The new UNE 41901: 2017 EX standard establishes sections to define how to carry out different studies of pavements with this test.
Testing of an in-service soil can be performed under different conditions, including:
a) as it is; Before starting the measurements, the surface will be swept with a soft hair brush without using liquids, in order to remove the loose particles present;
b) with normal cleaning; If the usual cleaning conditions are unknown, the surface will be cleaned using a damp cloth with distilled water and 50% ethanol;
c) with very thorough cleaning; It can also include the use of other contaminants in addition to water. The surface should be cleaned with a soft-bristled brush and 100 g / l ammonium chloride solution in distilled water. After cleaning, rinse with distilled water and 50% ethanol. For dry tests, fiberless paper and / or air can be used to accelerate drying.
It should be noted that the three mentioned surface conditions can give very different test results.
If tested as-is, or contaminants other than water are used, it must be recognized that the footing may become contaminated, in which case it must be cleaned and re-prepared in accordance with 5.2.2 for new use.
Different footings should be used for each state of contamination.
Depending on the purpose of the information on the PTV, different sampling methods can be used.
It is advisable to select on-site specific locations that can provide the full range of variability, for example places where there has been little or no pedestrian traffic, such as on corners, under benches, etc., and other locations, such as next to the passing doors, where pedestrian traffic can be significant. Variations in the cleaning method or intensity can also cause a variation in the PTV obtained.
If significant changes are detected between the results in different locations, the information regarding the means used for maintenance (especially in the case of mechanical cleaning) should be requested and confirm whether subsequent surface treatments of the installation have been carried out.
Our laboratory performs all these studies based on the UNE 41901: 2017 standard.