EP3947314A1

EP3947314A1 - Method for reducing or avoiding alkali-aggregate reaction in set concrete

Info

Publication number: EP3947314A1
Application number: EP19715036.0A
Authority: EP
Inventors: Volker Stanjek; Heinz Geich; Peter Jerschow
Original assignee: Wacker Chemie AG
Current assignee: Wacker Chemie AG
Priority date: 2019-03-27
Filing date: 2019-03-27
Publication date: 2022-02-09
Also published as: CN113574031A; JP7274600B2; KR20210132685A; JP2022528518A; KR102625642B1; CN113574031B; US20220185734A1; WO2020192916A1

Abstract

The invention relates to a method for reducing or avoiding the alkali-aggregate reaction in set concrete by means of mass hydrophobization of the concrete by way of adding organosilicon compounds to the concrete mass prior to its setting.

Description

Process for reducing or avoiding the alkali - silica reaction in hardened concrete

The invention relates to a method for reducing or avoiding the alkali-silica reaction in hardened concrete by mass-hydrophobizing the concrete by adding organosilicon compounds to the concrete mass before it hardens.

Concrete consists of a mixture of cement, aggregate (gravel naturally washed or broken, chippings and / or sand), water and concrete admixtures. In the following text, the word aggregate is used as a synonym for gravel, grit and / or sand.

The term alkali-silica reaction (= AKR) describes a destructive reaction that can occur in concrete structures or in concrete components under unfavorable conditions. It mainly takes place when the concrete parts are frequently exposed to water and / or an aqueous one

Come into contact with saline solution. This forms on the

Interface and inside (pores) of the reactive aggregates (A) contained in the concrete (e.g. gravel or grains of sand) a gel which is created by reaction with OH ions. If water also penetrates, the gel swells and a larger volume is created than the original volume on the unreacted surface or inside the aggregate (A). This expansion usually leads to cracks and further to the destruction of the concrete part. Aggregates (A) that either have a high alkali content or a high content of amorphous structural components show a particularly critical swelling behavior. The strain caused by the ASR can be measured using a suitable test setup. If this exceeds a certain level, it is called ASR sensitive concrete. If such a concrete is used, for example, for road or motorway construction, for

Traffic areas at airports, in tunnel construction and for

If pipelines are used, massive damage from the alkali-silica reaction must be expected within the next 10 to 20 years, which in extreme cases can even be complete

Make renewal of the road surface necessary. Concretes that in this experimental setup, however, have none or only one

have comparatively low elongation, can with

Road construction are used.

In principle, the ASR can thus be avoided by choosing the right unreactive aggregates (i.e. by choosing the right gravel, sand, etc.) during concrete production.

However, the problem is that the aggregates required for concrete production are not always available in the same quality. If the content of alkali ions and / or amorphous structural components is too high, they are considered reactive and there is a risk of ASR.

In areas in which the correct, sufficiently unreactive sand and / or gravel qualities are not available, these must partly be transported from regions several 100 km away. In view of the large amounts of sand and gravel that are used in the production of concrete, these transports are due to the associated

Energy consumption, environmental pollution and, last but not least, the corresponding costs represent a hitherto unsolved problem. The object of the present invention was to enable the use of types of sand and / or gravel which otherwise cannot be used in applications affected by the alkali-silica reaction, such as road and motorway construction.

The present invention relates to a method for reducing or avoiding the alkali-silica reaction (= ASR) in hardened concrete, in which a concrete mixture is produced, processed and then hardened, characterized in that the concrete mixture

(A) alkali-sensitive aggregates and

(B) at least one organosilicon compound,

where (B) is selected from

at least one silane (B1) of the formula (1)

R _a R ¹ Si (OR ² ) _3-a (1), where

R denotes monovalent, SiC-bonded hydrocarbon radicals with 1 to 3 carbon atoms,

R ¹ denotes monovalent, SiC-bonded hydrocarbon radicals with 4 to 22 carbon atoms,

R ^{2 can be the} same or different and

Hydrogen atom or monovalent

Hydrocarbon radicals means and

a is 0 or 1, and / or containing at least one siloxane (B2)

Units of the formula (2)

R ³ b (R ⁴ O) _c R ⁵ _d SiO _{(4-bcd) / 2} (2), in which

R ^{3 can be the} same or different and one

monovalent, you-bonded, optionally substituted aliphatic hydrocarbon radical with 1 to 3 carbon atoms or a divalent, optionally substituted, aliphatic

Hydrocarbon radical with 1 to 3 carbon atoms bridging two units of the formula (2) means,

R ^{4 may be the} same or different and may be a hydrogen atom or a monovalent, optionally

substituted hydrocarbon radical means

R ^{5 can be the} same or different and one

means monovalent, SiC-bonded, optionally substituted aromatic or aliphatic hydrocarbon radical with 4 to 22 carbon atoms,

b is 0, 1, 2 or 3,

c is 0, 1, 2 or 3 and

d is 0 or 1, with the proviso that the sum of b + c + d is less than or equal to 3 and the sum b + d is equal to 0 or 1 in at least 40% of the units of the formula (2),

This alkali sensitivity of the aggregate (A) according to the test method A shown in the description (method with 3% NaCl solution) based on the average swelling of three test specimens from the hardened concrete mixture stored in a 3% NaCl solution will be determined and the average swelling of the three test specimens from a hardened concrete mixture which contains alkali-sensitive aggregates (A) but no (B) (= reference sample), at least 0.1 mm / m after 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times).

