Comparison of the Properties of Asphalt Cements Modified by Nanoclay and SBS

The weaknesses of the traditional asphalt cements produced by the refineries are the main factors in premature failure of asphalt pavements. One of the measures to prevent these failures is the modification of the asphalt using additives. A variety of materials have been used for modification¡ among which are polymers and nano materials¡ including nanoclays. As the effects of these two types have not been compared in the literature¡ this paper describes the results of an experimental work¡ in which the effects of a type of nanoclay and Styrene-Butadene-Styrene¡ SBS¡ on the properties of 60/70 penetration grade asphalt cement have been investigated. Different amounts of each additive have been added to the asphalt¡ and the properties of penetration grade¡ softening point¡ penetration index¡ dynamic viscosity¡ and the rheological properties including phase angle and complex dynamic modulus have been studied. The results show that¡ both the additives have a stiffening effect on the asphalt¡ which increase the strength against permanent deformation. However¡ the stiffening effect is dependent on the type of additive and the amount of them used for modification. The SBS polymer has a better effect for improving the resistance against permanent deformation.