Abstract:Fibre reinforced concrete possesses more excellent properties of cracking resistance

reinforcing strength and toughness than plain concrete

hence can fulfill more requirements in the modern concrete constructions. In the current paper

the twisted ultra-high molecular weight polyethylene (UHMWPE) fibre of high strength

high elastic modulus as well as low density was employed as the reinforcement

the quasi-static mechanical properties of a new type of fibre concrete (FRC) were experimentally investigated. The C70 high strength concretes with four different fiber volume fractions (FVF) were developed by improving the process of preparation

then the splitting tensile tests

cubic uniaxial compression tests as well as the prism axial compression tests of the FRC were conducted

respectively

to investigate the effect of the FVF on quasi-static strengths and deformation behaviors of the FRC. The comparisons between the mechanical properties of current studied UHMWPE FRC and concrete reinforced by general UHMWPE fibre without treatment as well as the Polypropylene fibre have been performed. The results show that the fibre dispersed more evenly using this improved mixing method which promoted the workability of FRC. The integrity of concrete was maintained and fall-out of fragments was avoided due to the added UHMWPE fibre. The splitting tensile strength

increasing from 47.2% to 78.6% with the fiber content from 0.3% to 1.0% compared with the plain concrete

was significantly improved by the twisted UHMWPE fibre. However

the compressive strength of the concrete was not significantly enhanced by the UHMWPE fibre

while the improvement of the residual compressive strength was remarkable. Both the peak compressive strain and Poisson’s ratio increased with the increase of the FVF

whereas the elastic modulus had an opposite variation trend. The compressive toughness index ηc15.5 of FRC was 1.40~2.53 times of that of the plain concrete. Twisted UHMWPE fibre has improved the splitting tensile strength of concrete more significantly than the other two types of fibres

and enhanced the uniaxial compressive strength to a certain degree.