In a preferred embodiment of the invention

According to the method, the concrete contains an alkali-sensitive aggregate (A), which leads to an alkali-sensitive concrete that the average swelling of the test specimens determined according to test method A from a hardened concrete mixture which contains alkali-sensitive aggregates (A) but no (B)

(= Reference sample), at least 0.2 mm / m after 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times).

In a particularly preferred embodiment of the

The method according to the invention contains a concrete

alkali-sensitive aggregate (A), which leads to a so

alkali-sensitive concrete results in the average swelling of the test specimens determined according to test method A from a hardened concrete mixture which is alkali-sensitive

Contains aggregates (A) but not (B) (= reference sample),

is at least 0.3 mm / m after 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times).

Another object of the invention is a method for reducing or avoiding the alkali-silica reaction (= ASR) in hardened concrete, in which a concrete mixture is produced, processed and then cured, characterized in that the concrete mixture

(A) alkali-sensitive aggregates and

(B) contains at least one organosilicon compound, where (B) is selected from

at least one silane (B1) of the formula (1) ai (OR ² ) ₃ _-a (1) where

R denotes monovalent, SiC-bonded hydrocarbon radicals with 1 to 3 carbon atoms,

R ^{2 can be the} same or different and

Hydrogen atom or monovalent

Hydrocarbon radicals means and

a is 0 or 1, and / or containing at least one siloxane (B2)

Units of the formula (2)

R ³ _b (R ⁴ O) _c R ⁵ _d SiO _{(4-bcd) / 2} (2), where

R ^{3 can be} identical or different and is a monovalent, SiC-bonded, optionally substituted aliphatic hydrocarbon radical having 1 to 3 carbon atoms or a divalent, optionally substituted, aliphatic

substituted hydrocarbon radical means R ^{5 can be the} same or different and one

monovalent, SiC-bonded, optionally substituted aromatic or aliphatic

Means hydrocarbon radical with 4 to 22 carbon atoms,

b is 0, 1, 2 or 3,

c is 0, 1, 2 or 3 and

d is 0 or 1, with the proviso that the sum of b + c + d is less than or equal to 3 and the sum b + d is equal to 0 or 1 in at least 40% of the units of formula (2),

contains,

this alkali sensitivity of the aggregate (A) according to the test method B shown in the description (method with

( A) but does not contain (B) (= reference sample), at least 0.2 mm / m after 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times). In a preferred embodiment of the invention

According to the procedure, the concrete contains an alkali-sensitive aggregate (A), which leads to an alkali-sensitive concrete that the average swelling of the test specimens determined according to test method B from a hardened concrete mixture which contains alkali-sensitive aggregates (A) but no (B) (= reference sample ), at least 0.3 mm / m after 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times). In a particularly preferred embodiment of the

The method according to the invention contains a concrete

alkali-sensitive aggregate (A), which leads to a so

Contains aggregates (A) but not (B) (= reference sample),

is at least 0.4 mm / m after 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times).

(B) is preferably used as an aqueous preparation.

(B) is particularly preferably used as an aqueous one

Preparation which contains at least one silane (B1) of the formula (1) and at least one siloxane (B2) of the formula (2).

In a preferred embodiment of the invention, component (B) is used in an amount such that the after

Test method A determined the average swelling of the

Test specimens made from a hardened concrete mix containing alkali-sensitive aggregates (A) and (B) compared to the average swelling of a hardened concrete mix containing alkali-sensitive aggregates (A) but not (B) (= reference sample) after a storage period of 168 days (Steps A-1 to A-5 and repeating steps (B-1 to B4) ten times) by at least 20%, preferably at least 30%, particularly preferably at least 40%, particularly preferably at least 50% and very particularly preferably at least 70% is less. In a preferred embodiment of the invention, component (B) is used in an amount such that the after

Test method B determined the average swelling of the

Test specimen from a hardened concrete mixture, which contains alkali-sensitive aggregates (A) and (B), compared to the average swelling of a hardened concrete mixture which contains alkali-sensitive aggregates (A) but no (B) (= reference sample), after a storage period of 168 days (steps A-1 to A. -5 and ten repetition of steps (B-1 to B4)) is at least 20%, preferably at least 30%, particularly preferably at least 40%, particularly preferably at least 50% and very particularly preferably at least 70% less.

In a very preferred embodiment, component (B) is used in an amount such that both the after

Test method A as well as the average swelling of the test specimens from one determined by test method B.

hardened concrete mix, which is alkali-sensitive

Aggregates (A) and (B) contains, compared to the average swelling of a hardened concrete mixture, which

contains alkali-sensitive aggregates (A), but none (B)

(= Reference sample), after a storage period of 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times) by at least 20%, preferably at least 30%, particularly preferably at least 40%, particularly preferably at least 50% and very particularly preferably at least 70% less.

The invention is based on the surprising discovery that the organosilicon compounds (B) according to the invention are able to significantly reduce the extent and consequences of ASR. This makes it possible, for example, in road construction, to use locally available types of gravel if their use leads to a concrete that is not sufficiently alkali-stable. In this way, high transport costs for gravel from regions further, sometimes even several 100 km away, can be avoided. Since gravel transport over longer distances also requires a high Energy consumption is connected, is the inventive

Process is also able to make a significant contribution to reducing CO ₂ emissions and thus to the environment

to reach .

Examples of radicals R are alkyl radicals, such as the methyl, ethyl, n-propyl, iso-propyl, and alkenyl radicals, such as the vinyl, 1-propenyl and 2-propenyl radical.

The radical R is preferably the methyl radical.

