MX2008003801A - Use of polymer microparticles in building material mixtures - Google Patents

Abstract

The invention relates to the use of polymer microparticles comprising a cavity in hydraulically binding building material mixtures, between 1 and 100 vol.%of the cavity of said microparticles being filled with water. In this way, a significant concrete resistance to changes in frost and dew states is achieved, said microparticles providing improved protection of the concrete against the effects of changes in frost and dew states, with a diameter of between 0.1 and 1µand doses that are smaller than those in prior art by between 1 and 2 orders of magnitude. Furthermore, the pressure resistance of the correspondingly hardened concrete is significantly improved, which was not the case before. The invention also relates to compositions containing polymer microparticles and hydraulically binding building material mixtures, and hardened building material mixtures produced using such compositions.

Description

USE OF POLYMER MICROPARTICLES IN MIXES OF CONSTRUCTION MATERIAL DESCRIPTION OF THE INVENTION The present invention relates to the use of polymeric microparticles in mixtures of building materials that hydraulically bind to improve their resistance to ice, respectively the change of ice and thaw, compositions containing polymeric microparticles and mixtures of building materials that hydraulically bind, as well as as mixtures of hardened building material that is produced by the use of such compositions. For the resistance of the concrete against the change between ice and thaw, with the simultaneous action of deicing agents, the density of its structure, a determined resistance of its matrix and the presence of a determined structure of pores are determining factors. The structure of a concrete agglomerated with cement is interpenetrated with capillary pores (radius 2μm - 2mm) respectively gel pores (radius 2 - 50nm). The pore water contained in them differs in its aggregate state as a function of the pore diameter. While water preserves its usual characteristics in capillary pores, gel pores are classified in water condensed (mesopores: 50 nm) and surface water bound by adsorption (micropores: 2 nm), whose ice point can be located well below -50 ° C [M.J. Setzer, Interaction of whater with hardened cement paste, "Ceramic Transactions" 16 (1991) 415-39]. This has the consequence that even in the case of a deep cooling of the concrete a part of the pore water remains without freezing (metastable water). At the same temperature, however, the vapor pressure on water is less than on water. Due to the simultaneous presence of ice and metastable water, a vapor pressure gradient is generated, which produces a diffusion of the still liquid water towards the ice and its conversion into ice, so there is a dehydration of the smaller pores, respectively an accumulation of ice in the larger pores. This redistribution of water due to cooling occurs in any system with pores and depends significantly on the type of pore distribution. The artificial introduction of micrometric air pores in the concrete therefore produces, in the first place, so-called relaxation spaces for the expanding ice and the ice water. The pore water in the freezing state can expand towards these pores, respectively, the pressure can be absorbed internal and the tensions of ice and ice water, without presenting micro-cracks and with this damage of ice in the concrete. The principle with which these air pore systems operate has been described in the context of the mechanism of ice damage in concrete in a large number of abstracts [E. Schulson, Ice damage to concrete (1998), > http: // www. crrel. usace army.mil/techpub/CRREL_Reports/repo rts / SR98_06.pdf <; S.Chatterji, Freezing of air-entrained cement-based materials and specific actions of air entraining agents, "Cement t &Concrete Compositions" 25 (2003) 759-65; G.W.Scherer, J.Chen & J. Valenza, Methods for protecting concrete from freeze damage, US-Patent 6,485,560 Bl (2002); M.Pigeon, B.Zuber & J. Marchand, Freeze / thaw resistance, "Advanced Concrete Technology" 2 (2003) 11 / 1-11 / 17; B.Erlin & B.Mather, A new process by which cyclic freezing can damage concrete - the Erlin / Mather effect, "Cement t &Concrete Research" 35 (2005) 1407-11]. A prerequisite for a better resistance of the concrete in the case of change of ice and thaw is that the distance of each point in the hard cement of the nearest artificial air pore does not exceed a certain value. This distance is also called the distance factor or "distance factor Powers" [T.C. Powers, The air requirement of frost-resistant concrete, "Proceedings of the Highway Research Board" 29 (1949) 184-202]. Laboratory tests they have shown in this that, when exceeding the critical "Powers space factor" of 500μm, concrete damage occurs in case of change between ice and thaw. To achieve this with a limited air pore content, the diameter of the air pores, artificially introduced, should be less than 200-300μm [K.Snyder, K.Natesaiyer & K.Hover, The stereological and Statistical properties of entrained air voids in concrete: A mathematical basis for air void Systems characterization) "Ma terials Science of Concrete" VI (2001) 129-214]. The formation of an artificial air pore system depends essentially on the composition and grain shape of the additives, the type and amount of the cement, the consistency of the concrete, the mixer used, the mixing time, the temperature, but also of the type and amount of the air pore forming agent. Taking into account the corresponding production rules it is certainly possible to dominate the influences of these, but a great variety of undesirable impairments can be presented which finally has as a consequence that the desirable air content in the concrete can be exceeded upwards or downwards and has, therefore, a negative effect on the mechanical strength or the ice resistance of the concrete.

