Evaluation of Trapezoidal Shaped Grooves

Cost. Another objective of Phase Four was to compare the cost differences associated with trapezoidal-shaped grooves versus standard grooves. For the installation at MCAF Quantico in 2007, the costs for cutting the trapezoidal-shaped grooves averaged $1.75 per square yard, not including transportation and material costs. Comparably, the cost for cutting standard grooves would have been approximately $1.25 per square yard. It has been noted that the cost for cutting the trapezoidal-shaped grooves would be about 15% to 25% higher than the standard grooves until the cost of the blades decreases with large-scale production. Local labor rates, work hours, and other site specific factors can also affect pricing. The typical price range for grooving in concrete pavement ranges from $0.80 to $2.50 per square yard, depending on the conditions and material to be cut. Wear and Durability. Researchers monitored the trapezoidal-shaped and standard groove areas for differences in wear and durability. Specifically, they observed how the grooves endured over a long term, maintained their specified shape, and resisted rubber contamination. Approximately 5 months after the groove installation was completed at MCAF Quantico, researchers returned to the airport to conduct their first evaluation. It was noted that there was a difference in the amount of rubber contamination on the two types of grooves. There was less rubber buildup on the top edges of the trapezoidal-shaped grooves, whereas the standard grooves collected more rubber on the top edges. Figure 31 shows the rubber contamination on a standard groove area, and figure 32 shows the rubber contamination on a trapezoidal-shaped groove area. Note the increased buildup of rubber on the leading edge of the standard groove sections in figure 31, as compared to the lesser buildup on the trapezoidal-shaped groove shown in figure 32.

Leading-edge buildup

Figure 31. Rubber Contamination at MCAF Quantico—Standard Groove

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