MXPA00012514A - Method for sealing porous building materials and building components - Google Patents

Abstract

Disclosed is a method for sealing porous building materials, a polyurethane and/or epoxy resin based sealing composition and the use thereof in said method.

Description

PROCEDURE FOR SEALING MATERIALS AND POROUS CONSTRUCTION COMPONENTS Field of the Invention The present invention relates to a method for sealing porous building materials. Construction materials are hereinafter also understood as building components consisting of these materials (for example, walls, pillars) or construction works (for example, bridges). The invention also relates to a sealing composition and in particular to its use in the present process. The field of application is all kinds of porous construction materials, which may be in contact with liquids.

BACKGROUND OF THE INVENTION The construction components at ground level are in direct contact with water. In the above, there are the following cases: - soil moisture (water that is in the soil, capillary bound and can advance by capillary force, even against the force of gravity). - water that does not press (for example, water from rainfall, from drains or service in liquid form that can drip, that does not exert any hydrostatic pressure on the seal or that only exerts a slight transient pressure). - water that presses (permanently exerts a hydrostatic pressure on the seal). In the case of new constructions, the sealing of the construction components in contact with the ground is carried out within the framework of the rough construction measures as well as subsequently in the construction substance to be repaired and in the case of sealing works made defectively. In the framework of new construction measures, the seals (for example, masonry adjacent to the floor) is placed on the outside flat, or installed as the so-called horizontal containment in the joints of the masonry that opens The two measurements can also be made together. The construction design as well as the corresponding selection of material is indicated in DIN 18 195"Bauwerksabdichtungen", partas 1 to 10, Berlin: Beuth Verlag, and in the information sheets "Bauwerksabdichtungen mit kaltverarbeitbaren, kunststotfmodifizierten Beschichtungsstoffen auf Basis von Bitumenemulsionen 07.93"and" Bauwerksabdichtungen mit zementgebundenen starren und flexiblen Dichtungsschlámmen 03.92", editor respectively Industrieverband Bauchemie und Holzschutzmittel e. V., Frankfurt. As a rule, the subsequent sealing measures are used to repair missing or damaged horizontal contentions and are eventually carried out together with an internal vertical containment. Normally, at the time of repair, the external zone can not be accessed or can only be accessed with large jobs. The load cases indicated here also apply analogously to materials and building components that are not in contact with the ground and that, due to the environmental conditions, may be in contact with water. A special position occupies the building components in contact with the ground, made of waterproof concrete (concrete WU, for its acronym in German). In this case, the work joints (for example, wall-floor connection) are sealed according to plan, for example, by injection in the framework of the rough construction measures. Other fields of application are, for example: - protection against corrosion of reinforced concrete, by rejecting water or chloride solutions (see also "Korrosionsschutzprinzip W according to the guideline" Richtlinie für Schutz und Instandsetzung von Betonbauteilen Teile 1 bis 4", Berlin: Deutscher Ausschuss für Stahlbeton, DAfStb, 1991 -1992) - protection of porous building materials against anti-environmental liquids (eg building components that serve as a secondary barrier, gas stations, collection containers, etc.).

Current Technique The current state of the art regarding the practice of sealing porous construction materials and components can be consulted in the following table: From the above table, four essential procedures are shown in the sealing of building components in contact with the ground: 1) The seal is applied to a bottom (concrete, masonry, etc.). In the case of a seal arranged against the ground, a "positive liquid pressure" is assumed as charge and in the case of an internal arrangement, a "negative liquid pressure". The materials used so far in this field can be subdivided into three groups (Figure 1). The impregnations penetrate approximately 1 to 30 mm in the pore space and act by modifying the surface properties of the pore walls, without filling them or forming closed films (Figure 1a). The seals penetrate approximately 1 to 3 mm into the pore space, fill it completely in this area and occupy the outer surface of the building material with a thin film (Figure 1b). The coatings do not penetrate or penetrate the construction material; these materials act by a layer on the external surface of the construction material (Figure 1c). 2) The seal is subsequently installed by injection into a groove or crack (concrete WU work board or similar). In the foregoing, the groove or fissure is filled with a sealing material and the pore system of the construction material is maintained largely untouched thereby. 3) The sealing is subsequently installed by injection into the pore system, the pore system of the construction material is filled as far as the solids content of the injection material and the penetration depth allow. Usually, until now materials that can not completely fill the pore system after hardening are used. 4) The pore system is mechanically separated and partially replaced with impervious filler bodies. All procedures can also be applied to porous building materials and components that are not in contact with the ground and that, due to environmental conditions, may come into contact with water or other liquids.

