Montana Department of Transportation

ADA Detectable Warning Devices
Through the Americans with Disabilities Act (ADA), states are now mandated to construct or alter facilities in a manner making them accessible to people with disabilities. The ADA access board published accessibility guidelines (ADAAG) for public right-of-ways addressing detectable warning devices (DWD) in 1991, and issued them for comment in 1992 and 1994. Based on concerns about the specifications, the board suspended its requirement for detectable warnings on the surface of curb ramps and other locations where pedestrian ways blend with vehicular ways without tactile cues. After continued discussion, the moratorium was ended in July of 2001 with revised accessibility guidelines being issued in June 2002. Truncated domes are now the standard at curb ramp crossing where tactile devices are needed for the visually impaired. The information derived from this experiment will assist the Department in choosing the optimum DWD for use on transportation facilities in the State of Montana.

Aggregate Base Preparation
Creating premium road base out of troublesome aggregates or soils is part of a successful formula in building superior performing pavements. As traffic loads and volumes rise, and as long-term pavement performance gets increased attention, what lies under the pavement is getting the same attention as what is on top. Methods of building superior-performing road bases; either for reconstructed roads, or new roads on new alignments are getting a close look by state departments of transportation, designers, and builders. Stabilized, premium bases tame troublesome soils, when they are saturated or subject to pavement-destroying, long-term expansion. In addition, if water is the enemy of a pavement, premium bases can either waterproof a road structure to keep water out, or drain water right out of the pavement structure and into the roadsides, where it belongs. The base course is the layer immediately below the pavement or surface course, It may be located above the subbase, or if no subbase is placed, immediately above the basement soil. In this effort, the Montana Department of Transportation is initiating an experimental trail of various aggregate base preparations in effort to determine effectiveness of these treatments for potential use in future road construction projects.

Automated Fixed Anti-icing Device for use on Billings District Area Bridge
The West laurel interchange east bound lane has a documented accident history due to icy conditions during winter months. This structure is scheduled to be realigned in five years. Due to the current severity of the accidents at this location the Billings District is installing a fixed automated anti-icing device on the subject structure. Performance measures for effectiveness would be a reduced accident rate. Additional information to be collected would be the durability of the device and the cost of maintaining the equipment. A road weather information system (RWIS) will also be installed to complement the device. Information from the RWIS will provide critical data to support the effectiveness of the anti-icing strategy. The trail implementation of this device will be a determining factor if other bridge structures in the state could be made safer from its use.

Cement-Treated Bases (CTB)
Soil-cement is a mixture of pulverized soil material and measured amounts of portland cement and water, compacted to high density. As the cement hydrates, the mixture becomes a hard, durable paving material. A bituminous wearing course is placed on the soil-cement base to complete the pavement.

The soil material in soil-cement can be almost any combination of sand, silt, clay, and gravel or crushed stone. Local granular materials (such as slag, caliche, limerock, and scoria) plus a wide variety of waste material (such as cinders, fly ash, and screenings from quarries and gravel pits) can be used to make soil-cement. In addition, old granular-based roads, with or without their bituminous surfaces, can be recycled to make good soil-cement.

There are two primary types of soil-and-cement mixtures:

• Soil-cement
• Cement-modified soil

Soil-cement is a hardened material which contains sufficient cement to satisfy established weight-loss criteria based on standard freeze-thaw and wet-dry tests. Other terms such as cement-stabilized soils and cement-stabilized aggregate base are sometimes used. Cement-modified soil can be a hardened, unhardened or semi-hardened mixture of soil and cement. When small quantities of portland cement and moistures are added to a soil material, the chemical and physical properties of that soil material are improved.

Soil-cement is used primarily as a base course for:

• Roads and streets
• Airports
• Shoulders and parking areas
• Subbase for rigid pavements
• Subbase for flexible and soil-cement pavements
• Reconstruction and recycling of failed flexible pavements

Cold In-Place Recycling (CIR)
Cold In-Place Recycling is the milling, screening and crushing of existing asphalt pavement, adding new additives, mixing and re-laying the material to form a new pavement structure. Normally a new surface consisting of hot mix asphalt or a seal coat may be required. Traffic can use the surface the same day. The CIR process can also include Full depth Reclamation.

Full Depth Reclamation is the processing of existing pavement layers and some underlying base material to rehabilitate an existing asphalt pavement. Typically, additives are used to improve the characteristics of the existing materials. The process is completed in-place and can be used in either a "closed road" or "under traffic" situations. It is used frequently when pavement problems are severe and processing of the entire pavement structure is necessary. A new surface consisting of hot mix asphalt or a seal coat may be required.

