Use of fly ash and quarry waste for the production of the controlled low strength material

Abstract

This study investigates the potential of utilizing quarry waste and fly ash in the production of controlled low-strength materials (CLSM). Fly ash and quarry waste were mixed in various proportions and the properties of the mix were studied in both fresh and dry states. Cement in low proportions was used as a binder. Flowability, bleeding, density, settlement, air content, pH, and electrical resistivity of the mix was studied in their fresh state. The flowability of the mix was enhanced by the addition of quarry waste. However, incorporating higher amounts of quarry waste caused the mix to exhibit more bleeding, leading to greater settlement. Increasing the concentration of cement was found to mitigate bleeding in the mix. The corrosivity of the mixture was found to be in the permissible limits for use as an excavatable material in utility fills. Unconfined compressive strength, water absorption, density, SEM, and XRF analysis were performed on hardened samples. Unconfined compressive strength tests were performed on the various mix proportions of the samples at 1, 7, 14, and 28 days. The CLSM samples were found to have a low strength of 0.08 to 0.35 MPa at 28 days and hence suitable for use as an excavatable material. SEM analysis revealed that the C-S-H gel was the chief component that contributed to the strength gain of the mixture with time.