Effect of polyethylene fiber content on physical and mechanical properties of engineered cementitious composites

A series of experiments were conducted to study the effect of polyethylene (PE) fiber content (0%, 1%, 1.5% and 2% volume fraction) on mesoscopic and macroscopic behaviors of the engineered cementitious composites (ECC). As reference, the mechanical properties of mortar reinforced with steel fibers of 2 vol% was also discussed. Compressive test and bending test demonstrated that ECCs incorporated various fiber contents exhibit exceeding and stable ductility. Uniaxial tensile test result showed that ECCs maintain strong strain-hardening and multi-cracking characteristics even if the fiber volume fraction is reduced to 1%. On mesoscopic scale, single-crack tension test indicated that the fiber bridging complementary energy is significantly enhanced with the increase in fiber content, while the fiber bridging strength is firstly increased and then decreased. Furthermore, single fiber pull-out test was used to investigate the fiber-matrix interfacial behavior and characterized the slip-hardening behavior of PE fiber. Finally, discussions on pseudo-strain hardening indexes and critical fiber volume fraction indicated that the abundant tensile capacity of ECC is the key factor for the possibility of reducing fiber content without losing tensile strain-hardening and multi-cracking characteristics. (C) 2020 Elsevier Ltd. All rights reserved.