Crack Repair. Closing, sealing, limited flexibility bridging and bridging where structural strength is required. Munich airport

Transcription

1 Crack Repair Closing, sealing, limited flexibility bridging and bridging where structural strength is required Munich airport

2 Crack Repair WEBAC Chemie GmbH Fahrenberg Barsbüttel near Hamburg Germany phone: +49 (0) fax: +49 (0) Status: November With publication of this brochure all previous versions are no longer valid. Copyright by WEBAC Chemie GmbH. All the data indicated above are of an advisory nature representing our current state of knowledge and in no way binding. As the exact chemical, technical and physical conditions of the actual application are beyond WEBAC 's control, this information does not preclude examination of the products and / or procedures for the intended application and surface by the user. WEBAC is thus unable to guarantee results. The user is fully responsible for the observation of existing regulations and conditions when using the products.

3 Cracks - A Threat to Every Building Structure Cracks in solid types of constructions are a phenomenon specific to this construction style which usually neither affects the stability nor the usability of buildings. Building structures of mineral nature such as brickwork and concrete are perfectly suited for counteracting compressive strength. But they can only absorb minor bending and tensile stress which, besides shrinkage, are the main causes of crack formation. It depends on several factors how dangerous a crack is to the structure. These factors are the crack width, the thickness and density of the concrete cover in the crack proximity and, last but not least, the crack width modification which is influenced by short- and long-term temperature fluctuations and varying stress levels the structure is exposed to. Detrimental cracks (large-surface checking near the surface of > 0.2 mm crack width, extremely wide cracks, damp and water-bearing cracks with and without hydrostatic pressure) must be repaired since they affect the load-bearing capacity, usability and durability of buildings. The impact of cracks is assessed on the basis of observations, examinations, tests and statistic calculations. This assessment must also take into account all data, facts and figures from the actual building files and documents. The "Additional technical contractual terms and guidelines for structures of civil engineering" (ZTV-ING (RISS)) by the German Federal Department of Transportation and the "Guideline for the protection and repair of reinforced concrete" (RiLi SIB) of the German Committee for Reinforced Concrete (DAfStb) describe how and to what extent the buildings concerned shall be analyzed. These regulations are applicable to crack analyses and help to determine the objectives of the crack injections to be carried out. A durable protection of damaged building structures requires a comprehensive concept specially developed for the building concerned. To this aim a crack analysis is necessary which records and documents all crack characteristics and causes of crack formation in detail. Damaged pier of a railway bridge Arguments for crack repair Cracks endanger the stability and the load-bearing capacity of building structures. Cracks impair the usability of buildings due to excessive corrosion of the concrete and reinforcements. Cracks allow dampness to penetrate the building structure affecting its general usability. Cracks increase the risk of chloride penetration from exposition to de-icing salt and alternating frost and thaw (e.g. plinths, bridges, parking levels and water tanks). Cracks are a visual shortcoming. INTRODUCTION 1

4 Crack Repair CRACK ANALYSIS Core removal to assess the crack characteristics Checking near the surface, easy to analyze after cleaning the surface Separation crack Crack Analysis It depends on the analysis of crack characteristics, e.g. crack type, cause, geometry, width and width modification, degree of dampness and soiling, what kind of repair measures and filling materials shall be used. The crack areas must be cleaned in order to analyze and assess the crack course. Crack type The nature of cracks is characterized by their number and distribution. We differentiate separation cracks and cracks near the surface which is a decisive factor for the repair work. Cracks near the surface often form above the top reinforcement rods along the reinforcement, their course being parallel to the reinforcement rods, reticular around the reinforcement (checking) or arbitrary. They arise e.g. due to great fluctuations in temperature and/or humidity between core and shell and usually have a minor crack depth and close again after a few weeks. Separation cracks in contrast affect major parts of or even the entire cross section. We differentiate tensile cracks, bending cracks, thrust cracks, collection cracks and intermediate cracks. Crack width The crack width is the distance between the crack edges, measured on the surface of the building component, vertically to the course of the crack. Provided that a certain crack width (w) is not exceeded, it is not only the crack width itself but also the thickness and above all the density of the concrete cover in the crack proximity which are significant for a long-term corrosion protection of the reinforcement. The requirements stipulated in DIN 1045/ EN are to be observed. If a building structure is exposed to extreme pollution or designed for a specific utilization purpose it may be necessary to fill cracks of lower crack widths than suggested. Use crack gauges for assessing the actual crack width. In so doing, note down the date, time of day, weather conditions and the temperature of the building component during each measurement carried out for the diagnosis. Assessment of crack width by means of a crack gauge 2

