| The pavement performance testing is depending on the periodical manual examination, limitations, only when the surface of pavement can be detected, and difficult to timely found internal damage of pavement structure. It has some limitations. It is difficult to find the internal damage of pavement structure,and only when the disease of the pavement surface can be detected. The preventive maintenance measures formulated on this basis, belong to the routine maintenance of pavement distress not the true preventive maintenance. Therefore,it need to develop the on-line detection of structural response and state by using sensors and damage identification technology, which can identify the pavement performance status and potential damage at the same time.In this paper the health monitoring and evaluation system of the asphalt pavement were developed to provide the basis of pavement design, pavement construction, maintenance decision. The main research contents are as follows:Aiming at the damage types and reasons,the failure patterns were investigated and surveyed. It was found that the crack and permanent deformation were the typical failure patterns about the semi rigid base asphalt pavement.For the crack failure, the fatigue cracking of the semi rigid base and the asphalt pavement should be control,and for the permanent deformation,the deformation of asphalt layer should be control. Based on relevant researchs at home and abroad, the health monitoring and evaluation system were proposed,and the evaluation and prediction models were selected and evaluated. The tensile stress(strain) of the bottom layer of semi rigid base(asphalt pavement) and the vertical compressive stress of sub asphalt layer were choosed to identify the pavement health status. The health monitoring methods at full time domain were put forward, and the ideas and methods of damage cumulative were introduced.Through the temperature data measured on the highway field, Pavement temperature distribution at the sunny, cloudy, rain were researched. The temperature effect of the plain area,hilly area,mountain area,embankment and cutting were analysed. Temperature difference and temperature gradient of the pavement internal were collected and analysed. The temperature prediction model and adjustment coefficient were established.The dynamic modulus of asphalt mixture is the key material design parameters forthe system design method of mechanical experience.The regular of temperature and frequency on the dynamic modulus based on the existing achievements,and the dynamic modulus master curve of SMA-13,AC-20,ATB-25 were established. With the Witczak prediction model, dynamic modulus of each layer were revised based on the Pavement temperature,and the distribution characteristics of the dynamic modulus of each layer were researched.On the basis of the mechanical response of asphalt pavement, mechanics analysis model is established based on dynamic modulus. the influence of pavement mechanical under uniaxial load and multi axial loads were analyed. The influence of load, speed, temperature on pavement pavement response were researchded,while the loading frequency at different vehicle speed and depth of the pavement were studied.According to the field measurement temperature, on the basis of the asphalt mixture dynamic modulus changing with temperature, the negative temperature difference, daily temperature distribution, monthly extreme temperature, different weather conditions on the mechanical response were studied. Based on response surface method(RSM), The relationship between temperature on pavement mechanical response were researched,and the sensitivity of temperature were analyzed.Then the prediction model of pavement mechanical response baed on the temperature-load-speed was builded.The health status of asphalt pavement under realtime temperature were analyzed.The shortcomings of existing maintenance decision were analyzed, and the method of asphalt pavement maintenance decision based on health monitoring was put forward. |
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