DE2953652C1 - Hydraulic inorganic mass - Google Patents

Description

a) at least one alkaline hardening agent from the group consisting of sodium hydroxide, potassium hydroxide, calcium oxide, Sodium carbonate, potassium carbonate and calcium carbonate and

b) at least one neutral or approximately neutral hardening accelerator from the group of magnesium hydroxide, Aluminum hydroxide, magnesium oxide, aluminum oxide, sodium chloride, potassium chloride, calcium chloride, Magnesium chloride, aluminum chloride, sodium sulfate, potassium sulfate, magnesium sulfate, aluminum sulfate and / or magnesium carbonate

are included, the mixing ratio of curing aid a) to curing accelerator b) is between 1: 1 and 1: 6 and the sum of curing aid a) and curing accelerator b) 0.1 to 5 parts by weight.

2. Cement according to claim 1, characterized in that there is Portland cement as the curing aid used instead of calcium oxide.

3. Cement according to claim 1, characterized in that it is an ordinary component as a further component Cement, preferably a fast high strength portland cement, high alumina cement or white cement as Contains filler.

4. Cement according to claim 1, characterized in that it is used as aggregates sand, gravel or granular Contains blast furnace slag.

5. Cement according to claim 1, characterized in that it contains a weight-saving material.

6. Cement according to claim 5, characterized in that it contains finely divided perlite powder.

7. Cement according to claim 1, characterized in that it additionally contains a setting retarder.

8. Cement according to claim 1, characterized in that it additionally contains a setting deactivator.

The invention relates to a hydraulic inorganic mass with high setting speed, the stiff Hydrate the properties of rapid hardening, extremely high mechanical strength, low specific Weight, high corrosion resistance and significant expansion during hardening. the The invention therefore relates to an improved slag or blast furnace cement, which has a large proportion of gypsum contains.

It is already known that a hydraulic inorganic mass, which by adding 10 to 20 parts by weight of weakly calcined anhydrous gypsum or gypsum hemihydrate and not more than 5 parts by weight portland cement or calcium hydroxide to about 80 parts by weight of a fine powder of granulated blast furnace slag has been obtained with potentially hydraulic properties, namely a so-called "high sulphate cement" alone as cheap cement, which is essentially the same in properties as portland cement, or as a mixture with Portland cement can be used (Japanese Enzyclopaedia Chemica, Volume 5, 1961, Page 204, and Japanese Patent Publication No. 2617/64, page 6). However, the stiff hydrate tends to High sulphate slag cement of this type to weathering on the surface, so this slag cement for was hardly used for practical purposes.

The object of the invention is to improve the above-mentioned metallurgical cement with a high sulfate content and the creation of a hydraulic inorganic mass that provides a dimensionally stable hydrate which rapidly sets and hardens, high mechanical strength, high corrosion resistance, noticeable expansion during Cure and has high weather resistance and which are used with or without aggregates

This object was achieved by providing a sulphatically excited slag cement that exists

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1. 80 parts by weight of finely powdered granulated blast furnace slag, fi

2. 20 parts by weight of weakly calcined, anhydrous gypsum or gypsum hemihydrate and f |

3. Additions and »;

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is characterized by the fact that as additions v \

a) at least one alkaline hardening aid from the group consisting of sodium hydroxide, potassium hydroxide, calcium oxide, sodium carbonate, potassium carbonate and calcium carbonate and> 3 b) at least one neutral or approximately neutral hardening accelerator from the group magnesium hy-? ■; hydroxide, aluminum hydroxide, magnesium oxide, aluminum oxide, sodium chloride, potassium chloride, calcium chloride ·. rid, magnesium chloride, aluminum chloride, sodium sulfate, potassium sulfate, magnesium sulfate, aluminum sulfate; '; j and / or magnesium carbonate '; i

are included, the mixing ratio of curing aid a) to curing accelerator b) between 1: 1 and 1: 6 and the sum of curing aid a) and curing accelerator b) 0.1 to 5 parts by weight amounts to

The solution to this problem according to the invention was not possible with knowledge of the prior art. So although DE-AS 10 16 181 describes a sulphate-stimulated cement made from 80 blast furnace slag and 20% gypsum, however, nowhere does the use of a curing aid and curing accelerator suggest mentioned The mechanical strength values of the cement are very low.

