Effect of multi‐scale polypropylene fiber hybridization on compressive constitutive mechanics parameters of roller compacted concrete

Abstract

AbstractTo investigate the influence of hybrid effect of different sizes of polypropylene fibers (PPFs) on the compressive constitutive mechanical parameters of roller compacted concrete, nine groups of fiber reinforced concrete specimens containing different sizes of PPFs were designed and the uniaxial compressive testing was conducted. Based on the existing compressive constitutive model and the test stress–strain curves, the peak stress, peak strain, elastic modulus, and the post‐peak stage parameter with different fiber proportion were analyzed and discussed to find the optimum mixing proportion of different sizes of PPF, the calculation of compressive toughness factor were given. The results showed that the addition of PPF could improve the compressive properties of RCC. The axial compressive strength and compressive strain of RCC increased by 3%~16% and 7%~57%, respectively. Meanwhile, the coarse PPF can significantly enhance the ductility of RCC when subjected to uniaxial compressive loading, and the group of multi‐scale PPF hybridization had higher compressive toughness than groups blended with two types of PPF, showing a more obvious positive hybrid effect. Finally, multi‐scale fiber hybrid effect function was proposed, the results showed that the function can well reflect the influence of fiber hybrid effect on the compressive properties of RCC and can be used to predict the optimal fiber proportion of fiber reinforced concrete.