A comprehensive study on mechanical properties, durability, and environmental impact of fiber-reinforced concrete incorporating ground granulated blast furnace slag

Abstract

Concrete pavements are integral to sustainable infrastructure, offering longevity and resilience in construction and transportation. This study focuses on optimizing concrete pavements through the incorporation of steel and carbon fibers with Ground Granulated Blast Furnace Slag (GGBS) to enhance mechanical strength, reduce fracture development, and minimize carbon emissions. Utilizing 25 mixing designs with a consistent water-to-cement ratio of 0.40, varying ratios of GGBS, steel fibers, and carbon fibers (0.5 %, 1 %, and 1.5 % based on concrete volume) were explored. A comprehensive evaluation, including slump, compressive strength, flexural strength, split tensile strength, water absorption, abrasion resistance tests, carbon dioxide emissions, and cost analysis, was conducted at different curing stages. Results revealed a decline in compressive strength for all mix designs at 28 days, attributed to reduced cement strength with GGBS substitution. The 1.5 % steel fiber and 50 % GGBS mix demonstrated minimal compressive strength reduction (30.1 MPa, 5.5 % less than control), outperforming other mixtures. Steel fibers surpassed carbon fibers, likely due to \\erior distribution. Notably, 1.5 % steel fibers showed superior results, particularly with 50 % GGBS. Compressive strength generally increased with GGBS content, except for 1 % fibrous samples where 40 % GGBS produced optimal results. At 90 days, compressive strength increased for most designs, with G50S1.5 exhibiting over 38 % growth compared to the control. Steel fiber-containing samples outperformed carbon fiber-containing ones, showcasing the efficacy of steel fibers in enhancing compressive strength. Split tensile strength generally decreased, but steel fibers improved it, emphasizing their positive influence. Flexural strength increased in 28 and 90 days, with steel fiber-containing designs outperforming. G30S1.5 showed the most significant increase (33.3 %) at 28 days, and G30S1.5 exhibited the highest growth (32.22 %) at 90 days. Abrasion resistance tests indicated steel fibers and GGBS positively impacted abrasion reduction. G50S1.5 demonstrated the highest abrasion resistance (25 % increase over control). The environmental evaluation revealed lower CO2 emissions for GGBS-containing designs. G50S0.5 showed a 40.34 % reduction compared to the control sample. Cost analysis showed GGBS reduced costs, but fiber addition, particularly carbon fibers, increased costs. G30C1.5 had the highest cost increase (208.5 %), while G50S1.5 showed a marginal rise (3.9 %) compared to the control. Therefore, steel fibers in concrete pavements offer improved mechanical properties, durability, and reduced environmental impact, making them a viable choice despite a slight increase in cost. Conversely, carbon fibers are cautioned against due to their higher cost and inferior mechanical properties.