FRACTURE TOUGHNESS OF STEEL FIBER REINFORCED HIGH STRENGTH CONCRETE AND HIGH STRENGTH CONCRETE UNDER THREE-POINT BENDING

摘要

Through the three-point bending test on 100 specimens of steel fiber reinforced high strength concrete (SFHSC) and 45 specimens of plain high strength concrete (HSC) with the specimen size of 100mm×100mm× 515mm, the effects of the fiber volume fraction (ρ) and relative notch depth (a/W) upon the fracture toughness of plain high strength concrete were studied. The probability distribution of the fracture toughness (K) of high strength concrete was studied as well. The results show that the increment ratio of the fracture toughness increases linearly with the increase of ρ. The fracture toughness of steel fiber reinforced high strength concrete and plain high strength concrete decreases with the increase of notch depth. The theoretical distribution function of the fracture toughness of plain high strength concrete is in accordance with the Weibull distribution function according to the statistic analysis of experimental results. Based on the test results, the formula for calculating K was established.