Study On Early Temperature Characteristics Of Roller Compacted Concrete Base Asphalt Pavement

As urban roads in China tend to be overloaded gradually,the traditional semi-rigid strength attenuates rapidly and is easy to shrink and crack,leading to the occurrence of diseases on most urban roads before reaching the service life.As a rigid base,roller compacted concrete(RCC)can overcome the disadvantages of semi-rigid base and is gradually applied to heavy-duty roads.For cement concrete,its early age performance will have a certain impact on its long-term performance,and the temperature characteristic is one of the important influencing factors.Therefore,this paper takes the heavy load road lifting and reconstruction project in a Marine climate region as the background,and combines the research status of temperature field and temperature stress of early age of cement concrete at home and abroad to analyze the temperature field and temperature stress distribution and development law of RCC base course in early age,as well as the influence of asphalt layer on RCC base course.In this paper,the temperature field of RCC structure layer is numerically simulated and analyzed firstly.The heat transfer theory is adopted to select the heat exchange model with the environment and the heat of cement hydration model.Based on the principle of finite difference,the numerical simulation program of RCC temperature field in early age is written.Then the accuracy of the program is verified by the temperature field data measured in the field test.The results show that the program has a high accuracy in the simulation of the temperature field inside the RCC structure layer,but there are many influencing factors on the roof,and the simulation accuracy of the temperature field on the roof is general.The program is used to simulate the temperature field under different working conditions.The results show that different curing conditions and laying time have significant influence on the temperature field at the early age.Secondly,according to the non-linear distribution law of temperature field,according to the superposition principle and stress history to write MATLAB program to calculate the temperature stress of RCC structure layer at early age.The development law of temperature stress under different working conditions is analyzed.Finally,the temperature field and the temperature stress of RCC base layer with asphalt layer are analyzed,and the temperature stress of RCC structure layer without asphalt layer is compared,which provides theoretical basis for RCC base seam.To sum up,through the research on the above contents,this paper mainly comes to the following conclusions:(1)the selection of appropriate construction time and health maintenance method has a significant impact on the reduction of temperature difference and temperature stress within the layer of RCC structure.The results show that if a single health maintenance method is adopted,the white geotextile has the best health maintenance effect.Summer should choosein the evening construction,winter should choose in the daytime construction.(2)for compound pavement,asphalt layer will dramatically increase the temperature gradient of RCC base,so that the temperature stress increases sharply,resulting in cracks.In order to prevent this situation,it is necessary to conduct pre-cutting joint treatment for RCC base.