It is not possible to dose artificial air pores as such, but the incorporated air is stabilized upon mixing by the addition of so-called air pore forming agents [L.Du & K. J. Folliard, Mechanism of air entrainment in concrete "Cement t &Concrete Research" 35 (2005) 1463-71]. Air pore forming agents generally have a tensioactive structure and break air, introduced when mixing, into small air bubbles with a smaller diameter -as far as possible- of 300μm, and stabilize them in the wet structure of the concrete. There are two types. A type, for example sodium oleate, the sodium salt of the abietinic acid or vinsol resin, an extract of the pine roots-reacts with the calcium hydroxide of the pore solution in the cement binder and precipitates as salt Insoluble calcium These hydrophobic salts reduce the surface tension of the water and accumulate on the interphase surfaces between the cement grain, air and water. They stabilize the micro-alveoli and, therefore, find themselves again on the surfaces of these air pores in the hardening concrete. The other type -v.g. sodium lauryl sulfate (SDS) or sodium dodecyl phenylsulfate - in contrast, together with calcium hydroxide, form soluble calcium salts which, however, exhibit dissolution characteristics abnormal Below a certain critical temperature these surfactants exhibit a very low solubility, above this temperature they are easily soluble. By means of a preferential accumulation in the interfacial boundary layer between water and air they also reduce the surface tension, thus stabilize the micro-alveoli and preferably meet again on the surfaces of these pores in the hardened concrete. With the use of these air pore forming agents according to the state of the art there are a multiplicity of problems [L-Du & K. J. Folliard, Mechanism of air entrainment in concrete "Cement &Concrete Research" 35 (2005) 1463-71]. For example, longer mixing times, different revolutions per minute of the mixer, modified dosage stages can have the consequence in transport concrete that the stabilized air (in the pores of air) is expelled again. The transport of concrete with long transport times, poor temperature and different pumping and transport facilities, as well as the introduction of these concretes together with changed finishing work, the shaking behavior and the temperature conditions can significantly modify the content of air pores previously adjusted. This can mean, in the worst of the cases, that a concrete no longer meets the necessary limit values of a given class of exposure and has become, therefore, unusable [EN 206-1 (2000), Concrete Part 1: Specification, performance, production and conformity]. The content of fine materials in concrete (for example, cement with different alkali content, additives such as volatile ash, silicon or colored powder) also impairs the formation of air pores. It is also possible that reciprocal activities occur with fluidizing agents with defoaming activity that then expel air pores, but they can also be introduced further in an uncontrolled manner. All these influences that hinder the production of ice-resistant concrete can be avoided if the necessary air pore system is produced, not by the aforementioned air pore forming agents having a surfactant structure, but the air content comes from the addition, respectively, fixed dosage of polymeric microparticles (hollow microspheres) [H. Sommer, A new method of making concrete resistant to frost and de-icing salts, "Betonwerk &Fertigteil technik" 9 (1978) 476-84]. Because the microparticles generally have particle sizes of less than lOOμm, it is possible to distribute them in the structure of the concrete more finely and uniformly than air pores artificially introduced. In this way it is possible that even very small amounts are sufficient for a fairly good resistance of the concrete against change between ice and thaw. The use of such polymeric microparticles to improve the resistance to ice and the change between ice and thaw of the concrete, consequently, is already known in the state of the art [Cf. DE 2229094 A1, US 4,057,526 Bl, US 4 4,082,562 Bl, DE 3026719 A1]. The microparticles described therein are characterized mainly because they have a cavity that is less than 200μm (diameter) and this hollow core consists of air (or a gaseous substance). This also includes porous microparticles of the 100μm scale that may have multiple cavities and / or smaller pores. By using hollow microparticles for the formation of artificial air pores in concrete two factors proved to be disadvantageous for this technology to prevail in the market. . On the one hand, the production costs of hollow microspheres according to the state of the art are excessively high, and on the other, it is only possible to achieve a satisfactory resistance of the concrete against changes of ice and thaw by relatively high dosages.

