BS EN 12697-40:2020 pdf free.Bituminous mixtures – Test methods .In situ drainability.
BS EN 12697-40 This document describes a method to determine the in situ relative hydraulic conductivity, at specific locations, of a road surfacing that is designed to be permeable. An estimate of the average value for the surfacing is obtained from the mean value of a number of determinations on each section of road.The test measures the ability to drain water (drainability) achieved in situ of a surfacing. As such, it can be used as a compliance check to ensure that a permeable surface course has the required properties when it is laid. The test can also be used subsequently to establish the change of drainage ability with
time.For the test to be valid, the surface of the test area should be clean and free from detritus.Measurements can be made when a road is either wet or dry, but not ifit is in a frozen state.Place the permeameter over the surfacing at the point where the relative hydraulic conductivity is to be measured. Apply a vertical load uniformly on the base such that all four of the rubber feet on the standing board are in contact with the surface to be measured.A load of between 1 kN and 2 kN should achieve this contact.The load can be applied either mechanically or by two operatives of approximately the same mass standing on opposite sides of the standing board. If two operatives are used, the heavier operative should not weigh more than 50 % more than the lighter operative. Fill the standpipe completely with clean water. Remove the plunger and hang it by its rest on the top of the standpipe. Allow air bubbles to rise up through the water in the standpipe until they no longer rise through the water, which is dissipating into the road surface. If air bubbles are still rising through the water in the standpipe when the meniscus nears the 5 l mark, replace the plunger and refill the standpipe to at least 50 mm above the 5 l mark. Without delay, remove the plunger and hang by its rest on the top of the standpipe.BS EN 12697-40 pdf download.