DE19928339A1 - Method for lifting, aligning and fixing surface structures, e.g. sunken floor slabs, involves injecting a mixture of aqueous alkali silicate solution and isocyanate compound under the structure and then hardening in situ - Google Patents

Abstract

A liquid organo-mineral product (I) consisting of (A) aqueous alkali silicate solution and (B) an isocyanate with at least one reactive NCO group is used in a method for lifting, aligning and fixing surface structures by injecting (I) under the structure and then hardening (I) in situ to form an immediately load-bearing buttress. A product and method for hydraulically raising, adjusting and fixing surface structures by injecting a liquid, chemically reactive medium (I) under the structure so that the structure is lifted and/or aligned in phase 1 and the medium (I) is hardened in situ in phase 2 to form an immediately load-bearing buttress. Medium (I) is a liquid organo-mineral product comprising an aqueous alkali silicate solution (component A) and an isocyanate compound with at least one reactive R-NCO group (component B).

Description

State of the art

It belongs to the state of the art that, for example, displaced driving and / or Runway surfaces, as well as ramps and other foundation surface constructions with the help of flexible cushions or presses filled with gas or liquid are lifted and or aligned. In a second step, which is necessary for permanent fixation, the raised one is then used Surface construction wedged against the surface or by lifting the surface construction created cavity filled with a suitable material, which is then an abutment or support for the Represents surface construction. Solid and / or hardening fillers are used as suitable fillers Fabrics. These include, as is only listed here, for example: sand, ash, gravel, asphalt, cement, solid or liquid plastics. This method is a two-step process because the area con Structure raised and aligned in a first process step with a suitable device must then be in the following second process step with another device and or ME method is determined.

Recently, non-foamable cement suspensions or foamable plastics are being used on the Basis of polyurethane masses used for the purpose mentioned, in such a way that the Injekti pressure, the surface construction is raised and aligned and fixed by the pressed-in material should be placed.

Basically, one works in such a way that the injection material is sealed under appropriate holes the surface structure is pressed in to lift, align and fix it. You need a resistance bearing that is sufficiently stable against the injection pressure Prevents injection material from flowing away into unwanted areas. This is usually achieved in such a way that smaller areas around the borehole with injection are successively located over a large number of boreholes well filled, let this harden and then align the surface construction by lifting and to be determined. The number, size, position and the order in which the individual drill holes are included The injection material is an important part of technology and is used to a decisive extent determined by the processing parameters of the selected injection material. This relates both on suspensions and on solutions of injection materials.

Disadvantages of the prior art

From the injection materials available so far, due to users manure-related or product-specific characteristics or their combination a number of disadvantages len that restrict the application, make the process more expensive or not for ecological reasons make it more usable. Suspensions, emulsions or Liquids that occasionally contain solvents that do not participate in the chemical reaction can hold, used.  

While pure liquids, especially under pressure, easily follow the path of lowest resistance, this applies only to a limited extent to suspensions. When using Suspen sions as injection material that ent finely divided and / or coarse-particle solids ent in an aqueous phase hold, it proves to be a major disadvantage that the flow properties of such a suspension for the Intended use is inadequate and therefore both negatively affects the quality of the measure sen, as well as greatly restrict or make the use of such a material impossible.

Suspensions

The generally poor flow behavior of suspensions - compared to liquids and emulsions - on the one hand has a negative effect on the pumpability of such a material and on the other hand it forces it too large hose lines, which in turn have large holes for the purpose make the pressing process necessary. The injection material is based on a suspension sion after the pressure has been released under the surface construction to be aligned and defined, the more or less existing thixotropic flow behavior of a suspension is disruptive noticeable. In suspensions with a very low thixotropic behavior is undesirable Observe segregation of the suspension. If there is a high thixotropy, the first one the pump pressure separates the suspension, which over a certain distance only contains the aq phase through a filter formed by the solid itself. Make highly thixotropic suspensions practically their fluidity completely once the delivery pressure of the pumps has decreased. she can then no longer be stimulated to continue flowing, in particular not in a controllable manner gene, with the result that the existing cavity under a surface construction is not homogeneous can be filled. The construction then rests on stilts that are in and around the area of the borehole ches form. This highly undesirable phenomenon is known in the industry as "elephant feet". At Load of such foundation slabs can be observed that these are precisely because of their injection new cavities created with suspensions are particularly susceptible to breakage.

