Static structures (e.g. – buildings) – Relatively yieldable preformed separator – Separator inserted prior to or during pouring of two...
Patent
1996-04-30
1998-04-14
Wood, Wynn E.
Static structures (e.g., buildings)
Relatively yieldable preformed separator
Separator inserted prior to or during pouring of two...
5239605, 5239606, 277 75, 277 76, 404 47, 404 49, 404 64, B32B 314, E04C 200
Patent
active
057378894
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a device for sealing of concrete joints, comprising an elongate section having larger width than thickness, said section being intended to be cast into two concrete structures in order to seal the joint area between these and is provided with a swelling material at least at their longitudinal edges.
Concrete joints will always be present when a time delay occurs between casting operations. A typical example is the casting of a wall on a previously cast floor.
In practice, it is very difficult to make such concrete joints watertight. This is due to a number of factors, i.a. that the concrete may separate so that its heavier components attach themselves between the form and the steel reinforcement and thereby reduce the concrete quality. This situation may be aggravated because vibration of the concrete may be difficult at the bottom of a wall form. Problems easily occur if the surface against which it is cast, is soiled by sand, gravel, clay or other pollutants, or the surface has a layer of sludge. Furthermore thermal contraction during curing may cause cracks providing passage for the water.
Particularly where some water pressure against the structure is expected, it is therefore common to take special measures in an attempt to seal the joint. Such measures may include placing a swellable material on the cast surface before the next casting operation. One can also place an injection hose in the concrete joint for later injection of a sealing material. Swelling sections are entirely dependent upon contact with good concrete in order to form a pressure against the surroundings. This is difficult to obtain in contact with casting flaws, sand or foreign objects, and if a sludge layer forms during casting, this will prevent good contact with the concrete so that the water may penetrate under or through the sludge layer. In using an injection hose, the problems will generally be the same and in addition, the injected portions will only to a small extent be able to accommodate later movements due to settling, vibrations or thermal effects.
A third method entails using a device of the introductory type as an elongate joint web, usually called waterstop. The elongate joint web, which is known from e.g. EP-A1- 0219296 and GB-A-2205872, is made of a plastics material, usually PVC. One half of the joint web is cast into the first concrete structure, the remaining part of the web extending into the area where the next concrete structure is to be cast. There will be no mechanical connection between the joint web and the concrete, but the joint web may be provided with longitudinal ribs in order to extend as much as possible the distance the water has to travel to bypass it. Joining of the joint web must be done by hot welding, often under difficult and cramped conditions, and special joint pieces must be arranged in advance before casting where new concrete joints will occur. These joint pieces have a very complex form, which makes the jointing extra difficult. It is therefore well known that it is difficult to obtain a satisfactory result when sealing by means of joint webs.
SUMMARY OF THE INVENTION
The present invention aims at improving a device of the introductory type so that one avoids, or at least reduces, the drawbacks of the prior art.
This is obtained according to the invention by the section being made of a substantially form stable material and being provided with an internal cavity extending over a substantial part of its width.
The form stability makes the section easy to locate and keep in the correct place during casting, and the location of the swellable material at its longitudinal edges provides for its positioning distant from the joint area and therefore in good quality concrete, where an optimum function of the properties of the swellable material is ensured.
According to an advantageous embodiment of the invention, the longitudinal edge portions of the section are provided with injection holes communicating with injection conduits i
REFERENCES:
patent: 3896597 (1975-07-01), Deason
patent: 4740404 (1988-04-01), Otsugu et al.
Aanstad Ivar
Habberstad Bent
Ing. B. Habberstad AS
Kang Timothy B.
Wood Wynn E.
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