Abstract:
Styrene butadiene styrene (SBS) is the polymer type most commonly used
to manufacture polymer modified binders (PMBs). PMBs may need to be kept in a hot
storage tank for an extended period of time because of adverse weather conditions or
other uncertainties. Though PMBs show enhanced performance, a premature failure
might occur in asphalt concrete during hot storage on exposure to a combination of
heat and air. The aim of the current study is to examine the effect of hot storage on the
engineering properties of PMBs and asphalt mixtures. SBS-based PMBs were stored
in a storage tank at 180 °C up to 28 days in this study. It was estimated that more
than four fifths the SBS polymer remained after long storage periods. There was a
reduction in tenacity and elastic recovery test results, indicating that the degradation
of the SBSpolymer could occur after a long period of hot storage time. The otherPMB
test properties including toughness and storage stability did not vary significantly as
the storage time was increased. Even though the SBS polymer in PMBs appeared to
be degrading during storage, there was no change in the wheel tracking performance
of the PMBs in asphalt mixtures. The cracking resistance obtained in semi-circular
bend tests, by contrast, varied for the PMBs after hot storage. The results obtained
in this study show that degradation of the polymer in a PMB during hot storage may
not necessarily reduce the performance of asphalt mixtures.
