Research On Temperature Correction Of FWD's Deflection For Asphalt Pavement

Nondestuctive deflection testing using falling weight deflectometers (FWDs) is a effective tool to evaluate road condition, accurate FWD deflection data are key to the success of structural capacity study. Since asphaltic concrete materials are temperature dependent in nature, measured deflections and hence the structural capacity of pavement vary with temperature . Thus,a procedure to correct measured deflections to a standard temperature is required so that the comparision of data is a valid one. This paper study on temperature correction of FWD's deflection for asphalt pavement,so that we can evaluate road with accurate FWD deflection data,and FWDs can be widely used in testing field.There are the two main problems we need to solve about temperature correction of FWD's deflection:1, determination and prediction of asphalt concrete layers representative temperature 2, correct measured deflections to a standard termperature ,i.e. determine temperature correction factor.determination and prediction of representative temperature are on the basis of research achievement.Temperature data from the test sites were used to develop the temperature prediction model by regressive analysis. temperature correction of FWD's deflection for asphalt pavement depend on temperature stability of asphalt mix and thickness of asphalt concrete layer,viz these structural factors of asphalt concrete layer-moduli and thickness,as well as change of the whole structural stregth of different constructions result from the change of these structural factors.In fact the relationship between deflection and temperature is the relationship between deflection and asphalt concrete layer moduli.Hence ,in the sight of this relationship we analyse the influence of different structural factors on temperature correction by theoretical computation in this article. providing reference for temperature correction of deflection using data in situ .we collect deflection data relation to temperature from seven road in nanjing and hangzhou ,and develop the temperature correction model by statistical analysis.Finally, validation of the temperature prediction model and comparison of research results are studied.