EP3145891A1

EP3145891A1 - Accelerator for hydraulic binding agents with long processing time and very high early strength

Info

Publication number: EP3145891A1
Application number: EP15724985.5A
Authority: EP
Inventors: Emmanuel GALLUCCI; Patrick JUILLAND; Arnd Eberhardt; Lukas Frunz; Christian BÜRGE
Original assignee: Sika Technology AG
Current assignee: Sika Technology AG
Priority date: 2014-05-21
Filing date: 2015-05-20
Publication date: 2017-03-29
Also published as: US9919967B2; WO2015177232A1; US20170073267A1

Abstract

The present invention relates to an accelerator for hydraulic binding agents, comprising at least one phosphoric acid ester of a multivalent alcohol and at least one calcium compound. The accelerator according to the invention is capable of producing a very fast-curing mortar or concrete composition which has a high early strength and, nevertheless, very favourable processing properties and thus allows early dismantling or early loading and does not cause any losses in the final strength.

Description

ACCELERATOR FOR HYDRAULIC BINDER WITH LONG PROCESSING TIME AND VERY HIGH EASY TO FAST

Technical area

The invention relates to additives for hydraulic binders and systems made therefrom, such as concrete and mortar. In particular, the

The present invention relates to an accelerator for hydraulic binders comprising at least one phosphoric acid ester of a polyvalent one

Alcohol and at least one calcium compound. In addition, the concerns

Invention the use of a composition comprising at least one or consisting of at least one inventive

Accelerator for accelerating the setting and / or hardening of hydraulic binders and mortar or concrete made therefrom, in particular quick-setting cement, and a method for accelerating the setting and hardening of hydraulic binders and mortar or concrete made therefrom.

State of the art

In the manufacture of precast concrete or reinforced concrete elements or in roadway or runway repair, high early strength is required in many applications, so that the finished parts can be removed from the building after just a few hours

Formwork can be taken out, transported, stacked or prestressed or the roads or slopes can be driven or loaded. In order to achieve this objective in practice, in addition to efficient concrete recipes, with e.g. low w / c values or high cement contents, often also used for heat or steam treatments. These treatments require a lot of energy and additional equipment, so because of rising energy prices, significant investment costs and durability as well as exposed concrete problems

is increasingly ignoring this treatment and is looking for other ways to speed up the hardening process. As an alternative to heat or steam treatment also come

various additives, but these do not always give satisfactory results. Although many substances are known which accelerate the setting and hardening of concrete. Commonly used are, for example, strongly alkaline substances such as alkali metal hydroxides,

Alkali carbonates, alkali silicates, alkali aluminates and alkaline earth chlorides. However, these substances partially reduce the ultimate strength and the

Durability of the concrete.

From EP 0076927 B1 and EP 0946451 B1 alkali-free solidification accelerators for hydraulic binders are known which are intended to avoid these disadvantages. To accelerate the solidification and hardening of hydraulic binders such as cement, lime, hydraulic lime and gypsum and mortar and concrete made therefrom, an alkali-free solidification and hardening accelerator is added, this accelerator containing aluminum hydroxide and optionally aluminum salts and organic carboxylic acids.

Although such known accelerators accelerate the setting and hardening of hydraulically setting systems, they are expensive, their application is limited due to lack of durability and

insufficient effectiveness and at the same time reduce

Processing time and have a negative impact on the final strength of the concrete. Other disadvantages of such setting and hardening accelerators are also a relatively low early strength in the first few hours and days and the insufficient stability of the solution. The currently known systems in which the hydration of a concrete is accelerated by the addition of a setting accelerator, relate mostly to the shotcrete. The well-known methods for

Hydration control have the disadvantage that the cement mixtures after Tighten the accelerator very quickly. This is usually also desirable when used as shotcrete. However, such known systems are not suitable if the cement mixture has to be further processed after activation or if the processed concrete has to be loaded after a short time. In the known systems for the

Shotcrete application is not given further processability after activation.

A further development of such accelerators is taught in EP 21281 10 A1. That system uses esters of polyhydric alcohols as

Admixtures that allow a high early strength, but without

Processing time or the final strength too negative influence. However, ever higher demands on short production cycles of concrete moldings or as fast as possible loading of substrates make even this development for some applications still insufficient.

