DE2616170A1 - LOW POROUS CEMENT AND METHOD FOR ITS MANUFACTURING - Google Patents

Description

26 1 617

DIPL.-INQ. JOACHIM STRASSE, HANAU DIPL.-INQ. KLAUS QÖRQ, MUNICH

(8566) PATENT AGENCIES

HANAU RÖMERSTR. 19 POSTBOX 793 TEL .: (06181) 20803/20740 TELEQRAMME: HANAUPATENT TELEX: 4184782 pat MÜNCHEN 80 QRAFINQER STRASSE 31. TEL .: (089) 405645 TELEX 522054 ostpa

Westvaco Corporation April 13, 1976

New York, N.Y. 10017, USA Gö / Jg - 11 362 C9598206US)

Low porosity cement and process for its manufacture

The invention relates to low porosity cement and methods for its manufacture. In particular, the invention relates to methods for producing low-porosity cement from a hydraulic cement with alkali bicarbonates and LIgnosu1fonaten, which give cement slurries, give way to a longer one Setting time and lower expansion have what aids the A1kall aggregate reactions and other aids is due.

Cements are produced by calcining suitable raw materials, generally a mixture of calcareous and clayey materials, which results in sintering slag or cement clinker. Portland cements have by far the largest share of the quantities produced. Conventionally, the clinker is mixed with small amounts of gypsum, ie up to about 9 %, and usually ground in a kind of ball mill to a feiηvertel1 th consistency with a relatively large surface area, which then results in the finished cement.

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The gypsum-containing, ground clinker is with the required Amount of water mixed into a pulp. Correctly prepared cement slurry will set within a few hours and then slowly harden. Cement slurries are made with either fine aggregates or sand for the preparation of Mortar or with coarser aggregates such as gravel, stones and the like mixed for the preparation of concrete. The cement paste acts as a cementing substance. For strength and other properties of the resulting mortar, or Concrete is its composition decisive.

One of the most important for the properties of the hardened cement paste and consequently the main determinant of the mortar and concrete is the ratio of water to cement In the fresh mix. The lower the water-cement ratio, the higher the strength, the lower the shrinkage and the better the resistance to frost and corrosion. A low water-cement ratio is therefore used strived for - in conventional practice it usually lies between 0.4 and 0.6 - to obtain a concrete or mortar with minimal shrinkage and increased ultimate strength. However, a solution to this is not simply to be seen in the water-cement ratio of conventional Portland cements to reduce.

So unfortunately the fact that a decrease the water content the properties of the hardened egg Concrete improves, can only be used to a certain extent, since the lowering of the water content at the same time to a deterioration in the processability of the Concrete mix leads. The demand for more satisfactory Workability of the fresh concrete mix is the reason for the fact that the water content of the concrete mixes in practice is far more than the amount of water required for a

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complete hydration of the cement would be required. While the amount of water required for complete hydration of the cement is around 22-23 % , w-Ird In conventional practice, an amount of water of around 40 % and usually between 45-80% is used.

Even when using conventional water reducing agents (mainly lignosulphonates from sulphite waste liquor in the production of fuel), the added water can only be reduced by about 10 % . The water remaining in a concrete mix of ordinary cement is far more than the amount required for complete hydration of the cement. Thus, if it were possible to reduce the water content without deteriorating the workability or without other disadvantages, a significant gain in strength and an improvement in some other properties of the hardened concrete could be achieved.

Attempts have been made by tent for a long time Reduction of the water-cement ratio a cement to produce with low porosity. For example, Winkler U.S. Patent No. 2,174,051 discloses that one greater strength with a lower water-cement ratio can be achieved and that certain organic compounds such as tartaric acid, citric acid and the like can be added to influence the setting time.

According to U.S. Patent No. 2,374,581 to Braun, the common CgIpshal11 gen) Portland cement can be used in conventional Water-cement-ratios small amounts of whinestelic acid, Tartaric salts and bicarbonates are added to increase the setting speed at high temperatures to reduce when pouring concrete from oil wells.