Disadvantages of Current Procedures A sealing on the inner side of the materials and construction components requires both special materials and constructive solutions that allow to capture the negative liquid pressures, that is, to withstand the tensile stresses by the liquid pressure that acts . Special waterproof coatings of up to several centimeters thick are often applied to the masonry in several layers, or "WU concrete vats" that extend throughout the internal area in contact with the ground. Both procedures require a large investment in terms of material use and work. Seals on the outside against water are made with bitumen materials. In this case, so-called thick bitumen coatings are used, which are not resistant against external mechanical effects and are characterized by a high price. Damage can be caused, for example, by sharp objects (brick rubble, etc.), which perforate the soft bitumen mass when the excavation of the work is refilled. Since the coatings do not fill the pore space, in case of damage in those the construction material becomes directly accessible to the water. Seals on the outside against anti-ecological liquids are made by costly coatings. For the subsequent sealing with the help of injections, low viscosity materials, partly hydrophobic, which do not fill the pores, are often used. The materials known up to now, which work according to the principle of filling pores, are not able to completely fill them (see Pleyers, G .: Ist eine Porenverengung zur Reduzierung kapillar aufsteigender Mauerfeuchte geeignet? Stuttgart: Fraunhofer IRB Verlag, 1998. In: Jahresberichte Steinzeríall-Steinkonservierung Band 6 1994-1996, (Snet age, R. (Ed.)), Pp. 157-163, 1998). From the results of a completed investigation it is clear that all injection materials currently on the market for water sealing purposes are not suitable for the subsequent sealing of masonry saturated with water (see Sasse, H.R.; Pleyers, G .: Reduzierung von Mauerwerksfeuchte - Untersuchung und Entwickiung chemischer Bohrlochinjektionsveríahren ais wirksame Horizontalsperre für den nachtraglichen Einbau in Ziegelmauerwerk, Aachen: Instituí für Bauforschung, 1997, Forschungsbericht No. 496, 1997, IRB Verlag). Since the subsequent sealing of a pore system saturated with water must start from the moment of an injection measurement, there is in particular for this field of sealing technique the need for materials and procedures with better results.

OBJECT OF THE INVENTION • The aim of the invention is essentially the sealing of porous building materials and components. • All common porous building materials are taken into account, such as: - construction materials bonded with cement, such as concrete, mortar, pumice building materials, porous concrete and plaster. -Brick construction materials, such as brick with vertical perforations or solid brick. -materials of construction joined with lime, such as sand-lime brick, lime plaster and lime mortar, -natural stones, such as sandstone, tufa and calcareous stones. • All the liquids in question are considered, such as: -water, -saline solutions, -ecological liquids.

• The seal must act under any load case (humidity, liquids that do not press as well as positive and negative liquid pressure). • The materials used should be able to be applied with any application procedure (for example, brush application, flooding, application of plaster, injection without pressure, injection under pressure). • The sealing efficiency must be guaranteed permanently with any moisture in the subsoil until saturation with water at the time of treatment.

• Application techniques and necessary materials should be used more economically than current procedures. • The resistance against negative water pressure must be increased compared to known systems. • The sensitivity to damage (for example, due to an incorrect filling of the excavation of the work) must be reduced in comparison with known systems.

• In certain cases, the sealing must be adequate to increase the resistance to wear of the treated construction component and, eventually, also to increase its adhesion (for example, on surfaces on which traffic passes in parking lots).

