Effect of freezing-thawing cycles and high temperatures on concretes containing partial replacement of fine grain Blast and Electric Arc Furnace slags

Abstract This study examines the effects of industrial by-products, such as iron slag and steel slag, as partial replacements of fine grain at 10%, 15%, and 25%, individually and combined. The research evaluates the impact on physical changes and mechanical resistance under freeze-thaw cycles and high temperatures. Additionally, the study explores the effects of incorporating 0.3% polypropylene fibers by volume and 10% microsilica by cement weight. The durability of concrete samples at temperatures of 400°C and 800°C at the age of 90 days, exposed to gas furnace and freezing-thawing at the age of 28 days with 100 cycles, were investigated in terms of compressive strength. Samples subjected to 100 freeze-thaw cycles showed increased porosity and expansion of microcracks, leading to a loosened macrostructure and a 0.8% decrease in weight. Findings indicate that replacing slag in the fine grain and combining these materials with polypropylene and microsilica fibers improved mechanical properties like compressive strength. Additionally, incorporating 10% slag enhanced the mechanical properties of samples at 400°C and 800°C, with lower resistance loss compared to designs without additives. The inclusion of 10% microsilica and 0.3% polypropylene fibers, however, reduced sample resistance at 800°C compared to 400°C. Furthermore, the freeze-thaw cycle caused a 32.46% decrease in sample resistance compared to the control state. Microstructural analysis of GGBS in concrete using Scanning Electron Microscopy (SEM) revealed that the addition of GGBS produces a denser matrix populated with more angular particles, resulting in improved bonding properties compared to plain concrete.