| According to the data of the Transport Industry Development Statistics Bulletin,the total highway mileage and highway density were increasing.But it still less than the degree of the average annual growth rate of traffic congestion.The pressure of road traffic has not been significantly alleviated.The design traffic of the rode which has been used by more than 10 years can’t meet the current requirements,which caused the concrete pavement appearing a lot of damage due to the lack of the bearing capacity.And it’s not conducive to the economic development of the society that the repair of the cement concrete pavement needs more time.In the experiment,it improves the compressive strength and flexural tensile strength of the normal pavement concrete by incorporating early strength agent,milling type corrugated steel fiber and 40 mesh waste rubber powder,which is to improve the Bearing capacity and durability.The major work is as follows:(1)By means of orthogonal test,it was designed that two groups of three factors and three levels in the tow orthogonal test.The factors were the early strength agent,the steel fiber and the rubber powder,and the levels were respectively 0%-15%,0.25%-0.75%,5%-9% and 0%-15%,0.75%-1.25%,1%-5% in the tow test.It had been found that the best dosage of the three materials in range of the levels,testing 3 d,28 d cube compressive strength and flexural strength for 216 specimens of nine patients in each orthogonal test group,namely the dosage of early strength agent,steel fiber,rubber powder was respectively15%,0.5%,5% and 15%,1.25%,3%.(2)By intuitive analysis and variance analysis of orthogonal test data,it had been found it was higher than sensitivity of steel fiber that the sensitivity of rubber powder to the compressive strength of concrete,and because of the addition of rubber powder,the compressive strength and flexural strength of concrete reduced.With the increase of rubber powder content,the compressive strength and the flexural strength of the concrete were decreased.It was obvious that the enhancement of steel fiber to the 3d compressive strength and flexural strength of the concrete.The effect of 28 d compressive strength enhancement wasn’t it.(3)In the comparison test of cube compressive strength and flexural strength,there were four experiment groups,which were respectively the ordinary concrete,the rubber early strength concrete,the rubber and the best group X(early strength agent 15%,0.5% steel fiber and rubber powder 5%)and the best group G(early strength agent 15%,1.25% steel fiber and rubber powder 3%).they were a total of 72 specimens.Compared with the ordinary concrete,it respectively increased 88.2%,113.7%,21.5% and 33.9%,22.5%,39.1% that the 3d,28 d,90d compressive strength of the rubber and steel fiber early strength concrete I and II,and the flexural strength respectively increased 141.7%、158.3%,22.2% and 47.6%,26.5%、48.5%.Compared with the rubber early strength concrete,it respectively increased 2.1%、15.9%,1.5% and 16.8%,2.1%、15.9% that the 3d,28 d,90d compressive strength of the rubber and steel fiber early strength concrete I and II,and the flexural strength respectively increased 16.0%、24.0%,4.1% and 25.7%,4.9%、23.2%.(4)In the ring cracking resistance test,through observing the produce time,quantity,Length and width of cracks of each specimen,it was found the early strength agent could inhibit the occurrence of cracks by increasing the strength of concrete,rubber powder could hinder the development of the number of concrete cracks,but it was not obvious for inhibiting the late width of cracks,while the steel fiber could effectively restrain the growth of the crack width,but it would add other micro-cracks while the cracks developed to other directions across steel fibers,the cracks became tinier and more. |
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