CZ202392A3 - A circular mounting of a swing axle with reduced friction - Google Patents

Abstract

The circular bearing of the pendulum axle with reduced friction enables a better distribution of the forces arising from the weight of the vehicle on the friction surface of the semi-axle bearing (1, 2, 3), where there is a smaller ratio of the force of the lever (11) acting on the places where the forces are concentrated on the friction surface (14) . At the same time, it makes it possible to better maintain the center of the swing axis (9) to the gear pinion (7) with the gear wheel (6) and their subsequent longer service life.

Description

Means for producing a suspension of mass for insulating walls and a method of producing this mass from it

Field of technology

The invention relates to a means for the production of a suspension of material for insulating walls, in particular for the production of insulating walls in excavations in a single-phase method, based on bentonite, ground blast furnace slag and an activator for blast furnace slag. . The invention also relates to a method of producing material for insulating walls from this agent.

Current state of the art

During the construction of isolation walls in excavations made in the ground, the material from which the isolation walls are made is introduced into these excavations, while these isolation walls representing vertical elements designed to prevent the spread of possible soil impurities with groundwater, or are used in construction pits or surface mining as walls to prevent a large drop in the groundwater level and to reduce the amount of groundwater pumped out. In experiments carried out by drilling technology, such as drainage wells with additional horizontal sealing of deposits and old deposits, special requirements are placed on the properties of single-phase materials for insulating walls, such as a small change in rheological properties for as long as possible, high yield strength, low sedimentation , slight evaporation of the filtrate water and later solidification, the onset of which should begin at a certain point at the latest, and a particularly low permeability coefficient for water at low compressive strength.

While in the single-phase method one works first with a pure bentonite suspension as a carrier liquid in the excavation, and only in the second step the own sealing material, for example concrete or concrete containing bentonite, is prepared into the carrier liquid in a contraction way, the single-phase method allows the use of a self-hardening bentonite suspension- cement solves this task for vertical insulation walls in a particularly economical way, while ensuring that bentonite and blast furnace slag, which later form calcium silicate hydrate phases, are optimally evenly distributed.

For horizontal seals, it is not possible to use the two-phase method due to the problematic complete penetration of the bentonite carrier suspension by the sealing suspension that is added later.

For the single-phase method, DE-PS 36 33 736 describes ready-made dry mixtures based on relatively expensive cement-stable bentonites - ground blast furnace slag (HOS) - a little Portland cement (or another activator forming hydroxyl ions) - possibly additives to change workability - possibly additives of inert substances to increase the raw density. These pre-prepared dry mixes, preferably containing Portland cement, CaO or Ca(OH) ₂ as an activator forming hydroxyl ions for blast furnace slag, are prepared by intensive mixing with the required amount of water and are introduced into the excavation in a known manner.

It was found that, for example, when using Na-bentonite or cheaper, activated Ca-bentonite and when using relatively more expensive cement-stable Na-bentonite and activated Ca-bentonite and activating with cement - from the moment of production of the dry mixture until the beginning of consumption (mixing the suspension with water ) the required properties are not set, such as especially viscosity, evaporated filtrate water, solidification, strength and water permeability at the same level. The stirred slurry is usually a thin liquid; evaporated filtrate water and deposits are higher; curing rates are reduced to up to 28 days and water permeability coefficients can be higher.

In addition, the creation of properties in the solid state, such as the rate of hardening of known suspensions, can only be adapted with difficulty to the different requirements of the installation sites (temperature, time required).

The task of the invention is to create a means for the production of material for insulating walls, whose set required properties will be guaranteed regardless of the start of use, and which, among other things, does not need to contain cement-stable Na-bentonite or activated Ca-bentonite, and which will allow simple control of the properties in the hardened state. The task of the invention is also to create a simple method of producing material for insulating walls from the above-mentioned agent.

The essence of the invention

This task is fulfilled by a means for the production of a suspension of material for insulating walls, in particular for the production of insulating walls in excavations in a single-phase method, based on bentonite, ground blast furnace slag and an activator for blast furnace slag, according to the invention, the essence of which is that it consists of a dry mixture with stable storage properties, consisting essentially of bentonite and ground blast furnace slag, with the blast furnace slag activator kept separate until slurry mixing.

According to a preferred embodiment, the dry mixture contains non-activated bentonite. However, the dry mixture can advantageously also contain activated Ca-bentonite.

A , 2+ chelating agent for Ca ions and possibly other polyvalent cations and/or a precipitant of Ca ions can be added to the Ca-bentonite during preparation instead of or in addition to the per se known activating agents.

