CS273201B1

CS273201B1 - Method of alkali carbonate,hydrogen carbonate or silicate quantity determination for gypsum-free cement mixture preparation

Info

Publication number: CS273201B1
Application number: CS196687A
Authority: CS
Inventors: Frantisek Rndr Csc Skvara; Karel Ing Csc Friedman; Zdenek Ing Zahradnik; Jan Ing Horsky
Original assignee: Frantisek Rndr Csc Skvara; Karel Ing Csc Friedman; Zdenek Ing Zahradnik; Jan Ing Horsky
Priority date: 1987-03-24
Filing date: 1987-03-24
Publication date: 1991-03-12
Also published as: CS196687A1

Abstract

The solution concerns the problem of preparation of the cement mixture devoid of gypsum that has an extended initial setting time. To advantage, the cement mixture can be used in building. The gist of the solution lies in the fact that 0.5 to 2 percent by weight of alkali carbonate, bicarbonate or silicate is added to at least a single, to advantage a double to quintuple, of the analytically determined amount, while this amount reaches maximally 15 percent by weight of the total mixture and, subsequently, this amount is added to other components of the mixture, while the percents by weight relate to the weight of cement clinker.

Description

CS 273 201 B1 #

Yippee

The invention relates to a method for determining the amount of alkali carbonate, bicarbonate or silicate for preparing a cement-free gypsum-free cementitious composition having a prolonged onset of solidification.

Gypsum-free cements (BS cements) are a new type of inorganic binder which is based on the synergistic effect of a mixture of an inorganic electrolyte, in particular an alkali carbonate, bicarbonate or silicate, and an anioactive plasticizer, for example ligninsulfonate, sulfonated lignin or sulfonated polyphenolate. An important feature of these cements is the possibility of their processing at low water coefficient while maintaining good rheological properties. Due to the low porosity of hardened cement stone, BS cements are characterized not only by high short- and long-term strengths, but also by high corrosion resistance, ability to harden at low and negative temperatures and high resistance to high temperatures. These engineering properties of BS cements were discussed, for example, in the following articles: F.Škvára, L.Pekárek, B.Velička: The gypsum-free portland cement hydration and its thermal properties, Proceedings of the 8th Inter. Conf. Thermal Analysis 566-570

1985, Bratislava; Ovcarenko GI, F. Tamas: Properties of Alkali-Lignosulfonate Mixed Cements, Epitoanyag 36, 353-358, 1984; LGŠpynova et al .: Personalities of cement assemblies of long-lived ispolzovanija at abatable types, Cement (USSR), 11 (1985). The composition of BS cements is known from patent and journal literature, for example from US 3,689,294 (Brunauer); from M.Yudenfreund et al.: Hardened Portland Cement Pastes of Low Porosity, Cement and Concrete Research 2, 313-330 (1972) discloses a composition of a free-flowing expanded cement paste or mortar and concrete based on ground cement clinker with a surface of 600 up to 900 m / kg, containing at least 0.002 parts of grinding additive and at least 0.0025 parts of alkaline or alkaline-earth lignin sulphonate or sulphonated lignin and at least 0.0025 parts of alkali carbonate, the water coefficient being in the range w = 0.20 to 0 , 28. This composition of B3 cements was refined in US 3,959,004 (Stryker), where the authors concluded that alkali bicarbonate could be used in gypsum-free cements instead of alkali carbonate. Some of the problems associated with BS cements, such as a short onset of solidification, have been addressed in US 4,168,985 (Kolar et al.) Where a cement-based clinker binder containing cement having a specific surface area of 250 to 3,000 m / kg and containing 5 to 95% . % of cement particles up to 5 microns in size and at least 0.0025 parts by weight of lignin sulphonate based material, further comprising 0.05 to 80 wt. % water, 0.01 to 8 wt. alkali compounds, preferably carbonate, and other solidification-adjusting additives, which may be an oxygenated boron compound or an organic hydroxy acid salt. In a further phase, a composition of BS cements based on ground gypsum-free cement clinker having a specific surface area of 150-3000 m / kg and particle fractions of less than 5 microns, in the range of 5-95% by weight, was described in US 4,551,176 (Slag et al.). and 0.1 to 5 wt. % sulfonated polyphenolate, optionally containing quinone groups, and doped with Al, Fe or Cr salts and 0.1 to 10 wt. % of compounds of the group of alkali hydroxides, carbonates, bicarbonates, silicates and finally at least 20 wt. mixing water.