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US Patent No. 2,646,360 to Lea suggests a similar method Cement slurry, an alkali metal I I or an alkaline earth metal lignin sulfonate and an Alka1i meta I1saI ζ an inorganic one Add acid (e.g. sodium carbonate), about the water loss and so the initially required Reduce the addition of water.

On the other hand, U.S. Patent No. 3,118,779 to Leonard discloses that sodium carbonate acts as an accelerator when it dated a Portland cement without the presence of lignin Type (II (glpshaltlg) is added.

According to US Pat. No. 3,689,296 to Landry, formaldehyde-modified ones are used KaI ζ I um-LIgnosu1fonate in Port 1andzementen used to replace the usual total amount of Gfps addition or parts of it. The one for a mix of a particular Fluid level required amount of water extended.

Earlier efforts to produce low porosity cements emerge from Braunauer, U.S. Patent No. 3,689,294 by grinding Portland cements without plaster to one

specific surface area contents between 6,000 - 9,000 cm / gm (Blalne) and by mixing with alkali or alkaline earth gnosu1fonaten, Alkaline carbonate and water.

According to US Pat. No. 3,782,984 to Allemand et al, the addition of 0.5-5 % alkali metal meta acid carbonates to Port Iand cements accelerates the setting tent.

In the French publication "Les Adjuvants du Clment ", edited by Albert Jolsel (Solsy, France 1973), published by the author, it is stated on page 102, that sodium carbonate in ordinary portland cement

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acts as a retarder, and again on page 132, that sodium bicarbonate to equivalent Portland cement the usual catfish can be added.

The prior art described above is not intended to be exclusive to be considered and does not contain the entire technology for the production of low-porosity cement.

It is therefore the object of this invention to provide a method for the preparation of an improved fruitless cement paste to make low porosity available. Furthermore, the possibility should be created, concrete and mortar higher Strength with η i edrl gporösetn Portland cement without gypsum, with improved processability, longer setting time and to make available smaller expansion.

The solution according to the invention this object is achieved in that for the production of cement or cement slurry niedrigporösem according to an embodiment of a mixing scheme ground hydraulic gypsum-free cement with 0.1% - about 1.0% alkali metal or ErdaIka1I- LignosuIfunat or sulfonated lignin with 0 , 1 - 2.0 % AlkaI I-Bicarbonate and with 20 - 40 % water. According to a modified embodiment, the alkali bicarbonate is mixed with the cement and the lignin is added to the mixed water, after which the two mixtures are combined. According to a further modified embodiment of the method according to the invention, the lignin is mixed with the cement, the alkali bicarbonate is added to the water and then the cement is added to the alkali carbonate water. In another embodiment, lignin, bicarbonate and water are mixed together prior to addition to the ground cement. From these methods it follows that it is indicated for low porosity

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Cement is more likely to use alkali carbonates than alkali carbonates.

Further details, features and advantages of the invention result from the following detailed description.

Cements useful in connection with this invention are hydraulic cements. Hydraulic cements are not Portland cement only, natural cement, whiter Cement, alumina cement, grappie cement, hydraulic Lime and PozzoIan cement including those which are developed from industrial slag. The Portland cement is the most widely used hydraulic cement. Cement-

2 clinkers of the types described above are set to 3,500 cm / gm

2 (Blalne) and finely ground, d. H. up to 9,000 cm / gm.

As an aid to achieving the desired degree of fineness, grinding substances are usually used in the cement industry, which support the effectiveness of the grinding process. Satisfactory milling substances include water-soluble polyols such as ethylene glycol, polyethylene glycol and other water-soluble oils. In general, the grinding ingredients are added to the cement clinker in an amount of 0.005-1.0 %, based on the cement weight. The ground cement can contain a lot of setting inhibitors. Additional examples of grinding aids can be found in U.S. Patents 3,615,785 and 3,689,294. While it is typical to use grinding additives in the manufacture of cement, they do not form part of the present invention.

The method of the present invention proceeds as follows a gypsum-free hydraulic cement. After the

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Driving of the present invention, low-porosity mortars and types of concrete can be produced from the cement slurries
will. Labeled "low porosity" cement, like
If it is used more often, it is a loose or free-flowing and workable cement paste with a water-cement ratio (W / C) from below 0.40 down to about 0.2, with workable mortars and types of concrete with a W / C -Ratio from preferably 0.35 down to 0.25.