The dry mixture may contain additives known per se to improve workability. To increase the raw density, the dry mixture may contain known inert additives.

It is also advantageous if the activator is in the form of a powder. The activator can be cement, at least one alkaline earth hydroxide, which can have divalent or polyvalent ions. The activator can preferably be Ca(OH)

Further advantageous embodiments of the invention are described in the dependent claims.

Within the framework of the invention, it was found that the set properties of known pre-made dry mixes deteriorate with increasing time and storage temperature, as well as the reaction ability of the blast furnace slag, and an uncomplicated way was found which, due to the mixing ratios, guarantees time-limited set properties and therefore prevents deterioration properties (this deterioration of properties will be referred to below as incorrect storage, or incorrect storage). According to the invention, this incorrect storage is counteracted by producing dry mixes on a base

- bentonite

- ground blast furnace slag

- possibly an additive to change processability

- possibly inert additives to increase the raw density without activator, while the activator is added first when mixing the suspension from the mentioned substances or at any time after mixing the suspension from the mentioned substances and after swelling of the bentonite. The activator is preferably added in the form of an aqueous solution, for example in the form of a solution containing an alkali metal hydroxide, especially a NaOH solution, and contains at least one other alkaline compound, which can be, in particular, an alkali metal sulfate, an alkali metal chloride and/or an alkali metal carbonate. Therefore, according to a preferred embodiment of the invention, the solution has an activator in liquid form. A particularly suitable solution contains NaOH and Na 2 SO 4 . The effect of this solution is relatively independent of temperature, that is, it acts non-critically in the mass intended for the creation of insulating walls in a wider temperature range, for example in the range from 10 to 30*C. The action of other solutions may be temperature dependent, for example depending on the mixing ratio between NaOH and other alkaline compounds. At the same time, it is possible to find out this dependence in a simple way empirically and adapt it and

sobit suspension temperatures.

In the case of using alkaline activators, almost any type of bentonite can be used according to the invention.

The development of the strength properties of the material for insulating walls can be controlled in a simple way by adding the activator only at a certain point in time and/or adjusting the amount and amount of the activator to the development of the strength properties of the material for the insulating walls.

It is known to activate blast furnace slag, among other things, with a solution of NaOH, Νη200^ or water glass. That the different behavior of the alkaline activators, chosen according to the invention, than other dry pre-mixed reaction components before their use and the use of the activators, especially in the form of solutions and preferably added to the already mixed suspension of bentonite and blast furnace slag, as well as possibly to the additives, guarantees separately the suitable properties of the material intended for insulating walls, which depend not only on the reaction of the activator with the blast furnace slag, but probably also on the physico-chemical properties of the pre-mixed suspension at the moment of addition, could not be known from the current state of the art and probably could not be expected.

At sludge formation temperatures of up to 20'C, even after a certain delay of a few days until the addition of the activator solution from the up to that time well-mixable suspension with a high liquid limit, the same solidifying or hardening process will occur, which occurs after the addition of the same solution immediately after sludge formation, or suspension. At temperatures above about 20*C, the hydraulicity of certain ground blast furnace slag alone in suspension can cause an uncontrollable onset of solidification after only a few days without a chemical activator. In order to avoid this and to ensure that the properties are the same as at temperatures below about 20*C, according to a particularly advantageous embodiment of the invention, bentonite is used, to which a chelating agent was added directly during its production or treatment; for the formation of Ca ions or 2+ precipitator of Ca ions. In this way, the start of suspension solidification can be effectively suppressed until the activator is added.

It is known that the time development of the strength properties, especially the permeability to water, of materials intended for insulating walls is time-dependent. This dependence is surprisingly suitably influenced by the method according to the invention.

According to the invention, therefore, loose or packed dry mixtures are produced, always consisting of a certain content of bentonite and blast furnace slag, modified according to the required properties of materials for the production of insulating walls, as well as, where appropriate, known additives to improve processability and, where applicable, known inert additives to increase raw density and, in addition, from known additives for increasing tightness, such as, for example, reactive silicic acid according to, for example, DE-OS 38 00 776. These dry mixtures can be stored in a dry state indefinitely without changing, or without the mass of produced by them had other than predetermined required properties.

For the specified consumption, if alkaline activators are used, a suspension is made from the dry mixture and the activator.

