Microstructural behaviour of quarry fines stabilised with fly ash-based binder

Stabilised quarry fines have been explored as sustainable pavement construction materials. This study investigates the viability of such materials for applications in pavement structures, contributing to current knowledge on mechanical performance from the perspective of mineralogy, microstructure, and chemical composition of the material. This study uses fly ash-based material as stabiliser, promoting circular economy considering the availability of fly ash worldwide by 2030. Laboratory tests were performed including unconfined compressive strength (UCS), mineralogical analysis, and microstructure investigations by scanning electronic microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). Using different binders, Calcium was found to be the element with most variability in mass, and the UCS increased proportionally as the ratio of CaO/SiO2 or CaO/(SiO2+Al2O2) increased. As curing time accumulates to 28 days, more cementitious reaction products were generated and observed, and the void to solid ratio reduced in some samples, possibly leading to improvements in the UCS.

Automated summary

This study investigates the viability of stabilised quarry fines for pavement applications, focusing on the mechanical performance of the materials from mineralogy, microstructure, and chemical composition perspectives. Experimental results show that the element Calcium plays a significant role in the mass variability and increasing the CaO/SiO2 or CaO/(SiO2+Al2O2) ratio leads to improved unconfined compressive strength. Additionally, as curing time increases, more cementitious reaction products are generated, resulting in reduced void to solid ratio and potentially enhancing the unconfined compressive strength.