Thomas J Kazmierowski

Sustainable Pavements: Environmental, Economic, and Social Benefits of In Situ Pavement Recycling

The Ministry of Transportation Ontario, Canada, is committed to using technologies to help build a more sustainable transportation system that supports todays needs while protecting the environment for future generations. Cold in-place recycling (CIR) is an established pavement rehabilitation technology that processes an existing asphalt pavement, sizes it, mixes in additional asphalt cement, and lays it back down without off-site hauling and processing. The added asphalt cement is typically emulsified asphalt. A recent development in CIR technology is the use of expanded (foamed) asphalt, rather than emulsified asphalt, to bind the mix. This combination of CIR and expanded asphalt technologies is termed cold in-place recycled expanded asphalt mix (CIREAM). Both CIR and CIREAM technologies support the philosophy of a sustainable transportation system. More specifically, CIR and CIREAM meet the criteria for a sustainable pavement: safe, efficient, economic, environmentally friendly pavement that meets the needs of present-day users without compromising those of future generations.

Evaluation of Semiautomated and Automated Pavement Distress Collection for Network-Level Pavement Management

The Ministry of Transportation Ontario (MTO) and the University of Waterloo examined the feasibility of using automated pavement distress collection techniques in addition to data collected through manual surveys. Test sections including surface-treated, asphalt concrete, composite, and portland cement concrete pavement structures in 37 locations in southern Ontario, Canada, were evaluated. Distress manifestation index (DMI) values were computed for each section by MTO pavement design and evaluation officers using the manual evaluation data collected. DMI values were then computed for each section by using automated distress evaluation data. Before DMI values could be computed, the relevant data had to be extracted and verified, and the distress data had to be categorized. DMI values computed from data collected manually and by using automated systems were compared. Finally, a repeatability analysis was performed on both the manual and the automated techniques. Results indicate no significant differences among sensor-based equipment; however, there are significant differences among measurements obtained from digital image-based technology. The implications of such outcomes are discussed, including the specifics regarding methodology implementation in order to encourage practitioners to benefit from the preliminary investigation. Current available techniques can provide MTO with valuable information for pavement management purposes. The automated results are comparable with manual surveys. However, these surveys should be supplemented with manual surveys, especially for design purposes, because some of the pavement distresses were difficult to identify with the automated methods.

Implementation of Cold In-Place Recycling with Expanded Asphalt Technology in Canada

Cold in-place recycling (CIR) is a pavement rehabilitation method that processes an existing hot-mix pavement, sizes it, mixes in additional asphalt cement, and lays it back down without off-site hauling and processing. The added asphalt cement is typically emulsified asphalt. A recent development in CIR technology is the use of expanded (foamed) asphalt rather than emulsified asphalt to bind the mix. This combination of CIR and expanded asphalt technologies is termed cold in-place recycled expanded asphalt mix (CIREAM). The Ministry of Transportation Ontario (MTO) constructed a CIREAM trial section on Highway 7 in July 2003. The 5-km CIREAM trial section was constructed adjacent to an 8-km section on which conventional CIR was performed. CIREAM placement resulted in a smooth, hard, uniform surface that provided an excellent platform for paving operations. The CIREAM placement progressed in a continuous and efficient manner, with 5 km placed over a 3-day period. Indirect tensile strength testing was carri...

Development of Distress Guidelines and Condition Rating to Improve Network Management in Ontario, Canada

In 2006, the Ministry of Transportation of Ontario, Canada (MTO), completed a study with the Centre for Pavement and Transportation Technology at the University of Waterloo to evaluate the performance of automated and semiautomated technologies that collect pavement distress data. From that study it was recommended that MTO define concise guidelines for surveying pavement distresses at the network level by using automated collection technologies and semiautomated distress analysis and for the guidelines to give special attention to quality assurance. In light of that recommendation, the study detailed in this paper presents the development of pavement distress guidelines and a distress manifestation index (DMI) for network-level (DMINL) evaluations by using automated collection technologies and semiautomated distress analysis. To define and validate DMINL, sections evaluated in the previous study were considered. The relative effect of each distress was obtained by linear regression and statistical analysis. The principle used to define the weighting factors was that the distresses considered by the new guidelines should quantify with a minimum error the DMI estimated by the MTO traditional method.

Switching to International Roughness Index

The International Roughness Index (IRI) has become a well-recognized standard for measurement of pavement roughness. The main objectives of the study were to evaluate the consequences of switching to IRI roughness measurements, and to develop a procedure for switching from measuring roughness with a response-type device, used for more than 10 years, to an IRI device. The study consisted of two parts. In the first part, the repeatability and consistency of roughness measurements obtained by three different IRI-measuring systems using a 10-section calibration circuit was evaluated. In the second part, transfer functions relating IRI with a subjectively measured ride condition rating for a large pavement network consisting of asphaltic concrete, rigid, and surface-treated pavements were developed. Based on the results of the calibration circuit, the three IRI-measuring systems were proved equally capable of providing repeatable and reliable roughness measurements for network-level monitoring purposes, and their individual results correlated very well. However, because of systematic differences between the results, the IRI-measuring systems cannot be used interchangeably and without proper calibration. Based on the results obtained for the network, different transfer functions were required and developed for the four pavement types (asphaltic concrete, composite, jointed portland cement concrete, and surface-treated). IRI roughness measurements provided better prediction of the ride condition rating than the response-type roughness measurements. These results support the switch to IRI roughness measurements.

