e recycling of construction waste slurry is an urgent issue that needs to be solved in urban construction. To satisfy the requirements of subgrade filling, mechanical properties of fiber/cement-modified slurry were investigated. Unconfined compression tests were conducted for 7-day-cured specimens with a cement content of 5%, 10%, 15%, 20%, 25%, and 30%, respectively. Moreover, the effects of fiber contents (0.25%, 0.5%, 0.75%, and 1%, respectively) were also investigated for the specimens with a cement content of 20%. A formula satisfying the accuracy requirement was obtained by fitting the stress-strain curves using the back propagation (BP) neural network algorithm. Five parameters, including peak strength, failure strain, initial elastic modulus, residual strength, and energy dissipation, were used to characterize the short-term strength properties of fiber/cement-modified slurry. e analysis revealed that the cement content had a dominant effect on the short-term strength properties of fiber/cementmodified slurry, while the influence of fiber content was insignificant.
A certain amount of ferroaluminate cement (FAC) was substituted for MgO during the magnesium phosphate cement (MPC) preparation to obtain the MPC–FAC composite cement. The influence of FAC on the strength, water resistance, pH, and setting time of MPC–FAC composite cement were examined. The microstructure and chemical composition were also analyzed by adopting scanning electron microscopic energy-dispersive spectrometer and X-ray diffraction, respectively. The study showed that setting time of MPC–FAC composite cement was dramatically prolonged when FAC substitution for MgO was between 30 and 40 wt %. The strength of MPC–FAC did not decrease during the early curing time (1 h and 1 d), whereas it increased during the late curing time (3, 7, and 28 days). Moreover, the existence of FAC decreased the hydrated product K-struvite during the early curing time and thus dramatically enhanced the water-resistance of MPC–FAC. With the addition of FAC, a large number of cementitious materials of AFt and AFm, as well as flocculent colloidal substances of AH3, C–S–H, and FH3, were generated during the hydration of MPC, which were filled in the internal pore of the hydrate. Thus, the internal compactness of the sample increased, while the compact protective covering layer was generated on the surface to enhance the water resistance and strength in the late curing time.
Lime stabilization has been widely used in pavement subbases and ground improvement, but the investigation of the mechanical properties and the microstructure of lime stabilized loess is still insufficient.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.