Jointing RCC Pavement

Longitudinal joints may be constructed in one of three ways, as illustrated in figure 10. Vertical cold joints are placed by paving the width of the lane and then sawcutting full depth the following day to facilitate trimming the edge with a blading and loader operation. However, this results in waste and can also be time-consuming.

Waste can be reduced if a paver shoe is used and adequate compaction is provided, allowing the edge to remain in place. The adjacent lane is then paved to match the thickness of the existing lane, and a cold joint is formed. This type of joint has shown good performance but has no load transfer capability. The angular cold joint requires the use of a high-density paver with a shoe attached to the screed. The maximum angle for the joint is 15 degrees. A plate tamper can be used to improve edge durability; in this case, no sawcutting is used, which provides a low-cost solution to placing the longitudinal joint. The adjacent lane can be paved as soon as one lane is completed.

Fresh joints are placed as they are in asphalt concrete pavements. Coordination between paving operations and plant operations is key and breakdowns must be avoided. The process involves paving for about 30 minutes accompanied by rolling operations without compaction within 2 feet of the joint edge. The second lane is placed by moving back to where the laydown began and matching the original lane by rolling up against it. This joint can also be sawcut for sealing purposes, but the performance of this type of joint has been mixed. Poor performance has been noted on these joints when they are allowed to dry out before paving the adjacent lane.

RCC pavements are cured just as conventional concrete pavement, typically using curing compounds but perhaps at a higher rate to compensate for the openness of the surface. Although not typically done, the transverse cracks can be initiated via sawcutting to provide a more aesthetically pleasing surface. Early entry saws have worked well in this application as long as the cuts are made 2 to 6 hours after placement.