Research On The Seepage Characteristics Of Asphalt Pavement In Fujian Province

The existing asphalt pavement usually take surface slope as the main drainage way, without considering internal stagnant water of formation of pavement structure resulting from rainfall. Because the the factors of rainfall infiltration, permeable pavement structure, and the traffic load, the humidity of pavement and subgrade constantly changes, strength and stiffness drop, embankment subsidence, pavement cracking and other highway engineering disease are widespread. Therefore, it is important to realize the rule of moisture migration of roadbed and pavement and realize the influence of the moisture migration because of the traffic load.Based on the above, this paper aiming at three typical asphalt pavement to research the moisture migration of the asphalt pavement systematically under the condition of rainfall infiltration and rainfall-stress coupling infiltration and rainfall infiltration on craze pavement, based on Richard unsaturated flow equation, Biot consolidation equation, with rainfall as the main line, through the indoor test, the model calibration, reference predecessors’ test data, using numerical simulation method.1、Though SEM electron microscopy test to boserve pore size distribution in roadbed and pavement, it is found that pore and fracture are widespread in noncrack roadbed and pavement materials. According to the methods which Fredlund and Rahardjo proposed, moisture retention curve are determined.2、After the end of rain, the entire road surface layer close to saturation, and vertical negative pressure head distribution curve is full for inverted pavement and semi-rigid pavement.3、With rainfall-vehicle static load coupling effect, the negative pressure head values in three asphalt pavement are larger than it only considered the rainfall. The largest head value of pavement is semi-rigid pavement, with In inverted pavement, the added-values of surface course and upper base are between 1%～2%, while the added-values of Graded gravel layer are between 5%～7%.4、No matter it is in the precipation or after precipation, the performance of porous pavement is the best while the moving ability of flip pavement and the semi-rigid pavement are not as good as the porous pavement due to high degree of negative pressure and saturation. If the pavement is under the pressure of vehicles above, the inner void is compressed. This would lead to flowing pressure which affects the pavement deeply.5、If there are cracks on asphalt pavement structure, under the two kinds of rainfall, the suction head value around the cracks increase significantly. It is showed that cracks appearance greatly improve the pavement infiltration ability. However, when the crack width is in an order of magnitude (0～1 cm), the change of suction head is not big. The cracks just makes the surrounding significantly higher suction head.Based on the above, it can provide the reference, for seepage characteristics theory research and application in asphalt pavement.