Following a rigid set of testing protocols, data is being collected on highway traffic noise characteristics along with safety and durability aspects of the associated pavements. This report completes a comprehensive, long-term study to determine if particular pavement surface types and/or textures can be used as quieter pavements, and possibly be used to help satisfy FHWA noise mitigation requirements.
The full closure strategic analysis was conducted to create a decision process whereby full roadway closures for construction and maintenance activities can be evaluated and approved or denied by CDOT Traffic personnel. The study reviewed current full closure practices in Colorado and throughout the country, gathered stakeholder input, and employed an iterative development process to reach a systematic decision tool that can be applied to judging the merits of full closure scenarios. A number of case studies were created to more fully understand the methodology and adjust the tool to best match real-world scenarios. Project deliverables include a technical report and a series of electronic forms that can be used by CDOT to work through the process.
A report that evaluates the stability of re-vegetation of high elevation, decomposed, granite cut-slopes by using repeated applications of soil amendments.
A report that explains testing of standard mix designs to determine minimum-required performance levels for developing performance-based concrete mix design criteria.
Crack sealants are often utilized as a preservation tool in asphalt pavements. When a hot mix asphalt overlay is placed on top a pavement containing crack sealants, a bump and additional transverse cracks sometimes occur in the new asphalt overlay. These bumps and sometimes, transverse cracks are initiated during breakdown rolling and become progressively more severe upon further compaction. This paper presents results of a five-year study designed to identify factors that relate to the appearance of these bumps and consequent cracks.
This research project observes and analyzes traffic and accident history on Colorado State Highways and parallel arterial roads within a major southeast section of the Denver Metropolitan Area. The project focuses on the freeway section of C-470 between S. Santa Fe Drive and I-25 and comparisons with I-25 and the corresponding parallel east-west regional arterial corridors.
Wildlife fencing along highways can lower wildlife-vehicle collision rates by excluding animals from the road right-of-way. Still, animals can breach fencing and end up trapped within the fencing along the highway right-of-way, exposing wildlife and motorists to the risk of collision. Wildlife escape ramps are designed to allow animals safe passage out of the right-of-way. Few recommendations exist on effective design of escape ramps and monitoring data are limited.
Crack sealing and filling on hot mix asphalt (HMA) pavements are cost-effective pavement preservation techniques that improve pavement performance and extend the life of existing pavements. If performed in a timely and effective manner, crack sealing can extend the life of HMA pavements. CDOT sponsored this study to update its procedures and guidelines for crack sealing and filling of HMA pavements. The draft Guidelines included in this report reflect CDOT experience, current state-of-the-practice, and the most recent research findings, and address where and when to perform crack sealing and filling, material selection, installation methods, construction inspection, and follow-up evaluation.
Internally cured concrete has been rapidly emerging over the last decade as an effective way to improve the performance of concrete. Internal curing (IC) holds promise for producing concrete with an increased resistance to early-age cracking and enhanced durability. It is a simple and effective way to cure concrete.
The Colorado Department of Transportation (CDOT) has been collecting data from the Hamburg Rutter and the French Rutter for over 20 years. No specifications have been written in that time for either the Hamburg Rutter or the French Rutter. This is largely due to the need for a companion test to be developed so dry asphalt mixes would not be designed specifically for passing the Hamburg Rutter test. This report looks at the state of practice within other states that own similar equipment. Cracking tests that could be run with the Hamburg Rutter are examined from a review of literature to determine if there is a suitable companion test for the Hamburg Rutter that would work to keep asphalt levels in the mix high enough to prevent cracking and fatigue.
The objective of this project was to integrate the American Association of State Highway and Transportation Officials (AASHTO) Mechanistic-Empirical Pavement Design Guide, Interim Edition: A Manual of Practice and its accompanying software into the daily pavement design, evaluation, rehabilitation, management, and forensic analysis practices and operations of the Colorado Department of Transportation (CDOT).
An adequate longitudinal joint tie bar system is essential in the overall performance of concrete pavement. Excessive longitudinal joint openings are believed to be caused by either inadequate tie bar size or spacing or improper tie bar installation. If designed and installed properly, tie bars prevent the joints from opening and consequently improve load transfer efficiency between slabs and between slabs and shoulders, resulting in increased load carrying capacity. CDOT should adopt the mechanistic-empirical tie bar design procedure developed in this study.
The purpose of this study was to quantify the initial design life of a roadways pavement prior to rehabilitation and provide specific performance information through the analysis of pavement management data and historical experience. The analyzed data may be used to estimate the initial life of a pavement which can be incorporated into the LCCA within CDOTs M-E Pavement Design Guide. It will also provide guidance to CDOT and subcontractors in determining the cost-effectiveness of different pavement designs, construction and maintenance costs.
This report presents information and data produced by the Colorado Department of Transportation's long-term study of Portland cement concrete pavement (PCCP) textures used within the state. The information includes vehicle accident, friction, and texture data. This information was used as the for a review of proposed revisions to the CDOT texture measurement method, CP-77, and a specification for PCCP texturing found in Sections 106 and 412 of the Standard Specifications.
This study is the evaluation of two thin bonded epoxy overlays. These two products were compared on the basis of physical properties, including mean texture depth, surface friction, bond strength, ability to stop chloride intrusion, and anti-icing properties, as well as traffic safety and cost. Both overlays worked as intended when they were initially applied on the bridge decks. Mean texture depth and friction testing have shown that they both provide a durable wearing surface with good traction.
