REMAP - A Probabilistic Survery of Iowa's Perennial Rivers and Streams, 2007

This monthly report from the Iowa Department of Transportation is about the water quality management of Iowa's rivers, streams and lakes.

Vendor Ranking, February 21, 2011

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Vendor Ranking, March 16, 2011

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Vendor Ranking, July 21, 2011

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Vendor Ranking, July 12, 2011

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Vendor Ranking, July 1, 2011

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Vendor Ranking, June 30, 2011

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Vendor Ranking, June 21, 2011

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Vendor Ranking, April 21, 2011

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Vendor Ranking, April 21, 2011

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Vendor Ranking, August 3, 2011

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Vendor Ranking, August 16, 2011

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Vendor Ranking, September 7, 2011

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Vendor Ranking, March 22, 2012

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Ranking of HMA Moisture Sensitivity Tests in Iowa, RB00-012, 2012

Several agencies specify AASHTO T283 as the primary test for field acceptance of moisture susceptibility in hot mix asphalt. When used in this application, logistical difficulties challenge its practicality, while repeatability is routinely scrutinized by contractors. An alternative test is needed which can effectively demonstrate the ability to screen mixtures based on expected performance. The ideal replacement can be validated with field performance, is repeatable, and allows for prompt reporting of results. Dynamic modulus, flow number, AASHTO T283, Hamburg wheel tracking device (HWTD), and the moisture induced sensitivity test (MIST) were performed on plant produced surface mixes in Iowa. Follow-up distress surveys were used to rank the mixes by their performance. The rankings indicate both the quantity of swelling from MIST conditioning and submersed flow number matched the performance ranking of all but one mixture. Hamburg testing parameters also appear effective, namely the stripping inflection point and the ratio between stripping slope and the creep slope. Dynamic modulus testing was ineffective, followed by AASHTO T283 and ratios produced from flow number results of conditioned samples.