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Pervious concrete is a versatile no-fines material that requires unique, but not difficult, construction techniques and tools. If an attempt is made to construct a pervious pavement using conventional concrete placing techniques and procedures, the project will be less than satisfactory.
The “no-slump” characteristic requires direct placement by either tailgating or conveyor belt; pervious concrete cannot be pumped. While pervious concrete is a “no-slump” material, it must be placed with enough water to bind the cement-aggregate matrix together without exuding paste. Long-term serviceability depends upon constructing a sound, compact surface which has been thoroughly cured.
As with any pavement, the first step is to develop a sound base. Being a rigid pavement, pervious concrete does not require a strong base, but it should be uniform in character and non-expansive. Proof-rolled crushed rock provides such a base while also providing additional storm water storage. There are four different compaction techniques which have emerged in common practice placing pervious concrete. Two variations use rollers to compact the surface and two other variations use vibratory plate compactors.The type of construction method utilized should match the mix design and consistency to ensure the best placements. Roller compaction techniques include cross-rolling with a salt roller, and longitudinal rolling using a larger steel roller. Use of small riding rollers, as used to place asphalt, is feasible but rarely utilized. The salt roller is a solid steel roller perhaps three inches in diameter, polished smooth, and fitted with a long pole.