The present invention was based, therefore, on the object of providing a means to improve the resistance against ice and change between ice and thaw for mixtures of hydraulically bound building material that develops its full activity even with relatively low dosages. This objective is achieved inventively because microparticles are used whose cavity is filled with 1 to 100% by volume of water. Surprisingly, remarkable concrete strength was achieved against the change between ice and thaw when corresponding polymeric microparticles were used for the formation of air pores, whose cavity is not (only) with air, but with water. It is also surprising that these microparticles produce an improved protection of the concrete against the effect of change between ice and thaw having a diameter of 0.1 - lμm and dosages that are in 1-2 smaller magnitudes than described in the state of the art. This was so surprising because it had been based on the assumption that only air pores, artificially introduced in the form of air micro-airoles or air-filled microparticles, would be able to provide enough free space for the expanding and freezing water. According to the present invention, polymeric microparticles are used whose cavity is filled with 1 to 100% by volume, in particular 10 to 100% by volume, of water. Water-filled microparticles of this type are already known according to the state of the art and are described in EP 22 633 Bl, EP 73 529 Bl, and EP 188 325 Bl. These microparticles filled with water are distributed on the market also under the brand ROPAQUE by the company Rohm & Haas. These products have been used until now mainly in dyes and paints for the improvement of the covering capacity and opacity of paints or prints on paper, cardboard and other materials. According to a preferred embodiment, the microparticles used consist of polymer particles comprising a polymer core (A) based on an unsaturated carboxylic acid (derivative) monomer, as well as a polymer shell of an ethylenic unsaturated monomer, non-ionic having the core / shell polymer particles swollen with the help of a base. The carboxylic acid (derivative) monomers preferably consist of a compound selected from the group of acrylic acid, methacrylic acid, maleic acid, maleic acid anhydride, fumaric acid, itaconic acid and crotonic acid. The nonionic ethylenic unsaturated monomers forming the shell (B) are preferably used styrene, butadiene, vinyl toluene, ethylene, vinyl acetate, vinyl chloride, vinylidene chloride, acrylonitrile, acrylamide, methacrylamide, C 1 -C 2 alkyl ester of acrylic or methacrylic acid. The production of these polymeric microparticles by emulsion polymerization, as well as their swelling with the aid of bases such as, for example, alkali or hydroxides of alkali and ammonia or an amine are also described in the European patent publications EP22 633 Bl, EP 735 29 Bl and EP 188 325 Bl. The inventively used microparticles have a preferred diameter of 0.1 to 20 μm. The polymer content of the microparticles used can be - depending on the diameter and the water content in 2 to 98% by weight. The usual microparticles on the market (e.g., of the ROPAQUE® type) are usually presented as an aqueous dispersion, which must contain a certain proportion of dispersing agents with surfactant structure to suppress the agglomerations of the microparticles. But it is also possible, as an alternative, to use dispersions of these microparticles that do not possess surface-active substances (and that possibly have undesirable activities in the concrete). For this the microparticles are dispersed in aqueous solutions containing a rheological adjustment agent. This type of thickening agents having a pseudoplastic viscosity generally have characteristics of polysaccharides D.B.Braun & M.R. Rosen, "Rheology Modifiers Handbook" (2000), William Andrew Publ. ] Excellently suitable are microbial exopolysaccharides from the Gellan group (S-60) and in particular Welan (S-130) and Diutan (S-657) [E.J.Lee & R. Chandrasekaran, X-ray and Computer modeling studies on gellan-related polymers: Molecular structures of welan, S-657, and rhamsan, "Carbohydra te Research" 214 (1991) 11-24.] In the inventively used microparticles can be separated the surfactants dissolved in the aqueous dispersion because the microparticles are first coagulated eg with calcium dichloride (CaCl 2) and then washed with water, then it is possible to re-disperse it in any thickening dispersion agent. water in the form of an aqueous dispersion (with or without surfactants) It is possible, without a problem, to add the water-filled microparticles in the framework of the present invention directly as a solid substance to the mixture of matter for construction. are coagulated - as described above - and isolated from the aqueous dispersion by customary methods (e.g., filtration, centrifugation, sedimentation and decantation) and the dried particles below, which effectively allows to preserve the core containing water. To leave the water content in the microparticles as much as possible without changing, it can help to wash the coagulated matter with very volatile liquids. In the ROPAQUE types used with their (poly) styrene shell, for example, alcohols such as MeOH or EtOH have given good results. The water-filled microparticles are added to the mixture of building material in a preferred amount of 0.01 to 5% by volume, in particular 0.1 to 0.5% by volume. The mixture of building material, by way of example, in the form of concrete or mortar can contain in this the usual binders of hydraulic bonding as v. g. cement, lime, gypsum or anhydrite. An essential advantage of the use of water-filled microparticles is that only an extremely small amount of air is made in the concrete. This allows to achieve clearly improved pressure resistances of the concrete. These are located at approximately 25-50% above the concrete pressure resistance that has been obtained with the formation of conventional air pores. Resistance classes can thus be achieved which can otherwise be adjusted only with a substantially lower value of water value.

