About the research
The purpose of this project was to perform on-site and laboratory testing of a modified Iowa Department of Transportation (DOT) M-QMC mix placed on five slip-form concrete pavements in West Des Moines, Iowa. The aim of the project was twofold:
- Assess whether a modified mixture would be more likely to resist premature joint deterioration than conventional mixtures
- Assess the practicality of some innovative test methods being proposed for inclusion in future specifications and quality control plans
The modification of the mixture was based on findings of a multi-year, multi-university research plan seeking to better understand and prevent premature joint deterioration being experienced in Midwest locations. Because concrete placement was scheduled to occur late in the season, additional recommendations were made to reduce the risk of early age random cracking.
Several new test methods are being investigated as part of a Federal Highway Administration (FHWA) effort to develop more effective specifications based on measuring and accepting mixtures based on critical properties. These tests were conducted at the construction sites in order to evaluate the practicality of the proposed test methods in field conditions and assess if the acceptable results can be obtained in the field using mixtures such as the one specified.
- Test data collected thus far indicate that the M-QMC mixture is performing as intended, including improved resistance to deicing salts.
- The test methods under development appear to be contributing useful information, although not all of the methods are ideal for field applications.