Effect of aggregate moisture on adhesion of chip seal

Abstract

Chip seal involves the application of a thin layer of bituminous binder to the pavement surface followed by the spreading and rolling into it of single sized aggregates. There are several problems when using chip seal. One of the problems is moisture content on aggregate in chip seal. This will lead to the problem of aggregate easily dislodged and can reduce the adhesion between aggregate and bitumen. The objectives of this study are to determine the percentage of moisture content on different condition of aggregate and to determine the adhesion of chip seal at different condition of moisture content on aggregate. 80/100 penetration grade bitumen is used as a binder. There were three sizes of aggregate that have been used in this study namely, 6 mm, 10 mm and 14 mm. For each aggregate size, the percentage of moisture content are determined in four conditions of aggregate which are dry aggregate, partially dry aggregate, saturated surface dry aggregate and fully wet aggregate. Then, the vialit test and pull out test are conducted to determine the adhesion between aggregate and bitumen. From moisture percentage determination test, increasing the size of aggregate will increase the percentage of moisture content of aggregate. For vialit test, the percentage of aggregate retained will decrease when increasing the percentage of moisture content on aggregate. For pull out test, the average of maximum load increases when the percentage of moisture content of aggregate decreases.