Air Purification performance of photocatalytic concrete paving blocks after seven years of service

This paper reports the results of field pavement preservation research located on a state highway in Oklahoma regarding two accepted methods for measuring pavement macrotexture. The project has been ongoing for two and a half years and has used the outflow meter ASTM STP 583 and the Transit New Zealand TNZ T/3 sand circle to measure macrotexture on 23 asphalt and concrete pavement preservation treatments. As a result of the protocol which calls for monthly macrotexture measurements in the field, the researchers observed functional limitations regarding the accuracy of macrotexture measurements on both standard tests. The limitations are a function of the physical mechanics of the two methods. The paper furnishes guidance to researchers and practitioners in selecting a pavement macrotexture test method. Essentially, the paper finds that the sand circle should be used on pavements with macrotexture greater than 0.79 mm (0.03 in.) and the outflow meter should be used on pavements with textures less than 1.26 mm (0.05 in.). Both tests can be used accurately in the 0.79 mm (0.03 in.) to 1.26 mm (0.05 in.) range. These results apply to both asphalt and concrete pavements.