Research On Toughness Of Polypropylene-Steel Fiber Reinforced Self-Compacting Lightweight Aggregate Concrete

The purpose of this research was to research the flexural toughness and shear toughness of C40 polypropylene fiber and steel-polypropylene fiber reinforced self-compacting lightweight aggregate concrete.This article selects the volume of polypropylene fiber as 0.3%,0.6%,0.9%,1.2%,1.5%,the total volume of steel-polypropylene fiber was 0.9%,including the steel-polypropylene fiber as 0.1%-0.8%,0.3%-0.6%.0.5%-0.4%,research the flexural toughness used thirds point method and notched beam method,research the shear toughness used direct shear test,then according to the test results,drew the correlation expressions between the flexural toughness and shear toughness.During the notched beam method and direct shear test,setting five different depth preformed joint to polypropylene fiber concrete in the notched beam method and direct shear test to research the effect of joint depth on the flexural toughness and shear toughness of concrete.This paper mainly completes the following studies:(1)Research the flexural toughness and shear toughness of polypropylene fiber reinforced self-compacting lightweight aggregate concrete with different volume content used the thirds point method,notched beam method and direct shear test.Result shows that,in the range of selected volume,the flexural toughness and shear toughness of polypropylene fiber self-compacting lightweight aggregate concrete were increased with the increase of polypropylene fiber content.(2)Research the flexural toughness and shear toughness of steel-polypropylene fiber reinforced self-compacting lightweight aggregate concrete with different volume content used the thirds point method,notched beam method and direct shear test.Result shows that,with the same fiber volume,steel fiber has improved the flexural toughness and shear toughness of fiber reinforced self-compacting lightweight aggregate concrete,and its toughness was increased with the increase of steel fiber content.(3)Research the effect of joint depth on the toughness of concrete during setting five pre cut crack depth which are 10mm,20mm,30mm,40mm,50mm in notched beam method,5mm,10mm,15mm,20mm,25mm in direct shear test.Result shows that,there was size effect in notched beam method and direct shear test,flexural toughness and shear toughness indexes were increased with the increase of pre cut crack depth,with the high fiber content the size effect was more remarkable,and the influence should not be ignored.(4)Research the correlation between flexural toughness and shear toughness of polypropylene fiber reinforced self-compacting lightweight aggregate concrete with the theory of strength after bending cracking.Result shows that,there was a good quadratic correlation between flexural toughness and shear toughness,and overturn the relevant expressions.