Research And Practice On The Detection Methods Of Cement Concrete Pavement Freeways

In recent years, traffic volume has been increasing greatly. Some highways built in the past need rebuilding and extension because of the limit to community economy,technique standard and construction concept in the early years. Highways'rebuilding and extension are burgeoning questions for discussion and there isn't enough experience in rational and effective methods. It has been a question worthy of in-depth studies that how to detect the expressways'condition expediently and offer effect basic data for designing and construction.Based on the interrelated researches on the old road condition evaluation and countermeasure to road extension at mutual segment of Wu Huang freeway and the third annular urban road of Wuhan, it was studied that how to use ground penetrating radar (GPR) and Pressuremeter Testing to detect the freeway's condition and how to associate them with the traditional examining methods. It was studied that how to apply grey incidence theory in the analysis of pertinence in surface evenness mean-square deviation,pavement condition index,representative deflection and broken board rate. At last, an associated method of detecting freeway's condition was advanced and its validity was proved in practice.The results in the paper indicate that: GPR is comparative accurate in detecting pavement layer's thickness,structure hollows'location and size; modulus of deformation can be converted to modulus of resilience by the modifying method basing on the experiential relation advanced by Ministry of Machine Electronic Industries and the result is more consistent with the data obtained by loading plate test; the surface evenness mean-square deviation is correlative with pavement condition index and representative deflection by the grey incidence analysis and surface evenness detection can be used to narrow the range of other test; the associated detection method based on the maintenance data is an effective approach and the condition of freeway can be analyzed qualitatively by surface evenness examination,GPR detection,deflection test and be analyzed quantitatively by pressuremeter testing,boring through the pavement and the subgrade.The main conclusion is summarized and a further study's direction is anticipated at the end of the paper.