الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Environmental changes have a direct impact on the structural capacity of the pavement, and consequently its performance. While the subgrade soil/the unbound materials are sensitive to moisture variation, the Asphalt Concrete (AC) layers are more sensitive to temperature variations. Quantifying the effect of these two environmental factors, moisture and temperature, is necessary for incorporation in the pavement design process. The main goal of this research is to study the effects of the variation of subgrade moisture and asphalt surface temperature on the structural capacity of the pavement layers, and hence determine their influence on the pavement performance. Consequently, correlation models for Egyptian environmental condition that quantify the variation of the resilient modulus of subgrade soil and relate it to moisture variation were developed. Similarly, correlation models for Egyptian environmental condition to relate the modulus of asphalt concrete layers to the temperature variation were also developed.
On the other hand, in 1987, the Strategic Highway Research Program (SHRP) began the largest and most comprehensive pavement performance test in history, called the Long-Term Pavement Performance (LTPP) program. During the program’s 20-year life, highway agencies in the United States and 15 other countries have collected data on pavement condition, climate, and traffic volumes and loads from more than 1,000 pavement test sections. That information will allow pavement engineers to design better, longer-lasting roads, and to provide answers to HOW and WHY pavements perform as they do. To study the environmental effect on pavement structures, there is a sub-program called Seasonal Monitoring Program (SMP) within the LTPP program. The primary objective of the SMP is to provide information on variations in temperature and moisture content within a pavement structure.
The LTPP-SMP database was used in this study to come up with a list of sites that should be matching with environmental condition in Egypt. Consequently, environmental database was created for Egypt including but not limited to temperatures and rain fall intensity. This database was utilized to divide Egypt to pavement climatic zones. Statistical measurements were performed to come up with a statistical number related to Egypt conditions to be used in selecting the LTPP-SMP sites. LTPP-SMP sites could be then selected to be matching with environmental condition in Egypt and based on Egypt pavement climatic zones that have been developed in this study. Moisture and temperature data at selected LTPP-SMP sites were analyzed to determine the seasonal variability of these two parameters.
Data acquired from the LTPP-SMP database was analyzed to develop the required correlation models. The developed models should then be evaluated using different LTPP-SMP sites.
To facilitate the use of the research results, the developed models were applied to specific conditions in Egypt, and moduli seasonal adjustment factors (SAF) were then calculated. Algorithm and Tables for these factors at different regions were developed and provided in this research. Impact of environmental effect on pavement design and performance was also addressed in this research.