In an exemplary embodiment of the method, the equal hydraulic cement is 0.1 - about 1.0 %, preferably 0.3 - 0.8 % based on the weight of the dry,
ground cement of an alkali metal or alkaline earth metal sulfonate or alkaline earth metal-suIfied oil. The lignosulfonates occur as a by-product in the sulphite digestion of wood material
This digestion process contains large amounts of lignin and lignin products in conjunction with other materials. On the other hand, the sulphurised oils are produced in the reaction of oils which are produced in the alkaline digestion of the
Acid hydrolysis or other known recovery processes
with an inorganic sulfite such as sodium sulfite. Any of the various water-soluble sulphurized oils or sulphonates can be used in the present invention. However, it is preferable to use sulfonated oils that are free of hydrocarbons. Contain sulphate lines, such as those obtained in the reaction of sulphites with alka11-lines
do not have appreciable amounts of these hydrocarbons and thus can be used as they are. the
Sulphurized oils can be converted into water-soluble alkaline earth salts and used as such, as described in US Pat. No. 2,141,570.

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In a modified embodiment of the method can the sulphured lignin can be combined with the ground cement or with the mixed water, or it can be a part of the sulfated lignin to the cement and part of the Mixed water can be given. When applying these different There were no significant ways of working in the results Differences are observed. Therefore can be a part of the lignin to the ground cement and the other part to the Mixed water can be added.

AI kai I - bicarbonate is used in an amount of 0.3-2.0 %, preferably 0.7-1.5%, based on the dry cement weight. Sodium bicarbonate is preferred. It is unimportant how the bicarbonate is added, for example by direct inclusion of bicarbonate or by adding sodium ash and carbon dioxide saturation. It has been found that when using alkali bicarbonate, the setting time and the workability increases unexpectedly compared to the use of alkali carbonates at a water-cement ratio of below 0.4. It has also been found that when the alkali carbonate is added to the cement, an unexpected increase is achieved compared with the addition of alkali carbonate. Even more surprising was the fact that when the alkali carbonate was dissolved in the mixed water, even better results with regard to the control of the setting time and improved flow were achieved than when other mixing processes were used. The amount of water used is 20 - 40 %, based on the dry cement weight or a water-cement ratio (W / C) of 0.4 - 0.2. The way in which the bicarbonate is added to the water can be varied. For example, the bicarbonate can be added by itself, or soda ash can be added and saturated with carbon dioxide.

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In some cases it may also be desirable to add a third component to the low-porosity system in order to achieve a substantial extension of the plastic perlode of the mortar and the concrete, while still providing sufficient compressive strength after one day. These components used in small amounts, e.g. 0.1-0.2%, come from mainly two classes of substances, namely surfactants and conventional water reducing agents / anti-aging agents. Anionic surfactants can consist of the sodium salt of the sulfated alkali idiphenyl oxide, whereas nonionic surfactants consist of polyethy1, iykoI and the like. Substances from the class of water reducing agents 1 / Fig. I η de-delaying agents I are hydrocarbons such as wood molasses, sucrose, dextrose and hydroxy acids such as sodium gluconate. In low-porosity systems, typical air discharges or evacuating agents, such as, for example, tri-butyl phosphate, can advantageously also be used.

Another important aspect of the present invention is that the addition of alkali carbonate substantially reduces the potential for the alkali additive reaction that takes place in the formation of alkali (NaOH) in cement. The potential expansion when using alkali carbonate and alkali carbonate in low-porosity systems was measured using a highly reactive aggregate (crushed hard glass) according to the method specified in ASTM C-22. The results showed a lower expansion of a low-porosity mortar prepared with NaHCO in comparison with a corresponding Na ₂ CO system. In addition, small amounts (0.05 - 1.5 %) of lithium salts reduce the expansion of both alkali carbonates and. -Bicarbonate-containing low-porosity hard cement mortar η.

