Research on Joint Sealant Materials to Improve Installation and Performance : Final Report

016545412017Technical Report July 2014-January 2016Report Date: January 2016; Published December 2017PDFTech ReportFHWA/TX-17/0-6826-10-6826-10-6826DesignInstallationJoint sealersJoint sealingPavement designReinforced concrete pavementsRoad constructionCPCDCRCPJoint designPavement jointSealantUnited StatesTexas Tech University. Center for Multidisciplinary Research in TransportationChoi, PangilSenadheera, SanjayaWon, Moon C.Texas Tech University. College of EngineeringTexas. Dept. of Transportation. Research and Technology Implementation OfficeUnited States. Federal Highway AdministrationUS Transportation CollectionThe objectives of this project were to 1) identify failure modes and their mechanisms in joint seals in Texas, and to 2) identify what needs to be done to minimize the failures and improve joint seal performance. To achieve these objectives efficiently, a factorial experiment was developed that included pavement age, shoulder and base type and climatic condition as independent variables. Field surveys were conducted to identify failure modes and their respective failure mechanisms in accordance with the factorial design developed. Field operations of joint seal installations were observed and contacts were made with joint seal contractors, other state DOT personnel as well as joint seal material producers. The findings from this study included (1) joint sealant performance period is much shorter than the current pavement design period, which is 30 years, (2) it is quite rare to observe pavement distresses that can be solely attributable to poor joint sealant condition, (3) there are other variables that have more significant effects on PCC pavement performance than joint seal condition, (4) most of the joint seal failures appear to be due to hardening of the sealant over time, or aging effect, (5) discrepancies exist between TxDOT requirements in design standards and field practice, and (6) continued concrete drying shrinkage increases joint width over time. It appears that the condition of joint sealant does not have substantial effects on overall performance of PCC pavement in Texas. This finding is in line with the findings in several state DOTs. However, joint sealing has its own merit, such as keeping incompressible materials out of the joints