In DE-OS 24 35 890, although the use of an alkaline curing aid in the production of a sulphatically excited slag cement, but there is no indication of its use of a neutral or almost neutral curing accelerator, as well as any indication of this for the Subject of the application so critical mixing ratio of slag and plaster of paris.

Kühl, Zementchemie, Volume II (1958), p. 712 (3), teaches the use of an alkaline curing aid the production of a sulphate excited cement. Again, however, there is no reference to one neutral or nearly neutral hardening accelerator. True, the use of calcined dolomite mentioned, however, it is not used as a neutral hardening accelerator, but as an alkaline hardening aid used The term "hardening accelerator" is nowhere to be found in the citation, the same there is no reference to the critical mixing ratio of gypsum to slag.

Finally, in Keil, Hochofenschlacke (1963), p. 82 ff. (4), the use of CaO or Ca (OH) ₂ as an alkaline hardening aid in the production of sulphatically excited slag cements is described, but again there is no reference to the use of one neutral or almost neutral hardening accelerator, as well as the reference to the critical mixing ratio of gypsum to slag.

Instead of the calcium oxide used as a hardening aid, Portland cement can be used, which contains small crystals of calcium oxide in the matrix of the cement clinker substance.

The composition according to the invention shows a markedly rapid setting. The start and end times of setting at a temperature of 20 ^° C. are about 5 and 7 minutes, respectively, as can be seen from many of the examples below, in contrast to about 2.5 and 3.5 hours for conventional Portland cement or conventional slag cement with a high sulfate content or about 4 and 5.5 hours for a Portland cement that was mixed with 60% by weight of a finely divided powder of granulated slag.

The mean values for flexural strength and compressive strength of the rigid hydrate according to the invention im Mixtures with sand are shown in Table 1.

Table 1

Curing time

1 hour 1 day 3 days 7 days 28 days

Flexural strength (N / mm ² ) 1 2 8 10 11

Compressive strength (N / mm ² ) 6 16 34 41 45

These mechanical strength tests were carried out according to that described in JIS R 5201 for portland cement Standard method performed. Although the mixing ratio of cement to the standard sand for portland cement was set to 1: 2, for the composition of the invention this mixing ratio was set to 1: 1 and the water / cement ratio is set at 37%. The other conditions were the same as in JIS R 5201.

Table 2 shows the results of comparative tests on flexural strength and compressive strength for the stiff ones Hydrates of an ordinary portland cement, an early high strength portland cement and a conventional one Metallurgical cement with a high sulphate content.

Table 2

50

Type of cement Flexural strength (N / mm ² ) Compressive strength (N / mm ² )

ITag 7 days 28 days 1 day 7 days 28 days

Portland cement - 4.68 6.92 - 20.6 40.4

Early high strength portland cement 2.37 6.13 7.74 7.80 33.3 43.2

Conventional slag cement with 0.67 5.77 8.71 1.84 25.8 39.2
high sulphate content

As can be seen from Tables 1 and 2, with the cement according to the invention, the compressive strength is a achieved early high-strength portland cement in an hour after a day. The compressive strength also increases the hardening time is much greater than with conventional cement.

Conventional Portland cement tends to shrink in volume when it absorbs water. Hence this points rigid hydrate of portland cement alone always cracks. To avoid the occurrence of cracks, should at least two parts by weight of sand per part by weight of cement are added as an additive. This explains the Specification of JIS R 5201, according to which twice the amount of standard sand in the manufacture of cement paste to be mixed with cement.

However, the cement according to the invention exhibits a slight expansion during setting even then. when a cement paste hardens alone, so that no cracks whatsoever in the hardened or hardened

Substance occur. In the above-mentioned mechanical strength tests with the inventive Cement, the mixing ratio of cement to standard sand was set at 1: 1 in order to meet the test conditions to get as close as possible to JIS R 5201. Of course it is practically possible Aggregates such as sand, gravel and ground rock for economic reasons with your invention Mixing cement. However, the invention is directed to the fact that a paste or slurry of the Cement alkyne according to the invention as a molding compound, filling compound or wall coating material without any Aggregate can be used. In the case of the sole use of the cement according to the invention the resulting rigid hydrate exhibits mechanical strength that is significantly higher than that of conventional ones Slamming mixed cements is.

