Study On The Techniques Of Maintain And Widened Of Cement Concrete Pavement

Along with dramatic development of transportation industry, the overload vehicles are increasing more and more, which leads to heavy axle load for the cement concrete pavement, therefore, varying degrees of damage were appeared in quit a number of roads after using a few years. The cement concrete pavement has the characteristics, high maintenance cost, long curing time, serious traffic disturbance during the maintenance period; and hard to repair when damaged, furthermore, with escalation of the traffic volume, a great many of cement concrete pavement could not satisfied the requirement of current traffic volume. So these roads need to be widened.This thesis is supported by the highway reconstruction project of Henan G105 line S325 line intersection to the of YU-WAN highway junction, which maintenance and widen the cement concrete pavement. The research contents including disease criterion, maintenance programs, splicing technology of old and new pavement, design of mix proportion and performance test study of surface layer concrete for the repair portion and widened portion.(1) Investigate the disease of the cerement concrete pavement of the supported-project, using ANSYS software to analysis the factors which causing crack, fracture and else diseases. It is discovered that heavy traffic load, temperature and load stress coupling taken a great effect for concrete pavement fracture.(2) Proposed three kinds of board replacement ways: replacement of the whole board, local displacement and angular displacement, and also proposed appropriate criterion for each way. For local replacement, the length of the replacement should be 2/5 to 3/5 of the length of the board. Using ANSYS software to study the size the triangular patch, obtained the result when the length of right-angle side is not longer than the half-length of the board, the longer the size the better.(3) The splicing place of old and new pavement using set cross-tie for the thickNess direction of old pavement. Through the analysis of ANSYS, showing that decrease the distance between cross-site has not much improvement for load transfer effect. The effect of setting steps below the base of cement concrete pavement could be ignored. If only analysis the lap width of panels, the result show that the surface layer overlaps is appropriate about 30 cm. Moreover, setting asphalt concrete layer between new widen road pavement and basement. It could be known through ANSYS simulation analysis that asphalt concrete layer has stress-absorption function, and 3cm thickNess is more economical and reasonable.(4) Design of mixed proportion for ordinary concrete and steel fiber reinforced concrete, and did experimental study of the properties for steel fiber. The results show that for same age period, the flexural strength of steel fiber concrete is 16.2% to 20.3% higher than ordinary concrete, and also study the strength effect by different amount of steel fiber admixture, when the volume ratio exceeds 0.8%, the strength increase is not significant.(5). According to the function of stress absorbing layer, of YF type asphalt mixture, the void ratio control in less than 2% whetstone than between 6.5 to 7.5%, which YF-5 and YF-10 asphalt mixture respectively to thickNess of 2cm and 3cm stress absorbing layer; put forward stress absorption layer material of the technical requirements and the freeze-thaw splitting test, temperature constant velocity tensile test and seepage test indicates that the stress absorbing layer has good road performance.(6) Practical application the remedial measures and widening programs proposed above for the supported-project, and using the mixed proportion studied in this thesis to design and constriction, and the practical application effectiveness is preferably.