adopted to investigate the macroscopic durability, hydration-product phases and microstructural features of RCA-modified solidified soil. The test results show that under acid corrosion, the 120 d strength-loss rate decreases from 19.86% (RCA-free group) to 9.02% for specimens containing 15% RCA. Under alkaline corrosion, the 120-d mass-loss rate of the RCA-modified group reaches only 0.33%, much lower than 1.46% of the group without RCA. Under sulfate corrosion, the 120-d strength-loss rate drops from 5.65% to 2.02% after RCA addition. This work provides experimental data and theoretical support for the joint utilisation of multi-source solid waste and recycled aggregates in soil-solidification engineering.