Concrete brick paving differs from other forms of surfacing in that it comprises of small segments and therefore is criss-crossed by a network of close spaced joints filled with sand.
This means concrete brick paving is permeable and the drainage of the surface and underlying layers is critically important. (Make sure your contractor does not use plastic sheeting under the paving. See the article on Pavatile here: Warning: Don’t use plastic under concrete brick paving)
There is limited full scale testing worldwide, but from a study conducted by the late Dr Brian Shackel, formerly of the University of New South Wales, Australia, the following conclusions were drawn:
- Between 30% to 35% of rainfall will penetrate newly laid, un-trafficked, and unsealed brick pavements.
- Increase in pavement cross fall will increase surface runoff. (Recommended minimum slopes of 2%.)
- The permeability of the joints can be reduced by up to 50% with an application of a water based acrylic sealer.
- Similarly infiltration can be inhibited by using 10% of lime or 6% bentonite to the jointing sand.
Since no attempt is generally made to seal the joints in practice, attention should be directed towards reducing the consequences of water infiltration, particularly during the early life of the paving.
In practice care must be taken to select bedding sands not susceptible to water or seal the base if it comprises unbound granular materials or select base materials bound and waterproofed with cement, lime or bitumen.
The management of water runoff and infiltration becomes therefore a critical aspect that will affect the performance and integrity of the concrete brick paving.
Good surface and subsoil drainage is essential for satisfactory brick pavement performance.
Drainage needs to be considered during the design, specification construction phases of any paving project.