The benefits CIR can provide are:

• Reflective cracking is reduced or eliminated
• Geometrics are restored
• Rutting is eliminated
• Some base problems may be addressed
• Average production of two lane-miles a day
• Traffic is allowed through construction
• Roadway can be opened to traffic each night
• Existing natural resources can be used
• Cost effective

Emulsified Asphalt Treated Aggregate (EATA) Base Preparations
EATA is a Crushed Aggregate Course (CAC) material blended with an Emulsified Asphalt. CAC is pug-mill blended with CSS-1 emulsified asphalt. The intended benefit of using of EATA is to reduce chemical dust control products and provide an improved, temporary riding surface on highway projects, particularly during winter shut down. EATA was originally intended to improve the construction process by increasing the serviceability of the gravel sections and reduce the amount of dust control products that are currently being used on highway projects. A substantially important benefit would be gained if EATA would provide a smoother more durable and “cleaner” winter riding surface. The goals and objectives of EATA:

1. Reduce road dust, and reduce the need for chemical dust control products.
2. Provide a smoother improved temporary riding surface.
3. Reducing winter and construction maintenance.
4. Provide a firm, stable, and smooth platform to pave on.
5. Improve the constructability of the first lift PMS (reduce roll out and improve compactability)

Fiber-Reinforced Polymer (FRP)
FRP's are engineered composite designed materials using fiber-reinforced plastics. The basic components of FRP's are the continuous fibers and the matrix. The strength and stiffness of the composite is provided by the fibers, which have significantly superior properties than the bulk matrix material. Fibers are selected to carry the majority of the load applied to the composite element. Fibers used in FRP composites may either be glass or carbon; however, glass fibers are most commonly used. The properties of glass fibers are well known and predictable. They show good mechanical behavior and high strength. Glass fibers are also readily available at low cost. Although carbon fibers posses higher strength and stiffness, they are expensive and are only used when their specific properties are needed. The matrix is essentially the binder of the FRP. Its main role is to support and protect the load-carrying fibers, as well as transmit the applied load to the fibers. The most common type of resins used for the matrix of an FRP is epoxy and polyester. Most FRP composites are composed of a polyester matrix because of its low cost. Epoxy may be used in some high strength applications where the extra cost incurred is justified. Polyester resins are resistant to water, weather, aging, a variety of chemicals, and can be used at temperatures up to 79°C (175°F).

In general, glass fiber plastic composites have the following advantages:

• Good physical properties; including strength, elasticity, impact resistance, and dimensional stability
• High strength to weight ratio
• Good electrical properties
• Resistance to chemical attack and outdoor weathering
• Resistance to moderately high temperatures
• Suitability for fabrication by a variety of production methods
• Adaptability to a wide range of sizes

The most common fabrication method for FRP composites is pultrusion. The pultrusion process makes constant cross section parts of unlimited length. Continuous single fibers as well as fiber mats are fed through the process from spools. The fibers are fed through a wet-out bath that contains the resin matrix, catalyst, and other additives. The excess liquid resin is removed and returned to the bath. Finally, the fibers and matrix are pulled through the pultrusion die, and take shape of the final product. The final product is continuously being pulled out and is constrained in length only by building and shipping limitations.

Highways for Life (HfL) Culvert Rehabilitation Project
The purpose of Highways for ‘LIFE' (HfL) is to advance Longer-lasting highway infrastructure using Innovations to accomplish the Fast construction of Efficient and safe highways and bridges, (thus the acronym LIFE). And it's innovation that is the key to finding our way out the highway challenge. Innovations is an inclusive term used by HfL to convey all of the following: technologies, materials, tools, equipment, procedures, specifications, methodologies, processes or practices used in the financing, design or construction of highways. The three goals of HfL are to:

• Improve safety during and after construction,
• Reduce congestion caused by construction, and
• Improve the quality of the highway infrastructure.

Pavement Markings Evaluation
Compare current practice using epoxy type markings with various urethane modified type markings for long-term durability and retro-reflectivity. Various types of pavement grinds will be employed to see if this variable will affect performance of the products.

PavePrep Waterproofing Membrane
The purpose of this study is to evaluate the feasibility of using a waterproofing membrane and hot mix asphalt overlay to preserve a bridge deck in reasonable condition until that bridge can be replaced.

The main purpose of the waterproofing membrane is to limit the penetration of water through the old, existing PCCP deck surfacing. Once moisture penetrates through the surface, it tends to become trapped under the surface thus accelerating corrosion of the reinforcing steel, which causes additional cracks, spalls, and delaminations of the concrete.

A secondary purpose of this membrane is to function as a stress relief interlayer material thereby limiting reflective cracking.

The specific PavePrep® membrane used in this project was chosen due to the stringent traffic control specifications. Completely cleaning the deck surface for patching and repaving normally requires days of rerouting traffic and congestion. PavePrep® is a composite of specialized asphalt mastic with select geotextiles on its top and bottom surfaces. PavePrep's® surface is traffic-worthy once cooled to ambient temperature, permitting unrestricted vehicle flow until the final asphalt overlay is applied.

Radar Speed Display Trailer-mounted Device for Speed Reduction in Construction Work Zones
Determine the effectiveness of trailer mounted radar speed display devices in reducing speed in construction work zones.

Recycled Rubber and Plastic Mats as Weed Prevention and Erosion control around Guardrails
The Departments current use of erosion and weed control around guardrails is to pave the area with asphalt cement (AC). The objective of this project is to test two products made from recycled rubber and plastic mats to determine if this could be a cost effective alternative to paving with AC. These products wrap around the guardrail supports and keep the weed from growing and the soil in place. They can be mowed over without the mats hindering the blades.

Thin Whitetopping (TW)
Thin Whitetopping (TW) is a recently developed rehabilitation technique in which 100 to 160 millimeter thick, layer of high-strength, fiber-reinforced, portland cement concrete is placed over a milled surface of rutted and/or cracked asphalt concrete pavement. TW is typically performed in heavy traffic corridors to combat rutting and/or shoving. By bonding concrete to the underlying asphalt layer, the TW and existing asphalt perform as a load-bearing, composite section.