5 Crack width modification/ Crack movement In case of moving cracks, the crack width modification ( w) is of major significance for selecting the suitable filling material and thus for the success of the repair work. Crack width modifications can be caused at short-term level (by traffic loads), daily (by insolation) or at long-term level (e.g. by seasons). These features often occur in combination with irreversible modifications such as shrinkage phenomena, etc.. Filling materials which cure to form a rigid compound (like Epoxy Injection Resins) may only be used if the reason for the crack formation has been found and eliminated and if the filling will not be exposed to any (strong) movement. Otherwise new cracks may form next to rigid structural crack repairs. Moving cracks require elastic filling materials (of limited flexibility or limited compressibility like PU Injection Resin) in order to obtain a flexible bond between both crack edges. Soiling The repair work will only be successful if the cracks to be treated are free from sediments damaging the concrete, the filling materials or reducing their adhesive strength. Such sediments are: loose and brittle particles which reduce adhesion. carbonatized crack borders and edges which may embrittle which leads to secondary cracks. soiling such as oil, grease, etc. on the crack borders and edges which reduces the adhesion within the crack and during the patching procedure. deposits and encrustation which minimize the general adhesion. The crack areas should always be cleaned prior to any further measures. Crack causes Cracks are caused by stress resulting from loads, constraint and internal tension causing the local tensile strength of the concrete to the exceeded. Concrete characteristics prone to cause cracks: hydration heat development and discharge shrinkage creeping swelling Stress prone to cause cracks: loads impeded deformations ambient temperature settlement foundation soil deformation. Building sections particularly susceptible to crack formation Due to their location in the building structure and the selected construction sequence, the following sections require special attention: construction joints solid building components connections between thick and thin building components re-entering angles and cross-sectional clefts impact areas of strong, concentrated forces CRACK ANALYSIS 3

6 Crack Repair CRACK ANALYSIS Dry concrete with ambient moisture equilibrium Damp Water-bearing without hydrostatic pressure Dampness of Cracks, Crack Borders and Edges It is necessary to determine whether cracks are dry, damp or water-bearing in order to select the suitable filling material. As a matter of fact, dampness and water may cause uncontrolled curing processes if filling materials are not compatible with dampness. According to ZTV-ING (RISS), states of dampness are defined as follows: dry water penetration impossible no water access detectable in crack area water access possible but not occurred for a sufficiently long time crack borders and edges visibly dry (assessment via dry cores) crack edges assessed dry according to lab methods damp color shade modification in crack area caused by water but no water emergence signs of recent water emergence crack borders and edges visibly damp or mat damp (assessment via dry cores) water-bearing without pressure water visible in crack area in the form of fine drops water trickling from crack area water-bearing with pressure continuous water film emerging from crack Water-bearing with hydrostatic pressure 4

7 Objectives Closing procedure The closing of cracks prevents corrosion-promoting substances from penetrating and damaging building structures. Sealing procedure The sealing of cracks eliminates crack-related leaks in building components. Flexible crack bridging/ filling Flexible crack-bridging provides for a bond of limited flexibility between both crack edges which is related to the filling material. Crack bridging/filling where structural strength is required Structural crack-bridging provides for a tension- and compression-proof bond designed for restoring the load-bearing capacity of the building component. The strength of the bond depends on the filling material used. (Closing and sealing procedures are generally part of both, structural and flexible crack-bridging. But crack-bridging where structural strength is required excludes flexible crack bridging and vice versa.) Filling Materials It depends on the objective and the dampness of the structure which filling material shall be used. The injection materials used for repairing cracks should have the following qualities: low viscosity sufficient workable life good usability in a large temperature range minor volume shrinkage sufficient adhesive strength to concrete texture high aging resistance not corrosion-promoting compatible with all materials they will get in contact with Polyurethane foam resins (SPU) So-called SPU injection foam resins are quickfoaming resins based on polyurethane which are used for the quick and temporary stopping of pressing water. They react upon contact with water and form a fine cellular foam. For durable sealings, a secondary injection with a PU injection resin is necessary. WEBAC PU Injection Foam Resins for SPU-I For the quick, temporary closing and sealing of water-bearing cracks under pressure. For durable sealants, a secondary injection with a PU injection resin is necessary. Expansion in volume Expansion start (20 C) WEBAC 150 up to 40 times approx. 15 sec. after contact with water For use on surfaces in contact with potable water Tested and approved according to ZTV-ING (RISS) Registered with the BASt-List (SPU-I) WEBAC 151 up to 30 times approx. 20 sec. after contact with water For use on surfaces in contact with potable water WEBAC 155 up to 20 times approx. 50 sec. after contact with water For use on surfaces in contact with potable water Tested and approved according to ZTV-ING (RISS) Registered with the BASt-List (SPU-I) WEBAC 157 up to 8 times approx. 20 sec. after contact with water Flexible, therefore suitable for moving cracks 5

