DE1096815B - Process for improving the properties of concrete - Google Patents

Description

Method of improving the properties of concrete A not yet prior art method for improving properties of concrete is characterized by the fact that during the preparation of the concrete mixture, aqueous, dispersions of water-soluble caseinates and water-soluble resinates containing Regenerated from natural or synthetic rubber vulcanizates, which in turn may be can contain regenerating aids or plasticators.

According to another, which is also not yet part of the state of the art Processes for improving the properties of concrete are aqueous, water-soluble Dispersions of fresh natural ingredients containing caseinates and water-soluble resinates or synthetic rubber added to the concrete mix.

It has now surprisingly been found that similar improvements can be made the properties of concrete can be achieved if one considers the preparation of the concrete mix Mixtures of water-soluble high molecular substances and water-soluble ionogenic substances adds capillary-active substances. One can use a dry, advantageously if possible finely powdered mixture of these two substances mentioned in the concrete mix or add part of the same, for example the mixing water. Advantageously but one uses aqueous solutions of these mixtures. As a water-soluble high molecular weight Substances have water-soluble proteins, especially water-soluble caseinates, proven. Water-soluble salts have proven to be water-soluble capillary-active substances of fatty acids, resin acids or mixtures thereof, especially water-soluble Salts of rosin, shown to be suitable.

The present invention relates to concrete and to a method for the manufacture of the same, and in particular it relates to a method for Manufacture; of concrete with great chemical resistance and great water impermeability.

Concrete mixes made in the usual way of cement, water and an aggregate are produced, which the latter usually made of sand or Gravel, show certain disadvantages, which the serviceability of the so produced Reduce components. The impermeability of concrete to water, especially the the so-called »lean concrete, d. H. of a concrete with a proportionate small percentage of cement is made is quite limited, in particular, when water comes into contact with the concrete body under pressure. Such concrete mixes absorb water even after they harden and allow water to pass through insufficient resistance under pressure.

As a result, the moist ones often flake off when they freeze Concrete parts take place, causing the concrete body inevitably damaged and sometimes is even destroyed. Another limitation on the practicality of such Concrete mixes lies in the fact that they are produced by the chemical action of liquids and gases can be attacked. The destructive effects of sea water and salty water on concrete is known.

Many attempts have been made to overcome these disadvantages and Overcome limitations. An attempt was made to improve the tightness of the concrete body increase by increasing the relative proportion of cement it contains. In the meantime is the increase in the percentage of cement in the concrete over a certain amount Limit not only uneconomical, but also reduces the elasticity of the end product and causes stress during hardening, which is common lead to the formation of cracks. There is also an increase in the relative cement content Hand in hand with an increase in the required amount of mixing water, which in turn adversely affects the quality of the end product.

It is also known that the surface tension of water by adding organic lyophilic colloids and that when using these colloids in cement pastes reduce surface tension with a increasing plasticity of the pastes.

Also the joint use of air-entraining agents and non-ionic ones Dispersants in concrete and mortar mixes are known. With such mixtures however, the non-ionic dispersants do not contribute improvement contributes to the water tightness of the concrete, since it does not have any in the presence of alkaline earth ions capable of forming water-insoluble salts.

It is already the addition of various substances to the basic concrete mix has been proposed, however, it has not been possible to date to use a concrete to obtain which satisfactorily combines mechanical strength with chemical resistance and impermeability and the; Wine specialist and more economical Way can be made.

It is therefore an object of the present invention, a method indicate to produce a concrete. which avoids the disadvantages discussed above. It is a further object of the present invention to provide a concrete, -the -a -high resistance to chemical attack and a high level of water impermeability and which can be produced in a simple and economical way can.

With the focus on achieving the above goals and Other objects of the present invention include a method of making Concrete; consisting in the fact that an intimate mixture is produced, which is essential Components cement, water and an aqueous mixture of water soluble proteins and a substance selected from the group of water-soluble high molecular weight fatty acid salts and the water-soluble resin acid salts is selected, the intimate mixture also contains additives that harden this intimate mixture leaves, with a chemically resistant concrete body of high water impermeability is formed: Thus, according to the present invention, the properties of concrete much improved by making the. Concrete mix z. B. an aqueous solution of a water-soluble caseinate and a water-soluble one Resinats admits.

The use of an aqueous solution is particularly advantageous water-soluble caseinate and a water-soluble rosin salt.

