NEW PROJECT: WTI to Create a Guidebook for Transportation Agencies on Unpaved Roads

Gravel road in rural Montana with mountains in the background
The guidebook will aid agencies in making effective decisions regarding conversion of paved roads to unpaved.

For roads with very low traffic volumes, some transportation agencies have found that that these roadways can be maintained more economically and at a higher level of service with an unpaved or granular surface, as compared with attempting to maintain an old paved surface. Through this project, WTI will develop a comprehensive information resource on effective practices for converting severely distressed paved roads to acceptable unpaved surfaces. The guide will be developed based on needs identified in a previous WTI project, NCHRP Synthesis 485 Converting Paved Roads to Unpaved.

Laura Fay, who led the NCHRP Synthesis, will also serve as Principal Investigator for this effort. The main benefit of this project will be the availability of an easy to use guidance document for agencies that operate and maintain low volume roads. The guide will help agencies select candidate roads for conversion, conduct more effective and safer conversions, and communicate with the public on how and why a conversion is taking place.

Additional project information is available on the project page of the WTI website.

NEW PROJECT: MDT and WTI to Continue Research on Bridge Support Systems

WTI, MDT Research on concrete cap for bridge deck support
WTI & MDT Will continue research on concrete cap for bridge deck supports as a long lasting, safe and cost effective solution.

The Montana Department of Transportation (MDT) has found concrete-filled steel tube (CFST) piles connected at the top by a concrete pile cap to be a very cost-effective support system for short and medium span bridges. This type of system offers low initial cost, short construction time, low maintenance requirements, and a long service life. While the gravity load performance of these systems is well understood, their strength and ductility under extreme lateral loads (e.g., seismic events) is more difficult to reliably predict using conventional design procedures.

MDT has sponsored previous WTI research to investigate the performance of these systems under extreme lateral loads and to develop appropriate analysis/design procedures. The primary objective of this research, led by Michael Berry, is to further validate/improve MDT’s CFST to concrete pile cap connection design/analysis methodologies, and to ensure the efficacy of these methodologies for a wide variety of potential design configurations. This research has important potential benefits for evaluating and enhancing bridge performance during earthquakes and other seismic events.

Additional information is available on the project page of the WTI website.

WTI helps NW Bozeman neighbors bring their vision for safer streets to life!

Examples of temporary "pop up" street features for safer streets in Bozeman. These features use chalk, straw bales and planters to build temporary roadway features.
Examples of temporary “pop up” street features for safer streets in Bozeman.
WTI’s Bozeman Commuter Project is working with Bozeman neighborhoods to implement Pop-up Traffic Calming projects to reduce drivers speeds on residential streets, and bring more visibility to bikes and pedestrians. This weekend residents of Northwest Bozeman in the Valley Unit neighborhood will be setting up a temporary demonstration of curb extensions and a traffic circle at three intersections near Valley Unit park. Data will be collected via intercept surveys and radar speed detection units to better understand how these designs can reduce vehicle speeds and increase safety for local residents and those traveling by bike, foot, bus, stroller, walker or wheelchair.
Related News Story: AARP Highlights Bozeman Traffic Calming Project in National Publication

New Project Investigates Alkali-Silica Reactivity in Montana Concrete Structures

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.

New Project: Testing Ultra-High Performance Concrete in the Field

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.