Research And Analysis On The Old Cement Concrete Pavement Repair For Xiangtan-Shaoyang Section Of Hu-Kun Highway

The section of the old cement concrete pavement from XiangTan and ShaoYang(TanShao Highway) in HuKun highway is damaged seriously, causing poor driving comfort and numerous traffic accidents. In 2013, the average daily traffic of Xiangtan highway is more than 30000pcu/d. The traffic of the section between Xiangtan to TaLing which has the most traffic is over 5000pcu/d and it has reached saturation basically. Tan Shao highway has the high proportion of trucks, overloading of heavy vehicles is serious. Specifically, in the section of Xiangtan, Original road junction has been damaged severely because of the continuous maintenance in recent years, and the maintenance costs has increased continuously, the pavement needs rehabilitation badly.By means of the investigations for the pavement condition, basing on “Technical Specifications of Cement Concrete Pavement Maintenance for Highway( JTJ 073.1-2001)”, “Highway Performance Assessment Standards(JTG H20-2007)”, failures and the causes are able to be found out. The pavement performance evaluation indicator was calculated to understand the whole condition of the pavement according to the “Highway Performance of Assessment Standards”, and provide reference for rehabilitation. Origin Lab was employed to analyze the data of Tan-Shao Highway of the past several years to establish exponential models to predicate the pavement condition, and determine the rehabilitation time.Axle load and traffic survey was conducted on the pavement to calculate the average traffic volume and predict the average annual growth rate. According the equivalent axle load, the traffic was very heavy. Proper rehabilitation programs were chosen based on the original pavement structure and pavement condition. Five rehabilitation plans were recommended with reference to the specifications and rehabilitation experiences. The structural stress and bearing capacity of all the five alternative plans were qualified to meet the performance standard. Traffic organization, environment, economic effect and anticipated effect were taken into consideration to determine the final rehabilitation program.The approved rehabilitation program was: Plan I was recommended for old cement concrete of Xiangtan section: 2.5cm AC-10 isolating course+18cm CRC+1cm anti-cracking and waterproof tack coat with modified asphalt+6cm AC-20 C with modified asphalt+4cm SMA-13 with modified asphalt; Plan IV was recommended for K1247+120~K1250+000 of the left lane of Shaoyang section: 1cm anti-cracking seal coat with crushed stones and emulsified asphalt+10cm AC-25 C with fiber+6cm AC-20 C with modified asphalt+4cm SMA-13 with modified asphalt. The rest sections were recommended with plan III: 1cm anticracking and waterproof tack coat with modified asphalt+10cm asphalt treated crushed stone+6cm AC-20 C with modified asphalt+4cm SMA-13 with modified asphalt.The research results could provide references for Tan-Shao Highway and similar pavement projects.