Low Temperature and Moisture Susceptibility of RAP Mixtures with Warm Mix Technology

US Transportation Collection2018PDFTech ReportMogawer, Walaa S.Austerman, Alexander J.University of Massachusetts Dartmouth. Department of Civil and Environmental EngineeringNew England Transportation ConsortiumUniversity of Vermont. Transportation Research CenterUnited States. Department of Transportation. Federal Highway AdministrationNew England Transportation ConsortiumUnited StatesNew EnglandBindersCreepHot mix asphaltLaboratory testsLow temperatureMix designMoisture contentRecycled materialsWarm mix paving mixturesNETCR103NETCR103Final reportA major concern with the use of Warm Mix Asphalt (WMA) technologies has been their impact on the moisture susceptibility of asphalt paving mixtures. This is due to the lower production temperatures associated with mixtures incorporating these technologies which could lead to inadequate drying of aggregates. The moisture susceptibility concern may be compounded if high amounts of Reclaimed Asphalt Pavement (RAP) are added to the mixture. RAP is mixed with the heated aggregates in an attempt to avoid further stiffening of the binder present in the RAP. Therefore, if the aggregates in a mixture are heated at lower temperatures than the conventional temperatures due to WMA, the RAP will be exposed to less heat which might lead to residual moisture in the RAP being present in the mixture. Residual moisture may lead to adhesive and/or cohesive failures. The purpose of this study was to better understand the influence of moisture on the performance of plant produced high RAP content mixtures incorporating WMA technologies fabricated at reduced mixing temperatures.143