Evaluating the Performance of the Asphalt Mixes Containing Reclaimed Asphalt Pavement by Considering the Effect of Silo Storage Time

摘要

The use of reclaimed asphalt pavement (RAP) in hot mix asphalt (HMA) has been increasingin the last few decades because of its cost benefits and because of a compelling need to preservethe environment and natural resources. It is commonly assumed that HMA containing RAP (HMARAP)has an improved resistance to permanent deformation (rutting) and decreased resistanceto the fatigue cracking. This is due to the fact that asphalt binder contained in the RAP has beenoxidized over the years and is typically stiffer than virgin asphalt binder. However, during theproduction stage of the HMA-RAP, the blending between aged and virgin asphalt binders wouldbe incomplete or partial, which would lead to heterogeneous distribution of the aged and virginasphalt binders within the asphalt mix with RAP. Therefore, the purpose of this article is to evaluatethe effect of silo storage on the blending mechanismbetween virgin and RAP asphalt bindersand the impact that this would have on performance of the mix. Two plant-produced asphaltmixes (HL-3 and HL-8), typically used in the province of Ontario for surface and base courses inflexible pavements, were considered in this study. The mixes were designed with 15 and 30 %RAP, respectively, and the samples were collected immediately after the production (0 h) or atdifferent silo storage times (1, 4, 8, and 12 h). The temperatures of the collected materials wereclosely monitored and recorded. The findings of this research indicated that silo-stored samplesexhibited some improvement in their rutting and fatigue resistance. The examination of the dynamicmodulus master curves indicated that the rheology of the mixes evolved with silo storageand that blending between the aged and the virgin binders has been improved.