Surfacing against the cold
By Steve Skinner15 January 2010
Intermountain Slurry Seal adopted the micro surfacing process when it won the contract to resurface a 14.5 km of six-lane carriageway between Wasatch Mountain and Salt Lake City in Utah, US.
Previously, Utah state used an open graded surface course (OGSC) consisting of a thin layer of hot-mix asphalt and 13 mm of aggregate. While this surface initially provided motorists with a smooth ride, extreme winter temperatures prevented the OGSC from bonding correctly and in subsequent winters freezing and thawing created potholes.
Utah Department of Transport (UDOT) resident engineer, Deryly Mayhew said, "We were patching potholes constantly because the surface was cracking severely, so we decided to see if micro surfacing could perform better."
Intermountain Slurry Seal milled the OGSC and then used a Bergkamp M1 full-size continuous micro surfacing paver to apply two layers of micro surfacing totalling 14515 tonnes with 1678 tonnes of polymer-modified emulsion, 73 tonnes of cement and over 1 million litres of water.
The whole project saw the Bergkamp M1 pave in excess of 1 million m2.Following the resurfacing, Mr Mayhew said, "Last winter we only observed about seven potholes and those had more to do with the underlying asphalt surface than the micro surfacing. With the OGSC we had more than 700 potholes each year."