DE102007015463B4 - Water-blocking sealant and method of making a water-barrier sealant - Google Patents

Abstract

Water-blocking sealant obtained from a sealant suspension comprising: - 3-15% by weight of cement, - 6-65% by weight of fly ash, - 30-60% by weight of stone dust, with fly ash and stone dust having similar granulation, and up to 50% by weight of a clay / water suspension containing polymineral clay, whose granulometric constituency has at least 60% parts <5 μm, whose mineral constituents contain kaolinite, hydrogels and quartz, whose chemical composition is more than 24% by weight and at most 28% by weight of Al 2 O 3 and 50-60% by weight of SiO 2, having an exchange capacity of 15-30 meq per 100 g of dry clay; and in the clay the main constituent of exchange cations with Ca + 2> Na +> K +> Mg2 + is present.

Description

The invention relates to a water-barrier sealant and a method for its production.

DE 601 06 267 T2 describes a recyclate with at least 20% clay and 1 to 10% lime. The clay usually comes from the tailings of excavations or excavations, whereby the addition of lime ensures that the waste material meets the performance requirements for road construction materials in the United Kingdom. It is also envisaged to add 1 to 5% powdered fly ash to store the material for extended periods of time.

Waterproofing properties of clay suspensions and fly ash cement suspensions are off DE 33 47 377 A1 known.

AT 176 499 B discloses a mixture of clay and cement blended with raw wood vinegar in a concentration of 1 to 5 weight percent. In addition fly ash can be added.

The use of a water-ash mixture as a water barrier or hydro-isolation diaphragm is for example in DD 245 001 A1 disclosed.

Out PL 174 766 B1 a water-barrier sealant is already known.

The known sealant is very well suited to the formation of waterproof barriers in clefts of rock and on loose soils according to the injection method and on loose soils according to the method of Deep Soil Mixing.

Due to its rheological and structural mechanical properties, this known means does not guarantee the tightness of the water barrier under all geological conditions when previously prepared holes, cracks, ditches, excavations or similar, in particular narrow and deep depressions are filled with the suspension of this agent.

The object of the invention is to provide a water-barrier sealant which has improved sealing properties and is easy to handle.

Unexpectedly, it has been found that the addition of fly ash and stone dust with similar granulation as fillers of the known sealant consisting of a water suspension of clay and cement, while modifying its suspension inventory, allows the production of an effective water-barrier sealant by a process in which previously made in the soil wells are filled with a sealant suspension.

For the composition of the suspension clay is used, the granulometrierter component of which is formed from at least 60% <5 microns parts and in the mineral inventory of kaolinite, hydro mica (hydromica) and quartz are included. In the chemical component, the content of Al ₂ O _{3 is} 20-28% and the content of SiO _{2 is} 50-60%, with an exchange capacity of 15-30 mEq (milligram equivalent units) per 100 g of dry clay and a major component (core composition). on replacement cations Ca ²⁺ > Na ⁺ > K ⁺ > Mg ²⁺ .

In the stock of the agent is preferably Portland cement or possibly against sulfate-resistant Portland cement, or cement with low aluminum content and alumina.

The water content in the clay suspension is preferably adjusted so that the density of a freshly prepared suspension of the sealant after mixing of all components is 1.40 to 1.65 Mg / m ³ and preferably not less than 1.45 Mg / m ³ .

The sealant of the present invention is inexpensive, easy to set up on site and easy to use. Its rheological and structural properties allow the formation of effective water barriers. The practical experiments carried out have shown that 28 days after the establishment of counter-filter water barriers of the sealant of the invention, it had an axial pressure resisting force of at least 0.3 MPa and a filtration coefficient of less than 1 × 10 ^-8 m / sec , decreed.

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

Example I

The waterproofing sealant contains 7% by weight Portland cement, 52% by weight mixture of fly ash and stone dust and 41% by weight clay water suspension.

To prepare the sealant can any stone dust with a fly ash-like granulation, z. As lime dust, basalt dust, or dolomite dust can be used.

The clay used was characterized by the fact that its granulometric component was formed from at least 60% <5 μm parts, in whose mineral constituents were kaolinite, hydrogels and quartz; in its chemical constituent, the content of Al ₂ O _{3 was} 20-28%. and the content of SiO ₂ 50-60% and its exchange capacity was 15-30 mEq per 100 g dry clay and the main component of exchange cations Ca ²⁺ > Na ⁺ > K ⁺ > Mg ²⁺ .

The product is suitable for use in conditions that correspond to clean and slightly mineralized waters.