Examples of radicals R ¹ are alkyl radicals, such as hexyl radicals, such as the n-hexyl radical; Heptyl radicals, such as the n-heptyl radical; Octyl radicals, such as the n-octyl radical and iso-octyl radicals, such as the 2, 2, 4-trimethylpentyl radical; Nonyl radicals, such as the n-nonyl radical; Decyl radicals, such as the n-decyl radical; Dodecyl radicals, such as the n-dodecyl radical;

Tetradecyl radicals, such as the n-tetradecyl radical; Hexadecyl radicals, such as the n-hexadecyl radical; Octadecyl radicals, such as the n-octadecyl radical; Cycloalkyl radicals such as cyclohexyl, cycloheptyl and

Methylcyclohexyl radicals.

R ¹ radicals are preferably alkyl radicals having 6 to 16 carbon atoms, particularly preferably alkyl radicals having 8 to 12 carbon atoms, in particular the n- or iso-octyl radical.

The radical R ² is preferably an alkyl radical having 1 to 4 carbon atoms, particularly preferably the methyl, ethyl, n-propyl or iso-propyl radical. Examples of silane (B1) are hexylsilanes such as n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexyltriethoxysilane, cyclohexyltriethoxysilane, n-hexylmethyldimethoxysilane or n-hexylmethyldiethoxysilane, n-hexylmethyldiethoxysilane, n-hexyltriethoxysilane, 2,2-octyltriethoxysilane, n-octyltriethoxysilane, n-octyltriethoxysilane, n-octyltriethoxysilane, n-octoxysilane, octylsilane, n-octoxysilane, 2,2-octyltriethoxysilane , 4-trimethylpentyl-trimethoxysilane, 2,2, 4 -Trimethylpentyltriethoxysilan, n-decyltriethoxysilane n-, decyltrimethoxysilane, n-dodecyltriethoxysilane n-, dodecyltrimethoxysilane, n-tetradecyltrimethoxysilane, n- tetradecyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-hexadecyltriethoxysilane, octadecyltrimethoxysilane and

Octadecyltriethoxysilane.

The silane (B1) is preferably n-octyltrimethoxysilane, n-octyltriethoxysilane, 2, 2, 4-trimethylpentyl-

trimethoxysilane, 2, 2, 4-trimethylpentyl-triethoxysilane,

Hexadecyltrimethoxysilane, hexadecyltriethoxysilane, particularly preferably n-octyltrimethoxysilane, n-octyltriethoxysilane, 2,2,4-trimethylpentyltrimethoxysilane and 2,2,4-trimethylpentyltriethoxysilane.

Examples of radicals R ⁵ are the vinyl radical, the allyl radical, alkyl radicals such as 1-n-butyl, 2-n-butyl, iso-butyl, t-butyl, n-pentyl, iso-pentyl, neo Pentyl, tert. -Pentyl radical,

Cyclopentyl; Hexyl radicals, such as the n-hexyl or cyclohexyl radical; Heptyl radicals, such as the n-heptyl radical; Octyl radicals, such as the n-octyl radical and iso-octyl radicals, such as the 2, 2, 4-trimethylpentyl radical; Nonyl radicals, such as the n-nonyl radical; Decyl radicals, such as the n-decyl radical; Dodecyl radicals, such as the n-dodecyl radical;

Tetradecyl radicals, such as the n-tetradecyl radical; Hexadecyl radicals, such as the n-hexadecyl radical; Octadecyl radicals, such as the n-octadecyl radical; residues containing amino groups of the formulas H ₂ N (CH ₂ ) ₃ - H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ - or H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₂ NH (CH ₂ ) ₃ - ;

Aryl radicals, such as the phenyl, naphthyl, anthryl and phenanthyl radical; or alkaryl radicals, such as o-, m-, p-tolyl radicals;

Xylyl residues and ethylphenyl residues; and aralkyl radicals, such as the benzyl radical, the α- and the β-phenylethyl radical.

The radical R ⁵ is preferably an alkyl radical such as 1-n-butyl, 2-n-butyl, iso-butyl, tert. -Butyl, n-pentyl, iso-pentyl, neo-pentyl, tert. Pentyl radical, cyclopentyl;

Hexyl radicals, such as the n-hexyl or cyclohexyl radical; Heptyl radicals, such as the n-heptyl radical; Octyl radicals, such as the n-octyl radical and iso-octyl radicals, such as the 2, 2, 4-trimethylpentyl radical; Nonyl radicals, such as the n-nonyl radical; Decyl radicals, such as the n-decyl radical; Dodecyl radicals, such as the n-dodecyl radical; Tetradecyl radicals, such as the n-tetradecyl radical; Hexadecyl radicals, such as the n-hexadecyl radical or a phenyl radical.

The radical R ⁵ is particularly preferably an n-octyl radical, a 2, 2, 4-trimethylpentyl radical; an n-hexadecyl radical or a phenyl radical.

Examples of radicals R ⁴ are alkyl radicals, such as methyl,

Ethyl, n-propyl or iso-propyl radical.

The R ⁴ radical is preferably the methyl radical.

The radical R ³ is preferably an alkyl radical having 1 to 3 carbon atoms, particularly preferably a methyl or ethyl radical. Preference is given to using siloxanes (B2) consisting of units of the formula (2), the sum b + d being 0 or 1 in 40% of the units of the formula (2).

The siloxanes (B2) used according to the invention can be any linear, cyclic or branched siloxanes known to date. Component (B2) is particularly preferably organopolysiloxane resins (B2a) which consist of repeating units of the formula (2), with the proviso that b + d in

at least 30% of all repeating units of the formula (2) has the value 1 and the value 1 also in 100% of all

Repeating units of the formula (2) can have.

Likewise particularly preferably has b + d over all

Repeating units of the formula (2) averaged

an average of 0.9 to 1.6, with b = 1 in combination with d = 0, b = 0 in combination with d = 1, and b = 2 in combination with d = 0, particularly preferred values for the

Repeating units of the formula (2) are.

