DE102007007421B4 - Mixture usable as aggregate for concrete - Google Patents

Abstract

Substance mixture usable as aggregate for concrete, containing: a) 1-8% xanthan gum b) 1-6% viscous thickener, water-retaining c) 2-10% plasticizer d) 20-50% synthetic resin, cement-compatible e) 0,1-3 % Foaming agent f) 30-70% hardening accelerator g) 0.2-4% preservative whereby the total weight of all components of the mixture must be 100% by weight.

Description

The present invention relates to a mixture of thermosetting building materials, in particular concrete.

In the course of increasing industrialization in many countries of the world and a constantly increasing need for mobility of the people, the road and road construction is becoming increasingly important.

The most common road building material is bitumen. Bitumen has the advantage that it is flexible enough to go with the ground something, so that the roads built with it get no cracks and / or edge projections. In addition, a bitumen coating proves to be extremely resistant to abrasion, so that roads with a bituminous coating last a long time.

The disadvantage of bitumen is its high price and lack of availability of this petroleum derivative in many parts of the world. Additionally, because of its lack of heat resistance, bitumen is a non-road building material in many countries of the southern and eastern hemisphere.

An alternative to bitumen road construction material is the concrete. Concrete is a much cheaper material than bitumen, and the materials needed for a concrete mix cement, water and a filler such as sand are at least more readily available than bitumen in many parts of the world. In addition, concrete does not soften even in extreme sunlight. In order to build concrete roads, the subsoil under a concrete slab must be very strong. Otherwise, concrete slabs either break or settle locally, resulting in edge protrusions that put extreme strain on both the automobile and its driver.

The solidification of the substrate is a very complex process, in which usually the grown substrate must be replaced by a compressible material such as sand.

This problem occurs not only in road construction but more generally in the construction industry that processes concrete.

There has therefore been no lack of attempts to make concrete with additives so flexible that it achieves the flexibility of bitumen as possible.

Out AU 3512193 A For example, a mixture of substances is known which is added to a concrete mixture in order to increase its flexibility and reduce its shrinkage during curing.

The substance mixture consists mainly of two components, of which one component consists predominantly of chloride salts and the other component is an alkali metal silicate (water glass), preferably sodium silicate. The two components are premixed and then added to the concrete mix of cement, water and sand for use in road construction, for example.

This process has the disadvantage that the two components of the mixture already react with each other during premixing and the silicate already solidifies before it comes into contact with the concrete mixture, so that the actual effect of this mixture is limited in the concrete mixture.

In addition, there are still some problems in that water glass is classified as a dangerous substance and therefore may only be processed using gloves, goggles and apron and appropriate security precautions must be taken during its transport.

The DE 196 49 478 A1 describes an aqueous dispersion which can be used as aggregate for concrete mixtures. The concrete mixture described therein is preferably prepared by mixing cement, filler and optionally water with each other and then adding the dispersion according to the invention. Any other order of mixing the components is also possible. Basically, this dispersion is very advantageous because it is harmless to the environment and harmless to humans, increases the flexibility of the concrete and reduces the shrinkage of the concrete mix on curing. The disadvantage, however, is that a dispersion has a relatively high mass due to the water content and thus leads to high transport costs. Furthermore, the described therein Product not for admixture in cement, as this would only be possible if it were also a dry, powdery material.

It was therefore the task of finding a safe, environmentally friendly mixture of substances, which increases the flexibility of the concrete and reduces the shrinkage of the concrete mixture during curing. The mixture should continue to be suitable as a cement additive or as a mixture for other binders. The composition should have the best possible transport capabilities and it should allow the fillers are used in the concrete mix, which were previously considered cement poisons.

