News » Headlines
Investigation into cracks points to execution
  • | dtinews.vn | March 24, 2010 11:31 AM

>> Thang Long Bridge to get another makeover

>> New bridge, new cracks

The Institute of Transport Science and Technology under the Ministry of Transport revealed the main cause for cracking problems on Thang Long Bridge’s surface on March 23.

The bridge's cracked surface (Photo by Nhu Quynh)

The cracks are the result of stone mastic asphalt (SMA) cooling off more quickly than it should have when it was laid.

SMA composition consists of coarse aggregate, filler, binder, and fibre to provide a deformation resistant, durable surfacing material, suitable for heavily trafficked roads.

Doan Minh Tam, Director of the Institute revealed, “There are many causes for the flaws on Thang Long Bridge’s surface but the main reason was the way the material was in the execution of properly laying the surface on the site. The necessary temperature should be between 120-170C degrees while spreading, rolling and pressing the SMA. The outdoor temperature must be 15C degrees or higher however, because of cold weather and heavy winds, the SMA cooled too quickly which is the cause of the cracking problems on the surface.”

At present, the Institute continues to inspect and re-evaluate the issue. They have also proposed a solution to resolve the problem. At the same time, the Institute will keep monitoring other locations on the bridge.

“After fixing the flaws, the Institute will review mistakes from those who were involved in causing the cracking problems,” added Tam.

Leave your comment on this story