Therefore, depending on the application, there continues to be a need to develop a cost-attractive additive which significantly accelerates the setting and hardening process of compositions with hydraulic binders, and with which a fast-setting mortar or concrete composition can be produced which has high early strength and nevertheless has very favorable processing properties and thus allows early stripping or early loading and as possible causes no losses in the final strength.

Presentation of the invention

It is therefore an object of the present invention to provide a setting and / or hardening accelerator, for example a form of admixture,

which, on the one hand, increases the early strength by accelerating the reactions in the cement or concrete mixture but, on the other hand, does not significantly impair processability and thus further processability of the accelerated mixture over a certain period of time allows. Compared to conventional accelerators, the

present invention provide better results and / or have fewer disadvantages. According to the invention, this is achieved by the features of the first claim.

The advantages of the invention can be seen, inter alia, in that an accelerated by the present invention hydraulically setting

Composition, such as a cement, concrete or mortar mixture, despite high early strength remains long processable. Compared to non-activated concrete accelerator according to the invention causes massively increased early strengths, which allows early stripping or loading of the manufactured parts. At the same time, however, the processability of the accelerated mixture is maintained over a long period of time.

Further aspects of the invention are the subject of further independent claims. Particularly preferred embodiments of the invention are the subject of the dependent claims. Ways to carry out the invention

The setting and / or hardening accelerator for hydraulic binders according to the invention comprises at least one phosphoric acid ester of a polyhydric alcohol and at least one calcium compound.

By the term "polyhydric alcohol" is a hydroxy-functional

Compound having more than one hydroxyl group understood, for example, with two, three, four or five hydroxyl groups. Particularly preferred is an alcohol having three hydroxyl groups, that is, a trihydric alcohol. Suitable alcohols are, for example, polyhydric alkyl alcohols such as propanediol, butanediol, glycerol, diglycerol, polyglycerol, trimethylolethane,

Trimethylolpropane, 1, 3,5-pentanetriol, erythritol, pentaerythritol, dipentanerythritol, Sorbitol, sorbitan, glucose, fructose, sorbose or isosorbide. Particularly preferred is glycerin.

The above-mentioned ester is obtained by esterification from a polyhydric alcohol with phosphoric acid or its salts. Preferably, the ester is a partial ester or partial ester of a polyhydric alcohol, preferably a trihydric alcohol. By the term "partial or partial ester of a polyhydric alcohol" it is meant that the polyhydric alcohol has one or more free hydroxyl groups besides one or more ester bonds, the ester may be a mono, di-di triester, preferably a monoester, preferably a monoester Monoesters of a dihydric or trihydric alcohol, more preferably one

trihydric alcohol, more preferably glycerol. The phosphoric acid for the preparation of the ester can be present as free acid or else as salt or partial salt, where the term "salt" here and below refers to the product of a neutralization reaction of the phosphoric acid with a base and of the phosphates which form on drying. means that not all acid functions of the phosphoric acid have been neutralized.

Preferably, the remaining free acid groups of the

Phosphorsäureesters completely or partially neutralized, wherein the salt is a metal, alkali or alkaline earth metal salt, that is a salt of monovalent or polyvalent cations, preferably a sodium, potassium, calcium, magnesium, zinc or aluminum salt, preferably a sodium or Aluminum salt, is. In a basic, aqueous medium, the free acid groups

Of course, also deprotonated in anionic form. The calcium compound is preferably an inorganic and / or organic salt, for example with the anions oxide, hydroxide, sulphate, sulphide, carbonate, bicarbonate, chloride, fluoride, bromide, iodide, carbide, nitrate, nitrite, bromate, iodate, phosphate, phosphite, Lactate, acetate, gluconate, Stearate, citrate, propionate and / or mixtures thereof and / or hydrates of these salts. Particularly preferred are calcium oxide and calcium hydroxide, and / or the hydrates thereof, in particular calcium oxide. Very particular preference is given to calcium compounds which have a high specific surface area as solids, for example as powders. In the present case, this means a preferred specific surface area, measured by the BET method (N ₂ adsorption, measured according to DIN ISO 9277), of between 1 and 50 m ² / g calcium compound, preferably between 1 .5 and 30 m ² / g , in particular between 1 .9 and 10 m ² / g calcium compound.

