Post-fire bond-slip of self-compacting concrete with SD bars

Abstract

Abstract

Purpose The purpose of this study is to evaluate the thermal performance of self-compacting concrete (SCC) incorporating different supplementary cementitious materials when exposed to elevated temperatures. The research aims to compare the residual mechanical and bond properties of SCC mixes containing fly ash, ground granulated blast furnace slag (GGBS) and metakaolin under high-temperature conditions. Design/methodology/approach In total, 3 SCC mixes targeting a 28-day compressive strength of 45 MPa were developed using self-compacting concrete incorporating fly ash (SCC-F), GGBS (self-compacting concrete incorporating silica fume (SCC-S)) and self-compacting concrete incorporating Metakaolin (SCC-M). The specimens were exposed to temperatures ranging from 200 °C to 800 °C. Post-exposure, compressive strength, splitting tensile strength, flexural strength, bond strength and slip at peak bond strength were experimentally evaluated. Bond–slip relationships were established, and integrated degradation models were developed to quantify temperature-induced deterioration of mechanical and bond properties. Findings At ambient temperature, SCC-M exhibited the highest strength properties, while SCC-S showed slightly superior bond strength. At lower temperatures, marginal strength gains were observed for all mixes, with SCC-F showing the most pronounced improvement. With increasing temperature, SCC-F demonstrated the least degradation in strength and bond performance, attributed to stable pozzolanic reaction products and reduced spalling tendency. SCC-S showed moderate degradation, whereas SCC-M experienced significant losses beyond 400 °C, particularly in tensile, flexural and bond strengths, accompanied by increased slip and reduced bond rigidity. The degradation models effectively captured the progressive loss of properties with temperature. Originality/value This study provides a comprehensive experimental and analytical assessment of the high-temperature behavior of SCC incorporating different supplementary cementitious materials. The findings offer valuable guidance for material selection and predictive modeling of thermally exposed SCC in fire-resistant and sustainable construction applications.