Effects of fines in quarry dust on properties of mortar and concrete

Abstract

Quarry dust (QD) is being extensively used as fine aggregates for both mortar and concrete applications as an alternative to river sand. Because of the limited availability of river sand, it is necessary to search for alternatives and QD has been identified as one of the preferred options. The differences in chemical and physical properties of river sand and QD are significant enough to behave differently in their applications. One of the noticeable physical differences is the possession of fines in different quantities in QD and river sand. Particles smaller than 75 pm are considered as fines. Sieve and hydrometer analysis were carried out to find particle size distribution and fines content, respectively. Effects of fines on properties of mortar such as compressive strength, workability, tensile strength, drying shrinkage and sorptivity were evaluated. Mix proportion of 1:3 cement: fine aggregate was selected with fixed water cement ratio of 0.7. Quarry dust with different fines contents (i.e. 0%, 5%, 10%, 15% and 25%) and river sand were considered in this study. This investigation also extended to concrete properties such as workability, compressive strength and tensile strength for 0%, 5% fines content with river sand. Particle size distribution showed that QD contains excessive amount of fines. Overall the results showed that complete removal of UF would be a better option than using it without any modification.