| Taking the treatment of the disease of a cement concrete expressway in southeast China as an example,this paper studies the technology of super early strength fiber concrete quick pass-through board replacement.After the completion and operation of the expressway,the traffic flow increases rapidly,and in recent years,the overloaded and overloaded vehicles increase rapidly,leading to the pavement surface fragmentation,activity,subsidence,serious network cracks and other diseases,and the development is very rapid.Due to the slow growth of early strength of cement concrete in maintenance and maintenance,the maintenance cycle is long,which is not conducive to the normal operation of expressway and poses a certain threat to the safety of vehicles.In order to solve the above problems,this paper focuses on the following aspects:(1)Study on optimization of concrete reference ratio and super early strength admixtures.In the highway maintenance in the use of three kinds of cement concrete mixture slump test,construction selected to be the best mixing ratio of cement concrete,on the basis of 24 hours in order to achieve the super early strength,through a variety of admixture distribution way,optimizing the slump after the loss of small admixture combination type and dosage;(2)Study on mechanical properties and mix ratio of ultra-early strength fiber reinforced concrete.In order to further improve the performance of plain concrete,fiber reinforced concrete is a common and practical choice.Through different fiber blending schemes,the mechanical tests of strength,bending toughness,fracture toughness and impact toughness were carried out,and the optimal volume and economic volume of ultra-early strength fiber concrete were selected to determine its mixing ratio.(3)Research on hot curing technology of ultra-early strength cement concrete.In order to achieve ultra-early strength in low temperature environment,this paper adopts the maintenance mode of industrial electric blanket,and draws a conclusion by comparing the bending and compressive strength of pavement under different curing temperatures and time conditions.The results show that the higher the curing temperature is,it is not beneficial to the increase of the flexural strength of concrete,and even has a negative effect.The optimal curing temperature range is suggested to be20～30 ℃.It is proved that the industrial electric blanket can be used for pavement construction maintenance under low temperature environment in winter.(4)Study on fatigue performance of ultra-early strength fiber reinforced concrete.Of plain concrete,polypropylene fiber concrete,and three kinds of hybrid fiber concrete specimens under different stress level of fatigue test,through contrast test specimens under different stress level of fatigue life,fatigue equation and draw the S-N single logarithm curve,the curve obtained with typical road curve compared with concrete,The fatigue stress coefficient obtained is compared with the fatigue stress coefficient calculated according to the code.It is found that the fatigue life of concrete can be greatly improved by adding proper amount of fiber,especially hybrid fiber.(5)Research on construction and maintenance technology of super early strength fiber concrete technology for quick pass replacement board.The mixing technology,the best cutting time and the maintenance method under normal temperature construction conditions were studied to ensure the good effect in the construction and application of the test section,which provides a reference for the future large-scale application. |
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