Also particularly preferably has c over all

Repeating units of the general formula (2) averaged an average value of 0.1 to 1.8.

The unit -0R ^{4 is} likewise particularly preferably averaged over all repeating units of the formula (2)

an average of at most 10 mol% based on all -OR ⁴ units for a hydroxyl group. The organopolysiloxane resins (B2a) can be solid or liquid. The organopolysiloxane resins (B2a) are preferably liquid and at 25 ° C. and the pressure of the surrounding atmosphere, that is to say at 900 to 1100 hPa, have a viscosity of 1000 to

400,000 mPas. The weight average molecular weight of these resins determined by gel permeation chromatography is

preferably 200 to 200,000 g / mol, in particular 1,000 to 20,000 g / mol.

In the context of the present invention, the viscosity of non-pasty liquids is measured after heating to 25 ° C. with an AVS viscometer from Schott (Ubbelohde

Viscometer; a detailed description of the

Viscosity measurement can be found in DIN 51562, part 1).

The number average molar mass M _n is determined in the context of the present invention by means of size exclusion chromatography (SEC) against polystyrene standard, in THF, at 60 ° C., flow rate 1.2 ml / min and detection with RI (refractive index detector) a column set Styragel HR3 -HR4-HR5-HR5 from Waters Corp. USA determined with an injection volume of 100 mΐ.

In a further preferred embodiment of the invention, component (B2) is a polydimethylsiloxane (B2b).

The polydimethylsiloxanes (B2b) can be branched or

be unbranched. They are preferably unbranched. The

Polydimethylsiloxanes (B2b) preferably have

End groups of the formula -Si (CH ₃ ) ₃ or -Si (CH ₃ ) ₂ OH.

The polydimethylsiloxanes (B2b) are liquid and have at 25 ° C and the pressure of the surrounding atmosphere, i.e. at 900 to 1100 hPa, a viscosity of 1,000 to 1,000,000 mPas. The weight average determined by gel permeation chromatography

The molecular weight of these resins is preferably from 1,000 to 2,000,000 g / mol, in particular from 2,000 to 1,000,000 g / mol.

The compositions used according to the invention contain component (B2) in amounts of preferably 5 to 400

Parts by weight, particularly preferably 20 to 2000 parts by weight, particularly preferably from 40 to 100 parts by weight, in each case based on 100 parts by weight of component (B1).

In a preferred embodiment of the invention, the

Component (B) of the concrete mix in the form of an aqueous

Dispersion (DisB) added. In addition to the

Component (B) also includes suitable emulsifiers (C), water (D) and, if appropriate, further additives (E).

As emulsifiers (C) it is possible to use all emulsifiers which have also previously been used for the production of siloxane dispersions. Anionic, nonionic, cationic and amphoteric surfactants or their can be used as emulsifiers (E)

Mixtures are used. Alternatively, polymeric compounds that have emulsifying properties, such as

Polyvinyl alcohols, in particular polyvinyl alcohols with a degree of saponification of 75-95%, are used.

The component (C) used, if any, is preferably a nonionic emulsifier or a mixture of nonionic emulsifiers and ionic emulsifiers. Examples of the nonionic emulsifiers (C) used according to the invention are sorbitan fatty acid esters, ethoxylated sorbitan fatty acid esters, ethoxylated fatty acids, ethoxylated linear or branched alcohols having 10 to 20 carbon atoms, ethoxylated alkylphenols, pentaerythritol fatty acid esters, glycerol esters and alkyl polyglycosides.

The nonionic emulsifiers (C) are preferably sorbitan fatty acid esters, ethoxylated sorbitan fatty acid esters, ethoxylated fatty acids, ethoxylated linear or branched alcohols with 10 to 20 carbon atoms or ethoxylated triglycerides.

Preferably contain those used according to the invention

Compositions do not contain ethoxylated alkylphenols as these are known not to be environmentally friendly.

If nonionic emulsifiers are used as component (C), it can be just one type of nonionic emulsifier or a mixture of several nonionic emulsifiers. Preferably has at least one

nonionic emulsifier (C) an HLB value of greater than or equal to 12, in particular greater than or equal to 14.

Mixtures of non-ionic emulsifiers, of which at least one emulsifier has an HLB value greater than or equal to 12, are preferably used as component (C). The proportion of emulsifiers (C) with an HLB value greater than or equal to 12 in the emulsifier mixture (C) is preferably at least 30 wt. -%. The HLB value is an expression of the equilibrium between the hydrophilic and hydrophobic groups of an emulsifier. The definition of the HLB value and methods of determining it are generally known and are described, for example, in Journal of Colloid and Interface Science 298 (2006) 441-450 and the literature cited there.

As anionic emulsifiers (C) e.g. Alkyl sulfonates, alkyl sulfates and alkyl phosphates are used.

Examples of cationic emulsifiers (C) are all known quaternary ammonium compounds which contain at least one

carry substituted or unsubstituted hydrocarbon radical with at least 10 carbon atoms, such as

Dodecyldimethylammonium chloride, tetradecyltrimethylammonium bromide, stearyltrimethylammonium chloride, distearyldimethylammonium chloride, cetyltrimethylammonium chloride, behenyltrimethylammonium bromide, dodecylbenzyldimethylammonium chloride and

Benzyl trimethyl ammonium chloride.

If cationic emulsifiers are used as component (C), these are preferably aryl or

Alkyltrimethylammonium salts such as stearyltrimethylammonium chloride or cetyltrimethylammonium chloride, particularly preferred

Benzyltrialkylammonium salts, in particular trimethylbenzylammonium chloride or trimethylbenzylammonium methosulfate.

