Study on Triaxial Mechanical Properties and Micro Mechanism of Fly Ash Reinforced Cement Calcareous Sand

Abstract

In order to study the mechanical properties and micro-mechanism of industrial waste fly ash-reinforced cement calcareous sand (FCS), the triaxial unconsolidated undrained (UU) test and scanning electron microscope tests (SEM) were carried out on it. The results of UU test show that the peak stress and energy dissipation of the FCS sample first increase and then decrease with the increase in fly ash content. Fly ash enhances the cement calcareous sand by increasing both the cohesion and internal friction angle, and adding 10% content of fly ash gives the largest values. The SEM test results shows that the hydration products of cement and fly ash filled the pores and cracks on the surface of the calcareous sand, which increased the compactness and structure of the FCS samples. The porosity of cement calcareous sand can be reduced from 27.6% to 12.8% by adding 10% fly ash. A brittleness evaluation index based on energy dissipation is proposed to quantitatively characterize the brittleness of FCS samples. The results show that when the content of fly ash is 5%, the brittleness of FCS samples is the lowest. This study shows that the mechanical properties of cement calcareous sand can be effectively enhanced by adding the appropriate amount of fly ash.

Experimental Study on the Mechanical Properties of Diatomite-Modified Coastal Cement Soil

“…Cement plays a positive role in engineering seepage prevention and strength reinforcement, but cement production consumes a lot of energy and pollutes the atmosphere. The increase in carbon emissions exacerbates climate change and global warming, and dust pollution has a negative impact on human health [ 7 , 8 , 9 ]. In addition, soft soil after cement solidification usually is strongly alkaline, which easily pollutes groundwater and inhibits plant growth [ 10 , 11 ].…”