Experimental Study On Mechanical And Fatigue Properties Of Modified Rubber Concrete

With the increase of concrete strength,Its brittleness becomes more and more obvious,Which hinders the broader development of concrete.The broken waste rubber tires are added into concrete,Not only improves the inherent brittleness of concrete,But also benefits its dynamic performance,Effectively uses waste rubber resources,And saves resources and protects the environment.In this experiment,The rubber particles were modified by Na OH solution and Na₂SO₄ solution,And the effects of modification method,rubber particle size and mixing amount on the mechanical properties of concrete were explored through experiments;Three-point bending and tension fatigue tests were carried out on benchmark concrete,Rubber concrete and modified rubber concrete trabeculars to explore the effects of rubber modification and mixing amount on the fatigue life of trabeculars under various stress levels.The results show that:?1?The mechanical properties of concrete decrease with the increase of rubber content.Compared with the large particle size rubber,The small particle size rubber has better mechanical properties for concrete.NaOH solution and Na₂SO₄ solution modified rubber particles can improve the mechanical properties of rubber concrete to some extent,And NaOH solution has better effect.?2?The static load test and fatigue test of benchmark concrete,Ordinary rubber concrete and modified rubber concrete under three-point bending load are carried out.The results show that the failure phenomenon of concrete under static load is similar to that of flexural test.Compared with the reference concrete,The rubber concrete has larger deformation and obvious plastic characteristics when it is damaged.When the stress level is fixed,The fatigue life of modified rubber concrete is the longest when it is modified with NaOH solution,Followed by ordinary rubber concrete,The greater of the rubber content,And the fatigue life of concrete is longer.?3?Based on the knowledge of mathematical statistics,The fatigue life of rubber concrete is analyzed,It is concluded that the fatigue life of concrete is subject to two parameters Weibull distribution test under the same stress level.Two kinds of S-N fatigue equations named S-lgN and lgS-lgN are given.The results show that the single logarithm S-lgN fitting is better.The curves under different failure probabilities are drawn,The corresponding single logarithm fatigue equations are obtained,And the bending fatigue equations of benchmark concrete,Ordinary rubber concrete and modified rubber concrete are compared and analyzed to predict the fatigue life of concrete and provide basis for engineering application.