Effects of Coal Metakaolin on Compressive Strength and Microstructure of Cemented Soil

Abstract

In this paper, compressive strength tests are conducted on the cemented soil with five coal metakaolin (CMK) contents to study the effects of CMK on the cemented soil compressive strength and microstructure. It is found that CMK can enhance the strength of cemented soil. Especially, when the CMK content is 3%, its compressive strength is obviously higher than that of unmixed CMK cemented soil. The effects of CMK on the strength of cemented soil is analyzed and discussed by means of X-ray diffraction (XRD) and scanning electron microscopy image (SEM) analysis. The strength mechanism of cemented soil with CMK is explained by the analysis of hydration products and microstructures of cemented soil. The reason for the macroscopic mechanical property change of cemented soil is proved by the microscopic mechanism. In addition, the relationship of cemented soil compressive strength and age is statistically analyzed. The statistical formula is set up to predict the long-term compressive strength of cemented soil by age. The predicted strength agrees well with the measured strength, indicating that the statistical formula has good predictability.