The total dry weight of the water-soluble proteinates and the water-soluble ones Salts from the group of fatty and / or resin acids that lower the surface tension can be 0.04 to 1.20 /, of the cement weight. The best results will be however, obtained when 0.08 to 0.4% of the compounds mentioned are based on the cement weight.

By adding the above solution to the concrete mix it is possible to reduce the required amount of mixing water, but with the slump of the freshly mixed concrete, measured for example by the vibration test will. So by adding the above: solution, the plasticity and workability of the concrete is significantly improved. Furthermore, the additives according to the present invention reduce Invention for concrete mix the tendency of the freshly made concrete mix to Settling or water separation, so that concrete mixes according to the present Invention are manufactured, can be stored for a long time and also by tubes and can be transported in containers without separating the water occurs. The great insensitivity of concrete, according to the present invention was manufactured, versus storage and transportation is particularly important when large and extensive construction projects. Although the addition of the solution according to the present Invention increases the pore volume of the concrete, one still achieves a Increase in flexural strength and compressive strength of the finished concrete body, as well as a significant increase in resistance to chemical attack by liquids and gases and against the passage of water under pressure and against rising water.

The aqueous solutions or mixtures of water-soluble surface tension-lowering agents Salts and high molecular weight water-soluble or at least water-swellable substances are preferably added to the make-up water or a part of it. It is also possible, a stock solution diluted with water of the aqueous mixture of the surface tension-lowering ionogenic substances and the water-soluble or water-swellable high molecular weight Preparing substances and adding this stock solution to the mixing water or part of it to add. This has the advantage that as a result of the greater dilution Stock solution whose viscosity is reduced and that you have a more complete and faster even distribution of the additives in the mixing water achieved. The resin acids, the salts of which are advantageously used in aqueous solutions are those that contain a carboxyl group and are water-soluble Form alkali salts, such as rosin, spruce resin, balsam resin, extracted root resin, Abietic acid as well as the corresponding resins in oxidized or blown form, hydrogenated rosin, the carboxyl group being retained, also acidic ones Coniferous resins containing resin acids and oxidized resin acids, and more neutral high molecular weight components and acidic phenol-containing resins, for example those known commercially as Vinsol resins.

The proteins can be caseinates or any other animal or vegetable protein that is either soluble in water or at least in a water-swellable form or converted into such a form such as animal glue, soy protein, fish meal, etc.

The following examples are only intended to illustrate the present Invention, but not to limit it to specific details of the examples.

Example 1 a) A concrete mix was prepared in the usual way from 2000 parts by weight of Rhine sand from 0 to 7 rum, 250 parts by weight of Portland cement Z 225, 290 parts by weight of water. b) A concrete mix similar to (a) described, was prepared with the addition of 2 parts by weight of an aqueous Solution consisting of 8 parts of rosin, which is water-soluble with triethanolamine 8 parts by weight of caseinate, which was also made with triethanolamine made water soluble, and 284 parts by weight of water.

The above aqueous mixture was prepared so that only one Mixture made from 20% water-soluble rosin; 200/0 water soluble Caseinate and 60% water and then concentrated 40 parts of these Mixture diluted with 260 parts of water.

It has now been found that in order to achieve the same technical processability in case (b) as in case (a), measured by the slump of 12.5 cm, only 230 Parts of mixing water were required. In other words, the amount of the The required mixing water was at (b) 21% less than the required mixing water at a).

c) The experiment according to (b) was repeated, but instead of 2 parts of the aqueous mixture, 8.6 parts were used. In a manner similar to the above, it was found that only 200 parts of mixing water were required to achieve the same processability as in (a). In this case the reduction in the required amount of mixing water was 310/0.

Here, as in all of the following examples, the Dispersion, additional amount of water introduced when calculating the mixing water savings not taken into account because it is within the usual error limit.

The properties of the concrete bodies, which were manufactured according to (a), (b) and (c), were determined according to the German test methods as follows: Compressive strength ... . . . . . . . . DIN 1164/1942 Flexural strength. . . . . . . . . DIN 1164/1942 Slump. . . . . . . . . . . . . . DIN 1164/1942 Pore volume ............ pore volume checker of the chemical Laboratory for the clay industry Three prisms with the dimensions 40-40-160 mm were used to determine the flexural strength, and three cubes with an edge length of 100-100-100 mm were used to determine the compressive strength. The strengths of the test specimens were determined after 7 and 28 days of storage. The storage for the first 7 days was carried out in the water box, during the following 21 days in air, which had a relative humidity between 40 and 50 ° / o at a temperature between 20 and 22 ° C.

