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- Tunnels
- Dam Walls
- Underground Railway Tunnels
- Underground Garages
- Sewers & Shafts
- Water Purifying Installations
- Water Tanks, Septic Tanks, Drinking Water Reservoirs
- Swimming Pools
- Earth Retaining Walls
- Shrinkage Cracks Settlement Cracks Expansion Joints
- Moving Joints Construction Joints Honeycombed Concrete
- Pipe Penetrations Joints in Precast Concrete Segments
Type of material
2 comp. hydrophilic polyacryl gel with accelerator (A2)
Essentially Non-Toxic, KTW (Germany) Potable Water Contact Approved
Penetrates better than water due to ultra low viscosity and lower surface tension, swells upon contact with water
Cleans with water.
Properties
WEBAC 240 is a high-grade, polyacrylic, ultra low viscosity injection gel with excellent sealing qualities. The material is characterized by its high expandability and strength and absorbs regular movements of the structure easily. The gel can be adjusted for reaction times from approximately 15 seconds to 15 minutes at room temperature (viscosity increase / cure time). At 68°F / 20° C and standard adjustment (5% of powder B in water), WEBAC240 will flow freely for approx. 25 seconds after mixing and will be fully gelled after approx. additional 25 seconds. The standard gel time allows for a excellent material distribution and an ideal spreading rate in most applications.
The gel time can be adapted by a wide range to meet the actual jobsite requirements. Higher temperatures accelerate the reaction time, lower temperatures slow it down. Example: At 50°F / 10°C and standard mixing ratio, the product will flow for approx. 55 seconds and fully gel after an additional minute).
WEBAC 240 reacts to form a waterproof, flexible but solid gel with outstanding adhesion to dry and wet mineral surfaces. In a moisture saturated environment the material remains stable in volume. In the case of alternating dry and wet periods the gel shrinks and swells reversibly. When shrinking, the gel loses some of its volumethereby getting stronger. The process does not compromise the waterproof membrane effect in bladder / curtain injection.
The cured gel is insoluble in water and hydrocarbons and resistant to diluted acids and alkalis as well as to salts common in most structures. WEBAC240 is resistant to frost and thaw cycles.
Mixing Of Components
For storage stability, component A is supplied in two separate containers (A1 and A2). Mix component A1 and A2 in a mixing ratio of 20:1 parts by weight immediately before use. Empty the smaller container of component A2 completely into the larger container of component A1. Mix the components thoroughly with suitable equipment. Component A must be stored protected from direct light for good shelf life.
Component B is a powder concentrate and must be mixed with water on site immediately before use. Component B is an oxidizer and can corrode metals other than quality stainless steel. Dissolve the powder in clean tap-water in a clean plastic vessel by thoroughly stirring it for 2-3 minutes with a wooden, plastic or stainless steel agitator.
Component A (A1 + A2) and component B (concentrate + water) should be mixed in containers of equal capacity. Add the amount of water required for dissolving component B (approx. 5 - 6 gallons or 20-24 liters) by adapting the level of liquid to that of component A. To achieve a weaker gel, some water can be added to both coponents. After mixing, apply the material with a 2-comp. injection pump (WEBAC IP 2C-Gel Pump) at a mixing ratio of 1:1 (A:B, parts by volume).
Preparation
Prior to the injection work the composition of the structure and soil behind the structure need to be examined. This will provide information necessary to make assessments as to how to place the drill holes, which packers to use, desired gel time for the product and estimate of material consumption per drill hole and in general. In most cases the objective of injection is the creation of a waterproof injection curtain / bladder behind the structure. The ultra low viscosty of WEBAC 240 permit the gel also to penetrate into fine pores and fissures in the structure itself. Cracks and honeycombed areas in poured concrete or shotcrete and other openenings and grout imperfections in masonary brick and stone wall structures will be also sealed during the injection process. The low viscosity will allow capillary forces to actually soak up material even at very low injection pressures.
After completetion of the assessment drill holes are to be placed in a pattern that will allow for complete and undisrupted curtain creation behind the structure. The curtain / bladder will technically form a membrane which must be continous to stop water intrusion reliably. The drill-hole diameter is determined by the packer diameter selected. See pictures on right. We recommend the use of button head equipped packers for a tight and reliable seal during injection.
Curtain / Membrane Injection by using a Grid Pattern
The objective in curtain/bladder injection is to achieve a waterproof barrier / mambrane on the water side (positive side-outside) of the building. This is typically done by injection from the inside of the structure. As gel will spread out along the outside wall it will also penetrate into the soil and stabilize and waterproof it as an additional benefit in the waterproofing process.
After drilling the holes injection packers are installed. The type of packer depends on factors such as expected injection volume, type and condition of the structure and preferencesof the applicator. WEBAC supplies the right packers for your needs. Common are button head fittings for secure connection of the grout line. It is recommended to install packers in a fashion that material travel can be observed by leaving some drill holes unplugged to see material "ooze out" in a process called port to port travel. Gel emergence from adjacent drill holes is a good indicator for continous coverage of product which in return indicates that a complete and continous curtain is being created. It is recommeded to inject WEBAC 240 from bottom to top, beginning at the lowest drill-hole. However there can be reasons to deviate from this standard procedure such as, for example, a large cavity behind a certain injection area. Thanks to the short reaction time and excellent adhesion to minerals, a sealing gel curtain forms behind the building . The gel also penetrates shrinkage and settlement cracks as well as mortar joints in brickwork thereby sealing the structre itself. Continue the injection procedure for each drill hole until the emergence of material or the gel formation in the adjacent drill holes is observed or until the material spreading rate calculated on the basis of the soil analysis has been reached for each drill hole. Be aware that a prior accessment of the soil is only an indicator and not a gurantee that enough product has been injected. Soil properties may vary largely and the consumption rate may have to be increased depending on the volume of open pores in the soil and the structure itself. The reference value for the gel’s consumption rate can vary from approx. 1-15gal /square yard or 5-60 kg/m2 . Strongly cohesive, very dense soil will provide a low consumption rate while sandy soil or even large rocks behind the structure might cause cavaties that increase consumption. In the case of extreme cavaties and voids the injection of a hydrophobic foam such as WEBAC 151 might be advised prior to gel injection. This procedure however should be discussed with a WEBAC technician.See pictures on right.
Fulfills the requirements of the KTW recommendations for large- and small-surface sealings (D1 + D2) in contact with potable water(test certificate). Fulfills the requirements of ground water hygiene for large- and small-surface sealings (D1 + D2)(test certificate)Suitability test according to the requirements specified in the gel injection guideline 804.6102(former 835.9201) of the DB AG
TECHNICAL DATA
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