The Bureau of Survey and Design, Department of Highways, undertook the improvement and rehabilitation of a U-turn bridge on Highway No. 1 at Lam Sai (Outbound), Ayutthaya Province. The project involved resurfacing the asphalt pavement with a new asphalt concrete layer over a total width of 29.50 meters, covering the section from Km. 55+075 to Km. 56+300 (1.225 km in length). The budget for asphalt resurfacing work alone was approximately THB 15 million.

The original pavement structure was constructed with concrete. The project aimed to rehabilitate the existing surface by overlaying it with asphalt concrete to improve fatigue resistance and minimize rutting. Although the resurfaced pavement initially achieved satisfactory structural performance, cracks like those found in the deteriorated original surface often reappeared shortly after opening to traffic. These cracks — known as reflective cracking — significantly reduce the road’s performance and service life.