(W / Z value). But W / Z values in turn eventually restrict the ease of processing the concrete.

In addition, higher pressure resistances can have the consequence that the content of cement needed in the concrete to develop the mechanical strength could be reduced and, consequently, the price per m3 of the concrete will be reduced significantly. The advantages of the present invention can be summarized in the manner in which - The use of water-filled microparticles for a system of artificial air pores in the hardened concrete has the consequence in comparison with conventional air pore forming agents that the content of air in the concrete is clearly reduced, - that from extraordinarily low quantities of water-filled microparticles are sufficient to produce a large concrete consistency in exchange for ice and thaw, - that the pressure resistance of the concrete is clearly improved, - that the production of a pore system Air with the help of these water-filled microparticles clearly improves the resistance against other additives, additions, fluidizing agents, cementitious variant composition, different W / Z values and other parameters relevant to concrete technology, - that the use of water-filled microparticles clearly improves the application requirements of concrete with great resistance to ice and thaw change in terms of production, transport and ease of processing. The following examples clarify the advantages of the use of water-filled microparticles to obtain a large concrete consistency in exchange for ice and thaw and little collapse of the concrete due to ice. Another aspect of the present invention relates to a mixture of hardened construction material with high resistance to change of ice and thaw for the production of which polymeric microparticles having a cavity are used in the inventive manner. In a preferred embodiment, the mixture of hardened building material is concrete or mortar. Another aspect of the invention relates to compositions containing polymeric microparticles possessing a cavity, whose cavity is filled with 1 to 100% by volume of water, 10 to 100% by volume of water, and a mixture of building material that binds hydraulically. Preferably, the composition comprises microparticles comprising a core (A) of polymer, swollen with the aid of an aqueous base, which is based on an unsaturated carboxylic acid (derivative) monomer and a polymer shell (B) based on a ethylenic, nonionic unsaturated monomer. In one embodiment of the invention it is further preferred that the monomers of (carboxylic acid) derivatives are selected from the group comprising acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid and crotonic acid, and the monomers ethylenic, nonionic unsaturates are selected, preferably from styrene, butadiene, vinyl toluene, ethylene, vinyl acetate, vinyl chloride, vinylidene chloride, acrylonitrile, acrylamide, methacrylamide, C 1 -C 12 alkyl ester of acrylic or methacrylic acid. It is further preferred that the microparticles in the composition have a polymer content of 2 to 98% by weight. In addition, the polymeric microparticles are preferably characterized in that they have a diameter of 0.1 to 20 μm, in particular 0.2 to 2 mm. The microparticles preferably do not contain surfactants.

