EFFECT OF AGGREGATE PROPERTIES ON STRIPPING

Abstract

A laboratory investigation was conducted to relate some measurable aggregate properties to the stripping propensity of a mix of aggregate and asphalt cement. Several different types of aggregates were used in this study; each was characterized in terms of its physical properties, such as pore volume and surface area, and its chemical and electrochemical surface properties. Stripping propensity was determined by using a boiling water test. Under certain conditions, aggregates that have a relatively high surface electrical potential and those that impart a high pH value to water in contact with their surface were found to exhibit a high susceptibility to stripping. These results were interpreted in terms of electrochemical properties of the aggregate surface. It was also observed that the effectiveness of some types of antistripping additives was sensitive to the pH of water in contact with the aggregate and that curing the asphalt-aggregate mixture and precoating the aggregate improved stripping resistance considerably.