Sprayed seal road trials were laid at two sites in australia to evaluate the effectiveness of the antioxidant lead diamyldithiocarbamate (ldadc) in reducing the rate of asphalt hardening. Sections containing no antioxidant (control) and sections containing between 1 and 6% ldadc in asphalt were placed. Testing of samples taken duringconstruction showed that little or no degradation of the ldadc had occurred during mixing with asphalt or during the spraying operation. Environmental and occupational health monitoring was performed at one of the trials. Both trials were sampled 2 yr after construction and the asphalt recovered for testing. For all three of the asphaltsused, it was found that asphalt hardening had proceeded more slowlyin those sections containing antioxidant than in the control sections. Increasing ldadc concentration in the asphalt was correlated with a reduced binder hardening rate. The trials will continue to be monitored to determine whether the early improvements in asphalt hardening rate continue in the long term. This paper appears in transportation research record no. 1228, Asphalt mixtures and asphalt chemistry.
Samenvatting