Suitable phosphoric acid esters for the setting and / or hardening accelerators according to the invention are, for example, glycerol phosphates. Glycerol monophosphate is preferred, glycerol-2-phosphate or glycerol-3-phosphate being particularly preferred, and / or hydrates thereof.

The setting and hardening accelerator according to the invention is used in various fields, in particular in concrete and cement technology. The accelerator has very good

Properties as accelerator for hydraulically setting

Compositions, that is, to accelerate the setting and / or hardening of hydraulic binders, in particular of

Quick cement, as well as mortar or concrete made therefrom can be used. In addition, mortar or concrete can be produced with the accelerator according to the invention, which has a high early and final strength. The setting and / or hardening accelerator according to the invention is therefore particularly suitable when the hydraulically setting

Composition very quickly after application must be resilient or walkable, for example, in road or bridge construction, in the prefabrication of concrete elements in concrete and reinforced concrete precast elements or in runway renovations, especially at runways, so that the finished parts already de-energized after a few hours, transported, stacked or can be biased or the roads or slopes can be traveled.

Surprisingly, the inventive setting and

Hardening accelerator proved to be a particularly fast accelerator compared to conventional accelerators. In addition, the

accelerators according to the invention neither a significantly negative impact on the processing time, nor on the ultimate strength of the mortar or concrete produced therewith. The compressive strength of the invention

accelerated concrete is even higher after a few hours than in all known comparable systems.

As hydraulic binders or compositions, basically all hydraulically setting substances known to the concrete expert can be used. In particular, these are hydraulic

Binders such as cements, such as Portland cements or

Tonerdemmelzzemente and their mixtures with, for example, fly ash, silica fume, slag, blast furnace slags and Kaif kiernf. Further hydraulically setting substances in the context of the present invention are burnt lime or calcined paper sludge from papermaking residues. Cement is preferred as the hydraulic binder. Furthermore, additives such as sand, gravel, stones, quartz, crayon and as additives usual ingredients such as

Concrete plasticizers, such as lignosulfonates, sulfonated naphthalene-formaldehyde condensates, sulfonated melamine-formaldehyde condensates or polycarboxylate ethers, other accelerators, corrosion inhibitors, retarders, Schwindreduzierer, defoamers or pore formers possible.

The accelerator according to the invention can be used according to the invention

Use both in liquid and in solid form, both alone or as part of an additive. The invention therefore additionally relates to an additive in liquid or solid form comprising at least one accelerator according to the invention. Furthermore, the two essential components of the invention, the phosphoric acid ester of a polyhydric alcohol and the calcium compound, for the technical effect of the invention are not added at the same time, but can be added in temporally and spatially separate process steps of the mixture to be accelerated or already present.

In an advantageous embodiment of the inventive

Accelerator premixed, preferably without hydraulic binder.

In order to improve the processability and to extend the processing time after addition of the inventive accelerator to a hydraulic binder, the additive preferably contains a condenser in addition to the accelerator. As a condenser, for example

Lignosulfonate, sulfonated naphthalene-formaldehyde condensates, sulfonated melamine-formaldehyde condensates, sulfonated vinyl copolymers or

Polycarboxylatverflüssiger, as are known for example in concrete chemistry as Hochleistungsverflüssiger, or mixtures thereof, in question. Particular preference is given to polycarboxylate liquefiers, as described, for example, in EP 0056627 B1, EP 0840712 B1, EP 1 136508 A1, EP 1 138697 B1 or EP 1348729 A1. Particular preference is given to liquefiers which have been prepared after the polymer-analogous reaction, as described, for example, in EP 1 138697 B1 or EP 1348729 A1.

The accelerator or additive containing the accelerator may also contain other ingredients. Examples of other ingredients are solvents, especially water, or additives, such as others

accelerating substances such as thiocyanates, nitrates or aluminum salts, acids or their salts or amine-containing substances such as alkanolamines, retarders, shrinkage reducers, defoamers or

Foaming agent. If the accelerator according to the invention or the additive containing the accelerator is used in liquid form, is for the

Implementation preferably a solvent used. preferred

Solvents are, for example, hexane, toluene, xylene, methylcyclohexane, Cyclohexane or dioxane and alcohols, especially ethanol or

Isopropanol, and water, with water being the most preferred

Solvent is. The accelerator according to the invention or the additive containing the accelerator can also be present in a solid state of matter,

For example, as a powder, flakes, pellets, granules or plates and can be easily transported and stored in this form.

