Production of cement-free construction blocks from industry wastes

Abstract

This study explores the possibility of making carbon-negative and cement-free construction blocks using steel slag as sole binder and blast furnace slag as lightweight aggregates through carbonation activation. Both steel slag and blast furnace slag are by-products of steel making process. The goal of the study is to develop a clean production that can utilize slag and carbon dioxide to produce environment friendly construction products. Carbonation activation was implemented during the curing of the blocks to accelerate early strength gain. The physical and durability of slag-bond concrete blocks were examined through their density, water absorption, compressive strength and freeze and thaw resistance. An economic analysis was performed and a carbon balance was computed to evaluate the feasibility of making carbon-negative and economically-competitive slag-bond blocks. This study demonstrates that the proposed process consumes no natural resources, produces no wastes, is capable for carbon sequestration and is a clean production. The slag-bond concrete block is a carbon-negative product. In addition, slag-bond concrete block exhibited better mechanical and durability properties compared to the commercial cement block. The cost analysis suggests that slag-bond concrete blocks can be made at a lower cost compared to the commercial cement block if they are mass produced.