Study On The Structure Of Heavy-duty Cement Concrete Pavement For Resisting The Extra-heavy Load Traffic

The Extra-heavy Load Traffic is a purpose-special transportation to transport specific goods which with extra-heavy weight and can not be divided, such as nuclear power units, generator rotor and stator, chemical reactor. The axle load of the vehicles which transporting The Extra-heavy Load Traffic is usually exceeding the regulated limit. The cement concrete pavement without reinforcement will be destroyed easily by Extra-heavy Load Traffic. The damage includes pavement slab pumping, slab staggering and fracture, etc. The study on the properties of The Extra-heavy Load Traffic and analysis the stress of cement concrete slab is of great significance for preventing the slab from various diseases, improving the performance and extending the service life of the road.By analyzing the properties of the Extra-heavy Load Traffic, this paper puts forward the definition of The Extra-heavy Load Traffic and the formula used to distinguish the axle load of The Extra-heavy Load Traffic limits from other traffics. Research is elaborated as follows:1. The distinctive failure modes of the pavement for resisting the Extra-heavy Load Traffic is described after analyzed the properties of the Extra-heavy Load Traffic and the reasons why the cement concrete pavement is damaged at the initial stage. The Extra-heavy Load Traffic will speed up and aggravate the erosion damage and abrasion damage. Erosion damage is the main reason causing the slab fracture. The erosion damage and the slab fracture can promote each other, thereby causing surface transverse cracks, longitudinal cracks and net cracks.2. The finite element analysis is suitable to analyze the stress of the pavement for resisting the multi-axle and extra-heavy load traffic. The most unfavourable position of the slab is determined by taking into account both the stress distribution and the displacement of concrete slabs. The rule of the stress with different thickness and compositive elastic modulus of the basement is stated with finite element analysis. The Extra-heavy Load Traffic can be divided into two types:the concentrated loads and the intensive loads. The most unfavourable position of the slab with both the concentrated loads and the intensive loads is the slab corner. The stress of the slab with the concentrated loads is larger than the intensive loads.3. Increasing the thickness of concrete slab can effectively reduce the stress on the slab bottom, whereas increasing the compositive elastic modulus of the basement is not. Increasing the thickness of the slab, choosing the anti-erosion material with great strength can reduce the stress of the slab and extend the service life of the concrete pavement. The reasonable thickness of the concrete slab for resisting the extra-heavy load traffic is 0.42 to 0.50 meters after analyzing with finite element analysis.4. By analyzing the influence of the temperature stress on the Extra-heavy Load Traffic cement concrete pavement, the law of the temperature stress with different length and width of pavement was summed up. The temperature stress of ordinary concrete plate which is about 6 meters in length is on the peak. While the temperature stress of the cement concrete pavement resisting the Extra-heavy Load Traffic increases linearly with the length and width of the plate increasing. The reasonable range of plate dimensions is as follows:4 to 5 meters in length and 3.5 to 4 meters in width.