A disadvantage of existing solutions of BS cements and fillers, especially for use in mortars and concretes, is the relatively short onset of solidification, which is often not acceptable for construction practice. These problems are solved by increasing the concentration of substances known as solidification regulators of BS cements such as boric acid, sodium potassium tartrate, further increasing the monosaccharide content of lignisulfonate and increasing the concentration of ligninsulfonate or sulfonated polyphenolate. This solution delays the start of solidification of the BS cements with sand or aggregate, but very often at the cost of reducing short-term strengths within a few hours to 3 to 7 days of the mixture solidifying. A disadvantage of this solution is also the use of highly deficient additives such as boric acid or sodium potassium tartrate. To delay the solidification of the mixtures it is also possible to control also

CS 273 201 B1 by selection of sands or aggregates that minimize the start of solidification of the mixture. This solution is realistic, but in practice it means using only limited sites of sand and aggregate

The above-mentioned disadvantages are overcome by the method of preparing a cement composition free of gypsum with a prolonged onset of solidification according to the invention, wherein the cement composition comprises cement clinker having a specific surface area of 250-800 m ² / kg; grinding additive e.g. triethanolamine, athylene glycol; dodecylbenzenesulfonan triethanolamide; lignin, alkali carbonate, bicarbonate or silicate, filler such as sand, coarse or porous aggregate, heavy filler such as metal Pb, defoamer such as ethylhexanol, fine amorphous SiOg, fly ash, solidification regulator such as boric acid, hydroxyacid salts, organosilicon monosaccharides and mixing water. Before preparing the mixture, the amount of alkali carbonate, bicarbonate or silicate that has reacted with or absorbed on the sand and / or aggregate used is analytically determined. The principle of the invention is characterized in that from 0.5 to 2% by weight of the analytically determined amount is added to at least one, preferably two to five times, analytically determined amounts. % of an alkali carbonate, bicarbonate or silicate, this amount being at most 15 wt. % of the total mixture, and then this amount is added to the other ingredients of the mixture, the weight percent being based on the weight of the cement clinker.

In the system of concrete or BS cement mortar, the system: Ground cement clinker + alkali carbonate, bicarbonate or silicate + sulfonated polyelectrolyte + sand and / or aggregate + HgO has so far been assumed that the solidification regulator - alkali carbonate, bicarbonate or silicate + sulphonated electrolyte - only affects the grains of ground cement clinker. However, it has been shown that contact of the solidification regulator solution with sand and / or aggregate results in adsorption of both components, especially to the finest parts of sand and / or aggregate, resulting in the increasing fineness of the sand or the increasing proportion of dust aggregates shortens the start of solidification of the BS cement mixtures.

The most striking reaction, however, is the direct chemical reaction of an alkali carbonate, bicarbonate or silicate with the finest sand or dust particles of the aggregate, especially crushed. The finest parts of sand often contain clay materials, the characteristic of which is the ability to exchange cations, especially Na ⁺ to Ca ⁺ . In the case of kaolinite, this reaction can be described;

Ca- (kaolin) ₂ + NagCO4 + 2 Na - kaolin + CaCO3 (1)

In addition to clay minerals, sands or aggregates may contain other components, for example partially weathered, which have a cation exchange capacity. The chemical exchange reaction appears to be stronger than adsorption of alkali carbonate + sulfonated polyelectrolyte on the ground clinker surface. For this reason, a part, often a considerable part according to the exchange capacity of the contained minerals of the alkaline compound, is converted to insoluble CaCO 3. The entire system delaying the onset of solidification is then destroyed and significantly shortens the onset of solidification mixtures of BS cements with conventional sand and aggregates. Therefore, formulas for mixtures of BS cements with normal (real) sand developed on standard (pure) sand mixtures also fail. This relationship of solidification regulator to sand and aggregate has so far been neglected in the application of BS cements.

Experimental work has shown that this assumption is correct and by increasing the content of alkali carbonate, bicarbonate or silicate above the exchange capacity of sand or aggregate, the start of solidification can be significantly prolonged and an acceptable workability time of BS cements, sand and aggregates can be achieved.

