Experimental Study On Shrinkage Of Self-compacting Steel Fiber Reinforced Full-lightweight Concrete

Self-compacting steel fiber reinforced full-lightweight concrete is a new kind of composite material which is formed by adding a certain amount of steel fiber in the self compacting light weight concrete.The paper discusses the research situation and influence factors of early age crack resistance,autogenous shrinkage and drying shrinkage of Steel fiber reinforced self-compacting full-lightweight concrete.Moreover,the paper studies and analyzes early age crack resistance,autogenous shrinkage and drying shrinkage of self-compacting steel fiber reinforced full-lightweight concrete.On the basis of the existing experiments,the paper selects concrete strength grade C40.The test variables were the steel fiber content and the maximum particle size of the aggregate.The steel fiber is added by 0,0.8%,1.2%,1.6% in the range of0%~1.6%.The experiment aims to study the impacts of different steel fiber content on early age cracking-resistance,autogenous shrinkage and drying shrinkage.The maximum particle size of aggregate is 10 mm,16mm and 20 mm.It is mainly study the impacts of different maximum particle size of aggregate on early age cracking-resistance,autogenous shrinkage and drying shrinkage.The results show that the development speed of crack of self-compacting steel fiber reinforced full-lightweight concrete is fast in first 1.5d,and is more gentle after this time.Early age cracking-resistance increases with the increase of steel fiber content.When the steel fiber content is 1.6%,the crack development is almost the same as that of the content of 1.2%;Smallest area of early age nominal crack exists when steel fiber content is 1.2% and the largest aggregate diameter is 16 mm.Meanwhile,it has a higher cracking-resistance level than that when the largest diameter of aggregate is 10 mm and 20 mm..The value of autogenous shrinkage decreased obviously with the addition of steel fiber,and the value of autogenous shrinkage was the smallest when themaximum particle size of aggregate is 10 mm and steel fiber content was 1.2%.When the steel fiber content in the range of 0~1.2%,with the increase of steel fiber content,the drying shrinkage value showed a trend of decline.when the dosage increases to1.6%,decrease of shrinkage value is not obvious.When the maximum particle size of aggregate is 16 mm,the drying shrinkage value reaches the minimum.Finally,analyzing and fitting the experimental data synthetically,The fitting degree is better while the correlated coefficient is greater than 0.9.Comparing the fitting values with measured values,,it is concluded that good fitting curve fitting.