• a) 1–8% Xanthan Gum
• b) 1–6% scheinviskose Verdicker, wasserhaltend
• c) 2–10% Verflüssiger
• d) 20–50% Kunstharz, zementverträglich
• e) 0,1–3% Schaumbildner
• f) 30–70% Erhärtungs-Beschleuniger
• g) 0,2–4% Konservierungsmittel

wobei das Gesamtgewicht aus allen Komponenten des Stoffgemischs 100 Gew.-% ergeben muss.The object is achieved according to the invention by the provision of a substance mixture which contains:

• a) 1-8% xanthan gum
• b) 1-6% viscous thickener, hydrous
• c) 2-10% liquefier
• d) 20-50% synthetic resin, cement compatible
• e) 0.1-3% foaming agent
• f) 30-70% hardening accelerator
• g) 0.2-4% preservative

wherein the total weight of all components of the mixture must be 100 wt .-%.

• a) 1–8%, vorzugsweise 4% Xanthan Gum
• b) 1–6%, vorzugsweise 3% scheinviskose Verdicker, wasserhaltend
• c) 2–10%, vorzugsweise 5% Verflüssiger
• d) 20–50%, vorzugsweise 35% Kunstharz, zementverträglich
• e) 0,1–3%, vorzugsweise 1% Schaumbildner
• f) 30–70%, vorzugsweise 50% Erhärtungs-Beschleuniger
• g) 0,2–4%, vorzugsweise 2% Konservierungsmittel

wobei das Gesamtgewicht aus allen Komponenten wiederum 100 Gew.-% ergeben muss. Diese Mischung wird als Pulver trocken gemischt.The following specific composition has proven to be extremely favorable:

• a) 1-8%, preferably 4% xanthan gum
• b) 1-6%, preferably 3%, viscous thickener, water-retaining
• c) 2-10%, preferably 5% liquefier
• d) 20-50%, preferably 35% synthetic resin, cement compatible
• e) 0.1-3%, preferably 1% foaming agent
• f) 30-70%, preferably 50% hardening accelerator
• g) 0.2-4%, preferably 2% preservative

the total weight of all components must again be 100% by weight. This mixture is dry mixed as a powder.

As a viscous thickener, the water-containing locust bean gum has proved favorable. Xanthan Gum and locust bean gum have synergistic effects, as they both have a viscous effect on the concrete to be mixed with the excipient. However, together with the plasticizer, preferably polycarboxylic ether (as a powder), the concrete mix is very thin and free-flowing. Xanthan Gum and locust bean gum can also be replaced with methylcellulose.

Furthermore, the cement-compatible resin is also added as a powder (dispersion powder). Hostapur OSB ^{® has} proven to be suitable as a foaming agent because it forms micro-pores. As hardening accelerator it is possible to use all suitable accelerators, preferably calcium formate or calcium chloride. However, alumina-enamel cement can also be used as a hardening accelerator since this also leads to an exothermic reaction which accelerates the normal cement in the setting. Thor ^® preservative is particularly useful as a preservative.

Preference may additionally be given as synthetic latex ^® a polystyrene-butadiene copolymer latex, as alkaline earth metal formate calcium formate and as a preservative 2-n-octyl-4-isothiazolinone-3-ones, dissolved in propylene glycol.

• a. 0,01–0,5 kg, vorzugsweise 0,05–0,1 kg des erfindungsgemäßen Stoffgemischs pro kg Zement,
• b. Zement,
• c. Füllstoff
• d. gegebenenfalls Wasser,

wobei die Betonmischungskomponenten in üblichen Mengen eingesetzt werden.Another object of the invention is a concrete mixture containing:

• a. 0.01-0.5 kg, preferably 0.05-0.1 kg of the mixture according to the invention per kg of cement,
• b. Cement,
• c. filler
• d. optionally water,

wherein the concrete mixture components are used in conventional amounts.

The concrete mixture according to the invention is preferably prepared by mixing the cement, the filler and optionally the water with each other and then adding the substance mixture according to the invention. Any other order of mixing the components is also possible.

The concrete mixture according to the invention is viscous, so it is stable viscous and not flowable, as long as no kinetic energy is added. However, when the concrete mixture is pumped or shaken into a formwork, it becomes increasingly flowable and thus does not form any holes that reduce the flexural and compressive strength or cause optical disadvantages.