Advantageously, a suspension is first prepared from the dry mixture by preliminary mixing by adding a certain amount of water in the usual way, for example by careful mixing. A certain amount of alkaline activator is then added to this suspension immediately after mixing or swelling of the bentonite, so that the action of the activator starts immediately and after a certain time the required properties of the material for the intended insulating walls are created. However, the same amount of alkaline activator can be mixed into the same suspension at any later time, so that only at the time of later addition does the activator begin to work and the required properties of the material develop in the same time period, counted from the time of addition.

Alkaline activators are mixed at the moment of use, in powder form, for example into a dry mixture, but preferably into a suspension or into the distribution water.

However, mixing in the form of an aqueous solution of at least one activator into the distribution water or into the suspension is very advantageous, and a NaOH solution is particularly suitable. Alkaline salt solutions, for example Na ₂ SO ₄ , and solutions of two or more alkaline salts are also suitable. With a solution of NaOH and one alkaline salt, especially Na ₂ SO ₄ , it is possible to set the start and course of activation in a particularly well controllable way, as well as and the development of the required material properties for insulating walls.

Within the framework of the invention, blast furnace slag can also be activated with components of cement, clinker, alkaline earth hydroxides, especially Ca(OH) ₂ · It has been found that when using cement-stable bentonites, the evaporation of the filtrate water gradually increases significantly when the suspension is mixed until the beginning of solidification. According to the invention, this is countered by first producing a suspension without activator and adding the activator only after the bentonites have swollen. Another possibility of this counteraction consists in the use of alkaline activators according to the invention.

The added amount of activators depends mainly on the type, fineness and amount of blast furnace slag and on the type and amount of bentonite, possibly also on the type and amount of other added substances and is essentially determined empirically.

The invention eliminates the described disadvantages that activators can cause when they are present in a dry premix (improper storage). However, the invention can also be used when the components of the mixture are added to the material for insulating walls only on the construction site and are mixed with water into a suspension. At the same time, the use of alkaline activators prevents higher evaporation of filtrate water and enables the use of almost all known types of bentonite. When using activators containing alkaline earth ions, cement-stable bentonite or bentonite that has a chelating agent is preferably used

2+ 2+ for Ca ions or a precipitant for Ca ions. In this case, the activator is added only after the swelling of the bentonite.

In many cases, especially with the usual residual moisture of activated Ca-bentonites, it is advantageous to obtain the maximum na2+ swelling of the bentonite by additionally, preferably already during preparation, Bentonite is mixed with a chelating agent for ions.

Ca and possibly other polyvalent cations and/or a precipitant. - 2+ for Ca ions

2+

Precipitation of Ca ions by alkaline salts, whose anions form insoluble compounds with Ca, is known from patent 613 037

The following table 1 and table 2 contain the results of the experiments, from which it follows that the addition of the activator brings the surprising effect of guaranteeing the desired properties of the material for insulating walls only after the preparation of a suspension from other components of the material for insulating walls. The table values were determined as follows:

The suspension mixing procedure was used according to the prescription according to DIN 4127 (August 1986) - data in paragraph 6.1.1.

A 2 liter dosing mixer with a turbo mixer with a rotation frequency of 3000 min ^- '' was used. The mixing time was 10 minutes. The geometry of the mixing device and the vessel conformed to DIN.

Marsh time = Marsh funnel discharge time according to API RP 13 B (1982), paragraphs 2.2 to 2.4 for a discharge of 1.00 dm ³

Evaporation of filtrate water during filter press test according to DIN 4127 (August 1986) paragraph 6.4

Settling in a 250 ml cylinder (defined in API 10 (1990)) para 6.1

Start and end of solidification according to your own method:

the penetration of a steel ball of weight

9.7 g, or wire penetration.

Compressive strength = compressive strength in one axis according to DIN 18136 after water storage at test temperatures

Permeability coefficient for water according to DIN 18139 (November 1983) with variation according to Meseck, Mitteilungen des Instituts fur Grundbau und Bodenmechanik TUBraunschweig, Book No. 25 (1987) p. 109, after always three days of flow and subsequent further storage in a water bath.

Comparing the main column 1.1 with column 1.02 in Table 1, the following effect of incorrect storage results as follows:

line a2 immediately thinner liquid : 31 instead of 38 s/1 a3 increased evaporation of filtrate water: 67 instead of 40 ml a4 increased tendency to settle : 1.4 instead of 0.7% reduced compressive strength 7d: 0.6; 28d: 0.7 instead of 1.0 and 1.1 N/mm ² increased value to about 5 x E-10 instead of 6, or 2 x E-ll

The fact that the evaporation of the filtrate water of the usual pre-made dry mixtures of material for insulating walls gradually worsens until the beginning of solidification, even with proper storage, results from the comparison of lines a3 with b3 in columns 1.01; 1.02 and also

1.1.

