A Literature Review on Anti-Strip Additives in Asphalt Mixture

The loss of bond between aggregates and asphalt binder that generally begins at the bottom of the HMA layer and progresses upward is known to be stripping of pavement. Stripping has been existent since the advent of paving technology. It causes functional weakening of pavements leading to costly repairs. Adhesion of bitumen onto aggregate is explained based on theories like mechanistic tenacity, molecular orientation, chemical reaction, and thermodynamic balance of interfacial forces. Stripping is elucidated using several mechanisms namely, displacement, detachment, spontaneous emulsification, bitumen film rupture, water pore pressure, hydraulic scouring, chemical disbonding, microbial activity, osmosis, and blistering and pitting. Chemical composition of aggregates is also an important factor of the occurrence. In this paper we have discussed the mechanism of stripping, causes of stripping and finally the solution. Different Anti strip additives may minimize the severity of stripping based on their properties and workability. The goal of this paper is to introduce the readers with different anti strip additives and their workability in a simple way.