Providing a durable seal between two different objects having significant difference in their chemical nature has always been challenging. One of such cases is sealing of the concrete penetrative pipe (like utility pipe passing through concrete slab) located in swimming pools, water bodies and indoor wet areas. Now a days when most of the utility pipes are made up of PVC the dissimilarity in the nature of PVC and concrete has become even wider.
PVC have typically higher coefficient of thermal expansion as compared to concrete, which leads to regular friction between the two materials, even when the gap is properly filled with best performing cementitious grout/ sealing compound. The other key challenge offered by PVC pipe is the lack of bonding with the sealing material. So if one tries to seal the gap between pipe and concrete using polyurethane (PU) sealant there is high possibility of debonding between PVC pipe and the PU sealant. And if some epoxy based compound is used to seal the gap, the problem of limited bonding can be resolved, but at the cost of significant loss in flexibility.
The Sealstrong system for concrete penetrative pipe sealing is designed to tackle the problem of coefficient of thermal expansion mismatch, limited bonding with PVC material and stability against continuous water exposure.
Polyurea are a class of materials which posses the unique combination of high flexibility, toughness and bonding. Penetrative pipe sealing is not the only application where these properties are required simultaneously. The gap of concrete control joint which are provided to accomodate the thermal expansion of concrete has long been eigther left unfilled or filled using soft material like bitumen/ polysulphide. The absence of filler material in the joint eventually leads to spawlling at the edge of joint and presence of soft filler material do not provide much protection apparently because of its lack of toughness.
Filling the gap with rigid materials like epoxy is even worse idea as it will restrict any thermal expansion movement and will eventually lead to cracking at some other place in the concrete. Presece of Sealstrong in the joint gap will allow the gap to shrink or expand and protects the edge from wheel impacts.
Diagrammatic representation to show
the 2 different layers of Sealstrong Membrane