In a particularly preferred embodiment of the invention, the microparticles are contained in the inventive composition in an amount of 0.01 to 5% by volume, in particular from 0.1 to 0.5% by volume, based on the mixture of building material. Mixtures of building material that are included in the inventive composition preferably comprise mixtures of building material of a binder selected from the group cement, lime, gypsum and anhydrite. Mixtures of building material are preferably mortar or concrete. EXAMPLES Example 1: Tests were carried out with water-filled microparticles of the ROPAQUE® type (Company Rohm & amp;; Haas) of different particle sizes. A different water content in the core of the respective ROPAQUE® types is produced by differential drying. This depends on the drying temperature, the drying time and the low pressure (vacuum) used. The water content inside the microparticles can be determined by titration Karl-Fischer, when the shell of (poly) styrene dried externally in a solvent was previously dissolved appropriate (for example, acetone free of water). If a dispersion of ROPAQUE coagulated first with water and then with methane is washed, then the proportion of enclosed water (100% by volume) of the ROPAQUE microparticles can be determined almost completely by simple and rapid air drying at room temperature and normal pressure with the help of the Karl-Fischer degree. It should be noted that the water content determined does not exactly match the water content in fact in the microparticles, since between the determination of the water content and the use in the concrete there is always a time interval in which the water ( respectively the water vapor) can diffuse from the cavity through the shell of the microparticles. Even in the case of a relatively close analysis in time, therefore, the indicated water content can only represent an approximate indication. The most important indications according to the manufacturer, as well as the theoretical calculations regarding the water content in% by volume of these microparticles are summarized in table 1. The polymer content of the microparticles [in% by weight] is calculated as follows : Polymer content [in% by weight] = 100% - m (H2o) [in% by weight].

Table 1 (a) the indications were taken from the ROPAQUE® technical data sheet (Cía. Rohm &Haas). (b) the shell thickness d was calculated from the indicated data, when an ideal sphere is assumed in the microparticle: d = [l- (vacuum fraction / 100%) 1 3 • size / 2 (c) Water content of the microparticles [in% by weight] is calculated as follows: Water content [in% by weight] =% by volume • p? < H2o) [% By volume / 100% • m (H2o) + m (PS)] with m (H2o) = P (H2o) • p / 6 • (size - 2d) 3, with m (pS) = P (PS) • VPS and VPS = p / 6 • size3 [1 - (Vacuum fraction / 100%)], and with a density for the (poly) styrene shell of The concrete used in the examples contained 355 kg / m3 of the American cement "Lonestar Type I / II". All other additives (eg gravel, sand, etc.) had the usual composition for concrete. A water-cement ratio of W / Z = 0.55 was adjusted. Example 2: To determine the resistance of the concrete in the change between ice and thaw, a sample of commercial dispersion containing microparticles of the type was added.

ROPAQUE® according to ASTM C 666 (Procedure A) to the concrete and it was exposed to 180 freeze-thaw cycles in an ice-thawing chamber. The plastic content of air in the concrete and the strength of the pressure concretes after 7 and 28 days were also determined. The values determined for the resistance against change of ice and thaw of the concrete should not deviate by more than 10% from the reference (classic air pore forming agent).