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With the various combinations of additives and Mixing processes avoid the need to add plaster of paris, and the result is a more free-flowing, processable, low-porosity cement paste with extensive and controllable Binding tent. The obtained by using the additives and the method according to the present invention Excellent results were completely for the production of low-porosity cements with regard to the state of the art unexpectedly. According to the description above is any of the additives previously in portIand cements containing glps been used. However, none of the products made according to the prior art come with those according to the present Invention produced low-porosity cements achieved performance also only close.

The application of the present invention is evident from the following examples.

example 1

This example is intended to extend the duration of the cement slurry represent, which instead of AIkaI! carbonate with AI kaiI bicarbonate was produced. In this example Port Iand cement KII rter of type I, was wedded to 5.075 cm / gm (ASTM C-204), used with the following analysis.

3 Kl Inker 926 SiO ₂ 3 21.70 AI ₂ O 6.06 Fc ₂ O 2.51 CaO 67.5 MgO 0.99 Na ₂ O loss of recognition 0.06 K ₂ O Unsolvable 0.28 verb 0.62 6 0 9 8 4 5/0 0.14

-11-

The changes in physical properties (those of the Setting time was most noticeable) of cement slurries with Alkali carbonates and AIkaI I - bicarbonates are in Table 1 shown. The amount of sulphured lgnine was 0.45 percent by weight, based on the cement, kept constant, and the water-cement ratio was 0.25. the The amount of AlkaI carbonate was set so that it gave equivalent molar amounts of CO *.

Table 1

Comparison of alkali carbonates and bicarbonates in relation to on the properties of low-porosity cement slurries

Test type of kar- binding- compressive strength

No. Bonats % river * tent Cp.sl)

(Min.) 1 day 7 days

1 Na ₂ CO ₃ 1.26 4 + 13 10,400 11,600

2 NaHCO ₃ 1.0 4 + 38 10,200 18,950

3 K ₂ CO ₃ .1.5 H ₂ O 1.97 4 12 10,900 13,500

4 KHCO ₃ 1.19 4 + 19 9,600 16,580

Note: the flow units are chosen arbitrarily (see explanation below) and are used in all examples. The nature of the In 1 Table 1 used cement slurries depends according to the following scale:

1. Hardly plastic mush, only moves under difficult conditions, even when applying vibration;

2. plastic slurry, but not free flowing, flows easily under vibration;

3. Free flowing pulp, but thick, can without vibration to be shed;

4. easy flowing porridge.

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The results in Table I show an increase in setting time and excellent compressive strength after 7 days for bicarbonate systems as opposed to carbonate systems.

Example 2

This example shows the extended setting time of cement slurries, in which the use of alkali bicarbonate was preferred to alkali carbonate. In addition, the particular mixing processes according to the invention are shown in comparison with other mixing schemes in which the same substances are used. In this example, Port Iand cement clay was also ground to 5.075 cm ² / gm (ASTM C-204) as in Example 1.

In Table II are the changes in physical Features (which the tie-off tent was most noticeable) of cement slurries with AIkaI carbonates and AIkaIi bicarbonates recorded using two mixing schemes. The mixing scheme designation from Table II means that first all components within a bracket with each other and then mixed with the next component or components. In the test series 4 and 8, in which an embodiment according to the method of the invention is shown, takes place Mixing the cement (Z) with a sulphured A IkaIi-LignI η (LS) and mixing the AlkaI I-Bicarbonate (AK) with water (W) and then mixing the two mixtures. at the trials with odd numbers were alkali carbonates also in the remaining experiments in other training sequences AikaIi bicarbonates are used. The amount of sulfated LIgnins was at 0.45 weight percent based on the Cement, kept constant, and the water-cement ratio was 0.25. The amount of AlkaIi carbonate was set so that that they have equivalent molar amounts of CO "in all At games revealed.

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Table II

Comparison of alkali carbonates and bicarbonates and the effect of Mixing sequence on the properties of low-porosity cement slurries

Try ... _{,, T} ". ,. # _c , _o setting compressive strength

_N Mixing sequence carbonate type % flow. ₊ (ds!)

