LU82862A1 - METHOD FOR PRODUCING EDITABLE, LIGHTWEIGHT COLLOID CONCRETE, AND PRODUCT OBTAINED ACCORDING TO THIS METHOD - Google Patents

Description

Process for producing workable / light colloidal concrete and product obtained according to this process

The present invention relates to a process for the manufacture of workable, light colloidal concrete from water and cement, which contains additives, in particular to influence the physical and mechanical properties, and the product obtained by this process.

10 The concrete is to be used to manufacture molded parts.

* Colloidal concrete made of cement and water can be produced, for example, by the process described in German patent application P 27 18 236, which provides 15 cement and water in a mixer in a ratio of 0.25-0.6 for a period of about 2 Pre-mix minutes at a speed of about 300 m / minute and then subject to a mass acceleration of at least 2 g (g = 9.81 m / sec2) for at least 8 minutes.

20th

Such a product can serve, for example, to inexpensively replace the expensive paints, paints, varnishes or plastic coatings used for protection against corrosion, for example based on organic polymers. One of the main advantages of these mixtures is that the steel parts to be coated do not have any surface treatment ζ. · Β. by sandblasting, which are a high factor when calculating the production costs for the conventional ♦

Represents corrosion protection.

30th

If you want to make a concrete that can be sawn, drilled, sanded, milled, nailed and the like. is workable, which is not the case for the concrete described above, so one has to rely on the addition of supplements.

35

This is how the LU 56.300 describes a lightweight concrete that - 3 - reduces the concrete density down to values of around 1 kg / dm

Cooking salt adds. If, on the other hand, you do not use saline water, a mixture is created that is difficult to pour or pour. Syringes can be processed further and has long curing times. In addition to the salt, a hardening accelerator should or may 5. Swelling agents are added. According to the invention, the wood flour is not added in its original form, but as an aqueous slurry, since otherwise part of this light material would be atomized and lost due to the vortex caused by the stirrer.

] _q It is also important that the amount of water required to produce the wood flour slurry represents only 50% of the total amount of water to be used. After adding the additive, the mixture is intensely colloided for a further 1-5 minutes.

15

The process according to the invention can be carried out easily and without problems, provided that the individual process conditions are observed.

20th However, it turned out that even slight deviations from the individual process conditions, such as too high or too low moisture content of wood flour or an inadequate supply of wood flour lead to the failure of the manufacturing process.

25 λ

So in the case of an improper addition of the

Proportion of wood flour, climb up the mix on the wall of the mixer * and bind it, while a cavity forms around the Ruhrer wing, in which it rotates ineffectively.

30 While the ability of the colloidal mortar obtained by the method according to the invention to adhere to steel is very good, the new product shows a surprisingly good surface quality, which is favorable in view of the desired production of molded parts by casting or spraying.

a - 3 -

Supplement contains sawdust. The latter are impregnated with iron hydroxide and thereby mineralized, primarily using iron sulfate, which is neutralized with the help of lime milk in order to obtain iron hydroxide in this way.

5

The individual procedure is to soak sawdust with FeS04 solution for 30 minutes at 50 ° C, treat the soaked shavings with milk of lime until the p ^ is about 10 and add the mass first with cement and then with water.

10 w t However, a concrete prepared in this way does not have the excellent homogeneity that characterizes the so-called colloidal concrete.

15 The aim of the invention is to propose a method according to which, in a way which is simpler and cheaper than the known methods, a machinable colloidal concrete can be produced which has a favorable density and at the same time satisfactory mechanical properties.

20th

This aim is achieved by the method according to the invention, which is characterized in that a proportion of 25-60% water, in which 10-30% by weight sodium chloride is dissolved, in a mixer, based on the amount of cement, is stirred. 25 rers in a rotary movement such that the peripheral speed on the outer diameter of the stirrer min.

1500 m / minute is that the mixer is charged with cement, that the rotational movement of the stirrer is throttled to at most half the circumferential speed and the mixture is fed a proportion 30 of at least 10% by weight wood flour based on cement so that the Surcharge comes into the center of the funnel-shaped profile of the mixture formed by the stirring.

In fact, it has turned out that the addition of a 35 organic material to a water-cement mixture surprisingly succeeds in the course of an intensive colloiding process, if instead of using pure water, a certain amount is immediately used at the beginning of the manufacturing process - 4 -

A colloidal concrete produced according to the invention has the following mechanical properties, depending on the wood flour content:

Density after hardening falling to 1 kg / dm3 5 Compressive strength after 7 days up to 170 kp / cm ^

Compressive strength after 28 days up to 220 kp / cm2

These strength values are lower than the values that can be achieved with highly colloidal cement mortars without the addition of wood powder 10, but the values achieved are * * sufficient for the envisaged applications.

With the colloidal concrete produced according to the invention, molds and components of any geometry can be poured into molds or sprayed onto molds. The coating runs smoothly and without bandages.

Devices can be used to carry out the manufacturing process according to the invention, as described by the applicant in LU 81.524 and (A 613); please refer to the drawings. 1 shows a cross section through a suitable mixer and FIG. 2 shows a section through a stirrer which is excellently suitable for the present method.

One recognizes the jacket (1) of the mixer of the 2 foldable.

*

Has lid (2). The mixing device includes the stirrer (3) which is driven by the motor (5). The latter 30 is adjustable to 2 speeds, one of which is twice as high as the other. Even when the lids (2) are closed, the wood flour (S) can be added so that the aggregate reaches the center of the profile of the moving mix (10), as indicated by the arrow (S). For this purpose, a funnel of appropriate shape can be provided, which is inserted at an angle into the open space between the lid (2) and the shaft of the stirrer (3) »and through which the aggregate reaches the mix precisely at the intended location.

As indicated in FIG. 1, the material to be mixed experiences a movement during stirring 5, the shape of which reminds one of a lemniscate and the surface profile of which forms a central funnel. It is important that the knockdown goes into that funnel.

2 shows the stirrer which is preferably to be used. It is a two-tier agitator that has 3 blades "- per level. Are the wings offset by 120 ° in each level? the two wing series are in turn offset by 60 °. The blades are inclined at 12 ° to the plane perpendicular to the stirrer axis.

15

As far as the mass of the stirrer is concerned, it has been found that optimal results can be achieved if the ratio between the total diameter of the stirrer in the working position and that of the mixing container 1 / 1.3 - 1/2 20. is.

Λ *

Claims (6)

1. A process for producing workable, light colloidal concrete from water and cement, which contains additives in particular for influencing the physical and mechanical properties, characterized in that in a mixer a proportion of 25-60% based on the amount of cement Water, in which 10-30% by weight of table salt is dissolved, is set into a rotary movement by means of a stirrer such that the peripheral speed on the outer diameter of the stirrer is min. 1,500 m / minute is enough to fill the mixer with cement, to reduce the rotary motion of the stirrer to at most half the circumferential speed and to make up at least 10% of the mixture 15% by weight of wood flour based on cement is fed in such a way that the aggregate reaches the center of the funnel-shaped profile of the material to be mixed, which is formed by stirring. 20th .2. A method according to claim 1, characterized in that the wood flour is added in the form of an aqueous slurry. 3. Process according to claims 1 and 2, characterized in that the amount of water required for producing the wood flour slurry min. Represents 50% of the total amount of water used. 4. Process according to claims 1-3, characterized in that the mixture is added 1-5 after addition of the additive Colloided for 30 minutes by mechanical stirring. 5. Process according to claims 1-4, characterized in that a swelling agent and / or a hardness accelerator is added to the mixture. 35 6. Colloidal concrete produced by the method according to claims 1-5.