Fine limestone dust from ornamental stone factories: A potential filler for a high-performance cementitious matrix

Abstract

The benefits of using waste materials as supplementary cementitious materials (ASCMs) become greater as their use will minimize the chemical, biological and even visual pollutions caused when they are left in an unexploited form. For example, the estimated amount of industrial fine limestone dust (FLSD) released from ornamental stone factories is enormous. Accordingly, efficient recycling of these types of dusts in concrete provides many ecological and economic advantages. FLSD particles were found to have a spherical morphology due to the grinding and polishing steps used in the factories causing their emission. In this research, FLSD has been incorporated into different cement pastes. These pastes contained different replacement levels of 0, 15, 30 and 45% FLSD at various water-to-binder (W/B) ratios of 0.25, 0.35 and 0.45. They have been subjected to the effect of normal and sulfate attack conditions. The results showed that the paste mixture with a high FLSD replacement level did not demand for higher superplasticizer dosage in contrary to other types of dusts while gaining a high resistance to sulfate exposure. It has also been shown that the mixtures with 45% FLSD had the minimum deterioration due to sulfate effect. In addition, at a low W/B ratio of 0.25, the resistance to sulfate attack was significant, as confirmed using ultrasonic pulse velocity (UPV) and microstructure analyses. The mixture with W/B ratio of 0.25 and 45% FLSD has been deemed the optimum for the use in formulating high performance concrete. FLSD is proposed as a fine material with a high potential as a filler for HPC.