ίο The cement according to the invention is a cement that by adding a small amount of a new Hardening accelerator to the known, a high proportion of calcium sulfate containing cement is made, this metallurgical cement a small amount of conventional alkaline hardening agents Although contains the physical or chemical reason for the above, by the addition of a a small amount of a curing accelerator produced salient effects is not yet clear It is believed that a particular synergistic effect is produced by the alkaline curing agent and the curing accelerator, which leads to the favorable results described above

As mentioned above, it is possible to use the cement according to the invention with aggregates such as sand, gravel and to mix coarsely ground rock. It is also possible to use a granulated blast furnace slag as an aggregate that is not pulverized and has a suitable grain size. In this case, the The surface of the slag granules showed a slight activity in the reaction of the rigid hydrate, which is advantageous over general aggregates

More common than a specific gravity of at least 2.4 for the solidified hydrates Cements, the solidified hydrate of the cement according to the invention alone has a specific weight at most from 1.8 to. This light weight property is very beneficial to design and engineering of public works and architecture in general. In addition, the rigid hydrate forms des Cement alone is a dense coagulate, which leads to low water permeability and high weather resistance contributes over a long period of time. After all, the rigid and lightweight hydrate is fire resistant, so that it can be used as a fire-resistant material or a thermal insulating material.

In general, the main components of the blast furnace slag are 30 to 35% by weight of S1O2, 15 to 20% by weight Al2O3 and 40 to 50% by weight CaO as well as small amounts of Fe2O3 and MgO. By rapid cooling this liquid slag coming from the blast furnace with a stream of water becomes a granulate with wider Get pond size distribution. This substance is potentially hydraulic. One of the main raw materials of the invention Cement is made by pulverizing the dry slag granulate obtained in this way up to Scale made of portland cement.

If necessary, a required amount of an ordinary cement as a filler can be mixed with the cement of the present invention. As common cements, portland cement, high-strength portland cement, high-alumina cement, and white cement are suitable. It is also possible to add a weight-saving material such as finely divided perlite powder in order to achieve a low weight of the set cement.
If the cement according to the invention is to set slowly, a suitable amount of a known setting retarder such as glue, gelatin, peptone, starch, sodium lignosulfonate, sodium tartrate, sodium succinate, borax or sodium phosphate can be added.

If the cement according to the invention is used as a casting material, which requires rapid baking or setting, a suitable amount of a known setting activator such as (NH ₄ ^ SO ₄ , CaSO.4, ZnSO-t, FeSO ₄ , CuSO ₄ , NaHSO ₄ , _{KHSO 4} or colloidal silica added. Since the cement expands somewhat during hydration and solidification, the composition according to the invention is very suitable for casting. The invention is illustrated by the following examples.

example 1

A cement according to the invention was made alkaline by adding 0.5 parts by weight of slaked lime Hardener and 1.0 part by weight magnesia as hardening accelerator to a mixture of 80 Parts by weight of dried and granulated blast furnace slag crushed to the extent of Portland cement and 20 parts by weight of gypsum hemihydrate.

A paste prepared by adding 40 parts by weight of water to the obtained mass and kneading showed a flow value of about 200 mm as determined by the method described in JIS R 5201. The paste was also subjected to a baking or setting test according to JIS R 5201 with the result that the start and end times of setting were found to be 5 and 7 minutes.
The mechanical strength of the rigid hydrate of the paste was as follows:

Curing time

1 hour 1 day 3 days 7 days 28 days

Bending strength (N / mm ²⁾ 1.75 2.2 7.2 9.2 12.2

Compressive strength (N / mm ² ) 7.35 1.53 36.5 65.0 71.0

Such high mechanical strength of set cement has heretofore been for practical purposes unknown.

The rigid or dimensionally stable substance obtained had a specific gravity of about 1.8 versus one specific gravity of conventional concretes of about 2.4.

Substantially the same results as above were obtained when instead of slaked lime finely powdered calcium oxide or calcium carbonate is used as a hardening aid or hardening trigger became.

Example 2

A cement paste was produced by adding 36 parts by weight of water to a finely divided powder mixture, that of 80 parts by weight of granulated blast furnace slag, 20 parts by weight of gypsum hemihydrate, 3 parts by weight Portland cement as an alkaline hardener, 1 part by weight of magnesium chloride as a hardening accelerator and 0.01 part by weight of sodium lignosulfonate was used as a setting retarder. The paste showed a flow value of about 200 mm, a start time of setting of about 45 minutes and an end time of about 1 hour.

