||In view of the steel industry's desire to achieve the goal of circular economy, reducing industrial by-products and recycling is a major factor in sustainable development. Basic oxygen furnace slag (BOFS) is a by-product of smelting steel and has good engineering properties. But when it encounters water, it will cause engineering damage due to its slow expansion, which greatly limits its utilization of resources. At present, most of the applications are for road pavement and filling materials. Therefore, if the BOFS can be properly treated and utilized, the purpose of sustainable use of resources can be achieved.|
In this study, five different weight ratios of BOFS were used to replace natural aggregate respectively. In the cement mortar and concrete mixing time, adding cementitious capillary crystalline waterproofing materials, as a waterproof cement mortar and waterproof concrete. Followed by compressive strength test, water absorption test, fitness test, permeability test, specific length test to explore the conversion rate of BOFS and the applicability of waterproofing agent, as well as the mechanical properties, physical properties, durability properties, and used SEM and EDS analysis of the test results.
The swelling characteristics of BOFS were mainly observed by the specific length test. The test results showed that the volume stability of the test body increased and the swelling volume decreased significantly with time, indicating that the waterproofing materials had a significant effect on restraining BOFS swelling. Permeability test results show that permeability coefficient of waterproofing concrete significantly reduced, and concrete with 100% replacement of BOFS is even nearly impermeable. Finally, crystallization of waterproof agent containing cement mortar and concrete was observed using SEM, and found a lot of dense dendritic crystals. The mechanism of chemical reaction of hard crystalline material filled pores, blocking the infiltration path, resulting in increased compactness and durability of concrete.
The BOFS is wrapped by the waterproofing materials, thereby preventing water from contacting the BOFS and exerting the effect of stabilizing the volume change. The results of this study can be applied to the waterproof engineering effectively, and the application of the BOFS to the waterproof engineering is a useful material to be used. It can achieve the goal of high price and resource of byproducts, and meet the ultimate goal of sustainable development.