Bentoflex is a bentonitic waterproofing composite, specifically designed for use in construction, consisting of an original, patented, flexible

Transcription

1 Bentoflex is a bentonitic waterproofing composite, specifically designed for use in construction, consisting of an original, patented, flexible structure and sealed selvages. Bentoflex contains a sodium bentonite that is 90% montmorillonite. The production process evenly distributes the bentonite, which is then held in place mechanically through cohesion created by needle-punching. Bentoflex features containment layers with controlled degradability allowing the bentonite to be positioned in direct contact with the cement structure so as to waterproof it, sealing cracks and preventing transmigrations between the waterproofing surface and the building. Bentoflex is packed in different sized rolls to meet the most varied application needs. E06V03P00

2 Bentoflex's Structure The particular characteristics that distinguish Bentoflex are a result of the functions assigned to each of its five layers and, more specifically: A central layer with the function of reinforcement and support consisting of a non-woven fabric that originates a balanced needlepunching of the two external layers; Two external layers of "fibrocell," mechanically cohesive with the central layer and not glued, characterized by a specific material with controlled degradability with the function of containment until waterproofing is concluded; Two intermediate layers of sodium bentonite that waterproof and seal with the possibility, after the degradation of the outer layers, of developing their own characteristic of cohesiveness with reinforced concrete works and its own components. E06V02P01

3 Selvages and Joints Selvages free of bentonite allow the good execution of the work with annoying leaks during installation, keeping all the bentonite added during production inside and, thus, guaranteeing the quality of the final results. In addition to preventing the contents from leaking out, sealed selvages also guarantee: Fixing nails hold more securely; A better seal in areas where sheets overlap; The elimination of annoying dust means a safer working environment for workers on the job site. The water than comes in contact with Bentoflex in the area of the overlap joint transforms the bentonite into gel and makes it expand and so, thanks to the loss of consistency of the containment layers, the two layers of gelled bentonite weld together spontaneously. E06V02P01

4 Bentonite Bentonite is an argilloid, i.e., a natural clay-like material with distinct waterproofing characteristics. To better characterize this material - which, until now, has been used in various sectors such as pharmaceuticals, wine-making, zootechnics, steel-making and geology it will be helpful to compare it to clay. Clay, which we know for its characteristic of absorbing water, increasing its volume and becoming very sticky, can be defined as impermeable to water under pressure at a thickness of 1 meter. In fact, it is considered that an excellent quality, well-compacted clay has permeability close to 1 E-9 m/s, which is equivalent to the passage of water, on a sample of 1 m³, subjected to a hydraulic load of 1 m, for a day, of 86 g. The sodium bentonite contained in Bentoflex has a lower permeability of E-11m/s, i.e., a value 100 times lower than common clay and, thus, 100 times, more impermeable. Bentonite maintains this characteristic until reaching its liquid limit, which corresponds to an expansion normally greater than 16 times its initial absolute volume.

5 Waterproofing buried structures In construction, it is necessary to protect buried structures from infiltrations of water that are often acidic and, thus, aggressive for both the cement and the reinforcing iron. In particular, it is important to protect and isolate foundations and walls that are, or could come, in contact with water. Infiltrations can derive from the following situations: Filtration of rain water that impregnates the ground without creating head; Filtration of rain water with the cyclic formation of head; Flows of water in the subsoil with the formation of more or less strong and permanent head. In Italy, the water table is not at a fixed level for all sites and it can periodically fluctuate. Even on small job sites that don't need to go very deep, there is a risk of finding that you need eliminate the head in the work area. Waterproofing defects are difficult to eliminate and, even when possible, are very costly. It requires adequate planning at the drawing board to reduce problems on the job site and eliminate any problems for neighbours when near to the job site, in addition to guaranteeing the buried works are protected when construction is finished. A small increase in the initial investment is certainly more economical than doing restoration work, which often doesn't provide a long-term guarantee. E06V02P01

6 Under-foundation After preparing the lean concrete, lay Bentoflex, taking care of overlap the edges by 10 cm, including the selvage, and nail down. Make a 20-cm flap on the form for the next joint with vertical application. Use pre-hydrated bentonite to seal any iron bar or joints with rod heads. Protect the waterproofing with a concrete slab at least 5 cm thick and having the same characteristics as the subsequent floor. Lay the floor, also suitable to resisting the hydraulic thrust, in a reasonably brief time.

7 Vertical surfaces Stucco spacers and loose foundation with cement mortar and position Bentoflex, taking care to overlap the edge by 10 cm, including the selvage, also with the flap coming from the floor. Reinforce all the critical points such as corners and continuations with pieces of Bentoflex. Bury quickly with material that doesn't leave pockets after compacting. Close the application on the upper side with the application of a floorboard or flashing.