All sample mixes were in a gravity mixer with a Mixing time of 90 seconds carried out.

The following results were obtained: Table 1 Pore bending tensile strength Compressive strength Mixture retention (kg / cm2 (kg / c-2) (° / o) 7 days I 28 days 7 days I 28 days a) 6.0 15.9 27.0 72 140 b) 13.0 18.3 30.0 78 155 c) 13.0 21.5 33.3 85 170 As can be seen from Table 1, the addition of the mixture of the water-soluble triethanol compounds of rosin and casein, both of which had been made water-soluble by means of triethanolamine, led to an increase in the pore volume, at the same time as an increase in the flexural strength and compressive strength of the finished concrete body.

The resistance of the freshly made concrete mix to Separation was tested in the following way: 1 kg of the concrete mix was in one Vessel with a diameter of 10 cm on a vibrating table 100 and 300 strokes exposed.

A measure of the degree of water retention or the reduction in the risk of segregation is the amount of cement liquid that is deposited above the concrete mix. The results of this test procedure are summarized in the following table: Table 2 Water separation Mix 100 puffs 300 pounds a) 25.0 cm3 48.0 cm3 b) 1.5 cm3 8.0 cm3 c) 0.8 cm3 6.0 cm3 As can be seen from Table 2 above, the addition of the mixture according to the present invention in experiments (b) and (c) resulted in a very considerable reduction in water separation and a corresponding improvement in the storage and transport properties of the concrete mixture.

The resistance to water penetration under pressure was measured in the following way: Test plates with dimensions 160.140-40 mm were made from the concrete to be tested, and after 28 days a surface area of 36 cm2 was exposed on one of the two large sides of the plates exposed to water under a pressure of 4 atmospheres. The following results were obtained: Table 3 Amount of water, Time to pass through the plate Mixture of water through which passes inside g 40 mm thick plate of the next (Minutes) 60 minutes (cm3 ) a) 10 30 b) 100 2 c) 300 0 The resistance of the finished concrete to the penetration of oil under pressure was measured in a manner similar to that described above with reference to the penetration of water, and it was found that the time until the first drop of oil appeared on the underside of the slab (opposite side the slab to the side on which the oil acted under pressure) was about ten times as long for the concrete mixes (b) and (c) than for the concrete mix (a).

The prevention of capillary rise of water in the concrete body in accordance with the method of the present invention was made by the following laboratory procedure tested: concrete cubes with an edge length of 100 mm were half their height soaked in water. After lying in the water for 24 hours, the Concrete cubes removed from the water and split. The degree and level of humidification were then determined on the cleavage area. It was found that with mixture (a) the whole cube was soaked that with mixture (b) that part of the cube, which protruded above the water, was moistened to a height of 10 to 20 mm and that with mixture (c) the water penetrated the cube from all sides was to a depth between 10 and 15 mm, but that moisture penetration of the upper parts of the cleavage surface and no wicking effect had taken place.

Example 2 (a) A concrete mix was prepared in the usual way, consisting of 1400 parts by weight of Rhine sand 0 to 3 mm, 600 parts by weight of Rhine sand 3 to 7 mm, 286 parts by weight of Portland cement Z 225, 250 parts by weight of water.

(b) A concrete mix corresponding to the above was prepared, but with the addition of 1.5 parts of an aqueous mixture consisting of 2.5% gum resin that was treated with potassium hydroxide until it was soluble in water, 2.5% Potassium stearate, 15% casein, which with potassium hydroxide for swelling had been brought, the rest of the water.

It was found that the amount of mixing water required for concrete mix (b) to achieve a 12 cm slump equivalent to that achieved with mix (a) was 190 parts of water compared to 250 parts of water in the concrete mix (a). Reducing the amount of mixing water while maintaining the same workability of the concrete resulted in a significant increase in the resistance of the finished concrete body to chemical attack by liquids and gases. The test results with regard to pore content, flexural tensile strength and compressive strength are summarized in the following table Table 4 Pore bending tensile strength Compressive strength Mixture retention (kg / em2) (kg / cm2 (° / o) 7 days (28 days 7 days I 28 days a) 7.6 27.0 41 116 211 b) 12.2 27.0 42 106 215 The table above shows that, despite the increase in the pore content from 7.6 to 12.20 /, there was no decrease in flexural tensile strength and compressive strength after 28 days.

