Preparing the bands for installation
Before the bands are mounted, they first have to be unrolled on a flat surface and checked thoroughly, whether they are not damaged or deformed in any way. It is not allowed to mount bands that have lost their proper shape. A particularly dangerous phenomenon are deformations of external band anchors, these can be caused by improper storage or transport.
On the day before installation, it is best to unfurl the band roll in a heated warehouse. This action can be replaced by short-term heating of the band in the flame of a burner. One has to note, however, not to keep the band for a longer time at one spot. The best result is achieved by several heating passes with the burner moving slowly along the band axis.
Band installation at the target mounting spot
When mounting bands, one has to make sure for the lengthwise axis of the band to be found (if possible) at equal distances with respect to the division to be sealed, and for the band to be installed in such a way so that it cannot move during concreting. In case of expansion bands, one should note that the compensation duct be found in the slit axis.
In case of expansion joints exceeding 20 mm, and joints with a tendency to exhibit compressive deformations (-Vx), in order to reduce the risk of damage to the internal band, one should create a so-called deformation chamber or cover the compensation duct with a closed cell elastomer material.
The arms of an internal band should be embedded in the concrete at a depth allowing one to hide the anchor ribs in the reinforcement cover foreseen by the designer (at least 30 mm), this should prevent it from being torn away from the component.
Bands should be fixed by way of installation grips and tie wire, to the rebar, at maximum spacings of 25 cm. Internal Elastoflex type sealing bands of types FS and FMS with sheet steel are installed by tie wire routed through openings in the sheet edges.
Installation of closing bands
Closing bands are installed with their arms downwards, on the formwork panel describing the course of the expansion slit. its arms, below the final closing anchor, should be affixed to the formwork with double-headed nails (with limiters) or with nails up to 40 mm in length (nailed down to a maximum of 1/3 of their length and bent away at an angle of approx. 45°).
Due to the risk of damage to the external bands at the construction site, it is advisable to use TF trapezoidal protective profiles, appropriately selected to suit the widths of the bands used. This profile, ensuring protection of the band against damage, also forms the edges of the concrete component. Such a solution protects the concrete component from mechanical damage, edge cracks or impacts.
Installation of external bands
During the layout or unrolling of external bands at the construction site, execute formwork that shall not stand on the band's anchors, on a layer of lean concrete or packed soil prepared for later execution of the foundation slab. The best solution for the execution of front formwork at spots of foreseen divisions is the use of steel lattices with trestles.
If the concreting technology or the pressure of the concrete mix should require the use of system formwork, they should be laid out outside of the band, with the remaining space levelled out with a fibreboard panel or veneer and edge battens. After the execution of a first concrete slab, the band should be secured against damage.
Directly before the execution of a subsequent slab segment, the free band arm should be cleaned of contaminants, i. e. cement bleed water, sand, sawdust, ice, aggregate and concrete remains. During cleaning, the condition and quality of the band should be checked again. Damaged sections of the band should be repaired or replaced. It is not allowed to burden band insulating anchors i. e. with lower rebar of the slab passing the day joint.
In such a case, during concreting, there exists a great probability of emergence of air bubbles or pockets close to the deformed anchors. When securing day joints and expansion joints of walls by using external seal bands, there emerges the problem of their affixing to formwork. If they are made of wood, the bands can be affixed to them with double-headed nails (with limiters) or with nails up to 40 mm in length (nailed down to a maximum of 1/3 of their length and bent away at an angle of approx. 45°).
The bands are pierced at the joining belt (band part between the final insulating anchor and its edge). One cannot pierce the sealing par and the expansion part of insulating bands.
In case of installation of external bands horizontally, they have to be reinforced additionally, or the top sealing anchor has to be installed in such a way so as to prevent it from tilting during concreting.
Installation of internal bands
The greatest difficulty during the installation of internal bands is the execution of divided head formwork. One has to ensure that the formwork is stable. Ready formwork lattices for day joints, with profiled pockets for the installation of sealing bands, provide great help.
For internal expansion joint bands, the formwork must be composed of two layers of fibreboard, installed in such a way so that the first layer is found at the height of the expansion duct, with the second layer closely covering the band's arm.
In order to allow the internal band to close fully in the bottom slab or the ceiling, it has to be installed in a form resembling the shape of the letter V. The arm bands should be raised up to form an angle of 10°-15° with respect to the slab face. When installing internal bands at day joints and expansion divisions of walls, one should only ensure their stability by installing them with the use of installation grips and tire wire to rebar.
After concreting one band arm, the second, 'free' arm, should be secured against damage. Directly before the execution of a subsequent part, the free, un-concreted arm should be cleaned of debris and contaminants.
Installation of press-in masking bands
Press-in bands should be installed in previously executed and cleaned expansion divisions. In a temperature of at least 25 °C, in order to achieve greater susceptibility and flexibility of the bands, they can be heated before assembly with a burner or through storage at a heated location. Before installation, unfurl the profile at the slit, and, beginning on one end, press in the band using a batten or an edge profile, and hitting it additionally with a hammer.