8 Against bulkheads Regularize the surfaces, sealing the major water routes with appropriate cement mortars. Apply Bentoflex, taking care to overlap the edges by 10 cm, including the selvage, and nailing down at short intervals based on the support. Seal and anchoring bars with a hydro-expansive paste and continue waterproofing to a level higher than the next casting. Forming a new reinforced concrete structure.

9 Expansion joints At the expansion joints, the space between the two concrete interfaces must be filled with pieces of Bentoflex and a double layer will be positioned on the corresponding outer area.

10 General notices The surface where Bentoflex is applied must be free of extraneous materials, various types of detritus, stones, nails, etc., and other organic material; Remove any pools of water; Apply during dry weather; Avoid the passage of job site vehicles during laying; Avoid the formation of creases or folds; the fabric must be taut to the touch; To overlap the joints of the fabric, use the printed lines on both selvages as a reference because they indicate the minimum not to be reduced; If the installation is damaged, it is a good idea to apply a patch made of pieces of Bentoflex suitably cut to obtain an overlap of at least 10 centimetres per side; In the presence of sharp corners, in addition to the overlapping the vertical with the horizontal, just reinforce with a 40-cm piece. Alternatively, you can use a bentonite BentoTubo or simply, loose bentonite; For horizontal application, you can use normal nails while, on vertical surfaces, we recommend a nail gun and large head nails or the insertion of plastic heads; Before covering, protect the Bentoflex with a non-woven geo-textile weighing 200 g/m². Do not use rustication or egg crate; At the sidewalk level, terminate with the applications of a wood plank or flashing that serves as a plug; It is important to create a confinement of the bentonite waterproofing that limits its expansion as much as possible and so that it has a large capacity for expansion remaining, staying in a gel state, for any future sealing needs such as cracks, etc. The structures must be strong enough to resist the thrust of the water. E06V03P01 Considering that there is a great deal of variation in working conditions, our suggestions should be taken as advice that is not, in any way, exhaustive and, for this reason, in addition to the designers, the job site technicians are responsible for knowing the specific conditions at the site and for making a detailed evaluation.

11 Questions and answers What happens if the bentonite dries out? In nature, bentonite contains 30% moisture (in some cases as high as 50%). In the fabric, its content is between 10% and 15% and when installed, it returns to 30% to 50%. When it reaches 15% moisture, it becomes sticky. Removing 10% moisture requires 2 hours at 100 C. What should I do when there's salt in the water? Sodium bentonite's strong ability to attract water molecules can be partly deactivated when the bentonite comes in contact with soluble salt solutions. The chemical/physical mechanism of this deactivation process consists in the partial saturation of the electro-positive charges of the sodium with dissolved electro-negative ions rather than with molecules of water. This process can be partly neutralized by pre-hydrating the bentonite with pure water. Do I need to provide drainage in combination with Bentoflex? Absolutely not. Before burying, just apply a non-woven geo-textile to protect the bentonite composite. Can the Bentoflex composite be perforated for the passage of iron bar? It can be perforated for the area strictly necessary, taking care to seal the confining area with loose bentonite or pieces of Bentoflex. Is it possible to shape the Bentoflex pad? It can be cut and shaped with a sharp cutter, taking care to work on a perfectly flat surface. To avoid excessive spilling of bentonite, we recommend moistening the cut edges before separating them. How do I guarantee the security of the overlaps? Thanks to the special patented selvage, there is no bentonite spilled during movement and, for this reason, an overlap of 10 cm is sufficient, including the selvage, for obtaining the correct seal between sheets. There are reference lines on both selvages to guide the operation. Does the composite require the use of glues? There are no glues. The stability of the bentonite is guaranteed by mechanical cohesion through needle punching that uses the fiber of the central reinforcement. How is the bentonite/concrete bond achieved? The containment layer degrades, freeing the bentonite, which grips the concrete. What is montmorillonite? It is a mineral belonging to the phyllosilicate group and one of the main components of bentonite. A good quality bentonite must contain at least 80%. The name comes from the town of Montmorrillon in France.

12 Technical Data BENTONITE CHARACTERISTICS Montmorillonite content 90% Expansion in distilled water 16 times ph in aqueous suspension 9-11 Limits of liquidity 550 BENTOFLEX CHARACTERISTICS Bentonite content per m 2 Coefficient of permeability K Humidity of the bentonite Permeability of overlaps 5.5 Kg (mechanically determined as 6 kg) 1 E -11 m/sec 12% Null at 1 bar E06V03P00

13 Available packaging Bentoflex is supplied for manual application in standard rolls having the following characteristics: Height, including selvages Net length Length of composite Cardboard core Weight of roll 1.2 m 3.5 m m mm 27.5 kg Upon request, it is possible to produce Bentoflex in rolls of different heights and lengths for particular application needs that arise during the design phase of the waterproofing work.