Table 2 shows that the activator can be added at any time in a relatively wide time range without changing the set properties. This will prevent the hitherto difficult adaptation to different conditions on construction sites when using standard mixtures to which activators are already added at the factory (for example, the addition of retarders).

The reduced dependence of the strength properties on temperature results from a comparison of the values in columns 1.01 and 1.02 of rows d3 and d6 with the values in columns 3.01 and 3.02, respectively in columns 2.01 and 2.02 in table 1.

Table 1

The influence of the type of storage of the dry mixture of blast furnace slag activator (HOS) and the temperatures of sludge storage on the properties of the material for insulating walls

Recipe Sludge production immediately with DWM mixture about the production of dry Sludge production after simulating severe misplacement by storing dry mix for 1 day/60°C m ³ 1. 0 2.0 3.0 4.0 1.1 2.1 3.1 4.1 main columns bentonite always 55 tg of the same dose of Na- bentonite n kg BOYS*) 185.3 113.í 111.4 192.0 185.3 193.7 191.4 192.0 kg PZ 45F 9.1 9.1 in the water dissolve puppy kg of NaOH 1.1 2.6 1.3 2.5 kg Na ₂ SO ₄ 1.0 3.0 1.0 3.0 water 913 kg of water each time 1.01 1.02 2.01 2.02 3.01 3.02 4.01 4.02 1.1 2.1 3.1 4.1 4 columns test temperatures 10 '5 20 '0 10 '0 20 Ό 10 '0 20 '0 10 ’C 20 '0 20 '0 20 ’C 20 '0 20 '0 designation lines— fresh sludge (Immediately) al time according to Marsh s/1 31 38 42 41 31 31 36 31 45 36 36 a2 evaporated filter. v.O deposits after .7MPa/7.5' 15 40 21 20 24 21 26 61 19 20 21 . al 2 h % 0.1 OH 0.2 0 0.2 0.2 0 M 0.1 0.2 0.1 14 sludge after 4 hours inter- rolling mixing 15' rest/5 min mixing bl time according to Marsh s/1 '2 51 40 51 36 <2 31 35 <9 39 it.b. b2 evaporated filter .v.O , 5 ’ 81 125 26 35 21 32 34 210 32 32 b3 mx deposits after 2 h % 0.6 0.1 0.4 0 0.5 0.2 0.2 1.0 0 0.2 b4 start solidify ' o'clock IS I · 168 51 50 12 160 15 45 13 Art end solidify hrs. compressive strength 54 14 408 85 96 36 200 23 80 36 ¢2 10 x 10 cm after 3 days N/min 0.2 0.3 0 0.1 0.2 0 length after 7 days N/mm ² 0.1 0.05 0.2 0.1 d2 2 after 28 days N/mm 0.5 i, o 0.9 1.1 1.1' 1.1 1.4 0.6 1.4 1.1 1.1 length 2 after 56 days N/mm permeability coefficient Dro water k at 20°C (i=*30) po 3 days of flow at 1.2 i.l 1.5 1.9 1.5 1.5 1.8 0.1 2.0 1.9 1.8 length 20°C age 14 days ms ^-3 - 1-6-9 - 1-5-10 - 5-6-10 - dS 28 days m. with ³ 6-5-9 S-E-Π ι-6-ιο 1-5-10 5-5-11 1-5-90 1-6-10 6-6-10 1-6-10 1-6-10 l-r-IQ dS 56 days m. with 1 i-w 2«e-u 1-6-10 1-5-10 5-6-11 1-6-10 1-6-10 5-6-10 5-6-11 S-5-10 1-6-10 length

*) HOS 1

CaO = 41.3% SiOz = 37.0% A12 03 = 9.1%

400 m ² /kg

Table _2

Comparison of slurry properties of insulating wall material without activator with material to which alkaline activator is added 5 days after initial slurry mixing

Recipe m ³ production of sludge immediately after production of dry mixture DWM bentonite always 55 kg of the same dose of Na-bentonite as in the table 1 kg HOS 1*) kg PZ 45 F

