Experimental Study On Basic Mechanical Properties Of Fiber Reinforced Recycled Fine Aggregate Concrete

With the development of urbanization,China's construction industry has entered a period of rapid development.the demand for concrete is increasing,and large amount of construction waste such as waste concrete is inevitably generated.The waste concrete can be crushed and sieved to totally and partially or completely replacing the natural fine aggregate to make recycled fine aggregate concrete(RFAC),which not only consumes a large amount of construction waste,but also turns waste into treasure,saving non-renewable natural resources and having a major economy benefits and long-term social benefits.However,the disadvantages of high porosity and poor strength of RFAC have led to a significant limitation on its application range,resulting the utilization is low.Development of recycled fine aggregate concrete preparation technology and improvement of its performance.It is imperative.In this paper,after studying the basic properties of recycled fine aggregate concrete under different recycled fine aggregate replacement rates,different types of fibers are added to recycled fine aggregate concrete which is with 100% replacement of fine aggregate to prepare fiber reinforced recycled fine aggregate concrete(FRFAC),and strengthening the basic mechanical properties of recycled fine aggregate concrete by using fiber to inhibit crack germination and slow down crack development,and expand its range of applications.The main content as follows:(1)The slump values of SRFAC were batching by 20 groups mixture proportions,based on these results,the influence of recycled fine aggregate replacement ratio and fiber types on slump was studied.The mechanism of the performance of fiber-recycled fine aggregate concrete was analyzed by the skeletal effect of the fiber and the difference in fiber surface area.(2)the influence of recycled fine aggregate replacement ratio and fiber types on compressive strength were studied through the compression tests conducted on 60 sets of cube specimens of 150mm×150mm×150mm with batching by 20 group mixture proportions,and the failure mechanism of fiber recycled concrete was analyzed according to the volume ratio,size and distribution of the internal pores of concrete.The calculation model of compressive strength of steel fiber recycled fine aggregate concrete(SFRFAC)was established.(3)Using the improved Splitting tensile test instrument,a total of 60 sets of cube specimens of 150mm×150mm×150mm with batching by 20 groups of fiber-recycled FRFAC were tested for splitting tensile properties,the influence of recycled fine aggregate replacement rate and fiber types on the splitting tensile strength and splitting tensile deformation were studied.Determine the uniformity of steel fiber distribution by observing the overall distribution of fibers in the specimen and the number of steel fibers on the Splitting tensile surface.Finally,The calculation model for the peak load of SFRFAC was established.