DE1171791B - Process for the production of concrete with improved physical and chemical properties with the aid of plastic dispersions - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN 4ffl9Ws PATENT OFFICE Internat. Class: C 04 b

EDITORIAL

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German class: 80 b -1/05

B 62796 VIb / 80 b

June 7, 1961

4th June 1964

It is known that some properties of concrete can be improved by adding dispersions of thermoplastics or redispersible, dried powders made from dispersions of thermoplastics by adding these substances to concrete mixtures. For this purpose, dispersions of, for example, polyvinyl acetate or copolymers of vinyl acetate with maleic acid esters or dispersions of styrene-butadiene copolymers have already been used. However, dispersions of polymers of vinyl acetate are suitable as an additive to concrete mixtures only with difficulty, since concrete mixtures in general have an alkaline reaction and the Esterbindungen optionally be saponified the polymers at _pH values of about 13 on a large scale. The strength of concrete, for the production of which dispersions of polymers of vinyl acetate were used, therefore, after some time, especially in the presence of water, falls to the strength of unmodified concrete.

When using dispersions of styrene-butadiene copolymers it is very disadvantageous that these copolymers are not resistant to solvents and in particular to hydrocarbons, like gasoline.

It has now been found that the physical and chemical properties of concrete can be improved can by adding concrete mixes 0.5 to 50 percent by weight, preferably 1 to 40 percent by weight, based on the amount of cement, a copolymer of 20 to 80 percent by weight Vinyl chloride and 80 to 20 percent by weight vinyl propionate in the form of an aqueous dispersion or of a redispersible, dried powder from such a dispersion is added. For the procedure are especially dispersions or redispersible powders of copolymers from 35 to 55 weight percent vinyl chloride and 65 to 45 weight percent vinyl propionate are suitable. Dispersions Such copolymers can be prepared from the monomers in a customary manner by emulsion polymerization using non-ionic emulsifiers such as polyglycol ethers, protective colloids such as polyvinyl alcohol, or copolymers based on acrylic acid, methacrylamide or vinylpyrrolidone will.

Dispersions, for their preparation, where appropriate, partially acetylated or acetalized polyvinyl alcohols used as dispersants are particularly useful in the process.

It is particularly advantageous to use a 5 to 60 Ge process for the concrete mixes in addition to the copolymers for the production of concrete

with improved physical and chemical

Properties with yards of

Plastic dispersions

1

Applicant: j

Aniline & Soda Factory in Baden
Aktiengesellschaft, Ludwigshafen / Rhein

Named as inventor:

Dr. Hans Reinhard, Mannheim,

Dr. Wolfgang Sliwka,

Rolf Petri, Ludwigshafen / Rhine

weight percent, preferably 10 to 20 weight percent, based on the weight of copolymer, aromatic and / or araliphatic hydrocarbons, such as benzene, toluene, xylenes and tetrahydronaphthalene, or even higher-boiling aliphatic hairs Hydrocarbons, such as decahydronaphthalene, as well

as terpenes, e.g. B. turpentine oil, a-pinene or / 9-pinene to add. With such additives, surprisingly, concrete with particularly high strength is obtained. Instead of dispersions, it is also possible to use powders which are prepared from such dispersions by drying in the usual way and which can easily be redispersed in water. Polymers of this type are distinguished from polymers of vinyl acetate in particular by increased resistance to saponification of the ester bonds under the conditions present in concrete mixes or in moist concrete. For example, films made from dispersions of copolymers of 80 ^fl / o vinyl propionate and 20% vinyl chloride or 50% vinyl propionate and 50% vinyl chloride only lose 5 or 4.5% of their weight if they are left at 100% for 7 hours ° C treated with a sodium hydroxide solution at p _H. 13 The oil and gasoline resistance of such polymers is excellent, for example films made from dispersions of copolymers of 80% vinyl propionate and 20% vinyl chloride or 50% vinyl propionate and 50% vinyl chloride, if stored in HD motor oil at 80 ° for 3 hours C only 0.8% in weight.

