Towards sustainable bricks made with fiber-reinforced alkali-activated desulfurization slag mortars incorporating carbonated basic oxygen furnace aggregates

Abstract

This study examines the development of bricks made with fiber-reinforced alkali-activated desulfurization slag based mortars (AADS) with carbonated basic oxygen furnace (BOF) slag aggregates. This paper was executed in stages, including: 1) parametrical assessment was conducted to identify the impacts of alkali properties and the content of carbonated BOF aggregates on compressive and flexural strengths and efflorescence; 2) different fiber types (polyvinyl alcohol, basalt, polypropylene, and cellulose), and contents were added to improve the mechanical and durability (water absorption by immersion and capillary action, carbonation resistance, and high temperature) properties, and reduce both efflorescence and drying shrinkage; and 3) an environmental analysis was conducted to correlate global warming potential with the mechanical strength and to indicate the participation of each mix ingredient in carbon dioxide emissions into the atmosphere. The results showed that increasing both molarity of sodium hydroxide and the ratio of carbonated BOF aggregates to binder (desulfurization slag) above 8 M and 3, respectively, degraded the mechanical strength and intensified the efflorescence in the plain AADS. The addition of basalt and cellulose fibers increased the mechanical strength and reduced the efflorescence in AADS. Moreover, it was found that using basalt fibers produced better performance than cellulose fibers in minimizing the drying shrinkage and strength loss in carbonation, while adding cellulose fibers had a greater impact on increasing the mechanical strength.