Montana on the Move

Sep 29, 2011

On Wednesday, October 21, Gilman Construction began paving I-15 south of Lima, Montana, with Evotherm warm mix asphalt.  The project is part of an NCHRP 09-49A study evaluating the field performance of warm mix technologies.  The Federal Highway Administration had representatives present, along with their mobile asphalt pavement mixture laboratory.  Scientists and engineers from the Washington State University and the Montana D.O.T. also visited the site earlier in the week.  

The project wound up highlighting three ways to make money with Evotherm: fuel savings at the plant, incentive pay, and a faster paving operation. On the first day of Evotherm paving, the mix temperature was lowered 50 °F from 325 °F to 275 °F. Evotherm was injected using foaming equipment already installed at the plant.  The volumetrics were consistently within specifications throughout the day. The paving crew found they could reduce the number of roller passes needed to achieve target densities, thus allowing them to speed up their paving operation. Core samples taken from the road had an average density of 94.3%, resulting in incentive pay for the contractor. The employees at the mix plant and on the jobsite also noticed improved coating compared to their typical mix. 


 Author: Tom Girardeaux