Influence of basalt and hashma industrial waste powder on characteristics of self-compacting concrete

The stone industry generates huge amounts of solid waste powders causing serious several environmental problems. Disposing of these wastes safely requires a large cost. Exploiting and getting rid of them has become essential. This research investigates the impact of incorporating basalt industrial waste powder (BS) as a partial substitute for cement, as well as waste powder from hashma (HM) stone industry as a partial substitute for sand on fresh, mechanical, permeation characteristics of self-compacting concrete (SCC). In addition, the microstructure of the concrete using SEM, XRD and BET has been investigated. Furthermore, environmental and economic studies were conducted. Fresh properties of mixes were measured by slump flow, 𝑇50, V-funnel and J-ring tests. To measure mechanical properties of SCC were compressive strength, splitting tensile and ultra-sonic pulse velocity. BS was replaced cement by 5, 10, 15 and 20% and/or HM was replaced sand by same ratios. The result showed that BS decreases the fresh properties and use of HM required high dosages from chemical admixture to achieve SCC requirements. Compressive strength improved by incorporating BS with 5% optimum replacement ratio. However, incorporating HM significantly improves compressive strength with increasing replacement ratio. Maximum improved compressive strength reached 17% higher than control mix (without waste powders) by incorporating BS as cement with 30% HM as sand (mix B5H30). Sorptivity decreased by 20, 21 and 30% while, UPV increased by 9, 13 and 17% for mix containing 5%BS, 30%HM and (5%BS+30%HM) respectively.