The perfection of the process of polymerisation of PVC on the industrial scale has allowed the development of a sealing band manufacture technology adapted to the needs of the construction industry. Knowledge of technical parameters of the material from which bands are manufactured, as well as the conditions of their introduction into the relevant structure, allows full usage of their advantages at a structure's key points (day joints and expansion slits).
Besaplast sealing bands are an effective barrier for water flowing into the structure and site's interior. The water intrusion paths, penetrating the concrete's structure, seek out spots that are the least homogeneous and those characterised by interrupted continuity. That is why it's important to care for a proper mix and the correct concreting work technology. Particular care has to be taken with respect to tightness of process technical and construction joints. Expansion joints are visible divisions in component continuity, where the ends of the divided structure parts are separated by a slit with a standard width of approx. 20 mm. Improper execution or complete omission of the water insulation, or complete negligence with respect to this insulation may hinder, and in the extreme case, prevent the use of the structure altogether.
Appropriately selected and concreted Besaplast bands are an effective barrier against pushing water.
The effectiveness of Besaplast insulating bands is facilitated by their shape and length of the arms and anchors with ribbed surfaces. The route that the water must pass to circumvent the concreted band's arms is, thanks to this measure, markedly increased. The direction of water pressure influence changes often. The achieved 'labyrinth effect' forces a water pressure drop, and in the end, diminishing of its influence, and halt of further penetration at the intersection between band and concrete.
An important characteristic in terms of band choice are three parameters:
It is thus worth it to appropriately select the insulation, to limit the high costs of removal of damage or, in the extreme cases, of repairs required to the entire structure, should it be damaged by harmful influence of water and the aggressive substances dissolved in it.
a - sealing band width
b - expansion part width
c - sealing band thickness in the expansion part
f - height of insulating anchor/insulating rib
k - expansion profile width
Sealing band structure
In order to unequivocally designate the vocabulary used, concerning the structure of bands, and to simplify studying of subsequent tabs of our website, here are visual presentations of the individual Besaplast insulating bands.
|Internal sealing band for expansion joints||Internal sealing band for expansion joints|
|External sealing band for expansion joints||Closing sealing band for expansion joints|
|Press-in sealing band for expansion joints||Internal sealing band for day joints|
External sealing band for day joints
The descriptions above allow clear determination of the selected product in your order. By indicating the name of the selected band, i. e. Internal sealing band for day joints, and the additional trade name of the material, i. e. Besaflex, along with the symbol, A 200, one obtains a unique name.
Subdivision of sealing bands
Thermoplastic material sealing bands, and elastomer sealing bands, as well as uncoated sheet steel, are the only systems covered by relevant German norms as basic solutions for component protection.
For the majority of structures, the use of internal sealing bands is recommended. External bands are used primarily under foundation slabs and in foundation walls, as well as in horizontal structural components.
External sealing bands must have the following minimum dimensions so that they might be used in spots susceptible to influence by pressurised water:
- width a = 240 mm with six insulating anchors, height f = 30 mm,
- width a = 320 mm with six insulating anchors, height f = 20 mm.
For expansion joints with a space between the divided components, bands should be used that have a compensation duct, which, through their geometry and the material they are made of, may transfer larger movements between structural components. Internal bands are used usually for structural component thickness values exceeding 200 mm.
In case of lower thickness values of the components to be insulated, external bands are used. In particular cases, special bands for mechanical installation are utilised. The selection of insulation of the expansion joint must take place after the determination of the scope of allowable shifts and relevant approximate water pressure values.
closing band type
press-in band type
Closing sealing bands are used for closing expansion joints. As standard, they are used as additional protection for structures, in which external bands, and/(or) internal bands, are placed as well. The closing components, with two sealing anchors on one side, are used for closing of divisions susceptible to water not under hydrostatic pressure.
Closing bands with a minimum of four anchors are used as insulation from water under pressure equal to three metres of water column. The values given in diagrams on page 21, during selection of closing sealing bands for expansion slits with three anchors on one side, must be increased by an additional metre of water column against the presented values.
INDICATIONS CONCERNING STORAGE AND TRANSPORT
The bands should be stored on pallets, on a stable bottom surface, thermoplastic bands should be stored in a warehouse, if possible, and one day before the work, they need to be transferred to a heated room. While in storage, the free ends of the bands should be protected from damage. Thermoplastic material bands should be protected from direct influence of sunlight.
Bands should be transported on pallets, in a manner protecting them against hazardous atmospheric influences and protecting against mechanical damage. Possible damage to thermoplastic bands emerged during transport or storage is removed by spreading out the bands on an equal surface and thermal processing.