Mechanical Performance Analysis of Steel-sisal Fiber Reinforced Concrete: Based on Response Surface Methodology

Abstract

Driven by the urgent demand for sustainable infrastructure under global climate change, steel–sisal fiber reinforced concrete (SF–SiFRC) has attracted increasing research interest. However, existing studies have mainly focused on ultra-high-performance concrete and recycled aggregate concrete, while its application in ordinary concrete remains insufficiently explored. In this study, response surface methodology (RSM) was employed to systematically evaluate the effects of steel fiber (SF) contents (0.5%, 1%, and 1.5%) and sisal fiber (SiF) contents (0%, 0.2%, and 0.4%) on the mechanical properties of ordinary concrete, and to optimize their dosages and interactions. The results indicate that the incorporation of SF and SiF significantly improves mechanical performance. At the optimal combination (SF1.5SiF0.35), compressive, flexural, and tensile strengths increased by 12.7%, 53.5%, and 61.4%, respectively, compared with the control group. A carbon emission assessment was further conducted, revealing a significant reduction in carbon emissions with increasing SiF content. Notably, the SF1SiF0.4 mixture exhibited mechanical properties comparable to those of SF1.5SiF0, while reducing carbon emissions per unit volume by 15.95%. Similarly, the SF1.5SiF0.35 mixture demonstrated lower carbon emissions than SF1.5SiF0. These findings demonstrate that SF–SiFRC can enhance or maintain mechanical performance while substantially reducing carbon emissions, highlighting its potential as a sustainable construction material for low-carbon infrastructure development.