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.
Geosynthetic materials are routinely used in transportation applications to facilitate construction, improve stability, and enhance longevity. Departments of transportation have generally had good experience with these products, although a robust and non-proprietary design process for geosynthetic reinforced paved roads is still lacking. The Montana Department of Transportation (MDT) believes that geosynthetics can be used responsibly to provide cost-savings on a number of upcoming highway construction projects in the state, based on their in-house experience as well as previous research and evaluation by WTI. MDT desires experimental evidence of performance for these typical projects in order to proceed with future designs.
Principal Investigator Steve Perkins is leading a new study to conduct full-scale indoor testing of reinforced pavement test sections using a traffic simulator to provide performance data and to evaluate a spreadsheet-based design tool that can be used to augment current design procedures. The results from this study can be directly implemented into future MDT highway construction designs having similar conditions to the test sections. These recommendations will pertain most directly to operational conditions where a stable construction platform is established over relatively weak subgrade when it is advantageous to reduce base course thickness in order to save both time and money.
To follow this project, visit its webpage on the WTI website.
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.
The Transportation Research Board Committee on Resource Conservation and Recovery (ADC 60) has announced that its summer workshop will be held July 15-17, 2018 in Spokane, WA. This year’s theme will be “Waste Recycling, Upcycling, and Sustainable Transportation.” The call for presentation and poster abstracts is now open, and the deadline is April 9, 2018. Submission information is available here.
WTI research is prominently featured in the new issue of Solutions, the research newsletter of the Montana Department of Transportation. Three recently completed projects are profiled in feature articles:
- “Prefabricated Steel Truss/Bridge Deck Systems.” This study was a WTI and MSU Civil Engineering project led by Damon Fick, Tyler Kuehl, Michael Berry, and Jerry Stephens. It evaluated a prototype of a welded steel truss constructed with an integral concrete deck, which has been proposed as a potential alternative for accelerated bridge construction (ABC) projects in Montana. Steel truss bridges are relatively light weight compared with plate girder systems, which makes them a desirable alternative for both material savings and constructability. See the WTI website for more information.
- “Evaluation of Effectiveness and Cost-Benefits of Woolen Roadside Reclamation Products.” This research project developed three types of products for study: woolen erosion control blankets (ECBs), wool incorporated into wood fiber compost, and wool incorporated into silt fence. The project, supported by Montana Department of Transportation (MDT) and the Center for Environmentally Sustainable Transportation in Cold Climates, compared the wool products’ performance to roadside reclamation products commonly used for revegetating cut slopes. Rob Ament (P.I.) and Eli Cuelho served on the research team. Additional information is available on the WTI website.
- “Feasibility of Non-Proprietary Ultra-High Performance Concrete (UHPC) for Use in Highway Bridges in Montana.” 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, costing 20 times that of conventional concrete. The overall objective of the Phase I research was to develop and characterize economical non-proprietary UHPC mixes made with materials readily available in Montana. The research was led by Michael Berry. Additional project information is available on the WTI website.
The MDT Solutions newsletter is available on the MDT website.
WTI Research Scientist Laura Fay was interviewed last week by MINNPOST.com on the topic of local road agencies that choose to unpave roads. The discussion focused on Laura’s research sponsored by the Transportation Research Board, in which she surveyed local, state, or federal agencies on how they manage low-volume roads. The survey identified nearly 70 road projects in 27 states in which the road agency chose to convert a road to an unpaved, gravel road instead of re-paving it. The project will also result in a guidebook to help local officials decide if unpaving a road is safe and cost-effective. Read the full article here or go to the WTI website for more information about the research project.