The testing and performance of surface dressing binders for heavily trafficked roads

Advances in surface dressing, both in terms of equipment and a variety of new systems, has led to the process being more likely to be used on heavily trafficked road sites. A number of road trials, together with a country-wide survey, are reported which show that modified binders in surface dressing systems can reduce the risk of early failure. Some proposed test methods for specifying modified binders are also assessed and, although there are trends, these methods have yet to be demonstrated as accurately predicting road performance. Recent contractual experience of surface dressing on heavily trafficked motorways is also reported and shows that, by careful and detailed planning, surface dressings can be successfully laid and meet end-performance criteria. (A)