The inventive accelerator can, for example, in the solid

Physical state present and with a condenser, which is also present in the solid state, are mixed and stored or transported for a long time. The inventive accelerator can also be mixed with a liquid condenser and used as a liquid additive. The liquid additive may also subsequently be returned to the solid state, for example in powder form, e.g. by spray drying, with the aid of protective colloids or other drying auxiliaries.

The accelerator according to the invention or the additive containing the accelerator in the solid state of aggregation may also be part of a cement composition, a so-called dry mixture, which is storable for a long time and is typically packed in sacks or stored in silos and used. The accelerator according to the invention or the additive containing the accelerator can also be added to a customary concrete composition with or shortly before or shortly after the addition of the water. Has shown to be particularly suitable in this case the addition of

Accelerator according to the invention in the form of an aqueous solution or dispersion, in particular as mixing water or as part of the

Anmachwassers or as part of a liquid additive, which is added with the mixing water to the hydraulic binder. The accelerator or additive according to the invention can also be sprayed in liquid form before or after the grinding of the hydraulic or latently hydraulic binder onto the binder, the concrete, mortar, and non-hydraulic additives. For example, the hydraulic binder can partially with the accelerator or the

Admixture containing the accelerator can be coated. This allows the production of a hydraulic binder, in particular cement or latent hydraulic slag, which already contains the accelerator or the additive containing the accelerator and so as

Ready mix, for example, as so-called quick cement, can be stored and sold. After addition of the mixing water, this cement has the desired properties of fast setting and high early strength, without the need to add another additive in addition to the mixing water at the construction site.

In a further aspect, the present invention relates to a binder-containing mixture comprising at least one hydraulically setting binder and at least one inventive setting and

Hardening accelerator. Suitable binders are, for example, cement, in particular Portland cements or high-alumina cements and mixtures thereof with fly ash, silica fume, slag, blast furnace slag, gypsum and limestone filament or calcined lime, a latently hydraulic powder or inert microscopic powder. Containing as a binder

Mixtures are preferably concrete compositions in question.

Furthermore, the mixture can further additives such as sand, gravel, stones, quartz powder, crayons and additives such as conventional ingredients

Betonverfüssiger, for example, lignosulfonates, sulfonated naphthalene-formaldehyde condensates, sulfonated melamine-formaldehyde condensates or polycarboxylate (PCE), accelerators, corrosion inhibitors, retarders, Schwindreduzierer, defoamers or foaming agents included. Preferably, the binder-containing mixture contains in addition to the accelerator at least one condenser, preferably a polycarboxylate ether-based condenser (PCE). The accelerator of the present invention is preferably used in an amount of 0.001 to 2% by weight of phosphoric acid ester based on the weight of the binder and 0.001 to 10% by weight of calcium based on the weight of the binder to achieve the desired effect. Several accelerators can also be used mixed to achieve the desired effect.

In a preferred embodiment, the calcium compound is as

Solid used. It is advantageous, as described above, to use a solid having a high specific surface area. A high specific surface leads to an improvement of the accelerator effect. In order to achieve the same accelerating effect, less of a calcium compound having a high specific surface area can be used proportionally as compared with a calcium compound having a small specific surface area. It is therefore preferable for the present invention to meter the calcium compound such that a ratio of the total surface area of the

Calcium compound to the amount of hydraulic binder of about 50 to 70 m ² / kg of binder, preferably about 55 to 65 m ² / kg of binder, more preferably about 57 to 63 m ² / kg of binder results. The

Total surface of the calcium compound refers to this

mathematical product of the specific surface area (in m ² / g, according to BET (N ₂ adsorption, measured according to DIN ISO 9277)) and the amount used (in grams per kg of hydraulic binder).

The amount of the phosphoric acid ester to the amount of the calcium compound is preferably adjusted in this embodiment, that 0.001 to 0.05, preferably 0.005 to 0.04, particularly preferably 0.008 to 0.02 g

Phosphoric acid ester per m ² calcium compound can be used. In a further aspect, the present invention relates to a process for the preparation of a binder-containing mixture wherein the at least one accelerator according to the invention is added separately or premixed as admixture in solid or liquid form to the binder.

