Subgrade And Pavement Testing Technology And Quality Control

Aiming at the relatively lagging test situation in China, in this paper it carries a full-scale research on the sub-grade and pavement construction parameters based on the Luo-San highway in He-Nan, and it analyses the variabilities of them. After contrasting and analyzing the main design parameters' test methods of laboratory and field outside, it sets up the correlativities between the field bearing plate modulus and other parameters such as design dynamic modulus, Benkleman bean static deflection, field CBR value, consistency and density. By means of laboratory experiment, it assays the influence of the consistency on laboratory bearing plate modulus and laboratory CBR values, and establishes the relationships between laboratory and field values. Combined with the project, a more logical sub-grade quality test standard is put forward.By means of laboratory and field experimentation of typical semi-rigid base materials, the relationships among laboratory experimental values, field maintain values , field core values and construction criteria are put forward. And the relationships between different test methods are established. Using time-temperature conversion principle, it processes the intensity assessment of field cores, then offers the method of determining the test deflection of pavement surface.In this paper, it also analyses the disadvantages of methods in present pavement specification. By means of parallel field test experimentation, and gives the correlativities between test methods of specification and new pattern test methods, such as Road Surface Profiler, Ground Penetrate Rada test system, friction test vehicle, Falling Weight Deflectometer. Based on these correlativities, their test and quality control standards are formed. Imposing on the abundant FWD test data, a newly pavement intensity assessment standard is come into being. Recurring to the program EVERCALC5.0, the common rules of backcalculation modulus are introduced, moreover, the influence of instrument measurement error and input parameters are construed. Utilizing the characteristics of deflection basin, so that it can assess the intensity of whole pavement structure. At last, the correlativities of dynamic and static modulus are established at each structure layer.