HU193802B - Method for producing afterhardening material - Google Patents

Abstract

The process can be used especially for filling cavities by injection and for soil consolidation, water, cement and granular aggregate material being mixed with one another and the mix being allowed to harden. According to the invention, the mix is prepared by addition of peroxide and - if appropriate - bentonite. To prepare the mix, preferably hydrogen peroxide or barium peroxide, or else activated sodium bentonite, can be added. Expediently, the peroxide is mixed in the first step with the water or a part thereof, and the remaining components are mixed into the water containing the peroxide. To prepare 1 m<3> of mix, 300-500 kg of cement, 50-150 kg of loam/clay or/and 200-400 kg of sand, if appropriate 20-150 kg of bentonite and also 50-20 litres of 25-30% peroxide solution or a corresponding quantity of peroxide are used.

Description

FIELD OF THE INVENTION The present invention relates to a process for preparing a curing agent using cement, water and an additive.

When constructing tunnels, roads, underground storage facilities and the like, there are often unoccupied cavities behind the cladding or masonry, which can collapse under changing - possibly dynamic - loads and cause great damage. In mining as well as in tunnel construction, it is important to carefully fill the back behind the masonry. Typically, a cementitious compound is used to solve such cavity filling tasks.

There is a known method of repairing defective channels, in particular concrete and reinforced concrete drainage channels, by inserting a plastic pipe of smaller diameter into the existing channel and filling the cavity between the two pipes with cement mortar.

The currently known and used grouting agents often settle and do not provide perfect cavity filling, so they do not eliminate the risk of surface sinking, loosening of the masonry and various ground pressures.

Hungarian Patent No. 159,349 discloses a bulking solution in which sludge, cement, water glass and occasionally sodium nitrate and bitumen emulsion are mixed with water and the mixture is injected behind the tunnel wall. The problem is that bitumen, even when hot rolled, has very poor adhesion to the silicates, resulting in multiple layer separations, namely between the silicate-water glass, the bitumen silicate and the bitumen emulsion phases. Cracking reduces compressive strength and cracks open the way for water and crumbly sandy sludge. Thus, perfect cavity filling is not achieved with this material.

Injection mortars are also known which are prepared by mixing cement, river sand, bentonite and plasticizer. Although sodium bentonite increases the stability of sand-cement mortar and reduces water loss, this material cannot be shrunk-free.

Various chemicals for soil consolidation (acrylates, peroxosulphates, etc.) have long been known and are polymerized in soil by the addition of sodium thiosulphate. The use of furfural resins, silicones, and quaternary ammonium salts of fatty acids and polyurethane derivatives are also known in the art (Chem. Engineering News, 33, 1640, 1955).

A common disadvantage of plastic curing agents is that even small amounts of them are extremely costly, so they cannot be rationally used for bulking work. Even their use as agricultural soil2 as a cultivator is so expensive that it could not spread.

The main disadvantage of the cement mortar used in the above-mentioned sewer repair method is that it shrinks, thus making the concrete work of the existing concrete channel and the plastic pipe insecure.

SUMMARY OF THE INVENTION The object of the present invention is to provide a post-curing agent, such as is well-suited for use in gap-free cavity fillings, which, upon curing, does not shrink, swells significantly, and cures well without being expensive.

The invention is based on the discovery that the silicates catalytically decompose the peroxides, in particular hydrogen peroxide, that is, they can render it very rapid in its oxygen decomposition as follows:

2H ₂ O ₂ + SiO ₂ = 2H _? O + O ₂ + SiO ₂ In the process, silicate (mortar) acts as a catalyst. The rate of gas formation is influenced by the quality of the silicate and the concentration of the peroxide.

The invention is further based on the discovery that, using the reactive force of the gas produced, it is possible to fill cavities or cavities which are already inaccessible by means of a pressurized injection technique. (Injection radius of the long-used hot bitumen, known as classic hardener, is, for example, only 1.5 m at a pressure of 10 att)

Based on these findings, the object of the present invention has been solved by a process of mixing water, cement and particulate admixtures and allowing the mixture to solidify, which comprises adding peroxide and, if desired, bentonite. we produce it. Usually hydrogen or barium peroxide is used; the latter mainly when the curing agent is used in connection with radiation protection. Activated sodium bentonite is preferred as the bentonite component. Bentonite, by the way, slows down oxygen release - which may be necessary in some applications - and, due to its gelling effect, prevents water from flowing out of the mixture, which can be useful when injected.

Preferably a silicate-based material is used, in particular sand and / or clay; it is preferable to use coarse sand with a particle size of 0.2 to 2 mm (eg to fill cavities), or to use fine sand with a particle size less than 0.2 mm (eg to solidify clay soils). The most preferred cement is C 350 grade Portland cement. The clay is suitably mixed in a comminuted form.

According to another aspect of the invention, the mixture is prepared using a peroxide solution, preferably 25-30%, preferably hydrogen peroxide solution.

-2193802

Another preferred embodiment of the process is characterized by first mixing the peroxide with the water or a portion thereof and mixing the other components with the water containing the peroxide. 5

Finally, it is advisable to use 300-500 kg of cement, 50-150 kg of clay or / and 200-400 kg of sand, optionally 20-150 kg of bentonite and 5-20 liters of 2530% peroxide solution to make 1 m ^{3 of the} mixture, or an equivalent amount of peroxide.

The invention will now be described in more detail by way of examples.

Example 1 15

Crumbly sandy soil is solidified by injection technology using the material of the invention. The sandy soil to be solidified has a rough structure, i.e. a large pore.