Further examples are all known quaternaries

Imidazolinium compounds which carry at least one substituted or unsubstituted hydrocarbon radical with at least 10 carbon atoms, such as l-methyl-2-stearyl-3- stearylamidoethyl imidazolinium methosulfate, 1-methyl-2-norstearyl-3-stearyl-amidoethylimidazolinium methosulfate, 1- methyl-2-oleyl-3-oleylamidoethylimidazolinium methosulfate, 1- methyl-2-stearyl-3-methylimidazoline-methosulfate, 1 -Methyl -2-behenyl-3 -methylimidazoline methosulfate and 1-methyl-2-dodecyl-3-methylimidazoline methosulfate.

If component (C) is used to prepare the dispersions (DisB), the amounts involved are preferably 0.1 to 15 parts by weight, particularly preferably 0.3 to 8

Parts by weight, each based on 100 parts by weight

Component (B). The dispersions (DisB) preferably contain emulsifiers (C).

The water used as component (D) can be any kind of water such as natural water such as Rain water, ground water, spring water, river water and sea water, chemical water such as fully demineralized water, distilled or (multiple) redistilled water,

Drinking water or mineral waters.

The dispersions (DisB) contain water (D) in amounts of preferably 10 to 90% by weight, particularly preferably 20 to 80% by weight, in each case based on the total amount of the composition. Are particularly preferred in the inventive

Process highly diluted compositions with a water (D) content of 30 to 70% by weight.

In addition, the dispersion (DisB) added to the concrete can contain further additives (E). This can be all additives that were previously used in aqueous dispersions have been used, such as biocides and / or other preservatives, different from (B1) and (B2)

Organosilicon compounds, thickeners, substances for adjusting the pH value, fragrances, dyes, pigments such as iron oxide, alcohols and / or antifreeze agents such as glycols and glycol ethers.

Examples of optionally used thickeners (E) are polyacrylic acid, polyacrylates, cellulose ethers such as

Carboxymethyl cellulose and hydroxyethyl cellulose, natural gums such as xanthan gum and polyurethanes.

Examples of possibly used

Organosilicon compounds (E) are tetraethoxysilane,

Trimethylmethoxysilane, aminopropyltriethoxysilane and

Aminopropylmethyldimethoxysilane.

Examples of any substances used for

Adjusting the pH value (E) are not only aminosilanes but also amines, e.g. Monoethanolamine or alkali hydroxides. If it is necessary to ensure the constancy of the pH over a longer period of time, buffer systems such as salts of acetic acid, salts of phosphoric acid, salts of citric acid can be used, each in combination with the free acid, depending on the desired pH .

In a preferred embodiment, it contains the concrete

added dispersion (DisB) ethanol and / or methanol as component (E) in amounts of preferably 0.00001 to 1% by weight, particularly preferably 0.0001 to 0.5% by weight. The mentioned

Amounts of alcohol are usually formed during the production of the composition used according to the invention and / or during storage thereof.

The dispersions (DisB) are preferably containing such

(B1) silanes of the formula (1) and / or

(B2) silicone resins composed of units of the formula (2)

(C) emulsifier,

(D) water and

optionally (E) further additives.

The dispersions (DisB) preferably contain none of the components (A) to (F) or their reaction products

outgoing components.

With the above Components used according to the invention can each be one type of such a component as well as a mixture of at least two types of a respective one

Act component.

The dispersions (DisB) are preferably emulsions or suspensions, particularly preferably

Emulsions.

The dispersions (DisB) can be prepared by processes known per se. Usually the

Production by simply stirring all components in any order at temperatures of preferably 1 to 50 ° C and, if necessary, subsequent homogenization. The dispersions (DisB) have a solids content, that is a proportion of non-volatile compounds (for example, determined according to ASTM D 5095), of preferably 0.01 to 90% by weight, particularly preferably 20 to 80% by weight, in particular preferably from 30 to 70% by weight.

The dispersions (DisB) have a viscosity of preferably 0.5 to 10,000 mm ² / s, in particular 1 to 1,000 mm ² / s, each measured at 25 ° C. according to the above-mentioned test method (viscosity of non-pasty liquids).

A typical concrete recipe contains 400 kg of cement per cubic meter, the rest 0-70% by volume of gravel or gravel. Chippings with a particle diameter of 2-22 mm, preferably 2-16 mm and 30-100 volume% sand (in the case of 100% sand one speaks of mortar). The water to cement ratio is typically 0.45. The water-cement value can be between 0.3 and 0.7. If sand and gravel or chippings contain amorphous structural components, they are reactive, i.e. alkali-sensitive aggregates (A).

Examples of alkali-sensitive gravel (A) would be rhyolite or greywacke. Other reactive aggregates come from the following mineral groups: argillite, dacite, porphyry, tuff, slate, siltstone, opal, obsidian, cristobalite, tridymite, chalcedony, andesite, phyllite, slate, gneiss, gneiss granite, sandstone, latites, artificial glass, volcanic glass, Flint, cryptocrystalline and strained or metamorphic quartz,

Chert, some dolomitic limestones or granite. Component (B) is added in a ratio of 0.01-0.5% by weight, preferably 0.1-0.3% by weight, based on the solids content of the emulsion and based on the cement of the concrete. Of the

The time of addition can take place before or after the addition of water. Test method A (method with 3% aqueous NaC1 solution)

3 prisms made of concrete with the dimensions 75 mm x 75 mm x 280 mm are produced as test specimens and stored in accordance with Table 1. The swelling corresponds to the average value in

[mm / m] from the measurement of the swelling of the 280mm edge of the 3 test specimens after the 10th cycle = a total of 168 days, i.e. after steps A-1 to A-5 and repeating steps B-1 to B4 ten times.

