A high binder content (78%) polymer-modified bitumen emulsion used in a 'racked-in' sealing system was trialed from 1993 to 1995 as a surfacing in high traffic stress areas for New Zealand roads. The perceived advantage of this sealing system was that the polymer-modified emulsion would have better initial chip adhesion than a hot applied polymer-modified bitumen.
Four trial areas, comprising eight sites, were constructed using this system, including two roundabouts, and monitored for one year (1995). On two of the sites, control sections were constructed using a two-coat seal with 180/200 grade bitumen. Although the control sections also performed well, the polymer-modified emulsion sealing system is concluded to be a viable surfacing treatment for high traffic stress areas on roads.
Keywords: binder, bitumen, chip loss, chipseal, emulsion, New Zealand, PMB, polymer, roads, traffic