Experimental Study on the Strength and Stress–Strain Properties of Waste Concrete Fine Aggregate and Cement-Solidified Sludge.

In this study, waste concrete fine aggregates and cement are applied to sludge solidification and resource recycling. The unconfined compressive strength (UCS) test is performed to investigate the variation in the strength and stress–strain properties of the solidified sludge with the content and particle size of waste concrete fine aggregate, cement content, and curing time. The results show that incorporating waste concrete fine aggregates can improve the UCS of cement-solidified sludge, which can achieve the optimum effect when the fine aggregate content ranges from 12% to 15%. However, compared with the fine aggregate content, the cement content and curing time are the main factors in improving the strength of waste concrete fine aggregate and cement-solidified sludge (WCSS). The stress–strain curves of WCSS comprise four stages. The failure strain ε_f of WCSS with four fine aggregate contents decreases in a power function with the increase in q_u, and ε_f is mostly distributed when the content is 1.1–2.1%. A linear relationship is observed between E₅₀ and q_u. This study attempts to promote the recycling of waste concrete fine aggregates and obtain solidified sludge with excellent mechanical properties, providing some reference for practical engineering applications. [ABSTRACT FROM AUTHOR]