1 day 7 days

1 (Z + LS + AC) + W Na ₂ CO ₃ 1.26 4 + 13 10,400 11,600

2 (Z + LS + AC) + W NaHCO ₃ 1.0 4 + 38 10,200 18,950

3 (Z + LS) + (AC + W) Na ₂ CO ₃ 1.26 4 + 23 10,100 13,450

4 (Z + LS) + (AC + W) NaHCO ₃ 1.0 4 + 143 9,800 16,700

5 (Z + LS + AC) + WK ₂ CO ₃ -1.5 H ₃ O 1.97 4 12 10,900 13,500

6 (Z + LS + AC) + W KHCO ₃ 1.19 4 + 19 9,600 16,580

7 (Z + LS) + (AC + W) K ₂ CO ₃ -1.5 H ₂ O 1.97 4 + 20 10,800 14,300

8 (Z + LS) + (AC * W) KHCO ₃ 1.19 4 + 141 11,400 19,150

Note: the flow units are chosen arbitrarily (see explanation below) and are used in all examples. the
Nature of the cement slurries used in Table II
is based on the following scale:

1. Hardly plastic pulp, moves only with difficulty, even with the application of vibration;

2. plastic slurry, but not free flowing, flows
slightly under vibration;

3. Free-flowing pulp, but thick, can be used without blistering
to be shed;

4. easy flowing porridge.

The results of Runs 4 and 8 of Table II show
clearly the unexpected increase in the setting tent for bicarbonate systems compared to carbonate systems and significant additional

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advantages of dissolving bicarbonate in water, without the other properties (flow and compressive strength) to change significantly.

Be i sρ i e I 3

This example shows that the sulfated lignin is either mixed dry or dissolved in the mixed water can. Here a part of the clinker from Example 1 was on Grind a surface content of 4.525 cm / gm (Blalne). The mixture scheme designation from Table III means that first all components mixed within a bracket and then the next component or components are mixed in. In Experiment No. 1 in Table III, be for example first the cement (Z), the sulphated alkali lignin (LS) and the Alka1I carbonate (AC) that comes from here Sodium bicarbonate, mixed together. Below the water (W) was added. The amount of sulfiel— ten LIgnins was constant at 0.35 percent by weight of the Cement held. The water-cement ratio was 0.25.

Table III

Effects of the mixing sequence on the properties of low-porosity cement slurries

_K setting compressive strength

Mixing order, % flow tent (psI)

^Γ (Min.) I day 7 days

(Z + LS + AC) + W NaHCO ₃ 0.80 4 + 32 9,200 17,250

(Z + AC) + (LS + W) NaHCO ₃ 0.80 4 + 36 10,700 18,350

(Z + LS) + (AC + W) NaHCO ₃ 0.80 4 + 98 10,800 17,100

Z + (LS + AC + W) NaHCO ₃ 0.80 4 + 96 10,500 19,200

The data resulting from Table III clearly show that the sulfated lignin either added to the mixed water

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or can be dry mixed with the cement without the Remarkably changing properties of the pulp.

At game 4

This example also shows the superiority of low-porosity cement slurries that are produced with NaHCO instead of Na “CO were prepared. It was ground cement with different surface content of the clinker of type I different Origin used. In Table IV the comparative longer binding tents and higher compressive strengths 7 days for the NaHCO, cement systems with low porosity. The water-cement ratio was the same for everyone Attempt 0.25. The amount of alkali carbonate was set so that that it gave approximately equivalent molar amounts of CO * for each cement clinker for each surface area.

Table IV

Effects of different cement clinker and total surface area on the properties of low-porosity cements

inke w υ v> ι
flatter
arear
cm ^ / gm ι- carbonate-
i art % Flow Ligation
time
(Min.) Compressive strength
(ps I.)
1 day 7 days 15,400 B ¹ 6,500 NaHCO ₃ 1.20 4th 31 10,100 12,200 B ¹ 6,500 Na ₂ CO ₃ 1.60 4th 18th 11,700 19,550 A ² 5,650 NaHCO ₃ 0.60 4th 49 1,500 14,050 A ² 5,650 Na ₂ CO ₃ 0.76 2 20th 10,200 17,900 C ³ 4,800 NaHCO ₃ 1.00 4th + 63 11,800 13,200 C ³ 4,800 Na ₂ CO ₃ 1.26 4th + 32 12,500 Remarks: ¹ O, 80 % sul f lertes LI gn In

³ O, 50 % sulfated lignin

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Example 5

This example shows that cement with different Surface content and origin other than in example 1 can be used. The cement clinkers "B" and "C" are Portland cement clinker type I of various origins. W / C - 0.25 in a [Jen cases.

