A comparative study of laboratory and field performance of several applications of crumb rubber-modified (CRM) hot-mix asphalt in Louisiana is presented. Eight CRM asphalt pavement sections were constructed by eight different CRM processes or applications. These eight CRM sections were built at five state highway projects. A control section with conventional asphalt mixture was constructed at each project to compare with the performance of pavement sections built with CRM asphalt mixtures. To evaluate the mixture characteristics of the CRM and conventional mixes, laboratory tests of Marshall stability and flow, indirect tensile strength and strain, and indirect tensile resilient modulus were conducted on field compacted Marshall specimens. Comparisons of the field performances of the pavements were achieved through roadway core air void analysis, rut-depth measurement, international roughness index, pavement structure numbers measured through the Dynaflect (dynamic deflection determination) system, and vi...

Louisiana experience with crumb rubber-modified hot-mix asphalt pavement

This report documents highway community practice and research and development efforts in the automated collection and processing of pavement condition data techniques typically used in network-level pavement management. The scope of the study covered all phases of automated pavement data collection and processing for pavement surface distress, pavement ride quality, rut-depth measurements, and joint-faulting measurements. Included in the scope were technologies employed, contracting issues, quality assurance, costs and benefits of automated techniques, monitoring frequencies and sampling protocols in use, degree of adoption of national standards for data collection, and contrast between the state of the art and the state of the practice. Three case studies are included as examples of transportation agencies applying a variety of methods for pavement condition data collection and processing. This synthesis report included a review of published literature of North American and European resources and a survey of state transportation agencies, the Federal Highway Administration, Canadian provinces, and the World Road Association. In addition, information was gathered from the October 2002 Pavement Evaluation Conference, held in Roanoke, Virginia. Three previous syntheses (NCHRP Syntheses 76, 126, and 203) have summarized much of the background material and are referenced frequently in this report.

Automated pavement distress collection techniques

: Government agencies and consulting companies in charge of pavement management face the challenge of maintaining pavements in serviceable conditions throughout their life from the functional and structural standpoints. For this, the assessment and prediction of the pavement conditions are crucial. This study proposes a neuro-fuzzy model to predict the performance of flexible pavements using the parameters routinely collected by agencies to characterize the condition of an existing pavement. These parameters are generally obtained by performing falling weight deflectometer tests and monitoring the development of distresses on the pavement surface. The proposed hybrid model for predicting pavement performance was characterized by multilayer, feedforward neural networks that led the reasoning process of the IF-THEN fuzzy rules. The results of the neuro-fuzzy model were superior to those of the linear regression model in terms of accuracy in the approximation. The proposed neuro-fuzzy model showed good generalization capability, and the evaluation of the model performance produced satisfactory results, demonstrating the efficiency and potential of these new mathematical modeling techniques.

Prediction of Pavement Performance through Neuro‐Fuzzy Reasoning

Indirect diagnosis of pavement structural damages using surface GPR reflection techniques

With the ever-increasing emphasis on maintaining road assets to a high standard, the need for fast accurate inspection for road distresses is becoming extremely important Surface distresses on roads are essentially three dimensional (3-D) in nature Automated visual surveys are the best option available However, the imaging conditions, in terms of lighting, etc, are very random For example, the challenge of measuring the volume of the pothole requires a large field of view with a reasonable spatial resolution, whereas microtexture evaluation requires very accurate imaging Within the two extremes, there is a range of situations that require 3-D imaging Three-dimensional imaging consists of a number of techniques such as interferometry and depth from focus Out of these, laser imagers are mainly used for road surface distress inspection Many other techniques are relatively unknown among the transportation community, and industrial products are rare The main impetus for this paper is derived from the rarity of 3-D industrial imagers that employ alternative techniques for use in transportation In addition, the need for this work is also highlighted by a lack of literature that evaluates the relative merits/demerits of various imaging methods for different distress measurement situations in relation to pavements This overview will create awareness of available 3-D imaging methods in order to help make a fast initial technology selection and deployment The review is expected to be helpful for researchers, practicing engineers, and decision makers in transportation engineering

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A Review of Three-Dimensional Imaging Technologies for Pavement Distress Detection and Measurements

Pavement Network Definition.- Pavement Condition Survey and Rating Procedure.- Nondestructive Deflection Testing (NDT).- Roughness Measurement and Analysis.- Skid Data Collection and Analysis.- Pavement Condition Prediction Models.- Overview of Maintenance and Rehabilitation Methods.- Network-Level Pavement Management-Inventory and Condition Reporting.- Network-Level Pavement Management - M&R Work Planning.- Project-Level Management.- Special Application - Impact of Bus Traffic on Pavement Costs.- Special Application - Impact of Utility Cuts on Pavement Life and Rehabilitation Cost.- Special Application - Development of Council District Budget Allocation Methodology for Pavement Rehabilitation.- Pavement Management Implementation Steps and Expected Benefits.

Mohamed Y. Shahin

Papers

Pavement Management for Airports, Roads, and Parking Lots