Study On Super-Thick Cement Concrete Pavement Structure On Lean Concrete Base

The cement concrete pavement is one kind of long life pavement, which design reference period general is 20-30 years. But in the actual used process, many cement concrete pavements often appear the extensive damage after 5, 6 years. There are many reasons that cause early time destroy of cement concrete pavement, but the void is one of main reasons that cause early time crack of cement concrete pavement. The theoretical analysis indicates that increasing the pavement slab thickness is an effective way to lengthen the pavement life. This paper, depending on the actual engineering, has researched super-thick cement concrete pavement on lean concrete base from two aspects that are theoretical calculation and experiment.The load stress changes of super-thick cement concrete pavement on different design parameter are analyzed by ANSYS. With interfacial interaction considered, the conclusion that the super-thick cement concrete pavement approach to the separation type is obtained. The formation principle and distribution characteristic of void are researched. The influence of different void area and each design parameter to load stress is analyzed by ANSYS. The slab fatigue life with void is calculated, that is finded the conventional thickness cement concrete pavement fatigue life calculated according to critical load position, is basic same to the super-thick cement concrete pavement fatigue life calculated with 1/2×1.2×1.2m~2 slab corner void . The design thought of the super-thick cement concrete pavement is discussed initially.The thermal stress changes of super-thick cement concrete pavement on different design parameter are analyzed by ANSYS. The fatigue life and coupling stress of the super-thick cement concrete pavement are calculated. That is finded the effect that increasing slab thickNess lengthen pavement fatigue life is remarkable. The evaluation method of the joint load transfer capacity that is adapted to the E ground model is proposed. The arrangement condition of dowel bar is analyzed by ANSYS beam element. The surface contact stress of dowel and concrete is analyzed by ANSYS solid element. The results indicate there is stress concentration phenomenon in the concrete surrounded the dowel bar, which causes this part of concrete premature destruction. And the measure that dowel bar application performance is improved in polymer concrete is proposed initially.The compressive strength test, bending strength test, bendingelasticity modulus test, and permeability test are carried on.The experiments indicate, each mechanics performance of lean concrete has the good relevance and osmotic pressure is generally about 0.6-0.9MPa.