Performance Study Of Anti-Disturbing Concrete For Bridge Engineering

In northeast China,many highways have been built and put into use with the country’s great investment into infrastructure.Many bridges have been damaged in the using process.In order to ensure the traffic safety,we should enforce and maintain them timely.However,the traffic is very heavy due to the large volume of traffic.If we close the roads for maintenance,the vehicles need to detour for a much longer distance and cause big social problems.So the closure for traffic is not allowed sometimes.Therefore,it is urgently needed to reinforce the bridge by studying the reinforcement method of anti-disturbance concrete based on the existing reinforcement technology.At present,parts of the highways in Liangning Province have already started the projects of rebuilding and expanding.The anti-disturbance concrete could be used in the enforcing and widening for the structure of the existing bridges and the roads needn’t to be closed.The cost for this is only 30%of the money building a new one.In this way,we can not only save the construction funds,but also improve the value of usage for the original structures.The anti-disturbance concrete could be used when the traffic is moving,and it can reach the designing strength quickly and meet the requirements for the seasonly frozen areas.The parameters such as the amplitude and the vibration frequency of the ordinary bridges were collected in the study.And the repairing concrete was prepared by adding grouting material and crushed stone.We explored the affecting laws for the performance of the concrete after being disturbed by the factors such as the disturbance methods,disturbance time,different coagulation and hardening stages of concrete,fiber,early strength agent,polyvinyl alcohol through the observation of the technical indicators of strength,ultrasonic sound,single salt and so on.The results of the experiment has shown that disturbance has a great influence on the compressive strength of the concrete.More than 20%of its strength has lost after 3d.And there was a tendency of rising first and declining then on the loss of the compressive strength with the increasing of the times.If we explore the effect of disturbance on the compressive strength of concrete from the two stages of before and after the initial coagulation.Before the initial coagulation,the concrete’s delamination segregation is obvious and the compressive strength value decreases greatly after the concrete is disturbed.From the stage of before the initial coagulation to the final coagulation,the loss rate of the conpressive strength of the concrete by disturbance is comparatively small.We can improve the compressive strength of concrete by adding some proper amount of basalt fiber to it no matter it’s disturbed or not.The L20 fiber is better than L3 fiber for improving the anti-disturbance ability of concrete.For single type fiber,the anti-disturbance ability of concrete is the best when we add 0.3%of L20 fiber.For mixed type fibers,that of concrete is the best when we add 0.1%of L20 and 0.1%of L3.The anti-disturbance ability of concrete is better when we add single type of fiber of L20(with an amount of 0.3%)than we add mixed fiber(0.1%of the long fiber and 0.1%of the short fiber).Polyvinyl Alcohol(PVA)has a great effect on improving the anti-disturbance ability of concrete.After the addition of polyvinyl alcohol,the early strength of the concrete will not significantly reduced,and even increase slightly after 1 day.With the increase of the amount of polyvinyl alcohol,both the anti-disturbance ability and the strength of the concrete are improved respectively.And the anti-disturbance ability of the concrete is the best when added singly 0.03%of Polyvinyl Alcohol.We select sodium sulfate and calcium formate as the early strength agent.On the basis of 0.3%of basalt fiber in to the concrete,we hope that we can improve further the anti-disturbance ability of the concrete by shortening the condensation time.When we add 0.5%of sodium sulfate,we can see obviously that we can decrease the loss of early compressive strength.But when it’s on 28d,it’s of little significance for the sodium sulfate to decrease the loss of compressive strength when the 0.3%of basalt fiber has already improved the anti-disturbance ability of the concrete efficiently.When calcium formate is added into the concrete,the loss for the compressive strength is very big up to 20%to 30%.Therefore,calcium formate can’t improve the the anti-disturbance ability of the concrete.Adding the early strength agent will reduce the durability of the concrete.