Abstract
Asphalt concrete (AC) cooling rates provide important information that can help with planning operations and field decisions made during construction. An increased cooling rate reduces the time available for compaction; as the mix cools down, the asphalt binder becomes stiff and makes it more difficult to achieve proper compaction, which can affect pavement performance. MultiCool is a computer program that predicts the rate of cooling in a hot-mix asphalt mat during construction on the basis of information related to the start time of the paving operation, environmental conditions, existing surface, and mix specifications. The software was originally developed and validated for conventional AC mixes. The objective of this study was to validate the cooling rates calculated by MultiCool for nonconventional mixes such as warm-mix asphalt (WMA), mixtures containing high percentages of reclaimed asphalt pavement (RAP), and mixtures containing modified and alternative binders. The validation was performed by using construction data from the National Center for Asphalt Technology test track 2009 research cycle, which included a number of nonconventional mixtures as well as a control. Although results indicated that factors such as the use of WMA, high RAP contents, and modified and alternative binders affect the difference between the measured and predicted cooling curves, the differences were within the same tolerance as the original validation and the model can be used confidently with these materials.
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