Example 3 (a) A concrete mix was prepared which corresponds to that in Example 12 produced under (a).

(b) To the above concrete mix was added 1.5 parts of a mix added, which consisted of 5% sodium behenate, 15% casein, with triethanolamine swollen, 4% triethanolamine, remainder water.

The same technical workability as the concrete mix (a) shows, was achieved with concrete mix (b) using only 195 parts of mixing water used, which corresponded to a reduction in the amount of mixing water by 22%.

The following table gives comparative results with regard to pore content and mechanical properties: Table 5 Pore bending tensile strength Compressive strength Mixture retention (kg / c-1) (kg / -2) (%) 7 days 28 days 7 days I 28 days a) 7.6 27 41 116 211 b 7.6 32.8 62 154 282 As you can see, the addition of the mixture according to Example 13 reduced the amount of mixing water without increasing the pore content. The freshly prepared concrete mixture according to (b) showed great resistance to water separation, and the finished concrete bodies therefore had high mechanical strength and great resistance to chemical attack.

Example 4 (a) A concrete mix was prepared which corresponds to that in Example 2 under (a) described corresponded.

(b) 1.5 parts of an aqueous mixture were added to the above concrete mix Mixture added, which consisted of 5% of the potassium salt of alkylbenzenesulfonamidocaproic acid, 15% casein, which was swollen by adding an aqueous potassium hydroxide solution, Remainder of an aqueous solution of dilute potassium hydroxide.

In order to achieve processability with mixture (b) that corresponds to that of mixture (a), namely a spreading belt of 12 cm, 200 parts of mixing water were required, which corresponds to a saving of 20% of mixing water compared with mixture (a) . The pore content and the mechanical properties of the finished concrete body according to (a) and (b) are compared in the following table: Table 6 Pore bending tensile strength Compressive strength Mixture retention (kg / C-2) (kg / C-2) (° / o) 7 days I 28 days 7 days I 28 days a) 7.6 27.0 41 116 211 b) 10.6 29.5 47 131 248 It can be seen that according to the present invention, despite an increase in the pore content from 7.6 to 10.60f, an increase in the flexural tensile strength and the compressive strength was achieved. Concrete made according to (a) and (b) was used to form reinforced concrete articles. After a long period of storage, it was found that the reinforcing bars in the concrete produced according to (b) were free from corrosion, while the reinforcing bars in the concrete bodies produced in the same way and stored in the same way and made with concrete mix (a) showed strong signs of corrosion. Example 5 (a) A concrete mix was produced which corresponded to that described in Example (a).

(b) To a concrete mix as above was added 1.5 parts of an aqueous Mixture added, which consisted of 6.6 "/, gum resin, which is water-soluble with lithium hydroxide had been made, 13.40 /, pearl glue, rest of water. To get a slump with mixture (b) to achieve the same as that obtained with the mixture (a) became 200 parts Mixing water is required, which reduces the total amount of mixing water by 20 ° / o corresponded.

The following table shows a comparison of the pore content and the mechanical properties of concrete bodies made from mixtures (a) and (b) Table 7 Pore bending tensile strength Compressive strength Mixture retention (kg / C-,) (kg / cm2) (° / o) 7 days I 28 days 7 days I 28 days a) 7.6 27.0 41 116 211 b) 10.6 30.0 46 120 244 Again, there is an increase in the pore volume as well as an increase in the mechanical strengths.

Example 6 (a) A concrete mix was prepared which corresponds to that in Example 12 described under (a). (b) To a concrete mix As above, 1.5 parts of an aqueous solution consisting of 6.6 parts were added Sodium oleate, 13.4 parts of fish meal that was swollen with an aqueous ammonia, 78.5 parts of a dilute aqueous ammonia solution.

In order to achieve a processability for mixture (b) which corresponded to the processability of mixture (a), namely a slump of 12 cm, 225 parts of mixing water were required. This corresponds to a reduction in the total amount of mixing water by 10%. Pore content and mechanical properties are compared in the following table: Table 8 Pore bending tensile strength Compressive strength Mixture content (kg / C-2) (kg / cm2) (° / o) 7 days (28 days 7 days I 28 days a) 7.6 27.0 41 116 211 b) 9.5 27.0 42 125 230 Thus, while the pore content of the concrete body according to the present invention grew from 7.6 to 9.50 / , a simultaneous increase in the mechanical strength of the concrete body took place.