Table V

Effects of different clinkers and surface contents on properties of low-porosity cement slurries

clinker Upper
surfaces
area
cm ^ / gm Mixing scheme Flow Ligation
time
(Min.) Compressive strength
(psi)
1 day 7 days 14,850 B ¹ 6.225 (Z + LS * AC) + W 4 + 29 13,300 15,900 B ¹ 6.225 (Z + LS) + (AC + W) 4 + 58 13,200 16,500 B ¹ 6.225 Z + (LS + AC + W) 4 + 56 13,900 16,250 B ² 4,825 (Z + LS + AC) + W 4 + 45 11,200 17,250 B ² 4,825 (Z + LS) + (AC + W) 4 + 78 10,700 12,800 C ² 4,800 (Z + LS + AC) + W 4 + 73 10,300 14,450 C ² 4,800 (Z + LS) + (AC + W) 4 * 135 10,500 12,200 C ² 4,800 Z + (LS + AC + W) 4 + 127 10,100 14,450 C ² 3,900 (Z + LS + AC) + W 4 + 58 9,400 13,050 c ² 3,900 (Z + LS) + (AC + W) 4 + 180 8,900 11,850 c ² 3,900 Z + (LS + AC + W) 4 + 170 8,300

Notes: ¹ O, 55 % sulphurised lignin and 1.0 % NaHCO ₃ ² O, 50 % sulphurised lignin and 1.0 % NaHCO ₃

From Table V it can be seen that when using clinker of different origins or when grinding Clinker to various specific surface contents no significant differences could be observed.

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Example 6

The use of AI kaiϊ - bicarbonates, which is preferable to the use of AIka1I carbonates, also improves the flowability in cases where wall currents occur. The addition of the AlkaI I-Bicarbonate to the water also improves the flowability. The examples from Table VI illustrate this, with 0.45 % sulfated or sulfonated lignin and equivalent molar amounts of CO * with the ground clinker "A" and 0.50 % sulfated alkali lignin and equivalent molar amounts of CO * with the ground Clinker "B" were used.

Table Vt

Improvement of the flow behavior of low-porosity cement slurries with AI kaiϊ — bicarbonates and the preferred mixing sequences

Clin
ker Upper
surface mix
area follow
cm2 / nm (Z + LS + AC) + carbonate
art W. Na ₂ CO ₃ Flow Ligation
Time
(Min.) Compressive strength
(psi)
1 day 7 days 13,150 A. ^^ '^ VJ ill
5,025 (Z + LS + AC) + W. NaHCO 1-2 9 8,800 18,000 A. 5,025 (Z + LS) + (AC + W) Na ₂ CO ₃ 4th 35 9,700 14,050 A. 5,025 (Z + LS) + (AC + W) NaHCO 2 20th 10,200 19,550 A. 5,025 Z + (LS + AC + W) Na ₂ CO ₃ 4 + 49 7,500 13,500 B. 5,325 Z + (LS + AC + W) NaHCO 3 13th 11,400 13,350 B. 5,325 4 + 59 12,500

These results show that cement slurries made from gypsum-free, ground clinker were produced, in terms of their flow properties those produced with sodium carbonate Cement slurries were superior.

Example 7

When using bicarbonates, an extension was also achieved the setting time observed when made from sulphite liquors

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- ι

Isolated lignosulfonates were used. Seen as a whole however, better properties result when sulflerte A IkaIi lignins were used.