The cation exchange in sand or aggregate can also be carried out generally with an alkaline hydroxide, for example the following reaction:

CS 273 201 B1

Ca - (kaolin) ₂ + 2 NaOH -> 2 Na - kaolin + Ca (OH) ₂ (2)

The resulting calcium hydroxide, however, is considerably more soluble than the CaCO 3 contemplated in reaction (1), and is reacted with the alkali carbonate present in the mixture as part of the solidification regulator. CaCO2 is formed and the entire solidification regulator is destroyed again. Calcium hydroxide also promotes the hydration of the other binder components and, overall, upon addition of the alkaline hydroxide, it does not delay the onset of solidification but rather shortens it. Therefore, the use of alkali hydroxides in this case is impossible.

The basis of mixtures of BS cements, especially mortars and concretes, is cement paste. Its viscosity, strength development and onset of solidification are significantly reflected in the properties of cement-filler mixtures. The properties of the slurry of BS cements are significantly influenced by the concentration or ratio of the alkali component, for example alkali carbonate and sulfonated polyelectrolyte. The dependence of viscosity, time development of strength and setting time on the concentration of both gypsum-replacing components is not linear and in most cases has a flat character with some optimum. By selecting a combination of slurry performance properties, such as minimum viscosity, acceptable solidification start and strength increase, the optimum concentrations of the alkali component and sulfonated polyelectrolyte can be found. This recipe is then the basis for the recipe of mixtures of BS cements with fillers, in particular mortars and concretes.

The increase in the content of the alkali component, i.e. carbonate, bicarbonate or silicate, relative to the concentration used for reliable slurry preparation, must be determined experimentally for the particular sand or aggregate used. The basis for this increase is the analytical determination of the decrease in the concentration of the alkaline component solution after contact with sand or aggregate. This determination can be easily accomplished by detecting a decrease in the concentration of, for example, soda in solution after contact with a certain amount of sand by alkalimetry titration. It has been found that it is advantageous, particularly in view of the strength development, to increase the concentration of the alkali component relative to the weight of the sand or aggregate by an amount which is one to two times, preferably two to five times. reaction with sand or aggregate. Increasing the content of the alkali component, for example carbonate, bicarbonate or silicate, is best done in the mixing water. It is also possible to increase the content of the alkali component as a solid additive when grinding BS cements. However, this procedure is not optimal since it is not possible to determine an exact uniform concentration of the alkaline component with respect to different locations of sand or aggregate. Increasing the content of alkaline component in mixtures of BS cements with conventional sand and / or aggregate may be combined with a slight or slight increase in the sulfonated polyelectrolyte content. Even an increase in the sulfonated polyelectrolyte content leads to a prolonged start of solidification, but certainly to a decrease in the initial and, in some cases, long-term strengths. The level of increase in the alkali salt drawn by reaction with sand or aggregate can also be controlled to some extent by the onset of solidification of said mixtures.

The actual start of solidification of BS cement mixtures for construction purposes is further influenced by the following factors: details of the mixture preparation machinery, BS cement specific surface area and clinker location, BS cement grinding method, alkaline compound type, sulfonated polyelectrolyte type and water coefficient size.

The process according to the invention can advantageously be used in the construction industry for the preparation of cement mixtures free of gypsum with a prolonged onset of solidification.

The invention is illustrated by the following non-limiting examples.

CS 273 201 B1

Example 1

For the preparation of mixtures of cements and fillers, cements based on cement clinker were prepared by grinding cement clinker from common production of MS. cement works. Grinding was carried out in the absence of gypsum. Parameters and designations of individual BS cements are given in Table 1.

Example 2

For the preparation of mixtures of cements and fillers were used sand and aggregate MS. sands and aggregates were tested according to ČSN 72 1511 and 72 1513, where they showed satisfactory parameters. In addition to these tests, the reactivity of sands and aggregates with alkaline carbonate, in this case with NagCOy, was determined. The aim of this determination was to determine how the concentration of the original soda solution decreased after contact with sand or aggregates. The assay was performed as follows. 200 to 500 g of sand or aggregate was weighed. This amount was left in contact with the soda solution for 5 minutes. The amount of solution and soda concentration corresponded to the mixing ratios of mortars or concretes, i.e. 1.2 g of NagCO-1 per 32 ml of water per 200 g of filler. After 5 minutes of contact of the solution with sand or aggregate, the solution was filtered by vacuum filtration and the NagCO content was determined in the filtrate. The results of this determination are given in Table 2, together with the designation of the individual fillers used.