In another aspect, the present invention relates to a process for accelerating the setting and hardening of hydraulic binders and mortar or concrete made therefrom, wherein a mixture containing hydraulic binders, a setting and hardening accelerator according to the invention in an amount of phosphoric acid ester from 0.001 to 10 Wt .-%, preferably 0.01 to 1 wt .-%, particularly preferably 0.01 to 0.1 wt .-%, based on the weight of the cement and an amount of calcium from 0.001 to 10 wt .-%, preferably 0.01 to 1 wt. -%, particularly preferably 0.01 to 0.1 wt .-%, based on the weight of the cement added. If an additive containing the

according to the invention accelerator and preferably additionally added at least one condenser to a hydraulic binder, the added amount of the total additive 0.01 to 10 wt .-%, preferably 0.1 to 10 wt .-%, more preferably 1 to 5 wt .-%, based on the weight of the hydraulic binder.

With the present invention is an additive for hydraulic

Binder provided, which accelerates the setting and hardening process of the hydraulic binder without adversely affecting the

Processing times, the strength development or the durability of the mortar or concrete compositions produced therewith. The additive according to the invention and in particular the setting and hardening accelerator according to the invention is thus particularly suitable if the hydraulically setting composition has to be loadable or passable again very quickly after application, for example in road construction or bridge construction, in the prefabrication of concrete elements in precast concrete and reinforced concrete components or at runway renovations, especially at

Airstrips. This allows the finished parts already after a few hours be disassembled, transported, stacked or prestressed or the

Roads or slopes are driven.

Surprisingly, the inventive setting and

Accelerator according to the invention has neither a negative influence on the processing time nor on the final strength of the mortar or concrete produced therewith. The early strength after a few hours has proved to be significantly higher than in all comparable systems.

Examples

All percentages are, unless otherwise stated,

Weight percent (wt.%) Based on the weight of

Total composition.

1 . Liquid additives

1 .1. Preparation of the additives

Additive Z1

There were 5.0 g of a glycerol-2-monophosphate (glycerol phosphate disodium salt pentahydrate, available for example from Sigma Aldrich

Switzerland) in 160.0 g of a liquid polycarboxylate ether condenser (Sika® Viscocrete® 20 HE, available from Sika Schweiz AG). From this solution, between 1 and 1 .6 wt .-%, based on the cement, was added together with the mixing water to the mortar mixture.

Additive Z2

As a reference without accelerator according to the invention, the polycarboxylate ether condenser used for Z1 (Sika® Viscocrete® 20 U, available from Sika Schweiz AG) was used as additive. Of this between 1 and 1 .6 wt .-%, based on the cement, was added together with the mixing water to the mortar mixture.

Additive Z3

As another reference without accelerator according to the invention, another polycarboxylate ether condenser (Glenium® ACE30, available from BASF Admixtures Deutschland GmbH) was used as additive. Of this, between 1 and 1 .6 wt .-%, based on the cement, together with the mixing water added to the mortar mixture.

1 .2. Preparation of the Example Mortar Blends with Liquid Additives The cement used for the mortar blends MM1 and MM2 was a Portland CEM I 52.5R rapid cement.

The sand used (large grain 8 mm), the cement and in the case of MM2 also 3 wt .-% (based on the weight of the cement used)

Calcium oxide (Nekafin ^® 2 Netstal of Kalkfabrik AG, Switzerland, with a specific surface area (BET) of 1 .9 m ² / g) were dry blended in a Hobart mixer for 1 minute. Within 30 seconds, the mixing water in which the respective additive was dissolved was added and mixing was continued for 2.5 minutes. The

Total mixing time wet was 3 minutes. The proportionally adjusted water / cement value (w / c value) of the mortar was 0.4 in all mixtures.

1 .3. Mortar tests with liquid additives

To illustrate the effectiveness of the accelerator or additive according to the invention, the additives Z1, Z2 and Z3 were added to the mortar mixtures MM1 and MM2 (see Tables 1 and 2). Example B1 with additive Z1 represents an example according to the invention, while examples C2 to V6 represent comparative examples.

