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Benefits:
• Economic
Applications:
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Conventional
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Pervious Concrete Installation Process Step 3: Compaction
The final compaction or consolidation of the poured concrete mixture is accomplished with a steel-pipe roller immediately after screeding. This step must be completed within fifteen minutes of placement in order to avoid the hardening effects of evaporation. In the placement of conventional concrete, troweling operations are performed after compaction, resulting in a smooth surface finish. However, since this step tends to close off the uppermost voids of porous concrete, it is skipped in pervious installation. This sacrifice leaves the pavement fully permeable, and the rougher surface finish actually improves traction.
Although pavement-cracking does occur, it is not abundant, since pervious concrete contains minimal amounts of water. When cracks do arise, they do not significantly compromise the pavement, either structurally or aesthetically. However, if the prevention of random pavement-cracking is desirable, control joints can be placed soon after consolidation as a remedy. These can be formed with a rolling joint tool, or less ideally, with sawing equipment at a later time. Since pervious concretes shrink much less than impervious ones while drying, their individual joints tend to be larger in width. Control joints at ¼ the thickness of the slab generally provide good control of cracking, and are installed to line up with the joints of adjoining pavements at recommended intervals of twenty feet.
>>Next Step: Curing
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ConcreteAnswers for Architects, Engineers and Developers:
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