Properties And Applicationof Fiber Waste Rubber Powder Modified Concrete

Rubber concrete is a new type of concrete developed in recent years.However,compressive strength of waste rubber powder concrete is low,which affects its application in structural engineering.Based on mechanical properties and rule of different fibers on rubber concrete,fiber type and its content were optimized by using of fiber waste rubber modified concrete.According to the "test code for hydraulic concrete"(SL352-2006),ratio of elastic modulus to compressive strength of fiber waste rubber powder modified concrete are studied.In-site test,stress distribution of fiber rubber powder modified concrete restrainted by rock and shear performance of rock-fiber rubber powder modified concrete are performed.Based on the structural design of the fiber waste rubber powder modified concrete as stress absorbing layer,thermal stress distribution of sluice pier is studied.Through test of cooling water,temperature resistance of different sizes of rubber concrete members and water consumption of different sizes of rubber concrete members are studied.The results show that fiber waste rubber powder modified concrete is related to type of fiber.In three kinds of polypropylene fiber,carbon fiber and steel fiber,effect of steel fiber on the strength of rubber concrete is best.Steel fiber reinforced strength of rubber modified concrete,which is relation to steel fiber and waste rubber content.When rubber powder content is less than 5kg/m3,and content of steel fiber is less than 15kg/m3,compressive strength and flexural strength of rubber concrete are higher than the reference concrete(not with rubber and steel fiber concrete,the same below),as content of steel fiber increasing.For the same grade rubber powder modified concrete,whose rubber content is less than 40kg/m3,ratio of elastic modulus to compressive strength has a good linear relationship,y=[-0.04582x+5.7796]x 1000,where y is ratio of elastic modulus to compressive strength,x is rubber content.Fixed rubber dosage 5kg/m3 fiber content is less than 50kg/m3 and ratio of elastic modulus to compressive strength decreases as fiber content increasing.For concrete with different strength grade,ratio of elastic modulus to compressive strength is lower than that of corresponding reference when rubber content is 10kg/m3.Shear and shear friction coefficient of rubber concrete-rock foundation are higher than those of standard concrete;the increased,shear friction coefficient of rock-concrete enlarges with rubber content increasing.From 0.20m,0.65m,1.00m to foundation,the maximum temperature stress of concrete spillway were 4.7MPa,3.9MPa,1.6 MPa,and that of the fiber waste rubber powder modified concrete spillway of the same position of stress is 3.0MPa,2.5MPa,1.3MPa.From the same position,temperature stress of fiber waste rubber powder modified concrete is less than that of reference concrete.And temperature stress gradient decreases.The maximum temperature stress of reference concrete pier is 4.8MPa,and that of a set of stress absorbing layer pier is 3.OMPa,which is 62.5%of reference pier.So strain and temperature stress of fiber waste rubber powder modified concrete as stress absorbing layer setted in pier are less than those of reference pier.If temperature stress of concrete members with the same age and size is basically the same,temperature resistance of fiber waste rubber powder modified concrete members is good and amount of cooling water required is less than that of reference concrete.By fiber waste rubber powder,mechanical properties,volume stability and shear performance of concrete enhance,stress gradient and temperature stress of buildings on rock reduce.It is obvious advantages for temperature control.