Pavement layer coefficients had been identified as essential parameters to use the 1986/1993 AASHTO Guide for Design of Pavement Structures (AASHTO guide) in Rhode Island. Layer coefficients of granular subbase materials were estimated using the direct method recommended by AASHTO Guide. Resilient moduli were determined using a pneumatic testing system. Coefficients based on resilient moduli ranged from 0.08 to 0.14, and the average was 0.12 for eight subbase samples in Rhode Island. The pneumatic testing system was also used to determine resilient moduli of bound layeres. Based on results of a series of testing, layer coefficients were estimated using moduli at the loading magnitude of 20% of tensile strength and loading frequency of 0.5Hz. Recommended coefficients for wearing course (Class I-1), modified binder, and modified asphalt base were 0.40, 0.42, and 0.43, respectively. If all asphalt bound layers will be analyzed as one layer, the coefficient of 0.41 was recommended for pavement design and analysis in Rhode Island. Field study including FWD testing was performed to verify laboratory test results. Laboratory determined moduli were compared with backcalculated moduli based on FWD deflection data. Generally, FWD moduli are consistently higher than laboratory moduli with a wide range of variability. For the covering abstract of this conference, see IRRD number 863140.

Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS)* at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dis semination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all concerned if the printing and distribution of the volumes were handled by an international publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Corporation of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 39 (thesis year 1994) a total of 13,953 thesis titles from 21 Canadian and 159 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this impor tant annual reference work. While Volume 39 reports theses submitted in 1994, on occasion, certain uni versities do report theses submitted in previous years but not reported at the time.

The Kansas Department of Transportation (DOT) uses the 1993 DARWin version of the 1986 AASHTO Guide to design flexible pavements and rehabilitation strategies of flexible pavements. One of the inputs needed for the flexible pavement design procedure is the structural layer coefficient for each pavement layer. The Kansas DOT procedure to assign structural layer coefficients was developed years ago and based on an analysis of flexible pavement performance data and layer properties. It has been recently suggested that the Kansas DOT increase the structural layer coefficients because of changes in material and construction specifications. Different procedures can be used to estimate the structural layer coefficients for flexible pavement design. As part of the study entitled Determination of the Appropriate Use of Pavement Surface History in the KDOT Life-Cycle Cost Analysis Process an evaluation of the procedure that Kansas DOT uses to assign structural layer coefficients to different pavement materials was completed. This report provides the results of that evaluation.