Example 3

Mixtures were prepared from the cements and fillers listed in Examples 1 and 2 in different cement-to-sand or aggregate ratios and at different water coefficients. A different way of adding ingredients has also been combined. All mixtures were compacted on a 50 Hz vibrator after preparation. All of the mixtures shown in the following examples were compacted, even at low water coefficients. The rheological properties of mixtures of BS cements with fillers (sand, aggregates) were also studied. The rheological properties of BS cements with fillers are different from analogous Portland cement mixtures. For example, when compacting mixtures of BS cements, the mixture moves vertically. At a low water coefficient of BS cement mixtures (at 0.25 to 0.27), these mixtures have a particularly gummy character with a strong internal cohesion. Consistency of prepared mixtures of BS cements was monitored according to the nomenclature for Portland cements and for mixtures with sand the consistency ranged from liquid to wet consistency and for mixtures with sand and aggregate from very soft consistency to solid consistency. The start of solidification was defined for all studied mixtures, which was defined as the loss of formability of the mixture. The transition of BS cement mixtures from plastic to unformable, completely rigid even under vibration is sharp, with this transition occurring in the vast majority of cases in minutes, unlike Portland cement mixtures where this transition is smooth, in accordance with the dates of onset and the time of solidification. Sulfonated sodium ferric polyphenolate (36.7% solids solution), hereinafter labeled Ralentol, was used in the preparation of the mixtures. In addition, sodium ligninsulfonate, decalcified, partially devoid of monosaccharides and oxidized at elevated temperature in an alkaline medium, hereinafter referred to as Natroplast (powder), was used. Furthermore, sodium lignin sulphonate, descaled, practically devoid of accompanying monosaccharides, powder was used.

Example 4

Tables 3 and 4 show the results of the influence of different sand sites on the start of solidification of BS cements. These results further show the effect of increasing the NagCO2 content relative to the slurry formulation and the onset of solidification.

CS 273 201 B1

Example. 5

Table 5 shows the results of the influence of different forms of the alkaline component on the start of solidification of BS cement mortars with common building sand. The amount of alkali compound was determined to be equivalent, in terms of alkali metal cation content, to an amount of NagCO-j based on 0.5 wt%. of sand. The result shows that an equivalent amount of alkaline compounds, with the exception of NaOH, will extend the start of solidification practically the same. This result confirms the idea of the mechanism of action of sands on water suspensions of BS cements.

Example 6

Table 6 shows the effect of the different mortar composition and the increase in the alkali content on the properties of BS cements.

Example 7

Table 7 shows the properties of a BS cement mix using a slurry formulation and an increased alkali content.

Example 8

Table 8 shows the effect of the mixing method - the residence time of the contact of sand with an increased content of alkaline component - on the properties of the BS cement mortars.

Example 9, Tables 9 and 10 show the effect of the method of blending BS cement mixtures in different order of components.

Example 10 Tables 11, 12, 13, 14 and 15 show the properties of BS cement mixtures using slurry formulations and increasing the alkaline component.

CS 273 201 B1

Table 1

Method of preparation of BS cement, specific surface, grinding additives Designation p circulating mill, clinker Border, 690 m / kg, 1% sodium lignin sulphonate (partially devoid of accompanying monosaccharides) + 0.8% NagCO ^ (clinker weight) Border 690 (LS + N) p ball mill 50 l, clinker Lochkov, 500 m / kg, 0.04% dodecylbenzenesulfonic acid triethanolamide (clinker weight) Lochkov 500 (0.04% TEDB) ball mill 50 l, clinker Hranice, 370 m ² / kg, 0.05% triethanolamine, after grinding mixed with 5% SiOg drift (clinker weight) Border 370 (0.05% ΤΞΑ + 5% Komsil) p vibratory mill, clinker Prachovice, 530 m / kg, 0.05% triethanolamine Prachovice 530 (0.05% TEA) vibratory mill, clinker Čížkovioe, 560 m ² / kg, 0.06% dodecylbenzenesulfonic acid triethanolamide Čížkovice 560 (0.06% TEDB)