There has been no lack of attempts to increase the fluidity of, in particular, cement suspensions improve, but only marginal progress could be made. It is therefore important to note that a high borehole density with a diameter of 45 to 50 mm when injecting with Sus pension is necessary. However, this often weakens the surface construction to be machined in an intolerable way Way, so that the injection method with suspensions is inadequate and can only be used to a limited extent is.

Try adding water and / or grease to the suspensions before or after the injection process Neten viscosity reducers to give better flow properties have the disadvantage that because the reduction of the solid content, the prescribed strength values of the material no longer can be achieved.

Since the cavities under surface structures are often filled with water, this also occurs here Risk of segregation with the inevitably resulting problems described above, such as ent mixing and rearrangement or reduction of the solids content.

In suspensions with a low thixotropy it can be observed that once by the injecti Pressure-lifted plates after the end of the injection due to curing that started later action again, so that precise alignment of the plates is no longer possible. In such Cases must wait after appropriate waiting time via newly created drill holes that continue the construction weaken, be re-injected to make up for the deficiency. But this makes the measure more expensive and is, if it is the rehabilitation of busy highway sections, with additional Traffic congestion burdened.

liquids

When using pure liquids for injection under hollow surface structures, these are Problems of separation of the individual components of the liquid - in contrast to suspensions  - not available, or controllable. Still, liquids need to be injected under surface constructions have certain physical and chemical properties to make them suitable for to be able to use hydraulic lifting, aligning and fixing of surface structures. In order to the selection of injectables that are useful per se on the basis of pure liquids becomes very largely restricted.

For the sealing and solidification of porous geological formations have been around for years 1887 water glass solutions used. These inexpensive and also from an ecological point of view However, valuable products must go through a chemical reaction that takes place in situ, starting with the injection tion must expire, be converted into a resilient solid. The resulting xerogels However, they form only slowly and therefore cannot form a permanent abutment as a deformable mass form, which is necessary for hydraulic lifting of the surface structure. Furthermore, that is earlier "Hardener", which is chemically glyoxal, has recently been used as a groundwater hazard graded.

Processes based on pure water glass, whereby the silicate portion is subsequently hardened with CO ₂ gas or a calcium chloride solution after the injection, is also not to be used for the hydraulic lifting of surface structures, since no pressure-resistant abutment against which the injection pressure can be built can be built up could lift the surface structure and then hold it. It can be observed that with a slight and by no means controllable lifting of a surface construction, it drops again when the injection process is interrupted. When the injection packer is triggered, the injection material then swells out of the drill holes. The subsequent injection with the required "hardener solution" can no longer remedy the deficiency that has already occurred.

Plastic preparations, in particular based on acrylic resins, are known as sealing agents. These are injected into porous geological or artificial formations. This creates however, gels that cannot be used hydraulically and that are static and dynamic loads on the surface construction due to its own weight and the periodic cannot withstand the resulting loads.

When using foamable products, especially based on known polyurethanes, you have made the experience that due to the foam pressure occurring the lifting of the surface construction is not feasible with the required accuracy and reproducibility. This is because that such formulations tend to foam again after the injection process has ended exhibit. The intensity of the post-foaming process depends on those prevailing at the construction site Weather influences, such as temperature, humidity and water content in and below the one to be pressed Area formation. At low temperatures, e.g. B. near 0 ° C, the reactivity greatly slowed down, so that the surface construction is initially pressed in without lifting action. While This latency mixes the unreacted injection agent with the existing moisture action or the water. There is then no longer any inevitable foaming reaction controllable and can raise the plate many times the desired height. It must continue can be expected that shrinkage phenomena that can no longer be controlled will also be added later may occur.

