Experimental Investigation on Geo-Mechanical Properties of Controlled Low Strength Materials With Recycled and Alternate Components for Cement and Sand

Abstract

Construction industry commonly produces a significant amount of Quarry dust and hollow block powder as a by-product, posing challenges for its disposal due to limited space for storage and its fine nature. Previous studies have explored various avenues for ash reuse, including in cement, bricks, tiles, concrete, soil stabilization, raising ash dikes, backfilling low-lying areas, constructing roads and bridge abutments, and in agricultural applications. However, one less explored area is the reutilization of ash in developing Controlled Low Strength Material (CLSM), also known as flowable fill. CLSM is a self-compacting material consisting of fine aggregates, cement, water, and other recycled materials that flows like a liquid and hardens over time. Traditionally, river sand is the preferred backfill material due to its wide availability and favourable geotechnical properties. However, with the increasing demand and shortage of river sand, there is a need for alternative and cost-effective backfill materials that have minimal adverse effects on the environment, which can be fulfilled by CLSM. Additionally, due to its high flowability and self-compacting properties, CLSM can be used in locations where conventional backfill materials are not easily accessible or where compaction equipment cannot reach. Researchers have successfully developed CLSM using various recycling materials such as fly ash, quarry dust and GGBS. Industrial wastes can effectively partially replace cement and/or sand in CLSM, making it economical and environmentally sustainable. Key properties of CLSM to be evaluated include flowability, hardening time and compressive strength. This study focuses on evaluating different CLSM compositions using GGBS, FA, and BA partially replacing cement and Quarry dust to replace sand through experimental studies on flowability and compressive strength. The study aims to achieve maximum possible cement replacement with three different cementitious pozzolanic materials to make it more sustainable and to understand the effect of reducing cement content in CLSM properties.