8 Crack Repair Filling Materials (Continued) Polyurethane resins (PU) For flexible crack-bridging, low-viscosity, solvent-free, 2-component PU injection resins are used. They are characterized by their high flexibility and good adhesive tensile strength which is necessary to bridge minor crack modifications. This means that they will not open up again in case of crack width modifications resulting from temperature fluctuations and/or recurring stress and loads. In combination with SPU foam resins, PU resins are ideal for the quick closing of highly water-bearing cracks and putting into place durable sealants in case of high water pressure. Epoxy resins (EP) For crack injections where structural strength is required, solvent-free, low-viscosity 2-component epoxy injection resins are used in civil engineering. Thanks to their low viscosity, high internal strength and adhesive tensile strength these filling materials can be injected into cracks of > 0.1 mm crack width and reach even the finest ramifications. This way the structural strength of the building, its load bearing capacity and its deformability are perfectly restored. Epoxy resins are also used for closing cracks near the surface by means of impregnation and for repairing screed floors. If dampness is to be expected, epoxy resins compatible with moisture (e.g. WEBAC 4170) must be used to ensure sufficient adhesion on the concrete. WEBAC PU Injection Resins for PU-I For the closing, sealing and flexible bridging of dry, damp and water-bearing cracks (without pressure). For water-bearing cracks under pressure, a preliminary injection with a SPU injection resin is necessary. Pot life Viscosity (23 C) WEBAC 1403 approx. 90 min. approx. 80 mpa s For use on surfaces in contact with potable water (1 l, 20 C) For use on surfaces in contact with potable water Tested and approved according to ZTV-ING (RISS) Registered with the BASt-List (PU-I) For use on surfaces in contact with potable water 270 test according to DVGW regulations WEBAC 1405 approx. 50 min. approx. 160 mpa s (1 l, 23 C) WEBAC 1420 approx. 120 min. approx. 330 mpa s (1 l, 20 C) WEBAC 1440 approx. 120 min. approx. 230 mpa s (1 l, 20 C) WEBAC Epoxy Injection Resin for EP-I For the flexible bridging of cracks. Pot life Viscosity (23 C) WEBAC 4101 approx. 60 min. approx. 330 mpa s Highly flexible EP resin (1 l, 20 C) WEBAC Epoxy Injection Resins for EP-I and EP-T For the structural bridging of cracks. For use on surfaces in contact with potable water Tested and approved according to ZTV-ING (RISS) Registered with the BASt-List (EP-I, EP-T) Pot life Viscosity (23 C) WEBAC 4110 approx. 85 min. approx. 280 mpa s (1 l, 23 C) WEBAC 4120 approx. 60 min. approx. 150 mpa s Very low viscosity (1 l, 20 C) WEBAC 4170 approx. 50 min. approx. 90 mpa s Compatible with moisture Extremely low viscosity (1 l, 20 C) 6

