Experimental research on ductility enhancement of ultra-high performance concrete incorporation with basalt fibre, polypropylene fibre and glass fibre

Abstract The research aims to enhance the ductility characteristics of ultra-high performance concrete fibre material (UHPC-FM) comprising with different micro-synthetic fibres such as basalt fibre (BF) polypropylene fibre (PPF) and glass fibre (GF). As a sequence, consecutive dosages of these fibres such as 0.5%, 1.0%, 1.5%, 2.0%, and 2.5% of volumetric fractions were introduced into the mixes for preparing the UHPC-FM to achieve the goals. The observed results showed that both the type and amount of added fibres influenced on the properties of fresh and hardened UHPC-FM concretes. In addition, higher contents of fibre filament (FFs) resulted a decreasing trend in flow of fresh UHPC-FM mixtures, where pastes with PPF demonstrated the highest fluidity property. Moreover, compressive strength (CS) increased upon addition of 0.5% FFs and linearly decreased for introducing the higher amounts. Compared with the control specimen (UHPC-A0), the flexural strength of samples containing 2.5% BF, PPF and GF increased by 20.8%, 26.9%, and 27.9%, respectively. Modulus of rupture increased by 20.04% in case of BF, 24.92% for PPF and 26.05% for GF when compared with reference sample (8429.5-kN). Toughness indexes of BF, PPF and GF based UHPC-FM samples were around 4.64, 4.75 and 4.86 times higher respectively, in comparison to the control specimens. The microstructure observation and drying shrinkage test illustrate fiber can modify UHPC well, which corroborated the results of mechanical properties exactly. In addition, the results of the current test can be applied for ultra-high-performance (UHPC) panels and vibration-free UHPC material.