Influence of Polypropylene Fiber and Silica Fume on the Chloride Penetration of High Performance Concrete with Fly Ash

摘要

In this paper, the influence of polypropylene fibers (PPF) and silica fume (SF) on chloride penetration of high performance concrete (HPC) containing fly ash (FA) was examined. Three different HPC in which the amount of ordinary Portland cement is 360 kg/m~3, via., A concrete with 120 kg/m~3 of FA, B concrete with 0.9 kg/m~3 of PPF and 120 kg/m~3 of FA, C concrete with 0.9 kg/m~3 of PPF and 96 kg/m~3 of FA and 24 kg/m~3 of SF were used for the study. Chloride resistance of concrete was evaluated. From the tests, it is found that the incorporation of PPF and no SF has less influence on the chloride resistance of the fly ash concrete at the age of 28 days. SEM examines B and C concretes specimens illustrating that just incorporating PPF induced more porous fiber-matrix interfacial zone (FMIZ) in B concrete which is detrimental to the chloride resistance, but the microstructures of both the matrix and FMIZ in C concrete with PPF and SF are denser. The plastic shrinkage cracking test proves that the cracking areas on the surface of B and C concrete with PPF are 12.2% and 20.7% of A concrete without PPF respectively.