9 Repair Work According to the Type of Crack Depending on the filling material to be used and the crack width there are different methods to fill cracks. Injection (I) The injection procedure is used for filling cracks and cavities under pressure via filler necks (injection packers). Separation cracks and cracks in vertical surfaces are usually repaired by means of injection. Impregnation (T) The impregnation procedure, i.e. filling cracks without pressure, is used for filling cracks near the surface. This way cracks in horizontal or slightly inclined surfaces are closed from above. Application conditions specific to filling materials Characteristic EP-T according to TL / TP FG-EP EP-I according to TL / TP FG-EP PU-I according to TL / TP FG-PU Crack type cracks near the surface and separation cracks cracks near the surface and separation cracks separation cracks Crack course any, the crack width is decisive for the any any impregnation technique Crack width w approx. 0.2 mm w 0.1 mm in main areas of crack course w 0.3 mm in main areas of crack course Crack width none since impregnation is only suitable for short-term: w 0.1 w resp. w 0.03 mm modification filling crack areas near the surface (smaller value is decisive); daily: depending on strength development of EP; long-term: any Flexibility of filling w mm: 5 % material cured w > 0.5 mm: 10 % in the crack at approx. 15 C building temperature Crack causes known from crack analysis known from crack analysis not recurring known from crack analysis State of cracks dry or damp* dry or damp* dry, damp, water-bearing and crack edges with and without pressure Proceeding measures irrelevant none not yet filled, first repair measure repeated repairs possible Application ranges of filling materials and types (EP-T, EP-I and PU-I) depending on the dampness of cracks and crack edges Degree of dampness dry damp water-bearing without pressure water-bearing with pressure Closing procedure EP-T, EP-I, PU-I EP-T*, EP-I*, PU-I PU-I PU-I** Objective Sealing procedure EP-I, PU-I EP-I*, PU-I PU-I PU-I** Structural bridging EP-I EP-I* Flexible bridging PU-I PU-I PU-I PU-I** * using specifically recommended epoxy resins ** using quick-foaming PU (SPU) prior to PU-I 7

10 Crack Repair Injection pressure The injection pressure is the nominal value of the manometric pressure at which the filling material is delivered to the filler neck (packer). The filling level and the injection pressure must be constantly monitored. Excessive pressure may cause structural defects in low quality concrete which would further widen the existing cracks. The thumb rule for injections is as follows: Maximum Pressure (Pmax) = cube strength x 10 (bar) 3 Example: For C 35/45 / C20/25 concrete the injection pressure at the packer must be reduced to 150/83.3 bar. Injection Procedures Injection pumps Single- and two-component pumps are suitable for crack injections. WEBAC Single-Component Pumps are easy to use, clean and maintain. WEBAC Single-Component Pumps are recommended for the application of quick-reacting, multi-component materials. Single-Component Pumps When single-component pumps are used for injecting two-component materials the two material components must be mixed before filling the storage container of the pump. Two-Component Pumps When two-component pumps are used the two material components are delivered to the injection gun in two separate hoses and are mixed directly before their application. Injection packers Injection packers are filler necks which connect the injection pump to the building component during crack injections. The top of the packers are equipped with a zerk or button head fittings which serve as connection pieces to the pump. Depending on the type of connection between pump and building component we distinguish surface packers (installed on the surface) and drill-hole packers (installed in drill holes). Drill-hole packers Drill-hole packers are cylinder-shaped injection packers to be installed in drill holes made for this purpose. They consist of a spreading device and an injection fitting. Depending on the way of installation we distinguish "screw-in" mechanical packers and "hammer-in" packers. WEBAC Mechanical Packers are screwed into the drillholes. When tightening the packers a fabric-reinforced rubber sleeve is firmly pressed against the drill-hole sides so that the packers withstand even highest injection pressure in the drill-hole. WEBAC IP 2 8

11 WEBAC Hammer-in Packers are knocked into the drillholes. Their firm anchorage is obtained by their conical shape and semi-rigid lamella positioned in toroidal formation. They represent an alternative to mechanical packers if the building structure is solid enough to take the impact. When installing the drill-hole packers, make sure that existing reinforcements do not get damaged when knocking in the packers. Mechanical packers remaining in the building must be made of stainless materials and must have break-off points. Blow oilfree compressed air through dry cracks, rinse damp/wet cracks with water prior to the installation of packers. This also shows whether the drill hole is crossed by a crack. The packers must be installed in staggered rows and firmly tightened in the drill holes. Surface Packers WEBAC Surface Packers are glued directly onto the crack on the surface of the building component. The packer base is provided with a supporting plate to ensure optimum adhesion. Surface packers are firmly fitted on the substrate with a patching. The injection pressure depends on the crack width, the patching material used and the adhesion to the surface (always lower than for mechanical packers). Surface packers are designed for injections where the making of drill holes is prohibited. In general they are used for the injection of epoxy injection resins where structural strength is required. WEBAC Mechanical Packer WEBAC Surface Packer WEBAC Hammer-in Packer Patching When injecting epoxy resins where structural strength is required the cracks must be patched prior to the injection in order to ensure a high filling level in the cracks and to prevent the filling material from being washed out of the cracks. WEBAC Putty For patching cracks and installing surface packers Curing time (3-5 mm film thickness) Workable life WEBAC 4510 approx. 18 hours approx. 25 min Patching/installing surface packers WEBAC 4520 approx. 24 hours approx. 35 min Flexible/patching WEBAC 4525 approx. 12 hours approx. 30 min (20 C) For wet surfaces/suitable under water Patching/installing surface packers 9

