Stress-strain behavior of low-carbon concrete activated by soda residue-calcium carbide slag under uniaxial and triaxial compression

Abstract

The accumulation of soda residue (SR) and calcium carbide slag (CCS) wastes causes serious environmental pollution, which mitigation requires to expand their resource utilization channels. Based on our developed SR-CCS co-activated binder system (SCB), this study intended to prepare SCB-based concrete (SCBC) with compressive strength of 20–40 MPa. Through uniaxial and triaxial compressive stress-strain experiments, the development law of mechanical properties and deformation of SCBC was revealed, and the uniaxial and triaxial stress-strain relations were established. The results showed that the compressive strength of SCBC increased gradually with confining pressure, but the increment was less than that of ordinary cement concrete (OCC) of the same grade. Under various confining pressures, the stress-strain curve of SCBC had a shorter elastic rising stage, a longer plastic rising stage, and a smaller elastic modulus than OCC. Thus, it had a stronger plastic deformation ability. However, the falling stage was steeper, indicating its poor ductility. The quantitative relationships between compressive strength, peak strain, ultimate strain, elastic modulus, and confining pressure were established, which were in good agreement with the experiment values. The equations of the compression meridian failure criterion in parabolic and power function forms were established for SCBC. Based on the classical stress-strain model, the uniaxial and triaxial stress-strain relationships were established using statistical regression method. The results provided a theoretical basis for promoting the engineering application of SCBC and furnished solutions for reducing environmental pollution by SR and CCS.