Study on flexural and fracture properties of polypropylene fiber-reinforced high-strength geopolymer concrete
PENG Congyu
LUO Haohao
ZHANG Chi
FU Zhihao
LIU Wei
ZHAI Yingying
BIAN Yadong
Abstract：To investigate the effects of alkali activator modulus and polypropylene fiber content on the flexural and fracture properties of geopolymer concrete,high-strength geopolymer concrete was prepared using alkali activators with moduli of 1.1,1.3,1.5,and 1.7.Based on the system with a modulus of 1.3,a series of fiber-reinforced specimens were prepared by incorporating polypropylene fibers with volume fractions of 0.2%,0.4%,0.6%,and 0.8%.Through four-point bending tests and three-point fracture tests,the peak load,peak deflection,flexural toughness ratio,and multiple fracture parameters of the speciments were systematically measured.The results indicate that as the alkali activator modulus increases,the peak load,peak deflection,and flexural toughness ratio of geopolymer concrete initially increase and then decrease,reaching optimal values at a modulus of 1.3.The incorporation of polypropylene fibers significantly enhances the flexural deformation and fracture properties of the concrete.At a fiber content of 0.8%,the specimen achieved a maximum peak load of 22.92 kN,a peak deflection of 1.32 mm,and a flexural toughness ratio of 0.36.The critical crack opening displacement,fracture energy,and fracture toughness are increased by 31.82%,251.83%,and 15.80%respectively,compared with the non-fiber group.Therefore,the combination of an alkali activator modulus of 1.3 and a polypropylene fiber content of 0.8%is identified as the optimal one,synergistically improving the flexural and fracture properties of geopolymer concrete.
Keywords：polypropylene fibergeopolymer concreteflexural propertiesfracture properties
Publication Date：2025-12-25
Online Publishing Date：2026-01-27(First online date of this platform, not the publication date of the document)
Pages：9( 68-75,90 )