To determine the effectiveness of the accelerator or additive according to the invention, on the one hand the slump (ABM) (Table 1) and on the other hand the compressive strength (Table 2) were determined. No. Additive Mortar Mixture ABM to ABM to ABM to ABM to (% by weight) 0 min 20 min 40 min 60 min

B1 Z1 (1.38 weight-MM2 (with 3 215 205 151 1 1 1

% bez. Cement)% by weight of CaO

bez. Cement)

V2 Z2 (1.09 weight-MM2 (with 3 21 1 197 136 1 1 1

% bez. Cement)% by weight of CaO

bez. Cement)

V3 Z3 (1.10 weight MM2 (with 3 197 187 153 131

% bez. Cement)% by weight of CaO

bez. Cement)

V4 Z1 (1.60 parts by weight MM1 250 247 251 213

% bez. Cement)

V5 Z2 (1.60 weight MM1 263 245 237 231

% bez. Cement)

V6 Z3 (1.60 weight MM1 257 235 213 210

% bez. Cement)

Table 1: Slump size (in mm) after 0, 20, 40, and 60 minutes (min).

The spreading dimension (ABM) of the mortar was determined according to EN 1015-3.

The values shown in Table 1 show that the processability of the mortar mixed with the accelerator according to the invention remains largely unchanged in comparison to other or non-accelerated compositions. For the rapid production of prefabricated parts, as well as for road or piste construction, above all the values of the ABM after 20 min are important. An ABM value of over 200 mm after 20 minutes proves a very good workability during the time normally required for rapid-weight concrete applications. However, for an application in road or bridge construction or for the manufacture of prefabricated concrete elements, which have to be decoupled, transported, stacked or prestressed within a few hours, or for slope remediation, high early strength values (for example Compressive strength after 4 or 6 hours) even more important than that

Slump.

Table 2 shows compressive strength values (in N / mm ² ) of the inventive accelerated mortar composition B1, and the

Comparative Example Compositions V2 to V6 after 4 hours and 6 hours, measured with a needle penetrometer (Mecmesin BFG500 on prisms (40 x 40 x 160 mm) according to standard EN 196-1.

Table 2: Compressive strengths in N / mm after 4 and 6 hours (h).

Table 2 clearly shows the effect of the accelerator according to the invention in Example B1. In comparison with conventional accelerators (V2, V3 or V4), when the accelerator according to the invention is used, practically doubling occurs after 6 h, after 4 h almost a tripling of the strength values. The difference to the non-accelerated

Compositions (V5 and V6) are expected to be even greater.

Furthermore, it is found that the effect of the accelerator according to the invention, containing a phosphoric acid ester of a polyhydric alcohol and a calcium compound, is not merely a linear combination of the effects of the individually already accelerating components

Phosphoric acid ester (V4) or calcium compound (V2 and V3). In particular after 4 h, the compressive strength of the composition (B1) accelerated according to the invention is significantly higher than that of the individual accelerated compositions even despite the fact that the phosphoric acid ester is less concentrated in B1 than in V4. So there is a clear, surprising synergy effect to watch. 2. Individually added additives

2.1. Used substances

In all example mortar mixtures MM3, MM4, MM5, MM1 1, MM12, MM13 and MM14, a conventional Portland cement CEM I 52.5R was used. For the mixtures MM6 to MM9 a CEM IV / B cement fly ash mixture (50% by weight Portland cement CEM I 42.5R + 50% by weight siliceous fly ash) was used. The aggregate used in all sample mortar mixtures MM3-MM5 was conventional sand (maximum grain size 8 mm). For mixtures MM6 to MM14, a finer sand with a grain size of 2 mm was used. The condenser used was in all examples MM3-MM14 a product based on polycarboxylate (PCE) (Sika ^® Viscocrete ^® 20 HE, available from Sika Switzerland AG). The

Mortar mixtures MM3, MM4, MM7, MM8, MM9, MM1 1, MM12, MM13 and MM14 additionally contained calcium oxide (CaO), available under the

Trade names Nekafin ^® 2 of lime factory Netstal AG, Switzerland).

Mortar mixtures MM3, MM8, MM9, MM1 1, MM12, MM13 and MM14 additionally contained glycerol-2-monophosphate (glycerol phosphate

Disodium salt (GPD) pentahydrate, available for example from Sigma Aldrich Switzerland). The proportions of the additive GPD, CaO and PCE in weight percent based on the weight of the hydraulic binder used in the respective mixture MM3-MM9 are listed in Table 3. No mortar mix GPD (%) CaO (%) PCE (%)

