360R-06 Design of Slabs-on-Ground
—Joint filling and sealing
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| 5.5—Joint filling and sealing
Where there are wet conditions, hygienic and dust control requirements, and the slab is not subjected to wheel traffic, contraction and construction joints can be filled with joint filler or an elastomeric joint sealant. Joints subjected to wheeled traffic should be treated as discussed in Section 5.4. Isolation or other joints are sometimes sealed with an elasto- meric sealant to minimize moisture, dirt, or debris accumula- tion. Elastomeric sealants should not be used in interior joints that will be subjected to vehicular traffic unless protected with steel armored edges. Refer to ACI 504R for more information on elastomeric sealants. 5.5.1 Time of filling and sealing—Concrete slabs-on-ground continue to shrink for years; most shrinkage takes place within the first year. It is advisable to defer joint filling and sealing as long as possible to minimize the effects of shrinkage-related joint opening on the filler or sealant. Ideally, if the building is equipped with an HVAC system, it should be run for 2 weeks before joint filling. This is especially important where joint fillers are used in traffic-bearing joints because such materials have minimal extensibility. If the joint should be filled before most of the shrinkage has occurred, separation should be expected between the joint edge and the joint filler, or within the joint filler itself. These slight openings can subsequently be filled with a low-viscosity compatible material. If construction traffic dictates that joints be filled early, provisions should be made to require that the contractor return at a pre-established date to complete the necessary work using the same manufac- turer’s product. Earlier filling will result in greater separation and will lead to the need for more substantial correction; this separation does not indicate a failure of the filler. For cold-storage and freezer-room floors, joint fillers specifi- cally developed for cold temperature applications should be installed only after the room has been held at its planned oper- ating temperature for at least 48 hours. For freezer rooms with operating temperatures below 0 °F (–18 °C), the operating temperature should be maintained for 14 days before starting joint filling. There should be an understanding between all parties as to when the joints will be filled and whether provisions should be made for refilling the joints at a later time when additional concrete shrinkage has taken place. 5.5.2 Installation—Elastomeric sealants should be installed over a preformed joint filler, backer rod, or other bond breaker as described in ACI 504R. Semirigid epoxy and polyurea joint fillers should be installed full depth in sawcut joints. Joints should be suitably cleaned to provide optimum contact between the filler or sealant and bare concrete. Vacuuming is recom- mended rather than blowing the joint out with compressed air. Dirt, debris, sawcuttings, curing compounds, and sealers should be removed. Cured epoxy and polyurea fillers should be flush with the floor surface to protect the joint edges and recreate an |