Increasing sustainable aggregate usage in concrete by quantifying the shape and gradation of manufactured sand

Abstract

Sustainable fine aggregates are becoming an area of greater discussion. Manufactured sands are materials created by crushing larger aggregates that are not widely used. Interest is growing in the use of manufactured sand in concrete because it provides a way to improve the sustainability of concrete with a decrease in cost. However, manufactured sands typically have different shapes, gradations, and mineralogy in comparison to natural sand. There is concern that these differences can impact the performance of concrete that uses manufactured sands. This work quantifies the shape properties of manufactured sands and natural sands using the AIMS II, microscopic inspection, and the Uncompacted Voids Content (ASTM C1257 -Method A). Next, concrete mixtures are created with different proportions of manufactured sand and the workability is measured. This work provides a correlation between different methods to measure the shape and then relates these measurements to the impact of the workability and finishability of concrete. Adjustments to the Tarantula Curve are also suggested.