The concrete of the invention has a very good water retention capacity, what dazuführt that the concrete reaches optimum hardness even in hot and very dry conditions.

Furthermore, it is advantageous that xanthan gum and locust bean gum prevent the formation of water ice crystals down to -200 ° C, so that the concrete can be processed even at minus temperatures. Even at very low temperatures, the concrete remains physically stable, does not shrink and does not become brittle or brittle.

As a filler almost any material can be used that is available in the field of construction site or field of application. In particular, gravel, soil, sand or broken asphalt are suitable. The concrete mixture according to the invention is mixed on site, after addition of water, the mixture is straightened and compacted with so-called Vibprowalzen. After a very short curing time, a wear layer of asphalt can then be applied as needed, but it can also be dispensed with, for example for farm roads.

Xanthan Gum and locust bean gum can also be replaced with methylcellulose.

Another object of the invention is the production of building materials, preferably plates or stones, from the concrete mixture according to the invention.

The concrete mixture according to the invention can be used for any type of concrete construction, preferably for road, road construction and mounting, so that a further subject of the invention, this use and the corresponding concrete structures, preferably road, ways, and other mounting pads or structures ,

• – einer Betonmischung muss nur ein Hilfsstoff zugegeben werden, der nicht vorgemischt werden muss, um den Beton flexibler zu machen den Schwund beim Aushärten zu reduzieren. Dadurch reduzieren sich Fracht- und Lagerkosten. Das erfindungsgemäße Stoffgemisch ist nicht als gefährlicher Stoff klassifiziert, so dass es ohne Schutzmaßnahmen verarbeitet werden kann.
• – das erfindungsgemäße Stoffgemisch ist unbedenklich für die Umwelt,
• – eine erfindungsgemäße Betonmischung härtet sehr schnell aus,
• – mit dem erfindungsgemäßen Stoffgemisch ist es möglich, eine Betonmischung mit Füllstoffen herzustellen, die bisher als Zementgifte galten,
• – als Füllstoff in der Betonmischung können die üblichen Sande, darüber hinaus aber auch jede Art von Boden, kontaminiert oder unkontaminiert, und/oder Materialien wie Bauxit, Laterit, Vulkanasche, Bims und Asche aus Verbrennungsanlagen eingesetzt werden,
• – mit der erfindungsgemäßen Betonmischung können Baumaterialien und Betonbauteilen jeglicher Art, vorzugsweise Straßen- und Wegebeläge hergestellt werden, indem der Aushub der Baustelle und/oder sand- oder bodenartige Materialien, die im Baustellenbereich verfügbar sind, an Stelle der üblichen Füllstoffe als Füllstoff in der Betonmischung verwendet werden.

The following advantages can be achieved with the substance mixture according to the invention:

• - Only one adjuvant must be added to a concrete mixture, which need not be premixed to make the concrete more flexible in reducing shrinkage during curing. This reduces freight and storage costs. The substance mixture according to the invention is not classified as a hazardous substance, so that it can be processed without protective measures.
• The substance mixture according to the invention is harmless to the environment,
• A concrete mixture according to the invention cures very quickly,
• With the mixture of substances according to the invention it is possible to produce a concrete mixture with fillers which were previously considered cement poisons,
• - as a filler in the concrete mixture, the usual sands, but also any kind of soil, contaminated or uncontaminated, and / or materials such as bauxite, laterite, volcanic ash, pumice and ash from incinerators can be used,
• - With the concrete mixture according to the invention, building materials and concrete components of any kind, preferably road and pavement can be prepared by the excavation of the site and / or sand or soil-like materials that are available in construction sites, instead of the usual fillers as a filler in the concrete mixture be used.

Examples

example 1

In order to check the extent to which the mechanical properties, in particular the elasticity and the shrinkage behavior of a concrete have been changed by the substance mixture according to the invention and to what extent the shrinkage of the concrete mixture could be reduced, an experiment was carried out with and without mixed substance addition.