This creates three types of undesirable side effects: first, an unwanted ver more volume of propellant gas is formed, and on the other hand the calculated stoichiometric molar ratio changed between the specified reactants polyisocyanate / polyol, so that the the desired high molecular weight, which determines the physical usage parameters, can no longer be achieved is cash. Due to the increased proportion of propellant gas, accompanied by an increase that is many times higher foaming behavior, the usage properties such as strength, elasticity, adhesive behavior, shape conclusiveness etc. still uncontrollable and negatively influenced. Ultimately, one emerges interconnected open-cell pore structure that acts as a capillary. At the typical load The foam structure fills up with roadway slabs (pressure - relief - pressure = pumping action) hand water, which in a short time leads to mechanical and chemical destruction of the foam structure leads. Foam formulations, which are mainly foamed using physical methods, are subject to the same concerns, as the influence of moisture or water never on a construction site out  can be concluded and usually large amounts of water must be expected. The at the physical foaming method used blowing agents, such as CFCs, CFCs and volatile solutions Hydrocarbon-based compounds are sometimes lawful as environmentally harmful compounds Lich prohibited, so that their use must be excluded (TA-Luft and water cycle). Additional Lich these agents can diffuse through the plates and any tar layers, such as those on the road plates are common, loosen and so soften the actual rolling surface and the joint seal, whereby large Secondary damage arises. At the same time, the driving behavior is based on such an injection material-treated webs adversely affected. Because the polyurethane-forming reaction from polyisocyanate and a polyol, as well as the necessary auxiliary and by-products such as catalyst, foam stabilizer, Blowing agent is a highly exothermic reaction, highly catalyzed reactions are desirable in themselves evaluate fast reaction behavior, because of their fire risk to be classified as particularly critical. Polyurethane foams are particularly good heat insulators, but not the heat generated can dissipate quickly enough so that thermal overreactions can occur, with the result that the foam structure is weakened by partial thermal decomposition or on fire can guess. Self-ignition with complete destruction of the foam structure is also known Smoldering fires. The use of common flame retardants does not help here, since this is the process would be very expensive. In addition, these flame retardants are mostly subject to halogenated ones and phosphorus-containing polyester and polyether under the given construction site conditions hydrolysis, the end products of which pose a threat to the groundwater balance and accordingly cannot be used.

Necessity and advantage of a solution according to the invention

As is known, cause damage to runways, such as highways, airfields, railroad tracks and sagged foundations great secondary damage by setting up necessary long-term construction put. This results, for example, in traffic jams with their dangerous loads on motorways gliding phenomena, like all kinds of accidents.

In the case of airfields it is necessary, in order not to have to interrupt or redirect air traffic, if possible overnight, to make damaged runways usable again.

The same applies to rail routes, where redirection of train traffic with undesirable delays symptoms must be accepted.

When refurbishing bridge foundations, it is also desirable to block on if possible to limit short periods of time.

It therefore consists of both economic and ecological and economic ones Found an interest in a technology to quickly and therefore inexpensively fix the above indicated damage.

Taking into account the time factor, to reduce or avoid congestion, the Security and long-term reliability of the new technology presented here and with the inclusion of Economy and ecology the following solution is hereby disclosed.

Solution in principle

According to the new teaching, both damaged and displaced surface structures are raised, aligned and fixed in one injection step. According to the invention, an injection material and a method are used for this, the chemical properties of the injection material being optimized to the requirements required during the injection, such as flowability, reaction behavior, compressive strength, elasticity behavior and insensitivity to side reactions to one another. These include:

• - High reactivity of the chemical components under given construction site conditions.
• - No impairment of the reaction process of the injection material by moisture and or what water, mud etc.
• - Rapid formation of an abutment around the injection work in a hydraulic lifting process to implement.
• - Flowability of the injection material around a full and homogeneous underfilling of the hollow to ensure adequate surface construction.
• - Adjustable ratio of elasticity and compressive strength depending on the specified requirement profile.
• - Easy handling of the injection material at the construction site with quickly installable construction sites Facility.
• - Compliance with legal environmental regulations.

The required complex behavior and property pattern of an injection material for the inventor According to the intended use, the selection of the possible liquid plastics is very narrow.

Organomineral products, as described in numerous patents, are particularly suitable way for this purpose. These are used as adhesives for rock or for mountain consolidation tion known as products belonging to the prior art and are described, for example, in US Pat Publications EP-A-0 000 580, USA-A-4 042 536, GB-A1 186 771, DE-A-23 25 090, DE-A-24 60 834, DE-34 21 085, DE-34 21 086. Organomineral products which are found under the difficult reaction conditions on construction sites quickly and without foaming and where there is predominantly elastic deformability. Such, for application Particularly valuable properties can be produced according to the teaching of the document EP-0 329 187 len, whereby it should be noted that the basic recipes given there also for the one disclosed here Invention ideas can be used in principle, but that the recipes for the use of the hy drastic lifting, aligning and setting can be modified accordingly.

These formulations include the document EP-A-0 016 262, consisting essentially of an aqueous sodium silicate solution and a polyisocyanate, in a molar ratio such that the CO ₂ gas produced during the chemical reaction cannot develop a foaming effect.