The mechanical strengths of the solidified hydrate of the paste were as follows:

Curing time

ITag 3 days 7 days 28 days

Bending strength (N / mm ²⁾ 2.2 6.3 8.2 12.2

Compressive strength (N / mm ² ) 14.6 32.0 56.0 63.0

Essentially the same results were obtained when using aluminum chloride or magnesium carbonate were used as a curing accelerator in place of magnesium chloride.

Example 3

A cement paste was made into a finely divided powder mixture by adding 36 parts by weight of water produced from 80 parts by weight of granulated blast furnace slag, 20 parts by weight of gypsum hemihydrate, 0.5 Parts by weight of quenched FCaIk, 3 parts by weight of calcium chloride, 3 parts by weight of Portland cement and 0.2 part by weight Sodium lignosulfonate. The paste showed a flow value of about 200 mm, an initial time for that Setting of about 30 minutes and an end time of about 45 minutes.

The mechanical strength of the solidified hydrate of the paste were:

Curing time

1 day 7 days 14 days 28 days

Bending strength (N / mm ²⁾ 2.5 11.0 14.0 14.8

Compressive strength (N / mm ² ) 183 48.0 62.0 73.0

Example 4

A cement mortar paste was made by adding 100 parts by weight of sand as aggregate and 37 Parts by weight of water produced to a finely divided powder mass, which is made from 80 parts by weight of granulated blast furnace slag, 20 parts by weight of gypsum hemihydrate obtained as a by-product, 0.5 parts by weight calcium hydroxide, 3 parts by weight of calcium chloride and 0.2 parts by weight of sodium lignosulfonate. The paste obtained of the cement mortar showed a flow value of 179 mm, an initial setting time of about 30 minutes and an end time of about 45 minutes.

The mechanical strengths of the solidified hydrate of this mortar were:

Curing time

! Day 3 days 7 days 28 days

Bending strength (N / mm ²⁾ 2.0 8.6 10.1 11.0

Compressive strength (N / mm ² ) 163 34.6 40.7 44.8

After 28 days, the cured cement mortar was subjected to a water permeability test according to that in JIS R 1401 method, the result of which is shown below. For comparison, the Water permeability of Portland cement was determined using a cement / sand ratio of 1: 3 and resulted in a flow value of 160 mm.

... .... _ _{/ n /} . Amount of penetrated water (g) _<nn

Water permeab.l.tat (o / o) = ^{x 10} °

Cement Water Pressure Time Dry Ingress of Water

mPa (hours) solidified water (g) permeable

Sample (g) ity ( ⁰ Zo)

5 According to the invention 10 1 1370 13th 0.95 According to the invention 200 1 1370 22nd 1.60 Portland cement 10 1 1560 57 3.65

The extent of the change in length of the hardened cement mortar was determined according to that described in JIS A 1129 Method determined. The result is shown in the table below. The sample was under a natural atmosphere and hardened at a relative humidity of 80% at a temperature of 20 ° C. To the For comparison, the following table also shows the test values for Portland cement, in this table If the cement / sand ratio was 1: 2 and the water / cement ratio was also 1: 2.

Time (day) cement

Change in length with cement Change in length

according to the invention (χ ΙΟ " ⁴ ) portland cement (χ 10 ~ ⁴ )

Start 0.00 0.00

1 +6.59 0.00

3 +0.86 -0.50

7 -0.73 -5.20

14 -0.38 -6.50

28 +2.15 -7.60

56 +1.54 -7.80

Example 5

A cement paste was produced by adding 20 parts by weight of a finely divided perlite powder 0.15 bulk density used as the weight reducing material and 45 parts by weight sWas; it turns into a finely divided powder, which consists of 80 parts by weight of granulated blast furnace slag, 20 parts by weight weakly calcined anhydrous gypsum, 0.5 part by weight of sodium carbonate and 3 parts by weight of Portland cement as a curing aid, and 3 parts by weight of magnesium carbonate as a curing accelerator. the Paste showed a flow value of about 180 mm. The set solidified substance obtained from this paste had a specific gravity of about 1.0. The mechanical strength of the solidified hydrate of the paste were as follows:

^4U curing time

ITag 3 days 7 days 28 days

Bending strength (N / mm ²⁾ 1.76 3.13 4.36 4.53

Compressive strength (N / mm ² ) 4.52 12.05 14.01 23.02

. Examples

A paste was prepared by stirring a mixture made up of 80 parts by weight of a fine powder granulated blast furnace slag, 20 parts by weight of gypsum hemihydrate, 0.5 part by weight of sodium sulfate, 0.5 part by weight Sodium hydroxide and 40 parts by weight of water consisted.

