Concrete can be susceptible to expansive reactions between alkalis in the Portland cement and reactive forms of silica in the aggregates, which can ultimately reduce the lifespan of the concrete used in pavements and other structures. When this occurs, it can result in costly repairs or even replacement of infrastructure. While alkali-silica reactivity (ASR) has been documented as an issue in many states, little work has been conducted to determine the presence/potential of ASR in Montana. The primary objectives of the proposed research are to evaluate the potential for ASR in the state of Montana, and to develop a testing protocol for identifying potential reactive aggregates. This research will also identify/document existing ASR damage in the state and investigate the potential underlying geological features that may contribute to the presence of reactive aggregates. Finally, this research will evaluate potential techniques used to mitigate the damaging effects of ASR.
Sponsored by the Montana Department of Transportation (MDT), this research project will provide a better understanding of reactive aggregates (including severity) and a better understanding of potential ASR issues in the state of Montana. This information will be helpful in promoting sustainability and extending the service life of Montana concrete pavements and structures. Principal Investigator Mike Berry is conducting this research in partnership with MDT and the Montana Contractors Association.
Ultra-high performance concrete (UHPC) has mechanical and durability properties that far exceed those of conventional concrete. However, using UHPC in conventional concrete applications has been cost prohibitive, with commercially available/proprietary mixes costing approximately 30 times more than conventional concrete. Previous WTI research resulted in nonproprietary UHPC mixes made with materials readily available in Montana. These mixes are significantly less expensive than commercially available UHPC mixes, thus opening the door for their use in construction projects in the state. The Montana Department of Transportation (MDT) Bridge Bureau is interested in using UHPC in field-cast joints between precast concrete deck panels. The use of UHPC in this application will reduce development lengths, and subsequently reduce the requisite spacing between the decks and improve the overall performance of the bridge. Through this project, P.I. Michael Berry will build on the non-proprietary Phase I UHPC research he recently completed for MDT and focus on ensuring the successful application of this material in these field-cast joints.
If these mixes are viable for this application, Montana could take advantage of the cost savings of the non-proprietary mixes and ultimately improve the performance and durability of bridges. More information on this Phase II project is available here.
Professor Mike Berry and his students had the opportunity to show off their efforts to develop and test ultra-high performance concrete in a Montana State University (MSU) feature article and video published on the MSU website last week. The research stems from a collaboration between the Montana Department of Transportation, MSU College of Engineering, and WTI to formulate an affordable version of ultra-high performance concrete with materials available in Montana. In the video, Berry also discusses how the research has allowed many students to gain valuable “hands-on” experience testing the strength and durability of construction materials in the lab. The story also gained national attention last week when it was featured in the Daily Transportation Update of the American Association of State Highway and Transportation Officials (AASHTO). The article, photos, and video are available on the MSU website, and more project information is available on the project’s webpage.