That is, all the determined values > 90 (reference: 99) means proper protection of the concrete against ice damage. The crumbling factor represents a qualitative measure in relation to ice damage optically visible of the outer layers of the concrete, and is qualified as follows: 0 = good, 5 = bad. It should not, therefore, be worse than "3". The following variations were made: a) Microparticles of the ROPAQUE type with different particle sizes were used: Ultra-E (0.38μm) respectively OP-96 (0.55μm). The microparticles were present as a dispersion of approximately 30%. The water content of the microparticles amounts to 100% by volume. b) Dose of different amounts of microparticles were added: 0.01, 0.05 and 0.5% by volume of ROPAQUE® referred to concrete. For comparative purposes, a conventional air pore forming agent was included and the results were summarized in table 2. Example 3: (8) A commercial dispersion of the ROPAQUE type was previously coagulated with calcium dichloride (CaCl 2 / EtOH / dispersion = 1/1/1) and the surfactants dissolved in the dispersion (emulsifying agents) were separated by washing. The "surfactant-free" microparticles were then dried at vacuum at 40 ° C. To determine the strength of the concrete in exchange for ice and thaw these microparticles were placed as solid substance in the mixer and exposed again to 180 cycles of ice and thaw according to ASTM 666 C (Procedure A). The following variants were made in this: a) Microparticles having different particle sizes, Ropaque Ultra-E (0.38μm) respectively AF-1055 (l.Oμm) were purified from surfactants and dried: SF-01 (0.38μm) having a water content of 30% by volume of H20, SF-11 (0.38μm) with 45% by volume of H20, SF-02 (l.Oμm) with 40% by volume of H20, respectively SF-12 (l.Oμm) with 60% by volume of H20. b) Dose of different amounts of these microparticles were added: the load: 0.025, 0.05 and 0.25% by volume; 2nd load: 0.1, 0.25 and 0.5% by volume, referred to concrete. For comparative purposes a conventional air pore forming agent was again included. The results are summarized in table 3. Example 4: The "surfactant-free" microparticles according to Example 2 of a commercial type ROPAQUE were dispersed in a rheological setting medium (diuthan solution of 0.4% by weight) to inhibit an agglomeration of the dried microparticles in the water, respectively, the cement binder. In determining the strength of the concrete in exchange for ice and thaw, these microparticles were placed as a 20% dispersion by weight to a diuatane solution of 0.4% by weight in a mixer, and exposed again to 180 cycles of ice and thaw according to ASTM-666 C (Procedure A). The following modifications were made in this: a) Microparticles "free of surfactants" having different particle sizes [SF-11 (0.38μm) and SF-12 (l.OMm) were redispersed in a diuthane solution of 0.4% by weight: SF-D1 (0.38μm) with 45% by volume of H20, SF-D2 (l.Oμm) with 60% by volume of H20. b) Doses of different amounts of these microparticles were added: 0.1, 0.25 and 0.5% by volume, referred to the concrete. By way of comparison, a conventional air pore forming agent AE-90 was again included. The results are summarized in table 4 below. Table 2 (a) A concrete with air pore forming agent AE-90 is noted as Reference (Ref.). (b) The ice / thaw resistance factor is based on ASTM 666 C (Procedure A). (The values determined for the resistance to freezing and thawing of the concrete should not deviate by more than 10% from the reference (classical agent of air pore formation), ie, in general, all values> 90 indicate a protection enough of the concrete against ice damage. (c) The crumbling factor represents a qualitative measure in relation to the optically visible ice damage of the outer layers of the concrete, and is scored as follows: 0 (good) to 5 (bad.) (A concrete with good resistance in exchange for ice and thaw should be evaluated with at least grade 3.

Table 3 (a) A concrete with air pore forming agent AE-90 is noted as Reference (Ref.). (b) The ice / thaw resistance factor is based on ASTM 666 C (Procedure A). (The values determined for the resistance to freezing and thawing of concrete should not deviate by more than 10% from the reference (classical air pore forming agent).

That is, in general, all values > 90 indicate sufficient protection of the concrete against ice damage.) (c) The crumbling factor represents a qualitative measure in relation to the optically visible ice damage of the outer layers of the concrete, and is scored as follows: 0 (good) to 5 (bad.) (A concrete with good resistance in exchange of ice and thaw should be evaluated with at least grade 3. Table 4 (a) A concrete with air pore forming agent AE-90 is noted as Reference (Ref.). (b) The ice / thaw resistance factor is based on ASTM 666 C (Procedure A). (The values determined for the resistance to freezing and thawing of concrete should not deviate by more than 10% from the reference (classic agent for air pore formation). That is, in general, all values > 90 indicate adequate protection of concrete against ice damage.) (C) The crumbling factor represents a qualitative measure regarding the optically visible ice damage of the outer layers of the concrete, and is scored as follows: 0 (well) a 5 (bad.) (A concrete with good resistance in exchange for ice and thaw should be evaluated with at least grade 3.