WZ Λ Z ** 2 / vibratory mill, Simek Štramberk, 470 m / kg, 0.05% dodecylbenzenesulfonic acid triethanolamide Stramberk 470 (0.05% TEDB) p vibrating mill, clinker Maloměřice, 620 m / kg, 0.05% triethanolamine Malomerice 620 (0.05% TEA)

CS 273 201 Bl

Table

Labeling g NagCOj consumed per 100 g of sand or aggregate

Shooter 0 to 2 0,028 Tovačov 0 to 4 0.057 Bratčice 0 to 4 0.25 Stem 0 to 4 0,045 Suchdol 0 to 6.3 ^X 0.106 Chržín 0 to 6,3 ^X 0.114 Vojkovice 0 to 6,3 ^X 0,086 Chlum u Třeboň 0 to 6,3 ^X 0,049 Shirts 0 to 4 0.057 Klecany 4 to 8 0.014 Klecany 8 to 16 0,023 Vliněves 16 to 22 0,028 Předonín 8 to 16 0.017 Vojkovice 6.3 to 8 ^X 0,039 Chržín 6.3 to 8 ^X 0,079 Suchdol 6.3 to 8 ^X 0,081 Chlum u Třeboně 6.3 to 8 ^X 0.014 Dřice 2,7 to 4 ³³ 0.030

^x original sand fraction 0 to 8 mm xx original sand fraction 0 to 4 mm

CS 273 201 B1

Table 3

BS cement Lochkov 500 (0.04% TEDB) mortar w = 0.31 cement; sand 1 with 2,5 start of slurry solidification w = 0,25 140 minutes slurry recipe: 1 wt. cement NagCO ^ wt. Ralentol solidification start (min.)

Locality of sand Mash recipe Mash recipe + 0.4 wt. of sand

Na ₂ C0 ₃

Shooter 0 to 2 45 70 Suchdol 0 to 6.3 25 60 Tovačov 0 to 4 25 65 Bratoioe 0 to 4 10 40 Chržín 0 to 6,3 20 May 50 Stem 0 to 4 30 65 Vojkovice 0 to 6,3 20 May 60 Chlum u Třeboně 0 to 6,3 50 70

CS 273 201 B1

Table 4

BS cement Boundary 690 (LS + N), mortar w = 0.33 cement: sand 1: 3 wt., Slurry w = 0.25 onset of setting 110 minutes increase in the concentration of ^Ta ^CO, relative to the slurry recipe start of setting (min. )

Suchdol 0 to 6.3 Chlum u Tr. 0 to 6.3 Chržín 0 to 6,3 0% (recipe for porridge) 25 45 15 Dec + 0,16% 160 150 75 + 0,33% 180 180 145 -h O j 50% 250 155 150 + · 0.66% 105 130 105 + 0.75% 80 60 60 Vojkovice 0 to 6,3 Shooter 0 to 2 3 fractions of norm, sand (1: 1: 1) 0% (recipe for porridge) 17 100 ALIGN! 110 + 0,16% 80 - - + 0,33% 110 - - + 0.50% 130 - - + 0,66% 85 - - + 0.75% 40

Note:% are based on sand weight

CS 273 201 B1

Table 5

BS cement boundary 690 (LS + H), mortar w = 0.33 cement: pI3 1: 3 wt. sand Chlum u Tř. 0 to 6.3 amount of alkaline compound (% by weight of sand) setting time (min)

0.5% Na ₂ CO ₃ 155 0.79% HaHCO ₃ 160 (setting time 240) 0.66% K ₂ CO ₃ 190 0.5% Ha ₂ Si0 ₃ (water glass) 160 with Si0 ₂ : Ua ₂ 0 ratio approx. 1) (setting time 240) 0.37% NaOH 25

NB:

The visual workability of the mortar was in the following order depending on the addition of the alkaline compound:

K ₂ C ° 3> Ha ₂ CO ₃ > Na ₂ SiO ₃ > NaHCO ₃

CS 273 201 B1

Table 6

BS cement Hranice (LS + H), mortar w = 0.33 sand Chlum u Tř. 0 to 6.3, the mixing water contained 0.5 wt. sand IfágCO ^, or the original slurry recipe was used to increase the NagCO ^ slurry concentration relative to the cement slurry recipe (s) solidification start (min) 1: 1 1: 2 1: 3

