investigating the performance characteristics of asphaltic concrete containing nano-silica

Using nanotechnology materials in the asphalt pavement industry is new compared with portland cement concrete. the main objective of this study is to investigate the effects of nanosilica modification on some properties of a penetration grade asphalt cement and a typical asphalt concrete. 60/70 penetration grade bitumen was modified with different percentages of nanosilica (i.e. 1, 3 and 5%, by weight) and was used for making the asphalt concrete specimens. after evaluating the basic properties of the modified binder, the asphalt concrete specimens were evaluated based on the stiffness and resistance against fatigue cracking, moisture damage and permanent deformation. the fatigue life of the modified mixtures was also calculated using an already developed regression model. the results showed that penetration grade and ductility increase and softening point decreases with increasing nanosilica content. furthermore, results showed that the addition of nanosilica results in the increase of stiffness, tensile strength, resilient modulus, fatigue life and resistance against permanent deformation and moisture damage. the reduction of indirect tensile strength in wet the condition decreases with increasing nanosilica content. dynamic creep test results showed that, the flow number of the control mixture and the mixture containing 1% of nanosilica is much lower than 10000 loading cycles. however, the mixtures containing 3 and 5% of nanosilica do not reach to the tertiary creep region after 10000 loading cycles.