Crushed rock dust as filler material in concrete

Abstract

Abstract In India, it is estimated that out of 125 million tones (Mt) of stone aggregate produced every year, 17.8 Mt is crushed rock dust (CRD) which is presently used for land filling causing environmental problems such as loss of fertility of soil. This paper deals with the use of CRD as filler material in producing concrete. Cement is replaced with five percentages (C30-0%, C31-10%, C32-20%, C33-30% and C34-40%) of CRD by weight. Dynamic elastic modulus (Ed) Workability, density, flexural strength, compressive strength and ultrasonic pulse velocity (UPV) are experimentally investigated. Additionally, Scanning Electron Microscope (SEM) analysis is done on C30 and CRD concrete, to observe the internal microstructure of concrete. From the results, it is seen that, workability of CRD and C30 concrete decreased with increase of CRD in concrete. Up to 20% CRD in concrete, no significant difference is observed on compressive strength. Flexural strength is improved for all the CRD replacement levels in concrete. Relations between compressive strength, UPV and Ed are presented. The use of CRD by up to 20% of cement showed the best performance than C30 and is supported by SEM analysis. The use of CRD by up to 20% by CRD reduces cement usage and thereby mitigating global warming.