Alkus-sheets in Novatec’s wall and slab formwork systems
A leap in formwork technology
The perfect recycling cycle
Real profit for environment and contractor
As disposal of man made products (such as traditional plywood) gains more and more importance, customers often ask when purchasing: as to potential cost of disposal. In the case of alkus-sheets, great importance has been made as to effective recycling. Because of this, a return guarantee now offers for the first time a money-saving, environmentally friendly solution.
During the development stage, an objective of a one hundred percent recyclability was among the indispensable requirements. With the alkus-recycling concept old and used panels are recycled into similar products.
This too decides on durability and economic efficiency
Cleaning and repair
Good solutions for fast and effective repair
Make no mistake that, alkus-sheets also have to be cleaned after a certain number of applications. Surface scratches and penetrations cannot be avoided as everyday occurences on a building site is tough. But cleaning and repair of the alkus-sheets make for ease of use, as there are good, fast and practical solutions for both.
At the building site, it is possible to clean the panels without any problem by means of high-pressure water jet or with soft, rotating brushes. At a fixed price, you can have a thorough cleaning of panels and frames carried out at Novatec’s regeneration plant.
Minor mechanical damage, for example scratches, can be repaired with the use of polypropylene, hand held tools such as, recessing and shaping machines at the building site or at the contractor’s yard.
However, the much simpler solution is to entrust your formwork to us. We do not only repair the scratches, but also penetrations, large-surface damage and much more by means of a special method which also uses polypropylene.
Here too, we offer clear, fixed prices. We are your service partner for everything to do with formwork.
The damaged area of the thermoplastic synthetic material is preheated with the manual welding device, and then filled with a heated plastic strand.
The filled damaged area is then rendered smooth with a commercial recessing and shaping tool.
Penetrations and more extensively damaged areas are simply bored and plugged with plastic plates.
Building contractors, formwork contractors and keen cost estimators will be delighted:
A Forming face without swelling and shrinkage
In-depth research and persistent pursuance of an objective has finally paid off
Polypropylene, plastic composite construction, high modulus of elastictiy…! All very well, you will probably say, but how does that help me in practical application? Read on to find out what advantages the new alkus-sheet offers.
No swelling and no shrinkage
How often has it already annoyed you that forming faces are often penetrated by moisture after only a few applications. This leads to changes in dimensions, eventual delamination and the load-bearing capacity can sometimes drop by more than 50%.
With the alkus-sheet there is no swelling or shrinkage – once and for all. As no water can penetrate the panel, there are no changes due to moisture or to the geometry nor to the mechanical values. Further more, there is also no loss due to rotting.
Improved concrete surface
Up to now, the swelling performance of the plywood required the frame profile to project which resulted in the disadvantage that the profile nose left an impression in the concrete.
With the alkus-sheet, this flaw has been overcome. Diameter growth due to moisture is a thing of the past. And: the additional overall height of the panel can be statically used. This results in improved and more even concrete surfaces during the entire life of the panels.
Negative Disposal and The Environment
Up to now, plywood panels bonded with phenolic resin were as a rule disposed of by means of burning, with poisonous dioxin developing in the process. The consumption of timber resources, in particular in the area of tropical timbers, is another negative aspect. Over the years the world has seen many natural forests cut down in order to produce timber products such as plywood.
The alkus-sheet does away with all that. The plastic surface does not enter into a chemical reaction with concrete. This is why the use of a little amount of release agent is necessary (only in the area of the frames). Apart from that, the cleaning effort has been clearly reduced. Last but not least: old and spent alkus-sheets can be recycled to similar products. This protects the environment and the tropical rain forest.
Nail-holding as plywood
Nailing properties of Alkus are equal to that of plywood, one unavoidable disadvantage of plywood is that the face veneer chips off, moisture then enters and reduces the quality of the panel, reducing life expectancy.
The alkus-sheet is as nailable as plywood, however there is no chipping off of the face veneer. It goes without saying that the nail pull-out strength has been confirmed by comparative tests with plywood.
The different phases of damage when nailing on recesses.
In the case of alkus-sheets: smooth penetration of nails when fastening recesses. No further damage and no chipping off.
Removing of separating boards for recesses only results in simple nail holes without any craters.
Determination of push-in and pull-out force of nails.
In the case of mechanical damages, a costly repair with a 2-component epoxy resin compound is necessary to repair the plywood, generally at the cleaning or regeneration plant.
The alkus-sheet is repaired with the same material. This increases the quality of the repair and leads to an increased service life of the panels.
Extended life span
The sum total of advantages :
- no destruction due to moisture
- no chipping off of face veneer during nailing
- repair of cover with same material
results in a life span of the alkus-sheet which is as long as that of the frame itself.
New forming face as recyclable plastic composite construction
In the past 25 years, formwork technology has been developing to its present level. Large and small improvements have made the use of wall and slab formwork systems more and more economical. However, one thing had remained the same: the use of plywood as a forming face. The known disadvantages were accepted as alternatives were in short supply. However at the turn of the century – a decisive leap in technology was achieved with the development of the alkus plastic sheet.
The first ideas for the development of a new forming face were born at Meva – Germany. Both for ecological as well as for economic reasons, plywood could not be considered a permanent solution for a forming face for steel and aluminium frame formwork.
According to the points of view of the Formwork specialists for frame formwork, the objective of reserach had to be to eliminate the known disadvantages of plywood:
- swelling and shrinkage
- life span
- destruction due to water absorption.
- destruction of environment due to disposal
The positive properties, of course, had to be retained unchanged:
- load-bearing capacity through flexural strength, which is of utmost importance for the deflection and thus for the evenness of the concrete surface.
The problem of disposing of the phenolic resin bonded plywood faces which became more and more urgent lend a new dimension to the request for a total recyclability of the product. Research to find a suitable material was pushed ahead in several directions. Possible solutions such as:
wooden cores and plastic covering
were deliberately rejected. The realization took shape that the solution could only be found with an all-plastic panel. This, however had to be a composite of synthetic and other materials which would increase the load-bearing capacity, as the modulus of elasticity (measure for rigidity) of synthetic materials alone is not sufficient to achieve the required flexural strength. Numerous patents date from this phase of the development.
With this, the theoretical requirements on the product had been defined. Now it was necessary to create a product which could be utilized in industry through the interaction of science and practice.
This task was assigned to a development group, as all previous stages of development had shown that such complex developments could only be solved by means of the effective cooperation of experts from research and practice. The following companies were involved with the development of the plastic composite construction:
- Steinbeis-Transferzentrum für Kunststofftechnologie (STKT)
- GK Kunststoff GmbH
- MEVA as partner providing the industrial practice.