Mechanism And Mechanical Analysis Of Void Beneath Cement Concrete Slabs

In recent years, along with the highway construction development, cement concrete pavement in our country has been lengthening year by year. Among the cement concrete pavements completed, some have posed problems within their service life; some have even gone into serious dysfunction. Problems like slab breaking, slab staggering and bridge slab dent, etc. caused by void have caught more and more attention. Therefore, the research on void mechanism and its effect on the stress of cement concrete pavements is very necessary. The research will better guide our effort in the prevention and reparation of void. The thesis made some research on the problem of void as follows:(1)Microcosmic research of mechanism of void beneath cement concrete slabs. For the materials of base course are composed by solid, liquid, gas and gas-liquid contact membrane, through the principle of effective stress, the thesis analyzed the stress of base course beneath cement concrete slabs based on the triple-phase body theory of road materials. The author made a research on void mechanism and analyzed the evolvement of void from a microcosmic level, primarily analyzed the effect of the gas in base course beneath cement concrete slabs.(2)The thesis analyzed the effect of void on the stress of cement concrete pavements from both the dynamic and static perspectives. Based on the established researches, the author discussed the work laws and mechanical response of base course of cement concrete pavements under vehicle repetitive load and moreover analyzed the deflection and stress of base course of cement concrete pavements under vehicle vibration load when void occurs; The author analyzed the deflection value of the void road slab under different loads, different load positions, different void sizes and different thickness of slab by means of finite element software and made comparisons with achieved test results.