2011_AAPA_Study_Tour.. - Aapaq.org

5. Binders AAPA 2011 Study Tour Group ReportProperties of polymer modified bitumen emulsions for various applicationsProperties of emulsion Spray Bond coat Microsurfacing Crack sealantBinder content (%) 65 & 70 65 62 – 65 55Viscosity @ 50°C ( SF.s) 51 -20021 – 100 < 0.8 @ 25°C51 – 400Properties of residue binderSoftening point residue (min °C) 48 & 55 48 48¹ & 55² 80Elastic recovery @ 15°C onresidue (min %)50 & 55 50 50¹ & 55² 60Source: TG1Notes:1. These are the requirements when the PMBE is use for an overlay2. These are the binder requirements when the PMBE is used for rutfillingSummary and recommendationsGiven the similarity in traffic density and climatic conditions between RSA and Australia, the studygroup identified some opportunities for further investigation. It is recommend that adopting thefollowing practices relating to binders for implementation:• Increased use of field blended CRB for spray seals• Use of wet blend CRB for asphalt wearing courses• Use of PMBE’s for constructing spray seals in winter• Making usage of dilute emulsions for cover sprays• Making greater use of rejuvenation treatments to extend life of existing aged sealsThe adoption of these practices could lead to more durable and longer lasting surfacings. Tosupport these practices consideration should be given to make greater use of:• high speed mixing blenders and digestion tanks with augers for producing CRB• on-site measurement of CRB using a hand held viscometer to check compliance beforeuse• adoption of TG1 specifications for PMBE’s for spray sealing• use of DSR to develop performance based specifications for binders across thetemperature spectrum• use of TG1 storage stability test to measure segregation of PMBsV4-2 Page 53