Concrete mixes within the meaning of the invention are mixtures of cement and aggregates, such as sand and, if necessary, other additives as they are for

409 598/413

the production of concrete are common. Concrete produced according to the invention is particularly characterized by high flexural strength and compressive strength and is particularly suitable for road surfaces, Industrial floors, chemical-resistant screeds and S as facing concrete. In addition, concrete mixes, the vinyl chloride-vinyl propionate copolymers according to this process included, used for joining old concrete with new concrete, for repairs to old concrete and as cement plaster mixes will. The method is also very generally suitable for the production of concrete moldings in civil engineering.

The parts given in the following examples are parts by weight.

example 1

100 parts of a 50% aqueous dispersion of a copolymer of 80 parts of vinyl propionate and 20 parts of vinyl chloride are intimately mixed with a mixture of 500 parts of Eisenportlandzement EPZ 275, 500 parts of standard sand I (fine) and 1000 parts of standard sand II (coarse). 175 parts of water are added to the mixture in order to obtain a water-cement factor of 0.45. The production and compaction of the cement mixture is carried out in accordance with DIN regulation 1164, § 25. Test specimens are produced from the mixture, which are stored for 28 days at 65Vo relative humidity and 20 ° C and after this time they are subjected to flexural tensile and compressive stress in accordance with DIN 1164 § 16 and § 17. A flexural tensile strength of 75 kg / cm ² and a compressive strength of 340 kg / cm ^{2 are} measured. The same values for the flexural tensile strength and compressive strength of test specimens are also obtained if, instead of the 100 parts of aqueous 50% dispersion, a redispersible, dried powder prepared in the usual way from the above-mentioned dispersion is used and the test specimens at 20 ° C. for 28 days stored under water.

Example 2

According to the information in Example 1, a cement-sand mixture is prepared, but instead of a dispersion of a copolymer of 80% vinyl propionate and 20% vinyl chloride, it contains 100 parts of a 50% aqueous dispersion of a copolymer of equal parts of vinyl propionate and vinyl chloride . The flexural tensile strength determined on test specimens made from this plastic-containing concrete mixture according to the specifications of DIN regulation 1164 is 95 kg / cm ² , the compressive strength 365 kg / cm ² .

Example 3

A mixture of 30 parts of iron Portland cement EPZ 275 and 90 parts of a mixture of 35.6% coarse gravel with a particle diameter between 7 and 15 mm, 48% fine gravel with a Particle diameter between 1 and 7 mm and 16.4% sand with a particle diameter between 0.2 and 1 mm is mixed with 6 parts of a 50% strength aqueous dispersion of 50 parts of vinyl propionate and 50 parts of vinyl chloride and 0.15 part of tetrahydronaphthalene and then 8.5 parts Water mixed in an intensive mixer for 3 minutes. Test specimens are made from the concrete mix obtained 1. Manufactured. For comparison, test specimens (2) were made from a corresponding concrete mix produced, but no tetrahydronaphthalene was added. Also were used for comparison Test specimen (3) made from an appropriate concrete mix, but it is neither a plastic dispersion tetrahydronaphthalene was still added.

The water-cement factor was 0.4 for all concrete mixes. On the test specimens were after 28 days the following properties are determined:

Concrete-
Test specimen Liter weight
kg / cm ³ Flexural tension
strength
kg / cm ² pressure
strength
kg / cm ^! (D
(2)
(3) 2.34
2.29
2.25 82.9
76
55 455
410
385

Claims (2)

Patent claims: 1. Process for the production of concrete with improved physical and chemical properties with the help of plastic dispersions, characterized in that concrete mixes 0.5 to 50 percent by weight, based on the amount of cement, a copolymer of 20 to 80 percent by weight Vinyl chloride and 80 to 20 percent by weight vinyl propionate in the form of an aqueous dispersion or a redispersible, dried powder from such a dispersion is added. 2. The method according to claim 1, characterized in that the concrete mixes in addition 5 to 60 percent by weight, based on the copolymers, of hydrocarbons added will. 409 598/413 5.64 © Bundesdruckerei Berlin