12 Crack Repair D C r C -45 r t Section D-D D Injection Direction * t: r: Patching View C-C efficiency range of a packer distance between packers The distance between packers may only slightly exceed the efficiency range of the packer % shorter distances do not pose any problem. The ideal distance depends on the temperature related pot life and the filling material. * Successive use of the packers from bottom to top after filling material has emerged from the previous packer. Positioning of drill-hole packers (see ZTV-ING (RISS)) Injection Procedures (Continued) Flexible crack injections with PU-I Under normal conditions WEBAC PU Injection Resins (WEBAC 1403, WEBAC 1405*, WEBAC 1420, WEBAC 1440) are used for the flexible bridging of cracks. In case of waterbearing cracks under pressure it depends on the building whether a preliminary injection with a WEBAC PU Injection Foam Resin (WEBAC 150, WEBAC 151, WEBAC 155* or WEBAC 157) is necessary. Preferably, the injection shall be carried out via drill-hole packers without patching so that the filling level of the crack can be easily monitored. First of all drill-holes are made alternately on both sides of the crack. The distance between the drill-holes depends on the crack width, the thickness of the building component, the temperature-related pot life and the viscosity of the material (reference value: thickness of the building component/2). Then drill-hole packers (WEBAC Mechanical Packers) are installed and tightened in the drill holes. When filling non water-bearing cracks, these should be rinsed with water prior to the injection. This way PUR resins which react upon contact with humidity will reach their optimum flexibility through bubble formation in dry(ish) cracks. If a preliminary injection with a PU injection foam resin must be carried out in water-bearing cracks under pressure, SPU-I should only be used in those crack sections where it is necessary to stem the water entry in order to achieve optimum filling levels with the PU-I to follow. The injection with SPU-I is implemented in intervals so that conclusions can be drawn whether to continue or finish the injection process. In general the injection with PU-I follows via additional packers. If the secondary injection is carried out via the same packers (not blocked with SPU foams), make sure that the filling level required for a durable sealing of cracks with PU is achieved. Empty component A and B of the respective PU injection resin which are provided according to the required mixing ratio completely into a mixing vessel and mix homogeneously using a low-speed stirrer. Closing and sealing of a water-bearing crack under pressure with WEBAC PU Injection Resins * registered with the BASt-List 10

13 The injection is usually carried out by means of a singlecomponent pump (WEBAC Single-Component Pumps). The injection pressure depends on the material used and must be selected according to the instructions by the manufacturer. The injection procedure shall be effected from bottom to top against gravity until the crack is filled completely and the resin can be seen emerging from the adjacent packers and the surface of the building component. The building component should have a temperature of 5 C for the PU injection. Following the injection and as soon as the material has cured, the packers shall be removed and the drill-holes closed with mineral filling material. All cured resin residue must be removed. Locking pin Patching ~ 50 mm ~ 3 mm Crack injection with EP-I where structural strength is required In general, WEBAC Epoxy Injection Resins WEBAC 4110 (registered with the BASt-List), WEBAC 4120 (for concrete building components exposed to dynamic stress) and WEBAC 4170 (for damp or oily cracks) are used for crack injections where structural strength is required. First of all drill-holes are made alternately on both sides of the crack. The distance between the drill-holes depends on the crack width, the thickness of the building component, the temperature-related pot life and the viscosity of the material (reference value: thickness of the building component/2). The main areas of the crack borders must always be accessible by the adjacent packers for dampening purposes. Drill-hole packers (WEBAC Mechanical Packers) are then tightended in the drill-holes without installing the injection fittings yet. The fittings must be placed on the respective packer to be injected during the injection procedure itself so that the resin can be seen emerging from the packer to follow in order to monitor the crack filling level. If drill-holes are not admissible (for example in case of load-bearing reinforcements or buildings under a preservation order) surface packers must be used. Surface packers are glued with Epoxy Putty (WEBAC 4510 or WEBAC 4520) directly onto the crack, i.e. on the surface of the building component. Prior to their installation, a steel nail is knocked into the crack to prevent the injection canal from blocking when installing the packers on the building component surface. As soon as the adhesive has cured the nail shall be removed. Installation of surface packers with locking pin B A r r A r t Section B-B B Injection Direction * Positioning of surface packers (see ZTV- ING (RISS)) t: r: Patching View A-A efficiency range of a packer distance between packers The distance between packers may only slightly be exceeded % shorter distances do not pose any problem. In case of thick building structures surface packers should only be used for filling materials allowing for a long injection time and a long temperature-related pot life. * Successive use of the packers from bottom to top after filling material has emerged from the previous packer. 11