TABLE VI I

Comparison of alkali bicarbonate and alkali carbonate when in use a lignosulfonate derived from sulfite sludge

carbonate
art 1 % Flow at Ligation
Time
(Min.) Compressive strength
Cp. si)
1 day 7 days 15,250 Na ₂ CO ₃ 1 , 51 2 32 10,200 7,550 NaHCO ₃ , 20 2 72 500 game 8

From this example it becomes clear how a low-porosity, ground hard glass mortar which was prepared with NaHCO expands significantly less in comparison with a corresponding low-porosity mortar with Na 2 CO 2. Samples CI and C-2 in Table VIII show the reduction in expansion after 14 and 28 days when _{NaHCO3 was substituted for Na 2} CO ₃ (with the equivalent molar amount of CO ?) Samples C-3 and C-4 show a significantly reduced

dehnuna both with the NaHC0_ and with the Na "C0 -Syste- " 5 Zj

Men with low porosity when a lithium salt (Li ₂ CO ₃ ) was contained in the ground hard glass mortar. These examples show the reduced expansion of a low-porosity hard gas mortar when an alkali carbonate is replaced by an alkali bicarbonate, and also a reduction in the expansion of both the Na ₇ CO and the NaHCO mortars with low porosity when the Mixture a lithium carbonate had been added.

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Table VIII

Expansion of low-porosity toughened glass mortar rods that were made with different Alka1I carbonates

ρ__, _Ω alkali α expansion, % ^rroDe carbonate " 14 days 28 days

C-1 NaHCO ₃ 1.00 0.24 0 , 32 C-2 Na ₂ CO ₃ 1.26 0.50 0 , 56 C-3 NaHCO
^LI 2 ^C0 3 1.00
0.22 0.03 0 , 04 C-4 Na ₂ CO ₃ 1.26
0.22 0.01 0 , 08

Remarks: Glass: cement * 1.80

0.50 % sulfated lignin W / C - 0.275

Example 9

This example serves to illustrate the strength properties of low-porosity mortars (NP) made according to the procedure of this invention compared to conventional water-cement ratios with an acceptable water-cement ratio. When making the In the mortar, 2.25 parts of fine sand was used per one part of cement.

Mörte I results gkel t
i.)
7 days cement WC Pressure resistant I
(ps
1 day 8,000 NP ¹ .40 4,200 9,300 NP ¹ .32 6,000 8,800 NP ¹ .27 6,000 7,100 Type HI .60 2,300

Note: 0 ^ 50 % sulphurised lignin 1.0 % NaHCO ₃

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The results show that with the η I edr'r gporous aggregates good strength is achieved.

While the invention has been described herein with reference to various specific materials, methods, and examples is, it goes without saying that the invention does not apply special substances, combinations of substances and for this purpose chosen procedure is restricted. There can be numerous Modifications to these details are made, which will be readily apparent to those skilled in the art.

In the tables it says "p. S. I." for "pound per square inch" equal to 0.07031 - | ^ 2.

Claims;

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Claims (21)

