Installation of hot-applied crack sealants prolongs the service life of roads and highways. In the last decade the method has gained in popularity in North America since at a relatively low cost it can retard the need for more extensive repairs for as long as five years. Despite the fact that this method has been used for several years it is not without problems. The crack sealant, the procedure of installation and the equipment used for the maintenanance need to be carefully considered to minimize the risks of premature failure of the sealant. The results reported here show that the usefulness of the hot-air lance to condition the rout prior to installing the sealant is questionable since the temperature raise upon passage since the temperature raise upon passage of the lance is slight and that high temperatures can only be reached when the rout is blackened. Finally, viscosity measurement showed that sealants should not be kept at elevated temperatures for more than one hour since a prolonged exposure to high temperatures induces irreversible changes in the physical properties of the polymermodified sealants.
Abstract