| Popis: |
Hot-poured bituminous crack sealing has been widely accepted as a routine preventative maintenance practice, and with proper installation, it is expected to extend the pavement service life three to five years. However, the current specifications for the selection of crack sealants correlate poorly with field performance; hence, a set of new testing methods, which are based on sealant rheological/ mechanical properties, were developed recently. Measuring the mechanical properties of crack sealant at low temperatures is one of the criteria introduced as part of the developed performance-based guidelines. The main purpose of this study was to identify and validate the low temperature selection thresholds for the newly developed performance based guideline for selecting hot-poured bituminous crack sealants. In this study, selection criteria for crack sealant bending beam rheometer (CSBBR) and crack sealant direct tension tester (CSDTT) tests are identified. Two performance parameters for CSBBR test are used for the selection criteria: stiffness at 240s and Average Creep Rate (ACR). Both parameters were identified by comparing laboratory testing results with known sealant field performance, obtained from a long-term study in Canada. The selection criterion for the CSDTT test is extendibility, which is based on field values reported in the literature. The recommended selection criteria were used to predict the field performance of 12 sealants evaluated by the National Transportation Product Evaluation Program (NTPEP). The results show good correlation between the proposed selection thresholds and NTPEP field sealant performance. |
