Steel-Making By-Products for Cold-Region Infrastructure: Road Abrasive, Geopolymer Paving Brick, Snow Barrier and Mineral Carbonation

Abstract

The main focus of this research work is the valorization of steelmaking byproducts, basic oxygen furnace slag (BOFS) and blast furnace slag (BFS), for a wide range of construction and roadway applications. The study moves beyond simple disposal by engineering these by-products into road abrasives, geopolymer paving bricks, and lightweight snow barriers. Simultaneously, the work characterizes the intrinsic CO₂ sequestration potential of fresh BOFS. Indeed, this research begins by evaluating the efficacy of steel slags as sustainable precursors in cementitious binder systems. To mitigate the inherent volumetric instability caused by the high free lime content in BOFS, a novel approach involving mechanical grain refinement and ternary blending was employed. Experimental results indicate that a 50% replacement of Portland cement with an experimentally determined BOFS-GGBFS blend achieves a Grade 80 Strength Activity Index (SAI), while simultaneously suppressing free-CaO-induced expansion, identified through the performance-based ranking protocol developed herein. Moreover, evaluation of steel slags for winter maintenance applications revealed that steel slags outperform conventional natural abrasives. Property-specific testing highlights that the angularity, surface texture, and absorption capability of BOFS enhance ice-melting and friction performance, offering a higher-value alternative to conventional road abrasives. Two experimental methods are developed for the first time to evaluate steel slags for winter road maintenance (WRM): the modified ASTM C944 ice-melting test and the hybrid ASTM C1701–C944 clogging protocol. Concurrently, geopolymer paving bricks and aerated snow barriers are developed as environmentally friendly products. Secondary raw materials are activated with sodium hydroxide and sodium silicate solutions to produce geopolymer paving bricks with a compressive strength of 68.4 MPa and a flexural strength of 4.7 MPa, offering increased resistance to abrasion, freeze-thaw cycles, sulfate attack, and efflorescence. The original scientific contribution of this work is that paving bricks are characterized using a three-regime freeze–thaw protocol and compared with NaOH and KOH as activators. Meanwhile, aerated geopolymer snow barriers achieve a density of 1700 kg/m³ with compressive strength of 8.0–12.0 MPa and flexural strength of 4.5–6.0 MPa, structurally validating against national load codes for the most extreme climatic zones of Kazakhstan, bridging the gap between laboratory characterization and field-deployable infrastructure, which is a step rarely completed in the geopolymer literature...