The Experimental Research On Normal Section Crack Resistance Of Recycled Concrete Beams With Hybrid Fiber

With the rapid development of Chinese economy, more and more old building was demolished and rebuilt, it makes a large number of construction waste. In addition, according to statistics,4.3 billion tons of coal was used in 2015 in China,then generates a lot of fly ash waste. How to deal with these construction waste and industrial waste,and secondary use them reasonable, and it attracts more and more people’s attention. The results show that the concrete made with these buildings and industrial waste has low strength of ordinary and poor crack resistance, easy to crack and other shortcomings, which greatly influenced the extensive application of recycled concrete. In this paper, in order to improve the crack resistance of recycled concrete, we changes the organic fibers in the type, composition, incorporation analyze its effects on recycled concrete crack resistance, and the results are as follows:(1) through the experimental study on mechanical property and crack resistance with different types of organic fibers, different combinations of organic fibers,different rates of organic,we found that put organic fibers into the recycled concrete has no significant increase on the compressive strength of recycled concrete and it is more apparent on splitting tensile strength of recycled concrete. Analysis and compares the tension and compression ratio of recycled concrete, we got that hybrid organic fiber incorporation rate of 0.15%,0.2% with PP and PAN has a better crack resistance of concrete.(2) through the experimental study on mechanical property and crack resistance with different types of organic fibers, different combinations of organic fibers,different rates of organic,we found that put organic fibers into the recycled concrete has no significant increase on cracking load and ultimate load of recycled concrete beams.Analysis and compare the crack growth of the side beams, steel stress-strain, stress-strain of concrete,the load-deflection of beam middle, load-maximum crack width, and so on.we got that hybrid organic fiber incorporation rate of 0.15%with PP and PAN is best to improve the crack resistance of the beam. Analysis the maximum deflection and crack width formula in"Design of Concrete Structures", derived maximum crack width formula:whmax=Kwmax, K=-104r+0.89, r is the combination of hybrid combination of organic fibers; derived maximum deflection formula:δh=Nδ,N=330r+4.489,r is the hybrid combination of organic fibers.(3) simulated and analyzed the recycled concrete beams with ANSYS software and compared and analyzed the experimental data and ANSYS data,we got they are fit better...