Performance of Ternary Binder Blend Containing Cement, Waste Gypsum Wall Boards and Blast Furnace Slag in CLSM

Abstract

Controlled low strength materials (CLSM), is a self-flowing cementitious backfill material, most suitable for sustainability objectives since it makes use of wastes in large quantities. Wasted gypsum wall boards (drywalls), a construction & demolition waste, are known to pollute atmosphere by releasing harmful H₂S gas when dumped at landfills. Use of waste drywalls with flyash, as cement replacement in concrete and CLSM, have resulted in low strength mixes at initial & later ages, respectively. In this paper powdered drywalls with ground granulated blast furnace slag (GGBS), was used as secondary cementitious material along with stone dust as fine aggregates, to produce sustainable CLSM mixtures with varying binder ratios and water contents. Reduction in compressive strength at later ages was not observed for mixes with low water contents, hence use of GGBS instead of flyash with lesser water contents, is effective in resisting detrimental effects of sulfates present in drywalls.