VietNamNet Bridge – The bitumen surfaces of Highway 1 passing through Ninh Binh, Ha Tinh, Thua Thien-Hue, Khanh Hoa and Phu Yen provinces has subsided in many places because of the hot weather and overloaded vehicles.

Illustrative image -- Photo: VNA

The problems, which were also found on other new highways, were compounded by sloppy road-building work by some contractors.

This was revealed at a conference on Tuesday held by the Ministry of Transport.

A ministry task force inspected the road and discussed measures to remedy the situation.

The inspection revealed that about 70km of the 620km-long section of the highway that passed through Thanh Hoa and Thua Thien-Hue central provinces had slumped by five to seven centimetres.

About 90km out of the 593km length of Highway 1 passing Da Nang and Khanh Hoa also subsided to a depth of about 7cm.

Hoang Ha, director of the Science and Technology Department under the transport ministry and the deputy head of the task force, said that prolonged hot weather in northern and central areas last month lifted road surface temperatures to 60 to 70 degrees Celsius.

This softened the tar, which was further destabilised by the high number of vehicles using the highway, including many that were overloaded, said Ha.

The task force unit also said that other highways, including Highways 5, 3, 1A in the northern area, Highway 7 and 8 in the central area and Highway 1A in the southern area had also subsided.

A check on three weighing stations on Highway 1 and Highway 5 showed that 49 per cent of 24-tonne lorries were overloaded, and 50 per cent of 30-tonne lorries were overloaded.

Transport experts insisted the roads had to be quickly repaired because they could become slippery when it rained. The task force unit proposed to replace the tar being used at present with another kind of tar which was harder.

Tran Phuc Tu, general director of the Deo Ca Build-Operate-Transfer Joint-stock Company, proposed using additives while mixing the bitumen. This way, road surfaces could easily withstand temperatures of 60 degree Celsius, he said.

Deputy Minister of Transport Nguyen Ngoc Dong claimed that the ministry had been paying attention to changing technology and materials for road building and on inspecting and supervising construction work.

VNS