Mechanical installation of sealing bands (with the use of pressure systems)
Before commencement of drilling and embedding of anchors and flat form profiles, determine the type and technical characteristics of all required components. Appropriate installation of bands using compression flanges is possible only for load bearing components on a flat and properly prepared surface.
The concrete surface for the compression structure must be water-tight, there may be no fractures or cracks or other kinds of contamination. If the surface does not correspond to these requirements, it is necessarily to repair it with putty or synthetic material-based mortar. By drilling openings for later introduction of studs, strive for the openings to be straight. One can use the compression flange as a matrix so as not to shift the anchor spacing.
The executed opening should be cleaned using a brush or pump. The best solution for introducing thrust studs is the use of adhesive chemical anchors. If such a solution is not recommended, use anchors with metal studs. In order to remove surface flaws close to the anchors and along the entire joint of the component with the band, apply joint sealing adhesive, i. e. Betofix.
After pressing out the adhesive from its container, spread it out at the joint using a trowel with a flat metal surface. Between the prepared surface and sealing band, place a rubber tape band sized 80 mm x 3 mm. The sealing band and the rubber tape band should be prepared for application over anchors by drilling at the required spots.
The necessary drilling of the bands should be done with a hand punch. After installation of the entire sealing system (adhesive mass + rubber tape band 80 x 3 mm + sealing band + compression flange) and after application of nuts to the anchors, tighten them with a torque wrench with the minimum calculated torque. The extrusion of a large volume of adhesive from under the band should be treated as a confirmation of appropriate pressure.
The action of tightening nuts (screws) should be additionally repeated at least three times every two weeks. In case of diminishing works, tighten the nuts (screws) directly before concreting. In case of mechanical installation at a section extending beyond 1,5 running metre, use compression flanges with a maximum length of 1,5 r. m., and even better - one running metre.
At the installation of a further flat profile, notice that the neighbouring joints do not overlap, with separation between them not exceeding 4 mm. Depending on the components to be insulated, it is possible to execute pressure systems on both sides, using the appropriate bands.
|Step 1. Base surface preparation. Priming and application of joint sealing adhesive.||Step 2. Drilling of holes and embedding of sealing band and flat profile.
|Step 3. Installation of nuts and compression structure assembly, screw tightening.||Step 4. Concluded mechanical assembly. Subsequent pressure control.
The remarks indicated in this catalogue are current information included in standard DIN 18197 in its current version.
Joining bands (welding)
Before commencement of actual, permanent joining of band ends, the band layout needs to be designed and the band needs to be trimmed. care should be taken to ensure a smooth band trim end without damage or frayed ends. It is best done with a swift single knife cut along a steel profile, adhering at the same time to an appropriate trim angle. When executing pre-cast components at a manufacturing plant, one can use more precise angular trimmers.
|Step 1. Band measuring
||Step 2. Band trimmings into sections with an appropriate shape and size|
|Step 3. Melting band ends and joining them together.
||Step 4. Processing the weld point or applying a masking tape band|
Besaflex, Nitriflex, Poliflex, TPE, PE and PP bands are joined together by welding.
As a result of thermal processing using appropriate tools, the contact surfaces remain both somewhat melted and joined together. Melting is conducted until emergence of surplus melt material on both sides of the trimming axe or knife. Then, the heated blade needs to be taken back. The bands need to be welded together from the centre out to the eds. The melting temperature of insulation bands, manufactured of appropriate materials, is between 160 °C and 220 °C.
In situations most often encountered at construction sites, only simple (butt) joints may be made. Other types of joints, which are more difficult (joining corners to make forms such as the T, L, X, cross profiles, passages of various bands) should be made at the manufacturer's plant. An important factor influencing the seal of the entire system is the execution of joints by experienced personnel.
At the precasting plant, the quality of the executed joints should be tested with the use of a spark generator. This activity should be executed on a metal plate or panel. If a spark jumps the gap, from the generator through the executed weld joint, then this spot should be welded anew.
Elastoflex bands must be subjected to a more complicated joining process.
In this case, the joining takes place through curing, or in other words, through submitting rubber under pressure to heat. Such welds should be done in an autoclave or by using a curing device on a matrix approved for the relevant profile.
|applies to the following materials,
- Besaflex BS
-Besaflex według normy zakładowej
|joint may be created using the following welding device
When joining sealing bands, the following devices should be used
|weld axe||Blow heater||Heating blade and matrix|
|Welder||Spark generator||Curing enclosure|
Before the sealing bands are concreted, they should be cleaned of any possible contaminations. They must also be free of ice.
When pouring concrete, one should avoid single-side band pressure, the band may not tip or incline. During concreting works, it needs to be protected against mechanical damage. When the concrete mix is applied onto the band, even small damage spots may lead to the band tearing away. In case of components insulated with external bands, the concreting works should be conducted slowly, cautiously and from a low height, so that the anchors under load by concrete do not tip over and are fully concreted.
The concrete mix must be properly laid out and packed in the band's vicinity. At the same time, make sure that the vibrating device end touches neither the band nor the band mounting components.
In case of external bands, note that the band is not pulled out of too fresh concrete during formwork removal.