B7 MM3 (according to the invention) 0.15 3 0.9

V8 MM4 (Reference) - 3 0.6

V9 MM5 (Reference) - - 0.5

V10 MM6 (Reference) - - 0.6

V1 1 MM7 (Reference) - 3 0.6

B12 MM8 (according to the invention) 0.04 3 0.6

B13 MM9 (according to the invention) 0.075 3 0.6

B14 MM11 (according to the invention) 0.05 3 0.5

B15 MM12 (according to the invention) 0.1 3 0.5

B16 MM13 (according to the invention) 0.15 3 0.5

B17 MM14 (according to the invention) 0.2 3 0.5

Table 3: Example mortar mixtures containing GPD (glycerol-2-monophosphate

Disodium salt pentahydrate), CaO (calcium oxide) and PCE (polycarboxylate ether condenser). The percentages are by weight based on the weight of the hydraulic binder used.

2.2. Preparation of example mortar mixtures

Hydraulic binder, sand and (in the case of MM3, MM4, MM7, MM8, MM9, MM1 1, MM12, MM13 and MM14) calcium oxide and (in the case of MM3, MM8, MM9, MM1 1, MM12, MM13 and MM14) GPD were dry blended in a Hobart mixer for 30 seconds. Within 30

Seconds the mixing water and condenser were added and mixing was continued for 3.5 minutes. The total mixing time wet was 4 minutes. The proportionally adjusted water / cement value (w / c) Value) of the mortar was in all mixtures MM3 to MM9 0.45, in the mixtures MM1 1 to MM14 the w / c value was 0.5.

2.3. mortar tests

To determine the effectiveness of the accelerator or additive according to the invention, on the one hand the slump (ABM) and on the other hand the compressive strength (Tables 4 and 5) were determined. The spreading dimension (ABM) of the mortar was determined according to EN 1015-3. The compressive strength was measured with a needle penetrometer (Mecmesin BFG500 on prisms (40 x 40 x 160 mm) according to the standard EN 196-1.

Table 4: Slump size (ABM) in mm after 0 and 30 minutes (min) and compressive strengths in N / mm ² after 4, 6, 8 and 24 hours (h) of the example mixtures MM3-MM5. Also the invention admixed as individual components

Accelerator shows in Example B7 a much faster build-up of compressive strength than the non-inventive Comparative Examples V8 and V9. Table 5 shows that the strength values of the invention

accelerated mortar mixtures MM8 (Example B12) and MM9 (Example B13) after 48 hours are at least as high as those of non-inventive mixtures MM6 (Example V10) and MM7 (Example V1 1).

Sample Blends MM6-MM9. In addition, another MM10 mortar mixture was prepared which differs from MM9 only in that instead of 3% by weight of CaO having a specific surface area of 1.9 m ² / g, only 1% by weight of CaO having a specific surface area of 6 m ² / g were used. The values of

Slump size and compressive strength of MM10 were essentially identical to MM9. This shows the influence of the specific surface of the

Calcium compound on the effectiveness of the inventive

Accelerator.

The compressive strengths of the mortar mixtures MM1 1 to MM14 were also measured after 4 h, 6 h and 8 h. The results are shown in Table 6.

No mortar mix Compressive strength (N / mm ² ) after 4h after 6h after 8h

B14 MM11 (according to the invention) 0.8 3.0 7.6

B15 MM12 (according to the invention) 0.9 3.9 9.1

B16 MM13 (according to the invention) 2.1 7.5 13.6

B17 MM14 (according to the invention) 1.9 6.8 12.9 Table 6: Compressive strengths in N / mm ² after 4, 6 and 8 hours (h) of the example mixtures MM1 1-MM14.

The inventive examples B14 to B17 clearly show that there is an optimum range for the synergistic effect of the inventive

Accelerator there. As the proportion of GPD increases at a constant CaO, the compressive strength of the mortar mix increases. However, after an optimum value, in this case 0.15% by weight of GPD (MM13), the compressive strength drops surprisingly again (MM14).

These examples show the excellent effect of the accelerator according to the invention, which enables significantly higher early strengths, in particular after very short times, than conventional accelerators, without bringing about significant disadvantages in terms of processability, final strength or other properties.

By using the accelerator according to the invention in mortar or concrete compositions, even higher cycle times, earlier loading capacity or faster repair work can be carried out than with conventionally accelerated compositions of hydraulic binders.