The salts of resin acids and proteins, such as casein, can be formed are caused by the reaction of cations such as ammonia, organic amines such as triethanolamine, Ethylamine, tributylamine, morpholine or piperidine, furthermore inorganic cations, such as lithium, sodium, potassium, rubidium or cesium, preferably in their form Hydroxides with the resin acid or the protein.

Without being limited to a specific pH range, general found that the suitable solutions have a pH range between 7 and 10 or even more exhibit higher.

The relative amounts of rosin acids that can be obtained from natural coniferous resins, such as rosin, and proteinaceous substances, such as casein, can vary widely. Preferably, however, the amount of the casein or the like is between 20 and 1,000 % by weight of the amount of rosin acid. It should be noted, however, that the present invention is not intended to be limited to any particular weight ratio between the resin acids and the proteinaceous substances.

The total dry content of the aqueous solution can be within wide limits vary and is preferably between 10 and 70%. In essence, it comes on the ratio between the total dry matter of the solution and the total amount the concrete mix. Depending on the desired effect, the amount will be the aqueous solution that is added to the concrete mix, preferably adjusted so that that it is between 0.25 and 5 kg dry matter per cubic meter of concrete. Nevertheless the present invention is not intended to be limited to the relationship described above between dry matter of the aqueous solution and total concrete volume, as for special Purposes also relatively larger or smaller amounts of the aqueous solution Can give results. For practical purposes, a dispersion with a dry content will be used between 50 and 60% is used as a particularly suitable starting material. In a Concentration of about 50 to 60% dry matter is the solution of paste-like Nature. The solution is in the required amount of the concrete mix in added to an ordinary concrete mixer or in a high-speed concrete mixer. Preferably is first a homogeneous mixture of the pasty solution and such The amount of mixing water produced is the same to 3 times the amount by weight corresponds to the solution, and the liquefied mixture then becomes the remainder of the mixing water mixed in.

In summary it is about the advantages of adding an aqueous mixture from surface tension lowering substances and a high molecular weight substance, such as a water-soluble caseinate and a water-soluble resinate, to say the following about the concrete mixes according to the present invention: These The advantages are a reduction in the amount of mixing water required can be up to 25 to 30% without reducing the workability of the concrete mix. Furthermore, concrete mixes according to the present invention can be stored for a long time and transported without risk of water separation, so that the concrete mixes according to the present invention can be transported in closed containers or can be pumped through long pipelines without reducing their plasticity and homogeneity. By adding the solutions of the substances mentioned, additional Pores formed in the concrete, the amount of additional pores from the concrete composition depends. This improves the insulating properties of the concrete without reducing it the values for mechanical strength. Another advantage of the invention is based in the fact that when adding the aqueous solutions according to the present invention Cracking in the hardened concrete is avoided. Concrete, which is an aqueous mixture according to the present invention, also has an increased resistance against the passage of water under pressure and against capillary absorption of Water. The concrete made in accordance with the present invention also shows improved resistance to aggressive liquids such as salt water, Oils and the like, and against gases that can otherwise attack concrete structures. The water resistance of concrete made according to the present invention is of particular importance in the manufacture of dam structures, structures, who are exposed to sea water, in chemical factories, salt works, for the Erection of structures and foundations in damp subsoil for underwater structures and similar.

Concrete mixes comprising the aqueous mixes of the present invention contain, possess a high degree of elasticity that such concrete mixes also makes it valuable for joint sealing. Paintable mixtures of mortar and the Solutions according to the present invention can also be used as top coats, in particular for concrete and masonry surfaces.

Claims (3)

CLAIMS: 1. Method for improving the properties of Concrete, characterized in that in the preparation of the concrete mixture this dry or aqueous mixtures of high molecular weight, water-soluble proteinates and water-soluble, surface tension-lowering salts from the group of Adds fatty and / or resin acids. 2. The method according to claim 1, characterized in that that the total weight, based on dry matter, of the water-soluble proteinates and the water-soluble, surface-tension-lowering salts from the group of Fatty acids and / or resin acids 0.04 to 1.200 / 0, preferably 0.08 to 0.40% / 0, of the cement weight. 3. The method according to spoke l and 2, characterized in that an aqueous mixture of a water-soluble caseinate and a water-soluble rosin salt is used. Documents considered: German Auslegeschrift No. 1003 640; Rock Products Magazine, Oct. 24, 1931, pages 54 and 55.