Performance evaluation of sensor-and image-based technologies for automated pavement condition surveys

Even though companies that assess pavement condition compete to innovate by providing better software for automatic analysis and diagnosis, the industry as a whole remains limited, and data collection and storage methods are disparate. In fact, software and handling procedures are proprietary—each vendor has its own automated technology to detect, classify, and quantify surface distresses. In a research effort sponsored by the Ministry of Transportation of Ontario, Canada, the performance of sensor- and image-based pavement condition assessment was compared. First, a data management plan was created to allow efficient data manipulation. Second, a suitable set of similar distresses was selected as response variables of interest to design and conduct statistical experiments. Third, advanced analysis of variance was performed to allow statistical data comparisons among companies and among automated technologies. Finally, results were discussed and recommendations made. Overall, service provider measurements ...

Experimental Short-Wavelength Surface Textures in Portland Cement Concrete Pavements

A cooperative research effort was undertaken by FHWA and Canadas Ministry of Transportation for Ontario (MTO) regarding experimental texturing of fresh portland cement concrete pavement. The goal of the research was to develop techniques that can fabricate surface textures having most of the aggressive texture size wavelength content within the 2- to 8-mm (80- to 300-mil) wavelength range, with mean texture depth size at approximately 1 mm (40 mil). This wavelength range is relatively short, and it is difficult to fabricate ultraflat textures with elevation variation only in this wavelength range. The research was initiated by FHWA, and an experimental texture test site was constructed in Ontario, Canada, under the guidance of the MTO. Five texture test sections were constructed and evaluated at the Ontario test site. The short wavelength transverse textures averaging approximately 8-mm (315-mil) spacing are quieter and appear to offer equal or better skid resistance than conventional deeper transverse tining having 16-mm (630-mil) groove spacing.

VERIFICATION OF NETWORK-LEVEL PAVEMENT ROUGHNESS MEASUREMENTS

In 1997 the Ministry of Transportation of Ontario (MTO), Ontario, Canada, switched to international roughness index (IRI) measurements as an indicator of network-level pavement roughness within its pavement management system. Measurement of pavement roughness or ride quality in terms of IRI can be performed with different measuring devices. However, the individual measurements for the same pavement section may vary significantly because of the use of different measuring devices, different longitudinal profiles, and different measuring speeds. Recent evidence obtained by MTO indicates that the longitudinal profile measurements provided by different measuring devices contain systematic differences that range from 0.1 to 1.0 m/km. Such differences in IRIs cause significant concerns for agencies that contract out collection of network-level roughness measurements on a yearly basis. Through the process of verification and comparison of longitudinal profile measurements obtained with different profilers, MTO has gained insight into the functional relationships and factors that affect profile measurements in terms of precision and bias. The verification techniques used to obtain normalized, reproducible, and time-stable IRI measurements for IRIs supplied by different IRI providers are described. Preliminary findings and statistical analyses of IRI values measured on a verification circuit, which is composed of 12 sections with four different pavement types, are provided. In addition, the results of analyses of the various IRI measurements and their impacts on network-level pavement serviceability are discussed.

Use of Long-Term Pavement Performance Data for Calibration of Pavement Design Models

The benefits of long-term pavement performance data for calibration of the AASHTO flexible pavement design model for Ontario conditions are documented. To ensure that the AASHTO-Ontario pavement design model reflects Ontario pavement design practice and matches the observed pavement performance, long-term pavement performance data for 65 flexible pavement sections were used. Thirty-nine sections had original construction, and 26 sections received one rehabilitation treatment (overlay). The data for each section included the type and thickness of paving materials, subgrade type, pavement performance, and traffic loads. The results of the calibration and verification process indicate that for new flexible pavement design the AASHTO-Ontario model yields results that are in good agreement with the observed pavement performance. For overlays, there was a large difference between the predicted and observed performance. This indicates that considerably more observations (pavement sections) are required for assessment of rehabilitation designs than for the original construction because the overlays are not always built for structural reasons only. Possible avenues for using long-term pavement performance data to establish the values of input parameters such as structural layer coefficients and modulus of subgrade are also described. Even relatively limited long-term pavement performance data provide valuable information for the calibration and verification of pavement design methods.

APPLICATION OF NETWORK-LEVEL PAVEMENT MANAGEMENT SYSTEM TECHNOLOGY TO A UNIQUE PAVEMENT DETERIORATION PROBLEM

A study is described that was conducted in response to the premature deterioration of dense friction course/open friction course (DFC/OFC) hot mix surfaces with steel slag aggregates in the greater Toronto area. The deterioration manifested itself in the form of severe raveling and early formation of map cracking. A network-level pavement management system (PMS) was applied to this unique problem. A pavement condition evaluation was conducted, and a steel slag DFC/OFC-specific deterioration model was developed. The application of the PMS has been efficient. It facilitated estimating the rehabilitation needs, prioritizing the rehabilitation strategies, and demonstrating the most cost-effective budget.