Tom Kazmierowski

Pavement Preservation: A Solution for Sustainability

The Ministry of Transportation of Ontario, Canada (MTO), is dedicated to maintaining quality roadways in a sustainable manner. In recent years, MTO has implemented pavement preservation strategies to maximize cost savings in repair operations and to maintain pavement condition. Pavement preservation treatments are considered sustainable because they improve pavement quality and durability and extend pavement service life, while reducing energy consumption and greenhouse gas (GHG) emissions. Pavement preservation is a proactive, planned strategy that extends the life of the pavement and provides a cost-effective solution for pavement management. This paper outlines the various pavement preservation treatments used by MTO to achieve sustainability. These preservation treatments include crack sealing, slurry seal, microsurfacing, chip seal, ultrathin bonded friction course, fiber-modified chip seal, hot-mix patching, and hot in-place recycling. With use of the PaLATE software, pavement sustainability is quantified by comparing the energy consumption and GHG emissions generated for various pavement preservation strategies against typical rehabilitation and reconstruction treatments. This paper presents the benefits of pavement preservation by considering the service life of each treatment and calculating the associated energy consumption and GHG emissions per service year. Results indicate that pavement preservation strategies provide a significant reduction in energy use and GHG emissions when compared with traditional rehabilitation and reconstruction treatments. Although pavement preservation has been proved to be a cost-effective solution, there are numerous challenges and barriers to overcome. Some of the challenges and solutions as well as the strategies to promote pavement preservation for sustainability are presented in the paper.

Ten-Year Performance Review of In Situ Hot-Mix Recycling in Ontario

In today’s climate of environmental and economic constraints coupled with a diminishing aggregate supply, in situ hot-mix recycling provides an important alternative to conventional pavement rehabilitation. In situ hot-mix recycling, including hot in-place recycling (HIR) and cold inplace recycling (CIR), is proving to be an economical rehabilitation technique that conserves granular materials and energy and results in zero waste. The Ministry of Transportation and the Regional Municipality of Ottawa–Carleton have rehabilitated in excess of 80 projects using in situ hot-mix recycling techniques since 1987. The HIR process is suitable for roadways exhibiting a variety of surficial nonstructural distresses. The HIR process involves heating the existing pavement surface, scarifying, adding rejuvenator, fine aggregates, or beneficiating hot-mix (admixture) as required, mixing, reprofiling, and compacting this hot mixture in a continuous operation. CIR is suitable for roadways with moderate to severe distresses where reflection cracking is a concern. CIR involves milling the existing pavement, screening for oversize, addition of asphalt emulsion, and mixing; then this cold renewed material is spread, reprofiled, and compacted on the roadway in one continuous operation. An overview on the design, construction procedures, test results, and pavement performance to date of in situ recycling is presented. Ten years of performance monitoring of the in situ recycling projects has resulted in the evolution of design strategies and performance specifications. Their effectiveness, limitations, and future utility on highway contracts are discussed.

Validation and Implementation of Ontario, Canada, Network-Level Distress Guidelines and Condition Rating

The Centre for Pavement and Transportation Technology at the University of Waterloo and the Ministry of Transportation of Ontario (MTO) have been studying for the past 4 years the suitability of applying automated technologies for network-level evaluations in the province. Three projects have been developed for this purpose. The main results of these studies were a better understanding of available digital technologies, evaluation of the performance of semiautomated and automated technologies, development of new guidelines for pavement distress collection at the network level, design of an adjusted distress manifestation index, and recommendations for the use of semiautomated and automated digital technologies at the network level. The objective of this paper is to present the findings of the third and last phase of the project, Validation and Implementation of MTO Network Level Automated–Semiautomated Pavement Distress Guidelines and Condition Rating Methodology. The scope of the study was to validate and implement in the field MTO network-level distress guidelines and a distress manifestation index for network-level evaluations (DMINL), considering the use of automated technologies. A complete statistical analysis of data collected in the field through manual evaluations and semiautomated and automated technologies is presented. The performance of currently available technologies using network-level distress guidelines was assessed. Finally, from the field validation, distress guidelines were adjusted accordingly and DMINL equations were recalibrated.

Ten-Year Performance of Full-Depth Reclamation with Expanded Asphalt Stabilization on Trans-Canada Highway, Ontario, Canada

In 2001, the Ministry of Transportation Ontario, Canada, constructed its first stabilization project involving full-depth reclamation with expanded (foamed) asphalt on the Trans-Canada Highway, south of Wawa, Ontario. The project involved three mix designs, two with corrective aggregate and one without corrective aggregate. A control section of full-depth reclamation with the same thickness of hot-mix overlay (without expanded asphalt stabilization) was placed in the middle of the project. The project has been monitored annually for the past 10 years. Analysis of roughness data and pavement distress data indicated a significant difference between the test sections with expanded asphalt stabilized base and the control section. The expanded asphalt stabilization has delivered superior performance compared with the conventional full-depth reclamation with hot-mix overlay. Performance curves for the treatments on this project were compared with the ministrys average performance curve for full-depth reclamation (reconstruction) projects and with the performance of treatments on two adjacent projects. This project demonstrated the exceptional performance of the expanded asphalt mixes through 10 years of proven superior pavement condition and ride.