If swelling is to be continuously monitored, the measurement is carried out after each cycle. If long-term studies are desired, the number of cycles can be increased.

Test method B (method with 10% aqueous NaC1 solution)

3 prisms made of concrete with the dimensions 75 mm x 75 mm x 280 mm are produced as test specimens and stored in accordance with Table 2. The swelling corresponds to the average value in

[mm / m] from the measurement of the swelling of the 280mm edge of the 3 test specimens after the 10th cycle = a total of 168 days, ie after steps A-1 to A-5 and repeating steps B-1 to B4 ten times.

The invention has the advantage that in the concrete or plaster also reactive aggregates, for example the reactive ones mentioned above

Aggregates as well as reactive types of sand can be used, which are available locally and inexpensively, and nonetheless an ASR-stable concrete or plaster is available.

Another advantage of the invention is the simple and inexpensive addition of the additives to the concrete and

Mortar recipe.

Further advantages of the invention are that their use to increase the service life of buildings, traffic areas at airports, tunnels, pipelines, roads, bridges and structures generally leads that would otherwise be through a

possibly occurring ASR could be less durable.

The following examples describe the basic feasibility of the present invention without, however, restricting it to the contents disclosed therein.

In the examples below, all parts and percentages are based on weight, unless stated otherwise. Unless stated otherwise, the following examples are carried out at a pressure of the surrounding atmosphere, that is to say at about 1000 hPa, and at room temperature, that is to say about 20 ° C. or a temperature that changes when the reactants are combined sets at room temperature without additional heating or cooling.

Examples

Production example 1: Production of a dispersion containing silane (B1) and siloxane (B2)

In a 2-liter beaker, 38.4 g water, 38.4 g of emulsifier (POE (16) isotridecylether, available under the name ^® Arlypon

IT 16 at BASF AG, D-Ludwigshafen) and with 4.3 g of N- (2-aminoethyl) -3-aminopropyl-trimethoxysilane

(available under the name Geniosil ^® GF 91 from Wacker Chemie AG, D-Burghausen) using a rotor-stator homogenizer (Ultra-Turrax T50, IKA-Werke GmbH 6 Co.KG, D-Staufen) for 0, Mixed for 5 minutes at 4000 rpm. Subsequently, 100 g of 2, 2, 4 -Trimethylpentyl - triethoxysilane (sold under the name SILRES ^® BS 1701 from Wacker Chemie AG, D-Burghausen.) Was added and for 2 min at 4000 U / mixed min, wherein a gel-like paste arises.

Then, under further mixing at 4000 U / min within 2 min alternately 10 g of water and 122.4 g of an organopolysiloxane of the empirical formula (CH ₃₎ _{0, 7} (2, 2, 4 -Trimethylpen- tyl) _0.3 Si ( OCH ₃ ) _1.3 O _0.85 with an average

Molecular weight of about 800 g / mol and a viscosity of about 17 mm ² / s added, the paste-like consistency of the mixture being retained. Finally, with further mixing at 4000 rpm, 25 g of water and 389.6 g of 2, 2, 4-trimethylpentyl-triethoxysilane are added alternately over the course of 3 minutes, the paste-like consistency of the mixture is also preserved. The mixture is then stirred for a further 5 minutes at 4000 rpm.

Thereafter, while continuing to mix at 4000 rpm, 467.8 g of water are alternately added over the course of 5 minutes, a liquid emulsion being formed. Finally, 1.1 g of 99%

Acetic acid, 2.64 g of a first preservative ("Acticide MV", available from Thor GmbH, D-Speyer) and 0.36 g of a second preservative (MIT 10, also available from Thor GmbH, D- Speyer) and stir in at 4000 rpm for 0.5 min.

Building materials and test methods

Concrete compositions and test specimens

The concrete compositions are shown in Table 3 and Table 4. The formulations of Comparative Example 1 (C-Ex. 1) and Examples 1a & 1b (Ex. 1a & Ex. 1b) are identical with the exception of the dosage of the respective hydrophobing agent. The same applies to the concretes from Comparative Example 2 (C-Ex. 2) and Examples 2a & 2b (Ex. 2a & Ex. 2b). With the exception of the one not used in the model tests

All recipes of the air-entraining agent correspond to the standard composition "Oberbeton (0/8)", which is to be used for the WS basic test of coarse aggregates in accordance with the General Circular Road Construction No. 04/2013.

The concretes were manufactured using the following mixing process:

1. Mixing the dry components (approx. 10 seconds) 2. Adding water

3. Addition of additives (only examples 1a, 1b, 2a & 2b)

4. Mix for two minutes

The following test specimens were produced from each concrete in steel molds and compacted on a vibrating table:

Six prisms (75 mm x 75 mm x 280 mm) for the 60 ° C concrete tests according to test methods A and B with external alkali.

Three test specimens with an edge length of 150 mm for testing compressive strength and bulk density.

After manufacture, the specimens were in the mold

left, covered with a damp cloth and stored at 20 ± 2 ° C for 24 + 1 hours. After removal from the mold, further storage took place according to the intended test method.

Test methods

Fresh concrete testing

The fresh concrete density according to DIN EN 12350-6 was approx.

Determined 10 minutes after mixing.

The degree of compaction according to DIN EN 12350-4 and the slump according to DIN EN 12350-5 were determined approx. 30 minutes after mixing.

