Paper Title
Influences of Water Table Elevation on Structural Performance of Flexible Pavement Matrix With Different Subgrade Soil Types

Far-reaching research and many test methods have been performed and developed to investigate the effect of water on asphalt mixtures. Most of this work was related to stripping and durability. This paper presents a study on the effect of water table fluctuation on structural performance of flexible pavement matrix. Egypt road network covering north and delta regions are showing severe deterioration due to water intrusion that breaks the bond between aggregates and asphalt film causing raveling and stripping distresses. The main purpose of this paper is to identify the effect of variation in the soil type and hydraulic characteristics besides variations in the ground water table (GWT) and conditions on the water flow through typical flexible pavement systems. It also studying the watering effect on strength and durability of flexible pavement layered system. It was found that the effect of water existence in flexible pavement is very costly in terms of pavement life. The cost increase due to decrease in design-life and increase of maintenance cost by 7% to 84% according to elevation of ground water table and subgrade soil type. It also recommended to keep GWT far by at least 90% of matrix height or 1.0m (which is bigger) below the matrix bottom line Index Terms- Flexible pavement, strength, performance, ground water