520.3(g) 520.3(m) concrete placements o the material is saturated but without standing water. Deposit the concrete either directly from the transporting equipment or by conveyor onto the subgrade . Do not place pervious concrete on frozen material. Deposit concrete between forms to an approximate uniform height. Spread the concrete using mechanized equipment or hand tools without segregation. Where trucks or buses may access the concrete, utilize a paver equipped with compaction tampers. For other areas , a roller screed or vibrating screed may be used.
roller to eliminate seams. Do not allow rollers to bridge previously placed and cured concrete for 7 days or before the R epresentative is satisfied the concrete has achieved sufficient strength to prevent damage. Steel troweling may be used provided the surface voids remain open and the average density requirement and permeability values are met.
with polyethylene sheeting. Thoroughly secure the curing sheet at all exterior edges and interior laps to prevent removal from wind. Maintain curing for a minimum of 7 days .
concrete immediately upon f inal finishing to approximately 1/4 slab thickness using a pervious concrete cross rolling tool or saw cut after the concrete has achieved sufficient compressive strength to prevent aggregate from being dislodged . If joints are saw cut, remove fines produced from the operation by vacuum to avoid clogging. If curing is interrupted, control the operations o the polyethylene sheeting and curing is reinstituted within 60 minutes of the initial removal.
any time during the 24- hour period following concrete placement or if rain is forecasted to occur before final finishing and curing. I f a rainfall event occurs, immediately stop production, form a construction joint , and apply the polyethylene sheeting. With approval , a construction joint may be saw cut before resuming placement. Pervious concrete subjected to rainfall will be evaluated after curing for loss of mortar at the surface and repaired or removed and replaced at the discretion of the Representative.