Assessment of strength development in cemented coastal silt admixed granite powder

Abstract

The harmless treatment and even the effective reuse of wasted rock powders have become immediate tasks for multiple stone fabricating plants. However, there are poor techniques at present used to dispose of wasted rock powders properly and scientifically. In this paper, the concept of cemented coastal silt admixed granite powder (CCSAGP) was developed to address the recycling of granite powder as well as to improve the strength of cemented coastal silt. The granite powder, as an admixture, was first admixed into the cemented coastal silt, and the development of strength in CCSAGP specimens was assessed experimentally. This paper focuses on the roles of granite powder content, cement content, type of cement, and curing time in the development of strength in CCSAGP specimens. The results obtained show that the unconfined compressive strength of the CCSAGP specimens increases generally with an increase in granite powder content, cement content, and curing time. The inclusion of 10%-20% granite powder into the cemented coastal silt is clearly conducive to the development of strength in CCSAGP specimens, but the development of strength depends upon a number of factors. The role of the type of cement in the strength development of CCSAGP specimens is related to the growth in cementitious products, which demonstrates significant time-dependence. Moreover, scanning electron microscopy (SEM) experiments demonstrate that the microstructural evolution of the CCSAGP specimens exhibits three main effects, namely, a grain gradation effect, a cementation effect and a skeleton effect. Field investigations suggest that the field strength of deep mixing columns with admixing 10%, 15% and 20% granite powder is well enhanced when compared with columns without admixing granite powder.