Study On Temperature Contraction Crackcement Of Stabilized Sand Gravel Base In Cold Region

With the cement stabilized sand gravel base in highway construction, the widely application in environmental effect to crack under the characteristics are also widespread concern. For northeast cold, ambient temperature changes to the influence of the grass-roots craze. According to the grassroots level temperature contraction principle, the base crack analysis model is created. Asphalt surface of unpaved cases, from summer to winter, calculate gravel base of the average crack spacing. Comparison of the calculated distance and the distance. The results show that there are some differences between the two. The differences are due to temperature contraction theoretical calculation does not take into account is the primary internal temperature changes along the depth direction. Road Base internal contraction is not uniform. Therefore, it is necessary to further study cement stabilized gravel base of the crack spacing by the finite element method.Using ABAQUS software, establish of a temperature and shrinkage crack model, which contains a grassroots, sub-base and subgrade. To determine the density of each layer, modulus, Poisson ratio and the temperature coefficient of shrinkage, editing changes along the depth of the temperature field model, Set the boundary layer conditions, grass-roots direction along the length of road conditions. In case of Qiqihar City 5% of the cement of cement stabilized gravel base, gravel base of the critical crack spacing of about 15.7m. This is consistent with the actual survey results verify the validity of the model.Basic model has some applicability, road surface conditions change, such as primary material parameters, temperature and other loads and boundary conditions, cracks of cement stabilized gravel base model still applies. Width of the grass-roots model that has some effect, that the crack tip stress intensity factor and the primary difference between the length of an exponential relationship model. Using the finite element method, to analyze the surface layer of asphalt added gravel base case temperature shrinkage cracking. Gravel base of Asphalt surface layer the crack tip stress intensity factor is even smaller.In the cement stabilized gravel base on the paving asphalt surface, asphalt absorbs heat insulating layer has the role, so that gravel base temperature range is smaller, thus reducing the cracks. Therefore, in cement stabilized gravel base paving as soon as paving asphalt surface layer helps to reduce cracks in cement stabilized gravel base.Basic physical structure is very difficult to be buried sensors. Instrument is not easy to collect data in the field, which is the force deformation data of the physical structure. It selected material, which is similar with grass-roots level, in order to simulate grass-roots change in temperature deformation and forces. Analysis of cement stabilized gravel base temperature conditions of cracking, used to verify ABAQUS model.Thesis research in Pavement Structures and Materials in the design and research, and the surface reflective cracking of research has some meaning.