Characterization of Mechanical Properties of Waste Slurry Modified by Recycled Sand and Cement

Abstract

In order to study the modification effect of recycled sand on cement reinforced waste slurry (CWS), triaxial test, scanning electron microscope test and X-ray diffraction test were carried out. The mechanical test of recycled sand and cement reinforced waste slurry (RCWS) shows that the deviatoric stress-strain curve of RCWS samples changes from hardening type to softening type with the increase of recycled sand content; the peak stress increases with the increase of recycled sand content; recycled sand can enhance the shear strength of CWS by increasing both cohesion and internal friction angle. The microscopic test shows that recycled sand can improve the structural compactness by cementing with hydrated calcium silicate and can reduce the void ratio and orientation index of RCWS samples. Finally, the mathematical model between shear strength parameters and void ratio is established. The research shows that adding an appropriate amount of recycled sand and cement has a good modification effect on waste slurry. This is an effective method to treat two kinds of construction wastes: construction waste slurry and waste concrete.

Shear Behavior of Recycled Fine Aggregate Reinforced by Nano-MgO Modified Cement

“…The main chemical components of recycled fine aggregate are SiO 2 and CaCO 3 . The cement used in the test was PO32.5 ordinary Portland cement, and the basic physical properties are shown in Table 2 , which was sourced from the research of Lv et al [ 21 ]. The nano-MgO used in the test was produced by Shanghai Macklin Biochemical Co., Ltd. (Shanghai, China), model M813080, and was obtained in the form of white powder.…”