14 Crack Repair Injection with WEBAC Epoxy Injection Resins where structural strength is required Filling level Venting Filling level: 5mm or 15-fold crackwidth The crack can be widened parallel to the crack course by means of a special grinder (Filling material supply) Impregnation by means of brush application or casting Impregnation with WEBAC Epoxy Resins Injection Procedures (Continued) The cracks are then patched with WEBAC Epoxy Putty (WEBAC 4510, WEBAC 4520, WEBAC 4525 in case of damp crack edges) at an even layer of at least 10 cm width and 3 mm thickness, unless otherwise specified. A vent must be provided for on the highest points of the cracks. For building structures with short-term or daily crack width modifications during the injection, a viscoplastic putty (WEBAC 4520) must be used for the patching. Empty components A (resin) and B (hardener) of the respective Epoxy injection resin which are provided according to the required mixing ratio completely into a mixing vessel and mix homogeneously using a low-speed stirrer. The injection shall be carried out by means of a singlecomponent pump (WEBAC Single-Component Pumps). The injection pressure depends on the nature of the building (concrete or brickwork) and must be selected according to the instructions by the manufacturer. The injection shall be effected from bottom to top against gravity until the crack is filled completely and the resin can be seen emerging from the adjacent packers. The building component should have a temperature of 8 C for Epoxy injections. Following the injection and as soon as the material has cured, the packers and the patching shall be removed and the surface reprofiled. Filling cracks by means of impregnation with EP-T For filling cracks by means of impregnation, WEBAC Epoxy Injection Resins WEBAC 4110 (registered with the BASt-List), WEBAC 4120 (for concrete building components exposed to dynamic stress) or the special injection resin WEBAC 4170 (for damp or oily cracks) are used. Only fill cracks by means of impregnation on nearly horizontal surfaces. The cracks must be filled at least up to 5 mm deep or to the 15-fold crack width (the smaller value is decisive). Prior to the impregnation procedure, the cracks and crack areas must be cleaned appropriately (e.g. with an industrial vacuum cleaner). The cracks must be supplied with a sufficient amount of material within the pot life of the Epoxy resin which depends on the temperature of the building component. To this aim, the cracks can be widened along the crack course by means of a special grinder. 12

15 Epoxy resin must be poured into the cracks until they are fully saturated. In so doing, provide for adequate ventilation. Finally the surface must be restored to its original state by suitable measures, if necessary, (e.g. by scattering quartz sand or quartz powder on the surface). Note Please observe all existing regulations and the instructions in the technical data sheets on the respective WEBAC Products. Should you have any queries or specific problems, please do not hesitate to contact us. Published and copyright by WEBAC Chemie GmbH, Fahrenberg 22, Barsbüttel near Hamburg, Germany. No parts of this brochure may be reproduced or printed without the prior written permission of WEBAC Chemie GmbH. 13

16 Application Ranges of WEBAC Products: Crack Repair Closing, sealing, limited flexibility bridging and bridging where structural strength is required Waterproofing of Structures Remedial injection system for the repair of damp-proof courses Curtain Injections Post-construction surface sealing for undergrade building components Joint Sealing Sealing of construction and expansion joints in structural and civil engineering Foundation Pit Sealing Sealing of water-bearing cracks and joints in foundation pits of slot and sheet pile wall design Canalization Repair Sealing of joints and cracks in canals and shafts Surface Sealing Bituminous external sealing for undergrade building components Surface Protection Coating of industrial and useful surface areas Soil Stabilization Filling, solidification and stabilization of floors and brickwork Our Formula - Your Solution WEBAC Chemie GmbH Fahrenberg Barsbüttel near Hamburg Germany phone: +49 (0) fax: +49 (0) info@webac.de