The formulations mentioned in the document DE-34 21 086 can also be used, since in the molar ratios of polyisocyanate to sodium silicate specified there, an additional trimerization catalyst is used which also controls the generation of CO ₂ gas and prevents it in excess.

Technical solution

The technical solution according to the invention can be illustrated by the following examples. Reason In addition, the procedure is such that a special two-component dosing machine is used for injection uses the liquid plastic components in two separate pressure-resistant hoses to the injection site. There the two component flows are brought together under pressure then leads and pass through a "static mixing tube" that the components pass through the mixing geometry of the tube mixes intimately. The now chemically reactive injection material is passed through a borehole under the foundation construction using a pressure-resistant injection packer, where it spreads, hardens and so on under the pending injection pressure forms an abutment for injected liquid injection material, so that the injection work in a hydraulic lifting process can be implemented. This process is about controlling the Injection machine precisely controllable and can be broken off if the foundation construct ion has reached the desired position.

Depending on the construction site conditions, size of the surface structure to be pressed, re formula, mixing intensity, delivery rate of the injection machine is the injection process after 3 to 30 Minutes complete. Then the concrete slab or any other surface construction be released for the intended use without waiting.

The following FIG. 1 provides information about the reaction process of the process according to the invention:

Fig. 1

Viscosity course of injection formulations according to the invention

This time diagram shows how the state of the injection material changes. For example pressure-resistant solids have formed 3.5 minutes since the start of the chemical reaction Seal pheria around the borehole and thus, according to the invention, an abutment for the implementation of Create injection work in hydraulic work.

Fig. 2 illustrates the effect of an injection process under a surface construction. While in the first injection phase the material to be injected can be pressed in its liquid phase up to the periphery of the surface construction, it comes to rest there and hardens. Younger and thus still liquid injection material follows and also begins to settle and harden in its outer peripheral areas. In this way, an abutment is built up in a short time, which is used as a pressure cushion by the following liquid material in order to convert injection work into hydraulic work. Depending on the nature of the construction site, the flow radius of the injection material can be determined by accelerating or throttling the pump output. For injection work under surface constructions with short flow paths, it is therefore advantageous to use particularly highly catalyzed reaction components. For the same purpose, however, the injection process can also be interrupted for a short period in order to give the oldest reaction material time to finally harden and form the abutment required for the hydraulic work. The time of the permitted interruption results from the reaction profile shown in FIG. 1. After restarting the injection process, the hydraulic lifting phase can begin.

Fig. 2

Phases of the injection process

Input materials and basic recipes

The feedstocks disclosed and claimed for the state of the art are listed in the fol table summarized and only provide an overview of the important for the invention ingredients, their chemical characterization and their typical used in a recipe Share.

Table 1

The following Table 2 lists typical guide formulations calculated according to the concept of the invention. The Recipes can be modified accordingly in the context of the practice common in polyurethane chemistry are used to verify certain processing parameters and / or the properties of the end products adorn.

Table 2

Examples of use

Fig. 3 shows a section through a point of damage, as is often found on highways. The neighboring panels have shifted and the joint area has been extended or washed out. In addition, the plate on the right side is tipped. By injection via a single small borehole, the damage can be repaired according to the invention in a very short processing time.

Fig. 3

Comparative example, Fig. 4v

In a depression that simulates a road bed, a square concrete slab was placed on a sloping sand bed, so that one side was about 2 cm lower than the opposite side. In the middle of the lower part of the slab, an injection agent based on a fast-curing cement suspension was injected under the concrete slab through a 45 mm diameter drill hole. After about 30 seconds, injection material emerged from the side near the borehole and swelled on the concrete slab, whereupon the injection process was interrupted. Additional holes were then made to seal the sides adjacent to hole 2 and hole 3, respectively. After a waiting time of about one hour, the injected cementus pension in boreholes 1, 2 and 3 had hardened to such an extent that the plate 4 could be raised and aligned by injection pressure via the borehole 4 that had been created in the meantime.

The injection was stopped and the packer removed from hole 4. Immediately, triggered by the Ge weight of the slab began to swell cement slurry and the slab slowly sagged off again. The process was stopped by reinserting the packer into borehole 4. After sufficient hardening of the suspension, all packers were removed from the concrete slab away. The total workload took about 150 minutes. It was conditionally resilient Concrete slab after waiting 24 hours. However, the full resilience is only after the usual hardening time of concrete reached after 28 days.

