Research on Joint Sealant Materials to Improve Installation and Performance
Joints in Portland cement concrete (PCC) pavement are sealed with proper sealant materials to prevent intrusion of water and incompressible materials. Intrusion of water could result in corrosion of dowels or tie bars in CPCD, and tie bars or longitudinal steel in CRCP. Intrusion and collection of incompressible materials could cause surface spalling. Another important failure mechanism in PCC pavement in Texas is erosion of base materials caused by water infiltration along longitudinal joints between the outside concrete lane and asphalt shoulder. To improve the performance of PCC pavement, it is important to keep the joint seals in a good condition so that water and incompressible materials cannot get into joints. There are three elements associated with joint seal performance: (1) proper joint design, (2) quality of joint seal materials, and (3) proper installations. Currently, joint design is dictated in the joint design standards, JS-94. Joint seal material quality is controlled by DMS-6310. Joint sealant installation is governed by Item 438. There are discrepancies between TxDOT requirements and actual practice, potentially compromising the effectiveness of joint performance. The discrepancies need to be identified and design standards or specifications revised or field practices modified.