The embodiments described above are only for

Demonstration of the effect and do not limit the invention to the applications shown. The accelerator according to the invention and an additive in solid or liquid form containing the accelerator according to the invention can be used in any compositions containing hydraulically setting binders.

Claims

Accelerator for hydraulic binders comprising at least one phosphoric acid ester of a polyhydric alcohol and at least one calcium compound.

Accelerator according to claim 1, characterized in that the

Calcium compound, an inorganic or organic calcium salt or a mixture of inorganic and / or organic

Calcium salts, preferably calcium oxide and / or calcium hydroxide is.

Accelerator according to one of the preceding claims, characterized in that the calcium compound prior to use a solid having a specific surface area, measured by the BET method, of between 1 and 50 m ² / g, preferably between 1 .5 and 30 m ² / g, more preferably between 1 .9 and 10 m ² / g.

Accelerator according to claim 2, characterized in that the

Amount of phosphoric acid ester to total surface of

Calcium compound 0.001 to 0.05 g of phosphoric acid ester per m ²

Calcium compound, preferably 0.005 to 0.04 g of phosphoric acid ester per m ^{2 of} calcium compound, particularly preferably 0.008 to 0.02 g

Phosphoric acid ester per m ² calcium compound.

Accelerator according to one of the preceding claims, characterized in that free acid groups of the phosphoric ester are deprotonated or completely or partially neutralized with salt formation, wherein the salt is an alkali salt or a salt of polyvalent

Cations, preferably a sodium, calcium or aluminum salt.

Accelerator according to one of the preceding claims, characterized in that the phosphoric acid ester is a partial ester of a polyhydric alcohol, preferably a monoester of a di- or trihydric alcohol, more preferably of glycerol.

7. Accelerator according to one of the preceding claims, characterized in that the phosphoric acid ester is glycerophosphate or disodium glycerol phosphate or a hydrate thereof.

8. additive for hydraulically setting systems comprising at least one accelerator according to one of claims 1 to 7 and at least one condenser.

9. additive according to claim 8, characterized in that the

Liquefier Lignosulfonate, sulfonated naphthalene-formaldehyde

Condensates, sulfonated melamine-formaldehyde condensates, sulfonated vinyl copolymers, polycarboxylate ethers or mixtures thereof, or consists thereof.

10. A hydraulic binder-containing mixture comprising at least one hydraulically setting binder and at least one

Accelerator according to one of claims 1 to 7 or an additive according to one of claims 8 or 9.

1 1. A hydraulic binder-containing mixture according to claim 10, comprising the phosphoric acid ester in an amount of 0.001 to 2 wt .-%, preferably 0.01 to 1 wt .-%, particularly preferably 0.02 to 0.6 wt .-% based on the amount of the binder and

Calcium compound in an amount of 0.001 to 10 wt .-%, preferably

0.1 to 5 wt .-%, particularly preferably 0.5 to 3 wt .-% of calcium based on the weight of the binder.

12. A hydraulic binder-containing mixture according to claim 10 or 1 1, characterized in that the total surface BET of the calcium compound per kilogram of hydraulic binder 50 to 70 m ² per kg of binder, preferably 55 to 65 m ² per kg of binder, more preferably 57 to 63 m ² per kg of binder.

13. A process for the preparation of a hydraulic binder-containing mixture, characterized in that a

Phosphoric acid ester and a calcium compound are added together and / or separately from each other to a hydraulic binder.

14. Use of a phosphoric acid ester in combination with a

Calcium compound, in particular in the form of an accelerator according to any one of claims 1 to 7 or an additive according to any one of claims 8 or 9, for accelerating the setting and / or hardening of hydraulic binders and mortar or concrete produced therefrom.

15. A method for accelerating the setting and / or hardening of hydraulic binders and mortar or concrete produced therefrom, characterized in that a mixture containing hydraulic binder, a setting and

Hardening accelerator according to claims 1 to 7 or a

Additive is added according to one of claims 8 or 9.

16. The method according to claim 15, characterized in that the

Phosphoric acid ester in an amount of 0.001 to 2 wt .-%, preferably 0.01 to 1 wt .-%, particularly preferably 0.02 to 0.6 wt .-% based on the amount of the hydraulic binder and the

Calcium compound is added in an amount of 0.001 to 10 wt .-%, preferably 0.1 to 5 wt .-%, particularly preferably 0.5 to 3 wt .-% of calcium based on the weight of the hydraulic binder.