0% 90 85 45 + 0,5% 180 145 150

Table 7 BS cement boundary 690 (LS-t · H) start of slurry solidification w = 0.25 110 minutes composition of the mixture w additives start of setting (min) 1: 1,5: 3 Vojkovice 0 to 6,3 Kleeany 4 to 8 0.31 recipe for porridge 30 _ 11 __ 0.31 recipe for porridge, soda content increased by 0.66% wt. sand and 0.16% by weight of aggregate 130 1: 2,25: 3,1 Halls 0 to 4 Kleeany 8 to 16 0.35 recipe for porridge, soda content increased by 0.66% by weight of sand and by 0.24% by weight of aggregate 90

CS 273 201 B1

Table 8

BS cement Boundary 690 (LS + N), mortar w = 0.33 cementspiaek 1: 3 wt., Sand Vojkovioe 0 to 6.3 method of mortar mixing: sand + water, then cement between mixing sand and water and then adding cement delay + 0.50% wt. sand Na ^ dwell time of sand mixture and mixing start of water solidification before adding cement (min) with 25 s min 15 min

110

130

120

125

Table 9

BS cement Boundary 370 (0.05% TBA + 5% Komsil) slurry recipe: 1% NagOO ^ + 2% wt. Ralentol (cement weight) mixture start setting (min) mortar 1: 3, sand shooter 0 to 2 recipe mortar slurry 1: 3, sand shooter 0 to 2, soda content increased by 0.16% wt. sand to slurry formula 1: 1.5: 3, sand Strelec, Kleoany 4 to 8 soda content increased by 0.22% by weight of sand and 0.05% by weight aggregates, mixing: simultaneously cement + sand, then water with additives and then aggregates mixture 1: 1,5: 3, same composition and additives, mixing: sand with water and additives, then cement and then aggregates mixture 1: 1,5: 3, the same composition and ingredients, mixing: at the same time cement + sand + aggregate, then water with additives

100 ALIGN!

CS 273 201 Bl

Table 10

BS Cement Boundary 370 (0.05% TBA + 5% Komsil) mixture 1: 1.5: 3 medium fraction of standard sand, KLecany 4 to 8 recipe for slurry 1% fegCO4 + 2% wt. Ralentol (cement weight) IfegCO2 content increased by 0.21% by weight. % sand and 0.05 wt. Aggregates Mixing method Mixing Initial setting (min) Simultaneously Cement + sand + water with additives then Unwashed aggregates 95 Simultaneously Cement + sand + water with additives, then aggregate washed, dried 90 Simultaneously cement + sand + aggregate, then water with additives 95

Table 11

BS cement Lochkov 500 (0.04% TEDB), mortar w = 0.31 cement: sand 1: 2.5 slurry A recipe: 1 wt. 2 wt. Ralentol mash B recipe: 1% sand shooter 0 to 2 wt. cement NágCOp 3% wt. Ralentol recipe for porridge A + x wt. sand Na ₂ C0 ₃ start of setting (min) recipe for porridge B + x wt. of sand. Na ₂ C0 ₃ start of setting (min) 0% 45 0% 170 + 0.40% 70 + 0.40% 300 + 0.80% 55 + 0.80% 380 + 1,2% 10 + 1,2% 120

CS 273 201 B1

Table 12

BS cement Stramberk 470 (0.05% TSDB) recipe for slurry A: 1% NagCO4 + 2% wt. Ralentol (cement weight), slurry solidification start A w = 0.25 100 minutes slurry formulation B: 1.2% NagCO4 + 0.9% sodium ligninsulfonate (devoid of monosaccharides), slurry solidification start B w = 0.25 40 minutes composition mixture w ingredients start setting (min)

1: 1.8: 3

Shooter 0 to 2

Cages 4 to 8 0.31 recipe for slurry A, soda content increased by 0.18% by weight of sand and 0.06% by weight. aggregates

120

111 »8: 3

Shooter 0 to 2 Klecany 4 to 8 recipe for porridge B, soda content increased by 0.11% by weight of sand and 0.03% by weight. aggregates