Hardened concrete test

The compressive strength of the concrete compositions was tested in accordance with DIN EN 12390-3 after 28 days on three test specimens with an edge length of 150 mm. The solid concrete density was determined according to DIN EN 12390-7. The test specimens were stored in accordance with the national annex of DIN EN 12390-2 (7 days under Water, then in a climatic chamber at 20 ± 2 ° C and 65 ± 5% RH).

60 ° C concrete test with external alkali supply (ASR performance test)

The resistance of the three concretes to the alkali-silica reaction was investigated using test method A and test method B, a 60 ° C concrete test with an alkali supply from the outside.

In each case 3 concrete test bodies (prisms with the dimensions 75 mm x 75 mm x 280 mm) were stored according to Table 5 according to test method A and test method B. According to test method A, the

In step B-2, test specimens are stored in a 3% aqueous NaCl solution; in test method B, a 10% NaCl solution is used here.

The elongation of the test specimens was measured after 28 days (step A-5) and after each test cycle (step B-4). The

Exposure according to steps B-1 to B-4 was repeated 14 times for each concrete.

According to test method A, concrete suitable for road construction must exhibit an elongation of less than 0.3 mm / m after 10 repetitions of steps B-1 to B-4 (10 test cycles). At

In test method B, the elongation must not exceed 0.5 mm / m.

Fresh concrete properties

The properties of the fresh concretes are listed in Table 6.

Hardened concrete properties

The compressive strength fc and the bulk density D of the concrete are listed in Table 7.

60 ° C concrete tests with external alkali supply

Concretes with greywacke chippings (comparative example 1, examples la & 1b)

The average elongations of the concrete test pieces

Comparative example 1 and examples la & lb during the 60 ° C concrete test according to test method A, i.e. with external alkali supply by means of a 3% NaCl solution, are shown in FIG. In the case of the concrete from Comparative Example 1, a continuous increase in elongation up to an average value of 0.53 mm / m was found after 14 test cycles. After 10 cycles the elongation was 0.39 mm / m. The concretes from examples la & 1b showed up to a maximum of <0.10 mm / m (0.04 or

0.05 mm / m after 10 cycles) significantly lower elongation values.

The average elongations of the concrete test pieces

Comparative example 1 and examples 1a & 1b during the 60 ° C. concrete test according to test method B, ie with the addition of alkali from the outside using a 10% NaCl solution are shown in FIG. The concrete from Comparative Example 1 had the highest elongation values after 14 test cycles and reached an average value of 2.72 mm / m. After 10 cycles the elongation was 1.97 mm / m. In the case of the concrete from example la, an elongation value of 0.94 mm / m was determined after 10 test cycles and a value of 1.53 mm / m after 14 cycles. In the case of the concrete from Example 1b, the value was 0.34 mm / m after 10 cycles and 0.54 mm / m after 14 cycles.

Concretes with rhyolite chippings (comparative example 2, examples 2a & 2b)

The average elongations of the concrete test pieces

Comparative Example 2 and Examples 2a & 2b during the 60 ° C concrete test according to test method A, i.e. with external alkali supply by means of a 3% NaCl solution are shown in FIG. In the case of the concrete from Comparative Example 2, a continuous increase in the elongation values up to 0.24 mm / m after 10 test cycles and 0.28 mm / m after 14 cycles was found. The elongation values of the concretes from Examples 2a & 2b remained close to zero for the entire duration of the test.

The average elongations of the concrete test pieces

Comparative example 2 as well as examples 2a & 2b during the 60 ° C concrete test according to test method B, i.e. with external alkali supply by means of a 10% NaCl solution are shown in FIG. In the case of concrete comparative example 2, a continuous, almost linear increase in elongation was found throughout the course of the test, a value of 0.42 mm / m after 10 test cycles and a maximum of 0.59 mm / m after 14 cycles

reached. The increase in elongation of the concrete from Example 2a was significantly less than in the course of the first 6 test cycles Concrete from Comparative Example 2. After that, however, there was a higher increase in elongation, so that after 10 test cycles

Elongation value of 0.29 and after 14 cycles a value of 0.52 mm / m was reached. The elongation of the concrete from Example 2b remained close to zero over the entire 14 test cycles.

Claims

1. Process to reduce or avoid the alkali-silica reaction (= ASR) in hardened concrete, in which a concrete mixture is produced, processed and

then hardens,

characterized in that the concrete mix

(A) Alkali-sensitive units (A) and

(B) contains at least one organosilicon compound,

where (B) is selected from

at least one silane (Bl) of the formula (1)

R _a R ¹ Si (OR ² ) _3-a (1) where

R denotes monovalent, SiC-bonded hydrocarbon radicals with 1 to 3 carbon atoms,

R ^{2 can be the} same or different and

Hydrogen atom or monovalent

Hydrocarbon radicals means and

a is 0 or 1, and / or containing at least one siloxane (B2)

Units of the formula (2)

R ³ _b R ⁴ _c (OR ⁵ ) _d SiO _{(4-bcd) / 2} (2), where

R ^{3 can be} identical or different and is a monovalent, SiC-bonded, optionally substituted aliphatic hydrocarbon radical with 1 up to 3 carbon atoms or a divalent, optionally substituted, aliphatic

substituted hydrocarbon radical means

R ^{5 can be the} same or different and one

b is 0, 1, 2 or 3,

c is 0, 1, 2 or 3 and

d is 0, or 1,

with the proviso that the sum of b + c + d is less than or equal to 3 and the sum b + d is equal to 0 or 1 in at least 40% of the units of the formula (2),

contains,

this alkali sensitivity of the aggregate (A) according to test method A shown in the description (method with 3% NaCl solution) based on the average swelling of three test specimens from the hardened concrete mixture, which are stored in a 3% NaCl solution, is determined, and the average swelling of the three test specimens from a hardened concrete mixture which contains alkali-sensitive aggregates (A) but no (B) (= reference sample), at least 0.1 mm / m after 168 days (steps A-1 to A. -5 and repeating steps (B-1 to B4) ten times).

