Infrastructure developments with hard paved areas prevent the natural dissipation of rainwater. Their adverse effects are cumulative and can lead to long-term problems of disposing of water that can result in flooding. The Highways Agency aims to maintain rainwater runoff rates from their roads at current levels, despite road widening and the increase in rainfall predicted by climate change. Sustainable Drainage Systems (SuDS), which deal with runoff at source by mimicking the natural processes of redistributing rainwater to the air and the ground, reduce the severity of these problems. One such system is a reservoir pavement that can either eliminate or reduce runoff, or just temporarily store water and reduce run-off flows. There are several configurations of these pavements to cope with different site specific issues. Reservoir pavements, however, have been used mainly for lightly trafficked applications. This report describes a pilot-scale trial of flexible pavements with porous concrete bases that have the potential to extend the technology to more demanding traffic levels. An assessment is made of the hydraulic and structural behaviours of a variety of reservoir pavement types that indicates the potential of these pavements. This research, sponsored by the Highways Agency, was undertaken by TRL with industry collaboration.

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