Claims (20)

1. Use of polymeric microparticles possessing a cavity in mixtures of hydraulically binding building material, characterized in that 1 to 100% by volume of the cavity are filled with water.

2. Use according to claim 1, characterized in that the microparticles comprise polymer particles comprising a swollen polymer core with the aid of an aqueous base based on an unsaturated monomer of (carboxylic acid) and a polymer coating based on a ethylenic, nonionic unsaturated monomer.

3. Use according to claim 1 or 2, characterized in that the unsaturated monomers of (derived from) carboxylic acid are selected from the group acrylic acid, methacrylic acid, maleic acid, maleic acid anhydride, fumaric acid, itaconic acid and crotonic acid.

4. Use according to one of claims 1 to 3, characterized in that the ethylenic, nonionic unsaturated monomers are preferably selected from the group comprising styrene, butadiene, vinyl toluene, ethylene, vinyl acetate, vinyl chloride, vinylidene chloride, acrylonitrile, acrylamide, methacrylamide, C? -C12 alkyl ester of acrylic or methacrylic acid.

5. Use according to one of claims 1 to 4, characterized in that the microparticles have a polymer content of 2 to 98% by weight.

6. Use according to one of claims 1 to 4, characterized in that 10 to 100% by volume of the cavity of the microparticles are filled with water.

Use according to one of Claims 1 to 6, characterized in that the microparticles have a diameter of 0.1 to 20 μm, in particular 0.2 to 2 μm.

8. Use according to one of claims 1 to 7, characterized in that the microparticles do not contain surfactants.

9. Use according to one of claims 1 to 8, characterized in that the microparticles are used in an amount of 0.01 to 5% by volume, in particular from 0.1 to 0.5% by volume, based on the mixture of building material.

10. Use according to one of claims 1 to 9, characterized in that the mixtures of building material consist of a binder selected from the group cement, lime, gypsum and anhydrite.

11. Use according to one of claims 1 to 10, characterized in that the mixtures of building material are concrete or mortar.

12. Mixture of hardened building material having a high resistance against change of ice and thawing, characterized in that polymeric microparticles having a cavity according to one of the claims 1 to 11 are used for the production of the hardened construction material mixture.

Mixture of hardened building material according to claim 12, characterized in that the mixture of hardened building material is concrete or mortar.

14. Composition comprising polymeric microparticles having a cavity, whose cavity is filled with 1 to 100% by volume of water, preferably with 10 to 100% by volume of water, and a mixture of construction material that is hydraulically bound.

Composition according to claim 14, characterized in that the microparticles comprise polymer particles comprising a swollen polymer core with the aid of an aqueous base, based on an unsaturated monomer of (derivative of) carboxylic acid and a polymer coating based on an ethylenic, non-ionic unsaturated monomer.

Composition according to one of claims 14 or 15, characterized in that the unsaturated monomers of (derived from) carboxylic acid are selected from the group of acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid and crotonic acid, and because the unsaturated ethylenic, nonionic monomers are selected, preferably from styrene , butadiene, vinyl toluene, ethylene, vinyl acetate, vinyl chloride, vinylidene chloride, acrylonitrile, acrylamide, methacrylamide, C? -C12 alkyl ester of acrylic or methacrylic acid.

17. Composition according to one of the claims 14 to 16, characterized in that the microparticles have a polymer content of 2 to 98% by weight.

Composition according to one of claims 14 to 17, characterized in that the microparticles have a diameter of 0.1 to 20 μm, in particular 0.2 to 2 μm.

Composition according to one of Claims 14 to 18, characterized in that the microparticles are present in an amount of 0.01 to 5% by volume, in particular from 0.1 to 0.5% by volume, based on the mixture of building material.

20. Composition according to one of claims 14 to 19, characterized in that the mixtures of building material consist of a binder selected from the group cement, lime, gypsum and anhydrite.