• – ein Bohrschlammmischer-Set;
• – Wuchtsiebe zur genauen Ablösung von Gestein, Sand und anderen Teilchen aus der Wasser-Lehm-Suspension;
• – ein Suspensionsbehälter/Sammelbehälter;
• – ein Pumpen- und Rohrenleitungen-Set zum Auspumpen der Suspension und zur entsprechenden Wasserversorgung;
• – ein Silo mit einer Aufgabenvorrichtung für Flugasche und eventuell ein zusätzlicher Silo mit einer Aufgabevorrichtung für Steinstaub;
• – ein Silo mit einem Zementspeiser;
• – ein Schaufelmischer;
• – ein Tank zum temporären Speichern der Dichtungsmittelsuspension

The sealant is to be applied to the site, not far from where the water barrier is to be set up, using the following tools:

• A mud mixer set;
• - Soil sieves for the exact detachment of rock, sand and other particles from the water-clay suspension;
• - A suspension container / collection container;
• - a pump and tubing set for pumping out the suspension and the corresponding water supply;
• A silo with a fly ash task and possibly an additional silo with a stone dust feeder;
• - a silo with a cement feeder;
• - a paddle mixer;
• A tank for temporarily storing the sealant suspension

The sealant is made in two steps.

In the first step, a base-clay suspension with a density of about 1.18 Mg / m ^{3 is} made. For this purpose, the mud mixer is filled up with a measured amount of water and, while the equipment is working, a measured amount of clay is gradually added. The mixture is continued. From time to time samples are taken for a suspension density measurement. If necessary, water is added during the process to produce a base slurry of planned / desired density.

The process of preparing the base suspension is completed when the achieved density of the solution has stabilized and corresponds to the planned density.

Next, a portion of the base suspension is poured off and discharged through balancing sieves in the collection. Then the entire manufacturing process described is repeated until the required amount of solution has accumulated in the sump. In order to avoid sedimentation of the suspension collected in the container during production of the new portions, it is cyclically pumped through a closed container-pump-container cycle. The preparation of the suspension of the finished sealant takes place in the second phase, just prior to its use in the construction of a water barrier (a hydro-isolation diaphragm).

For this purpose, a measured amount of base suspension is pumped into the mud mixer and a fixed amount of cement is added. The solution is mixed for at least 5-10 minutes, after which, without interrupting the process, gradually added quantities of fly ash with added stone dust are added. Cyclic samples are taken for the density measurement.

In order for the suspension of the sealant to reach the planned density, water may be added. The manufacturing process is terminated when the suspension density of the mixture has stabilized and corresponds to the planned density.

Next, the finished sealant is collected in the second sump, from where it is directed by the pump through the pipe to the construction site of the water barrier.

After the required amount of sealant has been supplied, or after an interruption in the feed process that lasts longer than 15-20 minutes, the pump, tubing, and receiver for the finished sealant are rinsed with water.

Claims (7)

Water-blocking sealant obtained from a sealant suspension comprising: - 3-15% by weight of cement, - 6-65% by weight of fly ash, - 30-60% by weight of stone dust, with fly ash and stone dust having similar granulation, and up to 50% by weight of a clay / water suspension containing polymineral clay, whose granulometric constituency has at least 60% parts <5 μm, whose mineral constituents contain kaolinite, hydrogels and quartz, whose chemical composition is more than 24% by weight and at most 28% by weight of Al ₂ O ₃ and 50-60% by weight of SiO ₂ , having an exchange capacity of 15-30 meq per 100 g of dry clay, and in the clay the main constituent of exchange cations with Ca ^{+ 2} Na ⁺ > K ⁺ > Mg ²⁺ is present. Water-blocking sealant according to claim 1, characterized in that is provided as a cement Portland cement, sulfate resistant Portland cement or cement with a low aluminum content and with alumina. Water-blocking sealant according to claim 1 or 2, characterized in that the water content in the clay suspension is adjusted so that the density of a freshly prepared sealant suspension 1.40 to 1.65 Mg / m ³ and preferably not less than 1.45 Mg / m ³ . Water-blocking sealant according to one of claims 1 to 3, characterized in that it contains at least 5 wt .-% cement, up to 65 wt .-% fly ash and 30-50 wt .-% clay-water suspension having such a water content, the density of the freshly prepared sealant suspension is 1.40-1.65 Mg / m ³ . A process for producing a water-barrier sealant according to any one of claims 1 to 4, comprising the following steps: - a clay-water suspension having a density of 1.18 Mg / m ³ is prepared; The mud-water suspension is pumped into a mud mixer, cement added and mixed for at least 5-10 minutes, and then, without interrupting mixing, incrementally metered quantities of fly ash with added rock dust to provide a sealant suspension added; - samples are taken cyclically for a density measurement and to set a planned density of the sealant suspension; - The sealant suspension is collected in a collection and passed by the pump via a pipe to a construction point of the sealant. A method according to claim 5, characterized in that the sealant suspension of 7 wt .-% Portland cement, 52 wt .-% mixture of Fiugasche and stone dust and 41 wt .-% Tonlehm-water suspension is prepared. Method according to one of claims 5 or 6, characterized in that the loam-water suspension is pumped cyclically through a container-pump-container circuit.