The paste obtained showed a flow index of about 200, an initial setting time of 5 and a End time of 7 minutes.

The mechanical strength of the solidified hydrate of this paste was as follows:

Curing time

ITag 3 days 7 days 28 days

Bending strength (N / mm ²⁾ 1.76 3.13 4.36 4.53

Compressive strength (N / mm ² ) 4.52 12.05 14.01 23.02

The solidified hydrate was exposed to the atmosphere for a year with no signs of weathering occurred on the surface.

Essentially the same results were obtained when using magnesium carbonate instead of sodium sulfate was used. Potassium hydroxide could also be used instead of sodium hydroxide with similar results be used.

Example 7

A cement paste was made by adding 80 parts by weight of Portland cement as cement material and 70 parts by weight Parts by weight of water produced to a hydraulic mass, which consists of 80 parts by weight of finely powdered granulated Blast furnace slag 20 parts by weight of gypsum hemihydrate, 1 part by weight of calcium hydroxide and 3 parts by weight Calcium chloride consisted.

The paste obtained showed a flow value of about 200 mm, an initial time for the formation of the hydrate cake of 6 minutes and an end time of 10 minutes. This mixed cement is particularly suitable as Casting compound.

The mechanical strength of the solidified hydrate of the paste were:

Curing time

! Day 3 days 7 days 28 days

Bending strength (N / mm ²⁾ 1.77 4.86 7.06 12.06

Compressive strength (N / mm ² ) 3.93 14.15 23.02 52.06

Example 8

A low viscosity slurry was made by adding 55 parts by weight of water to a hydraulic one Mass prepared according to the invention, which consists of 80 parts by weight of a finely divided powder of granulated Blast furnace slag, 20 parts by weight of gypsum hemihydrate, 0.5 part by weight of calcium hydroxide, 1.0 part by weight of magnesium oxide and 0.4 part by weight of sodium lignosulfonate, whereupon the mixture was sufficiently stirred. The obtained slurry shows a flow value of 320 mm which is not described in JIS according to the following special method was determined: a cylindrical tube with an inner diameter of 50 mm and a height of 100 mm was placed on the center of the flat surface of a glass plate of 500 500 mm area posed. After pouring the entire volume of the sample into the cylindrical tube, the tube quickly became pulled upwards, whereupon the slurry spread on the glass plate. Then it became the greatest The diameter of the spread and the diameter at right angles to it are determined. The mean these two diameters were called the flow value.

The obtained slurry was poured into an open wide container at a depth of 15 mm so that the surface of the slurry was horizontal. The slurry showed start and stop times for hydrate cake formation of about 2 and 3.5 hours, respectively, and a specific gravity of 2.0. The solidified molding compound was taken out of the open container and exposed to a natural atmosphere at a temperature of 20 ° C. for 28 days, whereby a tough, light-weight sheet with a smooth surface was obtained. The plate obtained had a flexural strength of 4.3 N / mm ² and a compressive strength of 21.0 N / mm ² .

The method described above allows a smooth floor coating by simply adding the slurry is poured onto a rough concrete floor without leveling or smoothing.

Compared to all conventional cements, the cement according to the invention is extremely rapid Solidification, d. H. Formation of the hydrate cake and provides a rigid hydrate with an outstandingly high mechanical strength Strength, low specific weight, slight expansion during setting or hardening and is weatherproof. The two main raw materials, granulated blast furnace slag and gypsum, are very cheap By-products of blast furnace technology and the desulphurisation of oil. There is no need to have one Producing clinker, which saves oil and fuel. The additives are also very cheap materials. Therefore, the cement according to the invention can be used more effectively and cheaper than before for general engineering, Construction work, wall coatings and the production of cast objects as a casting compound and used for repair work in place of traditional cements.

Claims (3)

Patent claims: 1. Sulphatically excited slag cement, consisting of 1. 80 parts by weight of finely powdered granulated blast furnace slag, 2. 20 parts by weight of weakly calcined, anhydrous gypsum or gypsum hemihydrate and 3. additives, characterized in that as additives