EXPANSION JOINT DEVICE

Abstract: A prefabricated expansion joint device for forming a flexible, tight joint between two concrete construction parts (1.2). The device comprises two side elements (4.5) to be sealingly attached to each one of the constructive parts and an intermediate expansion element consisting of at least two members (8.9) separated depthwise so as to form between themselves a ventilation channel (10). Hereby, condensation and frost shattering can be avoided.

Description: Expansion Joint Device The invention relates to an expansion joint device for forming a flexible, tight joint between two construction parts, especi¬ ally concrete construction parts. In concrete structures, especially in buildings having pre¬ fabricated concrete members, it is desirable and in many cases necessary to achieve moisture-proof joints between the concrete members. Such joints, so called dilatation joints, must be flexible due to the varying width of the joint gap, caused by daily and/or seasonal temperature variations. A known method to achieve a dilatation joint is to insert a string or hose, consisting of e.g. cellular or foamed plastic, into the gap at the same distance from the joint surface and thereafter apply a sealing compound, e.g. of sili- cone rubber, against the string or hose, so that the compound fills up the external portion of the joint gap and adheres to the joint edges. According to the present Swedish standard rules, the depth of the sealing compound must not exceed half of the joint width, since otherwise there is risk of such tensile forces that either the adhesion between the sealing compound and the concrete is lost or the tensile strength of the concrete material is exceeded. Thus, the joint has to be rather shallow, resulting in that only minor tempe- rature gradients can be maintained depthwise. However, this includes a risk that humid air condensates at the inside of the sealing compound. In cold weather, such a condensation may case frost shattering at the edges of the concrete mem¬ bers adjacent the joint. The object of the invention is to accomplish an expansion joint device, which can be pre-manufactured and enables good adhesion to opposite construction parts while reducing the risk of condensation and accompanying frost shattering. According to the invention, this object is achieved for an expansion joint device having the features stated in the appended claim 1. Thanks to the ventilation channel extending in the longitudinal direction at the inside of the joint de¬ vice, a ventilating air flow can be maintained, and every tendency to condensation of air borne humidity is counter- acted. Also, moisture absorbed by the concrete material ad¬ jacent to the joint, e.g. upon rain fall against a building or moisture transport below the ground level, can be effecti¬ vely removed by such an air flow. Suitable embodiments of the expansion joint device are de¬ fined in the sub-claims. The invention will be described further below with reference to the drawing. Fig. 1 shows in cross-section a portion of two adjacent con¬ crete construction parts, e.g. two concrete members included • in a house construction, and an inventive expansion joint device connecting the two construction parts; Fig. 2 shows in cross-section an alternative embodiment of the expansion joint device. The inventive expansion joint device shown in Fig. 1 is mount to form a surface joint between the adjacent, mutually sub¬ stantially parallel edge portions of two concrete constructio parts 1 and 2. The expansion joint device 3 is in its en¬ tirety pre-fabricated in lengths of e.g. 1-5 m and comprises two opposite side elements 4,5 constituted by elongated, rath stiff strips having a width of e.g. 10-50 mm, in particular about 25 mm and a thickness of e.g. 0-3 - 1-0 mm, in particul 0.8 mm. These strips may consist of an epoxy plastic rein¬ forced by polyester fibre fabric, e.g. in the form of struc¬ tural members such as those described in the Swedish Patent application 7901093-0. It is also possible to use materials such as those used in roofing felt. In order to achieve the desired adhesion to the construction parts 1,2, the side element strips 4,5, on their outside faces being turned away from each other, are preferably pro¬ vided with a self-adhesive layer 6 and 7, respectively, e.g. consisting of a bitumen material mixed with rubber, such as the material sold under the trademark BETUTEN. In a manner known per se, the adhesive layer on the pre-fabricated joint device is provided with a protective paper which is removed in connection with the mounting between the constuctruction parts 1,2 and which is therefore not shown on the drawing. As an alternative to the seilf-adhesive layers 6,7, the side element strips 4,5 can be fastened by glueing, e.g- by means of an epoxy based glue contjaining a hardener,so as to en- sure an excellent adhesion to the concrete. Between the side elements 4,5, the joint device is provided with at least two expansion members 8 and 9, respectively, made of elastic material, which are separated depthwise of the joint and form between themselves a space or shaft serving as a ventilation channel 10. These expansion members 8,9 each have a size (in unloaded condition) of e.g. 10-100 mm with- wise and e.g. 6-8 mm depthwise. As a suitable material, a silicone compound can be used, but other elastic materials are possible as well, provided that they have sufficient ten¬ sile strength and adhesiveness, e.g. a mixture of polyurethane and soft epoxy plastic. Preferably, the external expansion member 8 is diffusion tight, whereas the internal expansion member 9 is gas permeable, es¬ pecially to air and steam.Hereby, air can flow from the inside into the ventilation channel 10 along the entire length of the joint 3. Such a permeability can preferably be achieved by making small openings or slots in the expansion member 9 and/ or by making the expansion member 9 of a porous, gas permeable elastic material. On the market, there are silicone rubber materials of s.c. "open" type which are excellent in this con¬ nection. ■ " A certain gas permeability can also be achieved in that the internal expansion member 9' is fastened, preferably by mean of a self-adhesive layer 11, only to one side element 4', see Fig. 2. In this embodiment, preferably, and air passage 12 is formed between the expansion member 9', e.g. formed as a window sealing strip, and the opposite side element 5', at least in an unloaded condition. During the mounting opera¬ tion, the expansion member 9' serves as a distance element, so that the side elements 4' and 5 ' will not converge wedge- like towards each other, especially in case the side element 4 ' , 5" are glued to the constuction parts 4' , 5' by means of epoxy based glue or putty. Moreover, the external por¬ tions (counted depthwise of the joint) of the side elements 4' ,5' diverge in V-shape in the area of the expansion mem- ber 8', and the edφ.es of the construction parts are bevelled correspondingly, so that an increased strength is achieved. ■ As mentioned above, the joint device is preferably pre-fabri cated in certain lengths. Such length units can easily be joined, e.g. by means of tubular extensions fitted at the inside of the ventilation channel 10 of each unit. On the drawing, construction parts of concrete or light¬ weight concrete are shown. In principle, however, it is pos- sible to accomplish joints by means of the inventive joint device also between other materials or between concrete, on the one hand, and some other material, on the other hand. Furthermore, the ventilation channel 10 does not necessarily have to be vertical but may, upon being mounted, be oriented horisontally or inclined. It should, however, be ensured tha the ventilation channel 10 " , at the end of the joint device o of a series of interconnected joint devices, has an outlet, through which air, especially humid air, can be exhausted. In this description and in the following claims, the expan¬ sion members 8 and 9 are said to be "separated" from each other depthwise. However, without leaving the inventive . idea, it is possible to connect the members 8 and 9 by one or more web portions. The essential feature is that one -or more ventilation channels are formed and that the flexibi¬ lity of the joint device permits large dilatation movements, while the attachment is very effective owing to the relative¬ ly large adhesion surface. O- PI _ j-. V :FO «\,

