Performance of pavement crack sealants in cold urban conditions

Twelve bituminous hot-pour crack sealants were evaluated over four years in temperatures ranging from –40°C to +40°C. Each sealant was evaluated over 900 linear meters of transverse and longitudinal routs of 12 × 12 mm2, 19 × 19 mm2, and 40 × 10 mm2 (width × depth). Results show that sealant source, rout size, and rout orientation affected sealant performance, i.e., debonding and pull-out levels. Debonding levels were 0–50% and pull-out levels 0–30%. Sealant failure was proportional to rout width; it was lowest in 12 mm wide routs and highest in 40 mm wide routs. This result is attributed to the proportional exposure of sealants to slow moving traffic. The increase of sealant failure over time was also found to be nonlinear. Three stages were identified in the failure–time plot. In stage 1, failure is rapid; in stage 2, it plateaus; and in stage 3, it increases again. Failure in stage 1 is thought to be related mainly to a weak sealant – asphalt concrete interface, whereas that in stage 3 is thought to be related to sealant weathering and stiffening. It was also found that standard test results correlate poorly with field performance.