In the US state of Iowa, tough paving specifications are resulting in contractors delivering road surfaces that will last longer. The Iowa Department of Transportation (I-DOT) expects to see a highway road surface last 20 years and recently let the contract for a 25.7km road resurfacing project for Highway 92 between Winterset and Greenfield.
The 40km link between the two towns sees an average 1,365 cars/day travel on the highway, which was last worked on in 1994 and its surface was due for replacement.
In the US state of Iowa, tough paving specifications are resulting in contractors delivering road surfaces that will last longer. The 1229 Iowa Department of Transportation (I-DOT) expects to see a highway road surface last 20 years and recently let the contract for a 25.7km road resurfacing project for Highway 92 between Winterset and Greenfield.
The 40km link between the two towns sees an average 1,365 cars/day travel on the highway, which was last worked on in 1994 and its surface was due for replacement.
Norris Asphalt Paving was selected for the asphalt paving portion of the project. The stretch of Highway 92 is 8.5m wide with two 4.25m lanes, while the route was widened 610mm on each side. The milling and roadbed prep work was subcontracted by Norris to other contractors. A 7.4km stretch on the eastern end of the project posed a challenge because it had a concrete base. For their contractor to mill the on-average 114mm depth, Norris Asphalt had to close the stretch to traffic for 17 days. The rest of the highway project was milled cold-in-place with traffic flow maintained throughout construction. The milled asphalt was recycled as the contractor used 20% RAP in its HMA mix.
For the highway project, Norris Asphalt laid 11,031tonnes of HMA for the base lift and 22,405tonnes of asphalt was placed for the intermediate and surface layers. An additional 6.765tonnes of HMA was used for the widened roadway shoulders.
The firm used a new paver, a1252 Roadtec RP-195e, which it had received just in time for the job. Roadtec helped train the crew, which was then able to start work immediately. The machine’s stability and good view from the operator station helped with the work according to the contractor. Another important benefit was the Guardian telematics system, which allowed the Roadtec engineers to address and repair a technical problem remotely within just 20 minutes.
The better stretch of Iowa Highway 92 is but one chunk of the 440km state highway that runs from east to west across the state. The work that Norris Asphalt Paving performed on the project was subject to the Iowa DOT’s Quality Management - Asphalt (QM-A) program, which holds the contractor responsible for mix design, sampling, testing, and making mix adjustments if necessary. Norris Asphalt’s finished road passed all of the I-DOT random density core tests, which check for voids. The finished asphalt paved surface achieved impressive profilograph-measured 12.61 to 12.9 International Roughness Index (IRI) scores.
The 40km link between the two towns sees an average 1,365 cars/day travel on the highway, which was last worked on in 1994 and its surface was due for replacement.
Norris Asphalt Paving was selected for the asphalt paving portion of the project. The stretch of Highway 92 is 8.5m wide with two 4.25m lanes, while the route was widened 610mm on each side. The milling and roadbed prep work was subcontracted by Norris to other contractors. A 7.4km stretch on the eastern end of the project posed a challenge because it had a concrete base. For their contractor to mill the on-average 114mm depth, Norris Asphalt had to close the stretch to traffic for 17 days. The rest of the highway project was milled cold-in-place with traffic flow maintained throughout construction. The milled asphalt was recycled as the contractor used 20% RAP in its HMA mix.
For the highway project, Norris Asphalt laid 11,031tonnes of HMA for the base lift and 22,405tonnes of asphalt was placed for the intermediate and surface layers. An additional 6.765tonnes of HMA was used for the widened roadway shoulders.
The firm used a new paver, a
The better stretch of Iowa Highway 92 is but one chunk of the 440km state highway that runs from east to west across the state. The work that Norris Asphalt Paving performed on the project was subject to the Iowa DOT’s Quality Management - Asphalt (QM-A) program, which holds the contractor responsible for mix design, sampling, testing, and making mix adjustments if necessary. Norris Asphalt’s finished road passed all of the I-DOT random density core tests, which check for voids. The finished asphalt paved surface achieved impressive profilograph-measured 12.61 to 12.9 International Roughness Index (IRI) scores.
