Study Of Pavement Temperature Field Model And Accumulation Of Strain In Road Base By Field Monitoring

For an actual pavement, it always suffers from complicated load condition. Not only the load caused by traffic is cyclic, but also the load caused by changing temperature field is cyclic. Especially in recent years, heavy vehicles and over load vehicles become more common, and extreme weather appears much more frequently. Those factors make it vital important to study the working performance of the actual pavements in our country.By burying different types of sensors, the pavements in service are monitored for one year. And based on the logged data, the temperature field and the path of strain of changing different types of road bases are studied. The sensors applied include temperature sensors, dynamic type strain sensors and static type sensors. And they are used to monitor pavements with different types of base including large stone macadam asphalt mixture base, cement-stabilized macadam base and foamed asphalt base, for one year.A temperature sensor logs a piece of data every 10 minutes. Based on the analysis of numerous data, the elliptical model for temperature field is established and proved. Comparing to the traditonal statistic method, this model is based on a simple model which is easy to be applied in other cases. Comparing to theoretical method, this elliptical model is much simple, and it can calo get the necessary parameters.A dynamic type sensor logs 100 pieces of data per second, it’s used to monitor the dynamic strain response of cement-stabilized macadam base to moving vehicles. And the test was performed every 6 months. By analysis of the logged data, the strains from different sections, from different distances respecting to curb, from different directions, and from different time are compared. Besides, the obvious affected radius on longitudinal strain at the bottom of base caused by a moving tire, and magnitude of strain caused by different types of vehicles are also induced.A static type strain sensor logs a piece of data every 10 minutes, and it’s used to monitor the strain and time in the cement-stabilized base and foamed asphalt base for 1 year. Combining with induced results from the study of dynamic data and survey of traffic volume, it’s figured out that almost all data static type sensor offered respects to the strain out of the influence of traffic load. In other words, it’s residual strain. According to that, by combing the synchronous logged temperature, two different methods are applied to transfer all the residual strain of two different bases to equivalent strain under the same temperature, which offers the whole process of accumulation of the plastic stain.The elliptical model of temperature field depicts the relation between changing paths of temperature at different level, it offers a new method for its prediction. And the two methods to induce the accumulation of plastic strain can help analyze the performance of base over time, and it also offers important data to support the study of fatigue of base in actual pavements.