The bulk weight is 1500 kg / m. 20

The pore filler-hardener mixture is prepared according to the following formula (per 1 m ^{3 of} mortar):

liter 30% hydrogen peroxide solution

420 kg C 350 Portland Cement 25

300 kg of coarse sand water with a mesh size of 2.0-0.2 mm

In the first step, the hydrogen peroxide is added to the mixing water, mixed thoroughly, and the other components are added or mixed with the hydrogen peroxide-containing liquid. The amount of water is chosen such that the mortar has a viscosity _{of 35} post-injection possible.

Together with the oxygen formed from the peroxide catalytically decomposed by the silicates, the three-phase mortar (solid phase, water and gas) can be very well injected, swells up into the soil pores, solidifies after injection and settles. larger than currently known mortars using the same amount of cement. The mortar provides perfect cavity fill ⁴⁵ and consequently perfect soil consolidation.

Example 2 ₅₀

Clay soils, i.e. soils with a low pore volume of about 2000 kg / m ^{3, are} solidified using a mortar made by the process of the invention using injection technology. To make a 55 m ³ mortar, add 15 L of 30% hydrogen peroxide solution to the mixing water and mix thoroughly with the water. To the resulting liquid are added 400 kg of C 350 Portland cement, 100 kg of prepared (shredded) clay and 100 kg of sodium bentonite. The three-phase mortar is injected into the soil in a manner known per se, where, when swollen and cured as described in Example 1, it provides perfect pore filling and effective soil consolidation. ⁶⁵

Example 3

A broken concrete duct is repaired by injecting a hard self-supporting plastic pipe inserted into it and filling the space between the two pipes with post-curing material. The curing mortar is prepared according to the following formula for 1 m ^{3 of} mortar:

liters of 25% hydrogen peroxide solution,

320 kg C 350 Portland cement,

350 kg coarse sand not exceeding 2 mm mesh size, kg activated sodium bentonite, water

Again, water and hydrogen peroxide were mixed first, and the other components were added to the premix. The resulting three-phase mortar, when injected into the gap between the concrete and the plastic pipe until swelling begins, not only results in a perfect, void-free filling of the annular cavity, but also positively influences the static tension of the supporting structure of the two tubes.

Advantageous effects of the invention include:

The gas evolved by the oxygen decomposition of the peroxide is non-explosive, non-toxic and even physiologically beneficial, and it maintains the liquid mortar in a liquid state for a certain amount of time due to its pneumatic agitating action, so that the mortar sucked from the site where it was injected. The gas formation, once it has practically ceased, contributes to the strengthening of the silicate bond, presumably through the incorporation of oxygen bridges. As a result, the compressive strength of the solidified mortar is also higher than that achieved only by cement and grain structure. A further advantage is that only part of the oxygen produced is incorporated into the silicate; the other part makes the mortar microporous and initiates slow gel diffusion. Thus, on the one hand, the material does not shrink, but swells to a certain extent and on the other hand, and on the other hand, also decreases in volume. Its swelling properties, excellent injectability and high strength make it suitable for all kinds of cavity filling tasks; of course, as can be seen from the examples detailed above, 'cavity filling' must be interpreted as broadly as possible, so that soil consolidation, that is to say filling of pores, falls within that concept.

The invention is not limited to the specific examples and applications described above, but can be practiced in many ways within the scope of the claims. Depending on the application, the quality of the components

-3193802 and its amount, and by varying the amount of mixing water, the viscosity of the mortar can be varied within wide limits. Apart from the fact that the mortar produced by the process of the invention is well suited for other purposes in filling any cavity (underground old cellars, storage tanks; , e.g. building blocks and building envelope structures', e.g. waterproofing structures, e.g. for sealing pores of concrete pipes, etc. can also be used.

Claims (11)

CLAIMS 1. A process for the preparation of a curing agent, in particular for injection cavity sealing and soil consolidation, comprising mixing water, cement and granular admixtures and allowing the mixture to solidify, characterized in that the mixture is prepared by adding peroxide. The process of claim 1, wherein the mixture is prepared by adding hydrogen peroxide. 3. The process of claim 1, wherein the mixture is prepared by the addition of barium peroxide. 4. A process according to any one of claims 1 to 3, characterized in that the mixture is prepared by the addition of bentonite, preferably activated sodium bentonite. 5. Process according to any one of claims 1 to 3, characterized in that the particulate additive is a silicate-based material, in particular sand and / or clay. 5 6. A process according to claim 5, characterized in that the mixture is prepared by coarse sand having a particle size of 2 to 0.2 mm or / and sand having a particle size less than 0.2 mm. 10 7. A process according to any one of claims 1 to 3, characterized in that C 350 Portland cement is used for the preparation of the mixture. 8. A process according to any one of claims 1 to 4 15, characterized in that the mixture is prepared using prepared (shredded) clay. 9. A process according to any one of claims 1 to 3, characterized in that the mixture is prepared, preferably from 25 to 30% peroxide solution, preferably hydrogen peroxide solution. 10. A process according to any one of claims 1 to 3, characterized in that it comprises a first step 25 mix the peroxide with the water or a portion thereof and mix the other components with the water containing this peroxide. 11. A method according to any one of the preceding claims, characterized in that the preparation of 1 m ³ KE30 smote 300-500 kg of cement, 50 150 kg of clay and / or sand 200-400 kg, optionally from 20 to 150 kg of bentonite and 25 to 30% 50 to 20 liters or a corresponding amount of peroxide.