2. The method according to claim 1, wherein the average swelling of the test specimens of a hardened concrete mixture which contains alkali-sensitive aggregates (A) but no (B) (= reference sample), at least 0.2 mm / m after 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times.

3. The method according to claim 1, wherein the average swelling of the test specimens of a hardened concrete mixture which contains alkali-sensitive aggregates (A) but no (B) (= reference sample), at least 0.3 mm / m after 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times.

4. Process to reduce or avoid the alkali-silica reaction (= ASR) in hardened concrete, in which a concrete mixture is produced, processed and

then hardens,

characterized in that the concrete mix

(A) alkali-sensitive aggregates and

(B) contains at least one organosilicon compound,

where (B) is selected from

at least one silane (Bl) of the formula (1)

R _a R ¹ Si (OR ² ) _3-a (1), where

R denotes monovalent, SiC-bonded hydrocarbon radicals with 1 to 3 carbon atoms,

R ¹ denotes monovalent, SiC-bonded hydrocarbon radicals with 4 to 22 carbon atoms, R ^{2 can be the} same or different and

Hydrogen atom or monovalent

Hydrocarbon radicals means and

a is 0 or 1, and / or containing at least one siloxane (B2)

Units of the formula (2)

R ³ _b (R ⁴ O) _c R ⁵ _d SiO _{(4-bcd) / 2} (2), where

R ^{3 can be the} same or different and one

monovalent, SiC-bonded, optionally substituted aliphatic hydrocarbon radical with 1 to 3 carbon atoms or a divalent, optionally substituted, aliphatic

substituted hydrocarbon radical means

R ^{5 can be the} same or different and one

monovalent, SiC-bonded, optionally substituted aromatic or aliphatic

Means hydrocarbon radical with 4 to 22 carbon atoms,

b is 0, 1, 2 or 3,

c is 0, 1, 2 or 3 and

d is 0, or 1, with the proviso that the sum of b + c + d is less than or equal to 3 and the sum b + d is equal to 0 or 1 in at least 40% of the units of the formula (2),

contains,

this alkali sensitivity of the aggregate (A) according to the test method B shown in the description (method with 10% NaCl solution) based on the average swelling of three test specimens from the hardened concrete mixture, which are stored in a 10% NaCl solution, is determined, and the average swelling of the three test specimens from a hardened concrete mixture which contains alkali-sensitive aggregates (A) but no (B) (= reference sample), at least 0.2 mm / m after 168 days (steps A-1 to A. -5 and repeating steps (B-1 to B4) ten times).

5. The method according to claim 4, wherein the average swelling of the test specimens of a hardened concrete mixture which contains alkali-sensitive aggregates (A) but no (B) (= reference sample), at least 0.3 mm / m after 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times.

6. The method according to claim 4, wherein the average swelling of the test specimens of a hardened concrete mixture which contains alkali-sensitive aggregates (A) but no (B) (= reference sample), at least 0.4 mm / m after 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times.

7. The method according to any one of claims 1-6, characterized

characterized in that (B) is an aqueous preparation which contains at least one silane (B1) of the formula (1) and at least one siloxane (B2) of the formula (2).

8. The method according to any one of claims 1 to 7, characterized in that the component (B) in an amount

is used, so that the average swelling of the test specimens determined by test method A from a

hardened concrete mix, which is alkali-sensitive

contains alkali-sensitive aggregates (A), but none (B)

(= Reference sample), after a storage period of 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times) is at least 20% lower.

9. The method according to any one of claims 1 to 7, characterized in that the component (B) in an amount

hardened concrete mix, which is alkali-sensitive

contains alkali-sensitive aggregates (A), but none (B)

(= Reference sample), after a storage period of 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times) is at least 30% lower.

10. The method according to any one of claims 1 to 7, characterized in that component (B) in an amount

hardened concrete mix, which is alkali-sensitive

contains alkali-sensitive aggregates (A), but none (B)

(= Reference sample), after a storage period of 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times) is at least 40% less.

11. The method according to any one of claims 1 to 7, characterized in that the component (B) in an amount

is used, so that the average swelling of the test specimens determined by test method B from a

hardened concrete mix, which is alkali-sensitive

contains alkali-sensitive aggregates (A), but none (B)

12. The method according to any one of claims 1 to 7, characterized in that component (B) in an amount

hardened concrete mix, which is alkali-sensitive

contains alkali-sensitive aggregates (A), but none (B)

13. The method according to any one of claims 1 to 7, characterized in that component (B) in an amount

hardened concrete mix, which is alkali-sensitive

Contains aggregates (A) and (B), versus the average Swelling of a hardened concrete mixture which contains alkali-sensitive aggregates (A) but none (B)

(= Reference sample), after a storage period of 168 days (steps A-1 to A-5 and repeating steps (B-1 to B4) ten times) is at least 40% lower.

14. The method according to any one of claims 1 to 7, characterized in that component (B) in an amount

is used so that both the test method A and test method B determined

average swelling of the test specimens from a

hardened concrete mix, which is alkali-sensitive

contains alkali-sensitive aggregates (A), but none (B)

15. The method according to any one of claims 1 to 7, characterized in that component (B) in an amount

is used so that both the test method A and test method B determined

average swelling of the test specimens from a

hardened concrete mix, which is alkali-sensitive

contains alkali-sensitive aggregates (A), but none (B)