Influence of Embedment Length on the Bond Performance of mineral-impregnated Carbon Fiber Reinforcements in fine-grained Concrete

Abstract

Mineral-impregnated carbon fibers (MCFs) represent an innovative reinforcement system that integrates high-performance fibers with inorganic matrices, offering superior thermal resistance, enhanced bonding with cementitious substrates, improved cost efficiency, and remarkable versatility and multifunctionality for advanced structural applications. As a promising alternative to traditional steel and fiber-reinforced polymer (FRP) systems, MCFs address critical limitations in thermal performance and concrete’s compatibility. A key factor influencing the engineering performance of reinforced concrete structures is the embedment length of the MCF reinforcement for reliable structural design. This study investigates the bond behavior of geopolymer (GP)-based MCF reinforcements in concrete numerically and experimentally, with a focus on the influence of embedment length. Experimental pullout tests revealed a bond stress–slip relationship (BSR) characterized by a linear elastic phase, exponential softening during debonding and stabilization at residual frictional stress levels. Longer embedment lengths improved energy absorption but resulted in reductions in maximum bond stress due to non-uniform stress distribution. Numerical simulations employing a spring element model accurately replicated experimental data, providing an efficient predictive tool for analyzing bond behavior. These findings establish a solid framework for optimizing the bond performance of MCFs and advancing their application in high-performance, resilient structural systems.