Moisture damage in asphalt mixtures refers to loss in strength and durability due to the presence of water. Egypt road network is showing severe deterioration such as raveling and stripping because the bond between aggregates and asphalt film is broken due to water intrusion. To minimize moisture damage, asphalt mixes are investigated to evaluate the effect of air voids, degree of saturation, media of attack and the conditioning period. Two medias of attack are considered and two anti-stripping additives are used (hydrated lime and Portland cement). The retained Marshall stability and tensile strength ratio are calculated to determine the resistance to moisture damage. The results showed that both lime and cement could increase Marshall stability, resilient modulus, tensile strength and resistance to moisture damage of mixtures especially at higher condition periods. Use of hydrated lime had better results than Portland cement.

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Silt soil cannot satisfy the requirements of highway construction because of its low strength. A new stabilizer from waste aluminum industry is developed (aluminum chops (AC) and wires (AW)) to evaluate the effect of reinforcing the subgrade with low-cost by-product materials on its mechanical and durability characteristics. Laboratory tests, including modified proctor compaction, compressive strength, splitting tensile strength, and CBR are developed to evaluate the mechanical properties. The durability properties are investigated by studying the influence of environmental conditions such as water immersion effect on compressive strength, mass loss after freezing and thawing cycles, water absorption by capillarity and wetting-drying durability. Moreover, a practical application about the base course thickness saving and its economically viable as well as correlations between mechanical properties are investigated. The results indicated that the aluminium fiber can effectively improve the mechanical and durability characteristics of silt subgrade where the increase in aluminum chops grade leads to improve the majority properties. While aluminum wires of 2.0 cm length produces reduction in CBR and compressive strength compared to smaller length. Stabilization with aluminium fiber has a remarkable influence in reducing the base course thickness (especially at using 4% of AW1.0) and increasing the construction cost saving (especially at using 1% of AW1.0).

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