- 21 patent claims: 1. A method for producing a gypsum-free, low-porosity, free-flowing cement paste, thereby marked that a) a ground, gypsum-free hydraulic cement with 0.1 - approx. 1.0 % alkali or alkaline earth lignosulfonate or sulfonated lignin and 0.1 - approx. 2.0 % alkali bicarbonate is mixed and b) 20-40% water is added to the mixed substances from a), all percentages being based on the dry weight of the ground cement. 2. The method according to claim 1, characterized in that the amount of lignin is 0.3-0.8 ' . 3. The method according to claims 1 and / or 2, characterized in that the amount of A IkaI I-bicarbonate is 0.7-1.5 % . 4. The method according to at least one of claims 1 to 3, characterized in that as A IkaIi bicarbonate Sodium bicarbonate, sulfonated as lignin AI kaiϊ - LIgnIn and as hydraulic cement Portland cement can be used. 5. A method for the production of a gypsum-free, low-porosity, free IfI5eßende cement paste, thereby marked that a) a ground gypsum-free hydraulic cement is mixed with 0.1 - approx. 2.0% of an alkali bicarbonate , - 22 - 609845/09 2 6 b) 20 - 40 % water with 0.1 - 1.0 % alkali or alkaline earth 1 ί-Li gnos u I fonat or sulfonated! Lignin can be seen and c) then the mixed substances of the process steps a) and b) combined v / earth, with all percentages on the dry weight of the ground cement are related. 6. The method according to claim 5, characterized in that the amount of lignin is 0.3-0.8 % . 7. The method according to claims 5 and / or 6, characterized in that a part of the lignin is added to the water and the rest Lignin is mixed with the cement. 8. The method according to at least one of claims 5 to 7, characterized in that the amount of alkali bicarbonate is 0.7-1.5 % . 9. The method according to at least one of claims 5 to 8, characterized in that as Alka1i bicarbonate Sodium bicarbonate, sulfonated as lignin AlkaII-LI gn I η and as hydraulic cement Portland cement can be used. 10. A method for producing a gypsum-free, low-porosity, free-flowing cement paste, thereby marked that a) a ground, gypsum-free hydraulic cement is mixed with 0.1-1.0 % alkali or alkaline earth lignosulfonate or sulfonated lignin, - 23 - 809845/0926 b) 20 - 40 % water are mixed with 0.1 - 2.0 % of an alkali bicarbonate and c) then the mixtures of process steps a) and b) be put together, where all percentages are based on the dry weight of the ground cement. 11. The method according to claim 10, characterized in that the amount of LIgnins is 0.3-0.8 % . 12. The method according to claims 10 and / or 11, characterized in that the amount of alkali bi-carbonate is 0.7-1.5 % . 13. The method according to at least one of claims 10 to 12, characterized in that as AIkaIi-Bicarbonate Sodium bicarbonate, sulfonated as lignin AIkaIf-LignI η and as hydraulic cement Portland cement can be used. 14. A method for producing a gypsum-free, low-porosity, free-flowing cement paste, thereby marked that a) 0.1 - approx. 1.0 % alkali or alkaline earth lignosulfonate or sulfonated lignin and 0.1 - approx. 2.0 % alkali bicarbonate are mixed with 20 - 40 % water, all percentages being based on the Dry weights of ground cement are based, and b) the mixture according to process step a) mixed with gypsum-free hydraulic cement. - 24 - 809Ri 5/09 ?. S. 15. The method according to claim 14, characterized in that the amount of lignin is 0.3-0.8 % . 16. The method according to claims 14 and / or 15, characterized in that the amount of Alka11 - Bicarbonate is 0.7 - 1.5 % . 17. The method according to at least one of claims 1 to 14, characterized in that as A IkaI I-Bicarbonate Sodium Bicarbonate, sulfonlertes as lignin AIkaIi-LIgnIn and as hydraulic cement Portland cement can be used. 18. A method for producing a gypsum-free, low-porosity, free-flowing cement paste, thereby marked that a) ground hydraulic cement with a part of alkali or Erdal ka I ι-Li gnosu I fonat or sulfonated! lignin is mixed, b) 0.1-2.0 % alkali bicarbonate is mixed with the other part lignin and 20-40 % water, the amount of lignin used in a) and b) being 0.1-1.0 % , and c) the mixtures of process steps a) and b) with one another are mixed, all percentages being based on the dry weight of the ground cement are. 19. A method for producing a gypsum-free, low-porosity, free-flowing cement paste, thereby marked that 609845/0926 a) a part of alkali or alkaline earth lignosulphonate or sulphonated lignin is mixed with 0.1-2.0 % alkali carbonate and 20-40 % water and then b) the other part of the lignin is mixed with ground, completely free hydraulic cement, the total content of lignin used in process steps a) and b) being 0.1-1.0 % , all percentages being based on the dry weight of the ground cement are, and then c) the mixtures according to the process steps a) and b) are mixed together. 20. NIedrlgporöseι cement composition containing aggregates, marked by a) Portland cement of a cement grind fineness (Blaine fineness) of about 3,500, which contains essentially no calcium sulfate, b) Alkali bicarbonate in an amount of 0.1 - 2.0 percent by weight, based on dry, ground cement, and c) Alkaline or alkaline earth lignosulfonate or sulfonated Lignin in an amount of 0.1-1.0 percent by weight, based on ground cement, whereby the Cement composition containing aggregates with a water-cement ratio between 0.4 and 0.2 was made. 21. Cement composition according to claim 20, characterized in that as alkali bicarbonate sodium bicarbonate in an amount of 0.7-1.5% and as lignin AI kaiI-lignin in an amount of 0.3-0, 8 % included 1st. 609845/0926 ORfGlNAL INSPECTED