Although susceptibility to polishing is not a problem at the construction stage but a result of an earlier decision, greater pavement slipperiness becomes apparent after some time of pavement operation. The source of this problem is at the design stage of an SMA composition. The proper selection of an aggregates for a mixture and the level of designed air voids content are crucial.
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FIGuRE 11.34 Mastic squeezed-out of SMA in wheel paths during trafficking of pavement. (Photo courtesy of Krzysztof Blazejowski.) |
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FIGURE 11.35 Polished SMA surface after 3 years of operation. (Photo courtesy of Krzysztof Blazejowski.) |
We may define the expected scope of an aggregate’s polishing resistance for wearing courses through the selection of the polished stone value (PSV) category. PSV checking consists of testing the microtexture loss of aggregate grains under standardized conditions according to EN 1097-8. Figure 11.35 shows the effect of polishing a pavement after 3 years of traffic. This pavement, except for polished grains, shows no other damage.