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1a is a schematic diagram illustrating the phenomenon that takes place during the impregnation of porous materials. Figure 1 b is a schematic diagram illustrating the phenomenon that takes place during the sealing of porous materials. Figure 1c is a schematic diagram illustrating the phenomenon that takes place during the coating of porous materials. Figure 2a is a schematic diagram illustrating how the sealing material penetrates deep into the pores of a porous building material and hardens into a solid closure. Figure 2b is a schematic diagram illustrating how the sealing material penetrates deep into the pores of a porous building material and hardens as a foam to form closed cells. Figure 3 illustrates is a schematic diagram of a laboratory test developed in accordance with the present invention. Figure 4 is a graph comparing the evaporation amounts determined in the laboratory test of Figure 3.

Detailed Description of the Invention For the penetration into the pore system of usual building materials (see the examples above), one or more component materials must be used, which (1) are of low viscosity (preferably <100). mPa.s at 12 ° C) and free of solvents, form by reaction after treatment of the construction material masses that fill the pores and that after hardening have a swelling capacity sufficiently marked by the liquid present, or (2) are of low viscosity (if possible <100 mPa.s at 12 ° C), in the reaction after the treatment of the building material in the pore system they increase their me, for example, by foaming and after hardening they have a sufficiently marked swelling capacity by the liquid present. Both solutions together constitute the total closure of the pores of the treated construction material, either by a complete filling with the material or by a complete filling with the foam of closed cells. The materials according to solution 1 are, for example, low viscosity epoxy resins, which consist of diluents of aliphatic, polyfunctional reagents, free of solvents and aminic, aliphatic hardeners, which are mixed shortly before application. For the application with brush and splice, the consistency can be regulated, for example, using suitable adjusting agents, from low viscosity to pasty. The materials according to solution 2 are, for example, modified polyurethane prepolymers with isocyanate contents of between 2 and 30%, which can be dispersed by suitable emulsifiers just before use with 40 to 95% by mass of water or they can be dissolved with 40 to 95% by mass of a suitable solvent. The catalysts promote strong foaming for the purpose of increasing me. Foam stabilizers can also support foam formation. For the application with brush and splice, the consistency can be regulated, for example, using suitable adjusting agents, from low viscosity to pasty. Depending on the water content of the bottom to be treated, the type of application must also be adjusted. This results in a specific type of action of the materials respectively. Dry bottom (absorbent, that is, soaked without pressure, for example, possible by flat application or by injection without pressure) The sealing material can enter the pore system by capillary forces and harden in that place. It forms an effective seal that can be further improved by liquid access. The material penetrates deep into the pores and hardens as a solid closure (Figure 2a) or as closed cell foam (Figure 2b). Wet bottom (limitedly absorbent, that is, soaked without pressure, for example, still possible by flat application or injection without pressure). The sealing material can enter the pore system by capillary forces and harden in that place. Since at the time of application the pore walls are moistened with a film of water, only an effective seal can be installed taking into account the following conditions: The sealing material penetrates the pore space, fills it up to the area of pore walls moistened with water and hardens in this state. Suitable studies have shown that the area of pore walls, after hardening the introduced material, still has the capacity for capillary performance of an untreated pore system. The water carrying capacity, especially in the area of pore walls moistened with water, is sufficiently reduced by suitable measures or their combination. The measurements can be: - after hardening, with the water present there must be enough swelling capacity to seal the area of pore walls moistened with water (Figure 2 a and b); - in the hardening, mixing or, by means of a chemical reaction, the water is removed from the walls of the pores and, in this way, a direct contact of the injection material and the walls of the pores is obtained (Figures 2 a ). Water-saturated bottom (non-absorbent, that is, application pressure is required) In order to achieve the desired volume of construction material, the sealing material must expel the water that is in the pore system by injection under pressure . However, with the above there remains a film of inevitable water on the walls of the pores. After the injection under pressure, the situation agrees with the situation after the injection without pressure on wet bottom. Therefore, the materials for pressure injection must have the same characteristics as those mentioned above to achieve the intended final state shown in Figures 2a and b. - It also applies that by means of a pressure application there should not be excessive mixing with the water found in the pore system.

