Effects of strain-hardening on anti-abrasion property of cementitious composites

Abstract

How to remarkably improve anti-abrasion of cementitious materials is a big issue in hydropower construction and operation. So the relationship between axial-tension behaviors of fiber reinforced cementitious composites and its main mechanical properties including anti-abrasion was focused on research based on stress-strain constitutive model. Different matrices with univariate change ware prepared by fiber Bonding Adjustment(BA) based on nano MetaKaolin admixture. Tension characters and relative properties ware measured by both different matrices with 2% fiber and different fiber dosages in same matrix. The result showed that tension behaviors are mainly decided by the mutual function between the fiber and the matrix, not only simply depend on matrix strength or fiber dosage. One of the preconditions of strain-hardening is that fiber bonding strength should be higher than tensile strength of matrix. Strain-hardening not only let tensile strength to be increased further, but also enlarges tension strain significantly, which lead to improve toughness and anti-abrasion outstandingly. The tension behaviors of 1.5% and 2.5% fiber dosages based on optimized matrix with 9%BA are strain-softening and strain-hardening respectively, but the later toughness and anti-abrasion are 43.7 and 5.52 times of former, and its anti-abrasion strength reached 209.3 h/(kg/m²) which is ten times more than high performance C50-silica fume anti-abrasive concrete. It's indicated that strain-hardening is one of the key method to make cementitious composites achieve broken change of anti-abrasive property and being turned from fragility to tenacity.

Keywords

Strain-hardening / Axial-tension constitutive model / Anti-abrasion strength / Mechanical properties / Toughness / Fiber bonding strength