Engineering Interlayers for Rigid Bases under Jointed Plain Concrete Pavement Slabs

This research’s goal is to develop recommendations for improving the interlayer (“bond breaker”) used between jointed plain concrete pavement (JPCP) slabs and lean concrete base (LCB). A full-scale test track was built and monitored to study the slab-base interaction. The test track included four independent slabs, one with asphalt concrete (AC) base and three with LCB and one of the following interlayers: curing compound, geotextile, and microsurfacing. The curing compound interlayer represents current practice in California, U.S., for JPCP with LCB. Test track monitoring included slab curling/warping and falling weight deflectometer (FWD) deflection. Experiment data collected from the track indicate that AC provides much better support to the slab than LCB with curing compound interlayer. When the slab curvature was very high, the corner deflection under FWD loading in the section with LCB and curing compound was up to three times larger than the corner deflection in the section with AC base. The geotextile performed similarly to the curing compound interlayer. However, the microsurfacing considerably improved the performance of the curing compound interlayer. The corner deflection in the section with LCB and microsurfacing interlayer was similar to the corner deflection in the section with AC base. This study demonstrates that, by using the appropriate interlayer, the cracking performance of JPCP with LCB can be improved and potentially match the performance of JPCP with AC base. This outcome results in the recommendation to allow continued use of LCB for JPCP construction in California if a microsurfacing or other interface with similar performance-related properties is used.