Claims: 6 C L A I M S 1. An expansion joint device for forming a flexible, tight joint between ^ wo " construction parts (1,2), especially concrete construction parts, the joint device (3) comprising two side elements ( . 4,5) to be sealingly attached to each one of said construction'parts arid an intermediate expansion element (8,9.) consisting .of an elastic material, c h a r a c t e r ! z e d . in that the " intermediate expansion element comprises at least two members (8,9) mutually separated depthwise so as to form an intermediate space (10) serving as a ventilation channel. ; 2. An expansion joint device as set forth in claim L, c h a r a c t e r i z e d in that a first, preferably ex¬ ternal expansion member (8) is diffusion tight, whereas a second, preferably internal expansion member (9) is gas permeable. 3. An expansion joint device -as set forth in claim 2, c h a r a c t e r i z e d in that said second expansion member (9) consists of a gas permeable elastic material. 4. An expansion joint device as set forth in claim 2 or 3, c h a r a c t e r i z e d in that said second expansion •* member (9') is attached, preferably by means of a self- adhesive layer (11), .to one of the side elements (4') only. 5. An expansion joint device as set forth in anyone of claims 1-4, c h a r a c t e r i z e d in that at least the external as seen depthwise of the joint, portions of the side element (4' ,5' ) diverge outwardly. OMFI

Inventors: DAHLBERG A, DAHLBERG P
Applicants: DAHLBERG A, DAHLBERG P, TAETIS PLASTTAETNINGAR AB
Application year: 1980
Main classification: E04B1
IPC codes: E04B1