• – 20 kg Zement,
• – 100 Liter Sand und
• – 5 Liter Wasser.

First, a concrete mixture was prepared, composed as follows:

• - 20 kg of cement,
• - 100 liters of sand and
• - 5 liters of water.

Thereafter, this concrete mixture was divided in the ratio 1: 1 and filled into two separate vats.

One concrete mixture was left as it was while the other concrete mixture was mixed with 0.1 liter of the composition of the invention, composed as follows: 4% Xanthan gum 3% viscous thickener, water-retaining 5% condenser 35% Resin, cement compatible 1% foaming agents 50% Erhärtungs accelerator 2% preservative

Subsequently, the concrete mixture according to the invention and the conventional concrete mixture were respectively poured into wooden molds measuring 50 × 20 × 1 cm (length, width, depth) in which the concrete mixture was cured in each case. Each 10 plates were made.

A visual assessment of the concrete slabs showed that the concrete slabs according to the invention had less faded than the conventional concrete slabs.

Thereafter, 10 concrete slabs were firmly clamped in one testing machine on one broad side and on the other broad side, 45 cm away from the clamping point, loaded with a hydraulic ram so long until they broke. During this experiment, the deformation of the concrete slab was measured optically.

It was found that the concrete slabs according to the invention averaged 2.5 times greater deformability before breakage.

Example 2

As already mentioned above, it is possible with the mixture of substances according to the invention to use substances as filler in concrete mixtures which were previously considered to be cement poisons. To illustrate this, three concrete mixes were produced, each containing 20 kg of cement and 5 liters of water. As a filler mixture contained mixture 1 100 liters of commercial construction sand, mixture 2 100 liters of topsoil from a construction site and mix 3 100 liters of ash from an incinerator.

The concrete mixtures were each intimately premixed in a concrete mixer and then each mixed in a vat with 0.1 liter of the mixture according to Example 1 and poured into the molds described in Example 1 into plates in which cured the concrete mixtures.

A visual assessment of every 10 of the concrete slabs showed that the shrinkage of the concrete mixtures during curing was low in all cases.

Thereafter, the panels were subjected to a variety of mechanical test methods such as compressive strength, ductility and surface hardness, whereby it was found that the mechanical properties of all concrete slabs were comparably good.

Claims (8)

Mixture usable as aggregate for concrete, containing: a) 1-8% xanthan gum b) 1-6% viscous thickener, hydrous c) 2-10% liquefier d) 20-50% synthetic resin, cement compatible e) 0.1-3% foaming agent f) 30-70% hardening accelerator g) 0.2-4% preservative wherein the total weight of all components of the mixture must be 100 wt .-%. Substance mixture according to claim 1, comprising a) 4% xanthan gum b) 3% viscous thickener, water-retaining c) 5% liquefier d) 35% synthetic resin, cement-compatible e) 1% foaming agent f) 50% hardening accelerator g) 2% preservative the total weight of all components must be 100% by weight. This mixture is dry mixed as a powder. A composition according to claim 1 or claim 2, characterized in that further a polystyrene-butadiene latex, and used as a preservative 2-n-octyl-4-isothiazolinone-3-one dissolved in propylene glycol. Mixture of substances according to one of claims 1 to 3, characterized in that is used as the plasticizer polycarboxylic. Mixture of substances according to one of claims 1 to 4, characterized in that locust bean gum is used as thickener. Mixture of substances according to one of claims 1 to 5, characterized in that hardening accelerator from the group calcium formate, calcium chloride or alumina melt cement is used. Use of the substance mixture according to one of claims 1 to 6 in a concrete mixture, including a. 0.01-0.5 kg, preferably 0.05-0.1 kg of the mixture according to the invention according to one of claims 1 to 6 per kg of cement, b. Cement, c. filler Use according to claim 7, characterized in that as filler any kind of sand, any kind of soil, contaminated or uncontaminated, and / or materials such as bauxite, latent, volcanic ash, pumice and ash from incinerators can be used.