The Evaluation of polyaminoamide as a surfactant additive in hot mix asphalt

The phenomenon of breaking the bond between the aggregates and the bitumen is known as stripping. Strip-ping of asphalt films from the surface of aggregate particles results in premature failure of asphalt pavement. This causes weakening of pavement resistance to rutting and fatigue. Furthermore, moisture damage increases the susceptibility of pavement to reveling, a distress that causes the loss of skid resistance on surface of the road and deterioration of pavement. Surfactant additive or adhesive agent is a surface-active agent that changes (lowers) the surface tension of rock materials. Introduction of surfactant additive results in increased strength of adhesive bond between bitumen and the rock materials surface preventing stripping throughout the service life of the asphalt concrete. Polyaminoamide is an organic water soluble compound that allows waterproofing mineral aggregate surfaces and acts as a bonding agent to bitumen. The objective of this research is to study the effect of polyaminoamide based and pholiphosphoric acid based liquid additives on stripping, moisture susceptibility, rutting and fatigue performance of asphalt concrete. In this paper, boiling water test was used to determine the percentage of stripped aggregates after boiling. The moisture susceptibility of asphalt mixtures was investigated by means of testing the retained indirect tensile strength after water immersion using Marshal stability test method. Wheel tracking test was also conducted on asphalt slabs prepared in the laboratory to determine rut resistance. Asphalt concrete with commonly used mineral filler was chosen as a control mixture. It was found that the adhesion additive not only improves stripping resistance, but also slightly improves asphalt rut resistance.