2011_AAPA_Study_Tour.. - Aapaq.org

4. Surface Treatments Questions and Responses AAPA 2011 Study Tour Group ReportPrimes and primersealsFor new works primerseals are not used, rather a prime and seal is preferred. If building apavement through winter a prime followed by a modified emulsion double seal is employed.When undertaking pavement rehabilitation under traffic it is common practice to build, prime andseal the road in half widths. Access to the road is maintained on the remaining lane through theuse of stop/go traffic control that may operate 24 hours per day for as many days as necessary.This is undertaken on sections up to 4km in length.ResealsReseals are not normally undertaken during an ‘embargo’ period from May to August due to poorperformance. It is considered that the embargo is partly related to the fact that the use of cuttersis discouraged due to the perceived health and safety risks of adding cutter on site and thepotential for bleeding in summer. Measures taken to improve aggregate adhesion and henceavoid the use of cutter include:• Spraying when pavement temperatures are 25°C and rising• Use of emulsion binders• Aggregate precoating• Prevent trafficking of the seal at night. Similar to rehabilitation sealing is performed in lanewidths with traffic control used to prevent access to the fresh seal overnight. Rolling andsweeping is undertaken the following day when the pavement has warmed. Traffic is onlypermitted on the seal when the pavement temperature is above 15°C.It is recognised that cutter is sometimes necessary, particularly with PMB’s (TG1). In these cases itis preferred that the cutter is added at the refinery or plant. If addition of cutter is required on sitethe contractor is required to provide a method statement addressing the risks. Maximum cutterlevels suggested are 5% for light traffic and 3% for heavily trafficked roads (TG1).Figure 4.5a – Diagram of diluted emulsion fog sprayV4-2 Page 15