Influence of Fiber Types on Strengthening Effect and Variability of Compressive Strength and Flexural Toughness of Concrete

Abstract

 In order to study the influence of steel fiber, polypropylene fiber and cellulose fiber on the compressive strength and flexural toughness of mixed concrete, the compressive strength and flexural toughness of concrete blocks were tested under different volume contents, and the results of the tests were analyzed by variation. The test results show that the compressive strength of three kinds of fiber concrete is increased by 26.5% on average compared with plain concrete. 7%、6.1% and 11.1%; the retention rate of secondary compressive strength reached 77. 9% respectively. 0%、45.7% and 58.0%; the maximum bending bearing capacity was increased by31.6%、3.5% and 14.0%; the bending toughness index I20, the new Kumar index pcsm and the toughness ratio rx calculated based on the load-deflection curve, the new Kumar method and the bending-tension strain curve respectively are 4.2、3.1、2. Six times, 19.9、9.8、6. Nine times and four times. 0、3.4、2. Seven times. Variability analysis results show that the variability of compressive strength of concrete mixed with fiber is less than flexural toughness. At the same time, the bending toughness index variation coefficient calculated based on the New Kumar method and the stress-strain curve method is smaller than the bending line method under load. Overall, the compressive strength and flexural toughness of steel fiber reinforced concrete are the most significant, and the number of variation systems is the smallest. The compressive strength of fiber-reinforced concrete and the flexural toughness of polypropylene fiber reinforced concrete are relatively significant.