1: 2.3: 2.85

Dumplings 0 to 4 0,31 recipe for porridge

Klecany 8 to 16

1: 2,3: 2,85 Halls 0 to 4 Klecany 8 to 16 recipe for porridge A, soda content increased by 0,21% by weight of sand and 0,08% by weight, aggregates

120

CS 273 201 B1

Table 13

BS cement Malomerice 620 (0.05% TEA) slurry recipe: 1% Ha ₂ CO 2 + 2% wt. Ralentol (cement weight.) Start of slurry solidification w = 0.27 60 minutes

composition of the mixture w additives start of setting (min) 1: 1.75: 3 recipe for porridge, contents Halánky 0 až 4- soda increased by 0.08 wt. Klecany 4 to 8 0.31 0.02 wt. 80 aggregates 1: 2: 3.5 recipe for porridge, contents Halls 0 to 4 0.27 soda increased by 0.18 wt. 45 Klecany 8 to 16 0.04 wt. aggregates 1: 1.75: 3 recipe for porridge, contents Halls 0 to 4 0.31 soda increased by 0.2 wt. 85 Předonín 8 to 16 % sand and 0.05 wt. aggregates • 1: 1.75: 3 Halls 0 to 4 0.31 dtto 85 Vliněves 16 to 22

CS 273 201 B1

Table 14

BS Cement Boundary 37θ (0, 5% TEA + '5% Komail) Recipe: 1% NagCO ^ + 2% wt. Ralentol (cement weight) slurry solidification start w = 0.25 160 minutes

composition of the mixture w additives start of setting (min) 1: 1,75: 3 Gallows 0 to 4 Vliněves 16 to 22 0.30 recipe for porridge, soda content increased by 0.28 wt. 0.08 wt. aggregates 110 1: 1,8: 2,75 Gallows 0 to 4 Vliněves 16 to 22 0.28 recipe for porridge, soda content increased by 0.27 wt. % sand and 0.05 wt. aggregates 90 1: 1,85: 2,6 Halls 0 to 4 Předonín 8 to 16 0.26 recipe for porridge, soda content increased by 0.32 wt. 0.07 wt. aggregates 85 1: 1,85: 2,4 Halls 0 to 4 Předonín 8 to 16 0.25 recipe for porridge, soda content increased by 0.32 wt. 0.08 wt. aggregates 75 1: 2,25: 3,5 Halls' 0 to 4 Předonín 8 to 16 0.32 recipe for porridge, soda content increased by 0.38 wt. % sand and 0.1 wt. aggregates 85 1: 1,5: 3 Suchdol 0 to 6,3 Klecany 4 to 8 0.31 recipe for porridge 35 1: 1,5: 3 Suchdol 0 to 6,3 Klecany 4 to 8 0.31 recipe for porridge, soda content increased by 0.53 wt. 0.06 wt. aggregates 65

CS 273 201 B1

Table 15 recipe for porridge:

1.3% KgCO ^ + 0.9% Hatroplast (cement weight)

cement composition mixture w ingredients early solidification

Claims

OBJECT OF THE INVENTION

Process for preparing a cemented gypsum-free mixture with a prolonged onset of solidification comprising a cement clinker having a specific surface area of 250 to 800 m / kg, a grinding additive such as triethanolamine, ethylene glycol, dodecylbenzenesulfonic acid triethanol amide, sulfonated polyelectrolyte e.g. carbonate, bicarbonate or silicate, filler such as sand, coarse or porous aggregate, heavy filler such as metal Pb, defoamer such as ethylhexynol, fine amorphous SiO 2, fly ash, solidification regulator such as boric acid, hydroxyacid salts, organosilicon esters or monosaccharides and Mixing water, where the amount of alkali carbonate, bicarbonate or silicate to be reacted with or absorbed on the powder and / or aggregate used is analytically determined prior to the preparation of the mixture, characterized in that %, to 0.5 to 2% by weight of the analytically determined amount is added to at least one, preferably two to five times the analytically determined amount. % of an alkali carbonate, bicarbonate or silicate, this amount being at most 15 wt. of the total mixture, and then this amount is added to the other ingredients of the mixture, the weight percent being based on the weight of the cement clinker.