Advantages of the invention • The invention is able to seal all types of porous building materials and components, for example: -construction materials bonded with cement, such as concrete, mortar, pumice building materials, porous concrete and plaster . -materials of brick construction, such as brick with vertical perforations or solid brick, -materials of construction joined with lime, such as sand-lime brick, plasters of lime and mortar of lime, -natural stones, such as sandstone, tufa and stones calcareous • The invention is able to seal against all types of liquids, for example: -water, -saline solutions, -ecological liquids. • The sealing acts under all load cases (humidity, liquids that do not press as well as positive and negative liquid pressure). • The materials used can be applied with any application procedure (for example, brush application, flood application, plaster application, injection without pressure, injection under pressure). "The sealing efficiency is guaranteed permanently with any moisture in the subsoil until saturation with water at the time of treatment.

• For an introduction by means of pressure injection, sealing efficiency can be permanently guaranteed in water-saturated and wet-pored systems. • The improvement of profitability is guaranteed in comparison with usual systems, since the products used are chemicals that can be prepared economically. • Compared to thick coatings, use as a flat seal requires significantly less material. Thus, for this application case, the improvement of the profitability occurs in a special degree in comparison with usual systems. • Thanks to the anchoring of the materials in the pore system, the efficiency and durability in the case of load "negative water pressure" is decisively increased in comparison with usual systems. • The sensitivity to damage (for example, due to an incorrect filling of the excavation of the work) is reduced in comparison with known systems, since there is no applied coating, but a sealing in the pore space of the construction material . This protects the sealing agent from mechanical actions. • In certain cases, for example, in the case of surfaces trafficked in parking lots, with a seal according to the invention, in addition to the protection against corrosion of reinforced concrete, the wear resistance requirements of the construction component can be met treated and adherence. Contrary to usual procedures, no additional measure is required (for example, additional layer of quartz sand).go.

EXAMPLES OF REALIZATION In order to demonstrate the efficiency of the commercial products and of the materials according to the invention, laboratory tests were carried out according to Figure 3. The design of the test is presented and illustrated in detail in Sasse, Pleyers (see above). Next, the trial is briefly described. For this test, a two-component, low viscosity epoxy resin was used, which consisted of the Bakelite® EPD-HD (A) product with the Rütadur® TMD (B) hardener in the proportion of mixture A to B of 100 to 29 parts in mass. The mentioned substances are commercial products of the company Bakelite AG, domiciled at 47125 Duisburg, Varziner Strasse 49. Natural stones with sealed flanks, of dimensions 300 mm x 50 mm x 50 mm were saturated with water, storing them in water until the constancy of mass . The natural stones saturated with water were injected with an injection pressure of approximately 6 bar into a hole in the center of the stone (see Figure 3, left). The amount of epoxy resin sufficient to fill the entire system of pores of the natural stone accessible by the reception of water without pressure was applied respectively. After a subsequent storage of 24 hours under water at 23 ° C, the sample bodies were prepared as shown in Figure 3 and checked for tightness. By weighing the sample stones prepared as indicated in Figure 3, the performance capacity of the plates of different depths for the capillary transport of water can be determined. The water that is in the container can only evaporate if it passes the prepared stone sections. If the water does not evaporate, the pores of the stone are completely closed. The amount of water that really evaporates is related to the surface of the stone sample and is indicated in kg / (m3 * d). In Figure 4 the evaporation amounts determined in this test are compared after 3, 5, 17 and 44 days and the evaporation amounts of an untreated stone. It is clearly observed that the amount of water transported by the treated stone is smaller than that of the untreated stone and that with the passage of time it is further reduced. The material is swollen by the present water and decreases the transport performance of the pores to a value of approximately 0.02 - 0.03 kg / (m3 * d). In Sasse, Pleyers (see above) it was observed and illustrated in detail that the transport performance of the pores should be reduced to a value less than 0.1 kg / (m3 * d), in order to guarantee the efficiency of a horizontal containment in the masonry. Also, in the same trial, commercial products were tested for this application case. None of the commercial products tested reached the limit value indicated above. All products allowed transport ratios of 0.5 kg / (m3 * d) and more. The test clearly emphasizes the special suitability of the process according to the invention and of the sealing composition according to the invention.