Experimental Study On Mechanical Properties Of Waste Fiber Recycled Concrete Beam

In order to understand the shear and flexural properties of fiber waste recycled concrete beams initial, this paper makes the test about the shear and flexural performance of the oblique section,In this text,12 and 14 rectangular section beam which has different waste fiber incorporation of recycled aggregate and different recycled aggregate replacement rate of are made respectively.The volume of waste fiber incorporation were 0.08%,0.12%,0.16%, fiber length is 12 mm,19 mm respectively,30 mm, replacement rate of recycled aggregates were 0, 50%,100% respectively. The size of beam section is respectively 2300 mm ×200 mm ×200 mm and 300mm×150mm×300mm.In this paper, we will have a preliminary understanding about the mechanical properties, failure modes and deformation characteristics of waste fiber recycled concrete beams under oblique section and normal section short-term loads, Meanwhile, studied and analyzed the oblique section and normal section bearing capacity, crack resistance, normal maximum crack width and deflection of waste recycled fiber concrete beams under normal using load condition, and in accordance with the relevant formula recorded in the current "code for design of concrete structures" GB50010-2010, the applicability of theoretical calculations has been analyzed about the cracking moment, ultimate flexural capacity, span deflection, maximum crack width and Shear ultimate bearing capacity by the oblique section of waste recycled fiber concrete beams.Through the analysis of the test results, this paper summarizes the following main conclusions:(1)The concrete strain of normal section of the waste fiber recycled concrete beams are accord with flat section assumption; waste fiber recycled concrete beams of shear failure are accord with flat section assumption within 40% of the ultimate load;(2)The incorporation of waste fiber can improve the cracking resistance of recycled concrete beams, makes the anti-cracking performance of waste fiber recycled concrete beams to achieve or even more than ordinary concrete beams. And it can better limit the development of the cracks, and improve the stiffness of the specimens.(3) The incorporation of waste fiber make ductility of waste fiber recycled concrete beam increased significantly. During the yield and reaching the ultimate load of the specimen tensile steel, compared to ordinary concrete beams and recycled concrete beams, waste fiber recycled concrete beams can still maintain the ability to hold a longer periods of time.(4) In each stage, carrying capacity of waste fiber recycled concrete beams are reaching or even higher than ordinary concrete beam. It is feasible to calculate the normal section flexural bearing capacity and shear capacity of oblique section of waste fiber recycled concrete beam in accordance with the formula recorded in the current "code", and the results are on the safe side.(5)It is feasible to check deflection of the waste fiber recycled concrete beam according to the formula recorded in current "code", and the results are on the safe side.(6)It is feasible to check maximum crack width of waste fiber recycled concrete beams according to the formula recorded in current "code", but compared with the ordinary concrete beams, It has a larger safety stock of maximum crack width which is calculated according to formula recorded in the "code". In this paper, correction coefficient has been raised.Coefficient v recommended to take 1.40Through the comprehensive comparison of the flexural properties and shear properties of oblique section of waste fiber recycled concrete beams, which has various waste fiber incorporation, we can find that, the flexural properties and shear properties of oblique section of waste fiber recycled concrete beams is not directly proportional to the length of the fiber.