Evaluation of Trapezoidal Shaped Grooves

Figure 41. The MCAF Quantico Friction Run 4L—10 Minutes After Heavy Rain Analysis of figures 38 through 41 indicated that the trapezoidal-shaped grooves provide comparable friction values to the standard grooves, making it nearly impossible to separate the two purely on their friction data. Rubber contamination, oil deposits, and other uncontrollable factors can cause abnormities in the data, which are likely reflected by random spikes in the data graphs, as well as the reduced numbers closest to the touchdown areas (due to rubber contamination). Researchers were not trying to identify specific numerical differences in the friction values but were trying to determine if the trapezoidal-shaped grooves provided comparable friction than the standard groove on the runway as a whole. It was interesting to note how the friction values collected within the ungrooved asphalt area deteriorated significantly with the increase in water exposure, while the trapezoidal-shaped and standard grooved areas maintained fairly consistent numbers throughout the rain event.

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