UNM Professors Work with State DOT to Improve Quality of Pavements in New Mexico

May 11, 2011

rafiIn New Mexico asphalt pavement is subjected to tremendous changes in temperature, sometimes as much as forty degrees in the course of a 24 hour cycle. Those temperature changes, combined with the constantly varying traffic loads the pavement must support, are very hard on materials. That is why the NM Department of Transportation is constantly searching for ways to prolong the life of pavement.

UNM Professor of Civil Engineering Rafiqul Tarefder has a contract with the NMDOT to find the best option for a perpetual pavement. The NMDOT defines that as asphalt pavement designed and built to last longer than 50 years without requiring major structural rehabilitation or reconstruction.

Tarefder’s project involves the materials and mechanics of pavement - looking at the layers of asphalt pavement and learning how the aggregate interacts with the asphalt binders, and experimenting with the ways the layers of pavement react to various stresses.

He works with a team at UNM that includes Civil Engineering professors John Stormont and Percy Ng, and Ph.D. student Damien Bateman to understand the kind of stresses that cause the asphalt to crack and deform.

Tarefder believes he can take the information he gets from examining the molecules at the nano scale and model it so that it will work at the micro and macro scale. He hopes to understand how tiny cracks in the pavement begin and grow into big cracks. And he plans to try to find a way to counteract the weakness between atoms that may be at the heart of pavement problems.

Tarefder has another 3-year contract with NMDOT for development and local calibration of advanced materials and distress models and plans to use them in the design of roadway pavements more efficient.

Today NMDOT tries to make pavement last longer by using extremely thick layers of asphalt, but that costs millions of dollars annually. Tarefder says if he can find a way to allow the transportation department to use thinner layers of pavement that can still withstand the constantly changing strains; it will save money for taxpayers. He says building pavement that can stand up to 50 years of traffic, with only minor resurfacing is one of the great infrastructure challenges of the 21st century.