195 dissolved in water kg NaOH kg NazSCU + 5.7 + 3.0 water

900

3

test temperatures 10 *C 10 *C sludge after x days of rest: stirred 5 -min time according to Marsh g/] evaporated filtrate water 0.7 MPa/7.5' ml sediment % start of solidification hours Std. end solidify hrs Std . compressive strength 10 X 10 Cm after 3 d N/mm ² p _O 7 d N/mm ² _P o 28 d N/,mm ² after 56 d N/mm ² permeability coefficient k for water at 20 C (i = 30 ) after 3 days of flow at the age of 14 dm«s“ ' at the age of 28 d . flPS' ¹ aged 56 d ms ¹ — > 5 —J approx. 70 30 approx. 2.5 approx. 280 approx. 480 0 0.3 1.1 1 · E-9 1 · E-10 after 5 min of mixing, on the 6th day, non-homogeneous mixed into the non-activated sludge after curing ₍₀₎ 1 5 48 0 0.15 1 .o 1 .30 1 · E-10 1 ♦ E-10

* ) see table 1

Claims (30)

A composition for producing a slurry of mass for insulating walls, in particular for making insulating walls in trenches in a single-phase manner, based on bentonites, ground blast furnace slag and activator for blast furnace slag, characterized in that it consists of a dry, stable storage composition consisting of essentially bentonite and ground blast furnace slag, wherein the blast furnace slag activator is held separately until the suspension is mixed. Composition according to claim 1, characterized in that the dry mixture comprises unactivated bentonite. Composition according to claim 1, characterized in that the dry mixture comprises activated Ca-bentonite. The composition according to claim 3, characterized in that the Ca-bentonite is preferably already treated with a Ca chelating agent and optionally 2+ other polyvalent cations and / or a Ca ion precipitator in place of or in addition to the known activating agents. Composition according to one or more of Claims 1 to 4, characterized in that the dry mixture contains known additives for improving processability. Composition according to one or more of Claims 1 to 5, characterized in that the dry mixture contains known additives of inert substances for increasing the raw density. Composition according to one of Claims 1 to 6, characterized in that the dry mixture contains known additives for increasing the density. Composition according to one or more of Claims 1 to 7, characterized in that the activator is in powder form. The composition of claim 8, wherein the activator is cement. The composition of claim 8, wherein the activator is at least one alkaline earth hydroxide. Composition according to claim 10, characterized in that the alkali metal hydroxide contains divalent or polyvalent ions. Composition according to claim 11, characterized in that the activator is Ca (OH) ₂ · The composition of claim 8, wherein the activator is an alkali metal compound. 14. The composition of claim 13, wherein the alkali metal compound is an alkali salt. Composition according to one or more of claims 8 to 14, characterized in that the activator comprises at least two activating agents. Composition according to one or more of Claims 1 to 6, characterized in that the activator is an aqueous solution containing an alkali, preferably with a pH value greater than 11. Composition according to claim 16, characterized in that the activator is a solution containing an alkali hydroxide, in particular a NaOH solution. 18. The composition of claim 16, wherein the solution is an alkali salt solution. Composition according to claim 18, characterized in that the solution is a Na ₂ SO ₄ solution. 20. The composition of claim 16 wherein the solution comprises two or more alkali salts. 21. The composition of claim 16 wherein the NaOH solution comprises at least one alkali salt. The composition of claim 21, wherein the solution comprises NaOH and Na ₂ SO 4. Method for producing a slurry of insulating wall mass, in particular for producing insulating walls in a single-phase process, wherein bentonite, ground blast furnace slag, or additives for improving workability, or additives of inert substances to increase raw density and at least one activator for blast furnace slag are mixed with water characterized in that an activator according to one or more of claims 13 to 22 is used as activator. 24. The method of claim 23, wherein the activator is admixed to the premixed suspension at any time. Method according to claim 23 and / or 24 ', characterized in that the activator is added only after the swelling of the bentonite. Method according to one or more of Claims 23 to 25, characterized in that a pre-mixed dry mixture of bentonite and ground blast-furnace slag is used and optionally an additive for improving processability and optionally an additive of inert substances to increase the raw density according to one or more of claims 1 to 7. A method for producing a slurry of insulating wall mass, in particular for making insulating walls in trenches in a single-phase manner, wherein bentonite, ground blast furnace slag, or additives for improving workability, or additives of inert substances for increasing raw density and at least one activator for blast furnace slag are mixed. with water, characterized in that an activator according to one or more of claims 8 to 12 is used and the activator is added to the premixed suspension after the bentonite has swollen. Method according to claim 27, characterized in that a pre-mixed dry mixture of bentonite and ground blast furnace slag and optionally an additive for improving processability and optionally an additive of inert substances for increasing the raw density according to one or more of claims 1 to 7 are used. Method according to claim 27 and / or 28, characterized in that the activator is added to the distribution water. Method according to claim 27 and / or 28, characterized in that the activator is premixed with water.