Filler technology of adding granite dust to reduce cement content and increase strength of mortar

Abstract

A large quantity of granite dust (GD) is being generated from the stoneware industry as waste to be disposed. GD is as fine as cement but is chemically inert, and thus its addition to concrete as cement replacement would increase the water/cement (W/C) ratio and reduce the strength. However, its addition as a filler to improve the packing density of the aggregate could reduce the cement paste volume needed to fill the voids and thus the cement content and carbon footprint. And, at least theoretically, such reduction of the cement paste volume without changing the W/C ratio would not reduce the strength. In this study, this prospective filler technology of adding GD to concrete for waste utilization and carbon footprint reduction was explored. A number of mortar mixes with different amounts of GD added either as cement replacement or as a filler to fill voids were produced for testing. The results showed that the filler technology is much better than the cement replacement method for waste utilization and cement content reduction, and in fact would also improve the strength and microstructure of the mortar produced.