Low-temperature characterization of hot-poured crack sealant by crack sealant direct tensile tester

The current specifications for selecting crack sealants correlate poorly with actual field performance. To address this issue and assist in predicting the low-temperature properties of hot-poured bituminous crack sealants, a modified direct tensile tester method has been developed. Sample geometry is modified to accommodate testing sealants. A sensitivity analysis considering various loading rates, sample lengths, and cross-section areas was conducted to define both optimized specimen geometry and testing protocol. Two types of sealants, having a wide range of rheological behaviors (one polymer-modified and one having crumb rubber), were tested at low temperature. Results showed that the rich polymer-modified sealant has a high resistance to failure compared with the sealant with crumb rubber-modified. Each sealant was tested at the lowest corresponding expected service temperature. A performance parameter, strain energy density, was proposed to differentiate crack sealant material in the laboratory.