Asphalt Pavement Cold Recycling Design Method And Performance Evaluation

Since reform opening,freeway construction of our country is rapidly developed in last 10 years. At the end of 2005, the total lengths of freeway have exceeded 50 thousand kilometers. Many freeways have been closed to the design usage life, affecting traffic speed and safe. Many high grade roadways have been into the period of maintenance and rebuilding.Comparing asphalt pavement cold recycling technique with traditional asphalt pavement maintenance methods, this technique has remarkable economic benefit, social benefit and environment benefit.Firstly, This paper is based on asphalt pavement recycling techinique experiences and research results. Old asphalt pavement performance is evaluated and representative RAP samples are obtained by different methods, in order to evaluate asphalt aged extent. Slow-setting cationic asphalt emulsion's constitutes are determined.Secondly, design methods of cold recycling are introduced in paper,Marshall and Superpave design methods are used. To different cement content cold recycling mixture, mix design and pavement performance evaluation are performed and lab test standards of asphalt emulsion cold recycling mixture are constituted. Based on Micromechanics method, amount of RAP in plant mixture is determined for quality control and quality assurance. Based on FEM, aged asphalt layer's effection mechanism is analysised.Finally, asphalt emulsion cold in-palce recycling's construction technics and in-place quality inspection standards are summarized.The conclusions of this paper indicate that asphalt pavement recycling technique is very applicable and economic measure for the present situation that many freeways are need to maintain or rebuild, so this technique has extensive application prospect.