Example 1, Fig. 4.1

In a depression that simulates a road bed, a qua was placed on a sloping sand bed Dratic concrete slab placed so that one side is about 2 cm lower than the opposite Side rest. In the middle of the lower part of the plate, a packer was used NEN borehole of 20 mm diameter inject the injection agent according to the invention under the concrete slab graces. After approximately 30 seconds, injection material appeared on the 3 sides near the borehole before which the injection process was interrupted for about 100 seconds. After curing the injected material, the injection is continued through the same borehole. It happened next injection material at the point away from the borehole. The injection process was now interrupted for 30 seconds. After another injection, the concrete slab began to lift until she had reached the horizontal. The injection process was then stopped, the packer removed without liquid injection material spilling out of the borehole and the plate widening The entire injection process lasted 5.5 minutes. To Trimming the edges and cleaning up was the panel after a total machining time of 12 mi grooves free for traffic use.

Example 2, Fig. 5

The damage pattern shown in FIG. 5 appeared on plates 241 and 242 on a busy highway. The two plates had sagged about 20 to 30 mm towards the joints. An approx. 4 long plate part was removed and re-poured due to damage, but was then broken again over the entire width of the plate by heavy goods traffic. The road was closed for one week for the repair work, which led to numerous traffic jams.

According to the material and method according to the invention, plate 241 was first drilled through hole 01 raised, aligned and fixed. Immediately afterwards, the fraction of Plate 242 lifted, aligned and fixed. So much injection was finally made through hole 03 Pressed in material until the cross crack was filled. Leaked injection material was removed sand and the construction site cleaned and cleared. After a processing time of 35 minutes since The construction site could be closed to traffic. It could be right there after observed that fully loaded heavy trucks, the plates 241 and 242 without any Impairment could happen at full speed.

Fig. 5

Claims (15)

1. Product and method for hydraulic lifting, alignment and setting of surface construction by injecting a liquid chemical-capable agent under the surface area structure that lifts and / or aligns the surface construction in a first phase and that in in a second phase, the injected agent hardens in situ and forms an immediately resilient abutment, the agent capable of the chemical reaction being a so-called liquid organomineral Product is that of an aqueous alkali silicate solution designated with A component and from a isocyanate compound denoted by B component, which is reacted with at least one reactive R-NCO Group is provided. 2. Product according to claim 1, characterized in that the aqueous alkali metal solutions have a dissolved solids content of 5 to 65% by weight and an Me ₂ O content of 5.0 to 25% by weight, preferably 30 to 55% Have wt .-% dissolved solids. 3. Product according to claim 1, characterized in that the isocyanate compounds 0.1 to 55 wt. % reactive NCO groups, preferably 15 to 35 wt .-% reactive NCO groups. 4. Product according to claim 1, characterized in that the components A and B further substances are admixed, which influence the reaction behavior. 5. Product according to claim 1 and 2, characterized in that the components A and / or B. contain other substances that the physical properties of the reaction product in ge modify as desired. 6. Product according to claim 1 and 4, characterized in that the substances influencing the reaction chain-extending, trimerizing and / or activating epoxy groups kata lysators, emulsifiers and reactive liquefiers. 7. Product according to claim 1 and 5, characterized in that the physical properties modifying substances with NCO groups reacting compounds based on polyesters, Represent polyethers, polyamines and epoxy compounds. 8. Product according to claim 1, characterized in that preferably organomineral products are set, which are modified according to claims 2 to 7. 9. The method according to claims 1 to 7, characterized in that one with early injection can initially limit the area of action of the injection material and seal it and then raises and exits the surface structure in a controlled manner using the injection pressure judges. 10. The method according to claims 1 and 8 characterized in that the product at the same time both a high elasticity, as well as a high pressure resistance. 11. The method according to claims 1 and 8 characterized in that the product during the phase the injection can displace water and or other liquids or suspensions. 12. The method according to claims 1 and 8 characterized in that the product under the natural Freezing point can be reacted by water and used. 13. The method according to claims 1 and 8, characterized in that the product with regard to its physical usage properties and / or its chemical structure is long-term stable. 14. The method according to claim 1 and 8, characterized in that components A and B by means a suitable dosing machine in separate hoses to the surface construction are passed through a closed mixing device under conveying pressure and over a injection seal that seals the outside can be injected under the surface construction. 15. The method according to claims 1 to 14, characterized in that under surface structures Road slabs, runways, sleepers of track bodies, foundation bodies or floor slabs ver will stand.