| The transverse crack of asphalt pavement is the main factor that affects the strength of pavement structure.It is very important to study how to prolong the service life of asphalt pavement and accurately predict the development law of transverse crack.At present,most of the prediction models of the transverse crack of asphalt pavement are mainly aimed at the low temperature shrinkage crack,and the factors affecting the transverse crack of asphalt pavement are multi-factors and multi-index.Therefore,this paper considers many factors together,the asphalt pavement transverse crack prediction model and optimization to do the following research:1.Considering the impact of high and low temperature,its cumulative degree,and precipitation on pavement performance,and combining the feasibility of obtaining data,it is determined that the main environmental parameters of the survey are the humidity coefficient,the accumulated temperature above 30?,and the annual average minimum temperature.Based on the environmental factors of the survey,Based on the service life and the pavement performance status,the asphalt pavement structure and cracks in different sections were investigated.2.Because the temperature shrinkage coefficient of cement stabilized macadam material can reflect its crack resistance,the effects of cement content,gradation type and mixing method on the temperature shrinkage performance of cement stabilized macadam material were studied,and the traditional strain gauge measurement method was used.It is optimized,and a high-precision temperature shrinkage coefficient measurement method using glass-ceramics as a compensation material and a shielded wire as a lead is established,and a new temperature compensation formula is applied.3.Based on the surveyed road structure and crack data,combined with the external environment and traffic load factors,a partial correlation analysis is performed on the factors that may affect the lateral cracks of the asphalt pavement.The surface layer mixture type is a modified SMA asphalt mixture,and the base layer is a cement stabilized macadam semi-rigid base layer.The road data is based on a multiple regression method to establish a baseline model.4.Using the established benchmark model equation of asphalt pavement transverse crack prediction as a starting point,referring to AASHTO design method and the concept of thickness coefficient,the equivalent thickness coefficient of asphalt pavement is proposed as a means to correct the influence of asphalt mixture on the surface layer.At the same time,the influence of base material temperature shrinkage coefficient on transverse cracking of asphalt pavement is found out,and the crack resistance of base material is characterized by temperature shrinkage coefficient.5.The measured value of the transverse crack of the asphalt pavement is compared with the predicted value calculated according to the prediction model to verify the validity of the model,and the influence of the newly established prediction model of the transverse crack of the asphalt pavement on the low temperature crack of the asphalt pavement Factor sensitivity analysis for reference in pavement design. |
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