Infiltration measurements were made using a double-ring infiltrometer. The equipment is shown in
Figure 1. The inner and outer sections were made square with hinged corners. The inner section
was 1m x 1m square so that a much larger area of paving was sampled in each test than has been
common in previously reported infiltration tests conducted on PICP. The perimeter edges of the in-filtrometer that were in contact with the pavements were provided with a bitumen impregnated
(BIP) seal to create a waterproof attachment to the pavement surface. The determination of the infiltration
rate through the surface of the pavement was calculated from the time taken for a 20 mm
drop in the water level within the frame depicted in Figure 1. This procedure was based on Australian
Standard AS4693.5–2004. Care was taken to ensure that the water depth in the outer section of
the device remained close to the level in the inner section to ensure the boundary condition eliminated
horizontal movement of water from the inner ring. The use of silicone or other substances
that can leave a permanent mark on the pavement surface was deliberately avoided.