The Application Of FWD In The Evaluation On Concret Pavement Property

With the development of China highway construction, As a kind of advanced nondestructive examination device the FWD is used more and more widespread. At the same time its test and experiment techniques have developed accordingly. FWD can offer more accurate properties parameters of pavement which will be applied as the scientific data to service for evaluztion on pavement properties. All these show the obvious advantages of FWD.The thesis introduces the development situation of China highway and the application background of nondestructive test technology in the highway construction fields. What is more ,it reviews the development history of FWD, rigid pavement structure theory analysis model and the study of pavement materials dynamic parameters, then put forward the content and meaning of this study. In detailed, it introduced the FWD application study on concrete road strength assessment, which include the relation between deflection basin and load axle vertical displacement, the actual measure characteristics of FWD deflection basin and backcalculation in situ material properties using an appropriate analysis technique.It introduced substantially the FWD application study on existing concrete pavement joint load transfer capacity evaluation. To the rigid road construction, the joints distresses and dis-function are very common, and the main distress types include drop off, bumping and concrete pavement comer break. In the aspects of pavements structures it takes the forms of the deficiency of load transfer capacity and non even cavity beneath cement concrete slabs. Based on the engineering practice, this thesis develops a cement concrete pavement finite element analysis procedure. Furthermore, it analyses the stress distribution of joint load transfer steel bar and base supporting condition by using theory method. Through the collection of multi -type load transfer bar base cavity dimension data measured near the joints or the joint comer which come from the indoors cement concrete test section, this paper studies the evaluation of rigid pavement joint load transfer capacity, the position determination of ground cavity, the prediction of dimension of cavity systematically and proposed practicable evaluation table, evaluation indexes and evaluation procedures. Finally, the application of FWD in the evaluation on pavement properties of LEIYI expressway is introduced to prove the research fruit.