阅读说明：本技术 用于包含硫铝钙石的水泥的添加剂 (Additive for cement containing tialite ) 是由 P·朱兰德 E·加卢奇 A·埃伯哈特 L·佩加多 L·卡德拉斯 D·舍嫩贝格尔 L·佛伦 于 2019-11-22 设计创作，主要内容包括：本发明公开了用于包含基于硫铝钙石的熟料的水泥基粘结剂的水合反应的缓凝剂和调节剂的组合。缓凝剂为钙络合剂,优选选自糖酸、糖、糖醇、羟基羧酸、磷酸盐/酯、膦酸盐/酯、硼酸盐/酯和胺。该调节剂具有通式(I)其中M为H、NH-4或选自元素周期表第Ia、IIa、IIIa、Ib、IIb、IVb、VIb、VIIb或VIIIb族的单价或二价金属,并且如果M是二价金属则存在第二当量的R-SO-3,和其中优选地M选自H、NH-4、Li、Na、K、MgX、CaX或NiX,其中X＝RSO-3,和其中R选自H、NH-2、OH或选自具有1-18个C原子的烃基链,其可以被N和/或O替代和/或其可以是直链或支化的和/或其可以含有一个或多个不饱和键和/或环脂族和/或芳族基团。本发明的缓凝剂和调节剂的组合可用于控制所述包含基于硫铝钙石的熟料的水泥基粘结剂的早期阶段水合反应。更特别地,通过本发明的缓凝剂和调节剂的组合可以延长开放时间,同时促进包含水泥基粘结剂的水泥基混合物的固化,所述水泥基粘结剂包含基于硫铝钙石的熟料。本发明还公开了本发明的缓凝剂和调节剂的组合的用途,以及用于控制包含基于硫铝钙石的水泥基粘结剂的早期阶段水合反应的方法。(The present invention discloses a combination of retarders and modifiers for the hydration reaction of cement-based binders comprising a belite-based clinker. The retarder is a calcium complexing agent, preferably selected from sugar acids, sugars, sugar alcohols, hydroxycarboxylic acids, phosphates, phosphonates, borates and amines. The regulator has the general formula (I) Wherein M is H, NH 4 Or a monovalent or divalent metal selected from groups Ia, IIa, IIIa, Ib, IIb, IVb, VIb, VIIb or VIIIb of the periodic Table of the elements, and if M is a divalent metal a second equivalent of R-SO is present 3 And wherein preferably M is selected from H, NH 4 Li, Na, K, MgX, CaX or NiX, where X ═ RSO 3 And are andwherein R is selected from H, NH 2 OH or from a hydrocarbon chain having 1 to 18C atoms, which may be substituted by N and/or O and/or which may be linear or branched and/or which may contain one or more unsaturated bonds and/or cycloaliphatic and/or aromatic groups. The combination of the set retarder and the modifier of the invention can be used to control the early stage hydration reactions of the cement-based binder comprising the tialite-based clinker. More particularly, the open time can be extended by the combination of the retarder and the conditioner of the invention, while promoting the curing of a cement-based mixture comprising a cement-based binder comprising a tialite-based clinker. The invention also discloses the use of the combination of retarder and conditioner of the invention, and a method for controlling early stage hydration reactions of a cement-based binder comprising a tialite.)

1. An additive for controlling early stage hydration reactions of cement comprising a tialite-based clinker, comprising:

a) at least one retarder S selected from calcium complexing agents, and

b) at least one regulator R of the general formula (I)

Wherein M is H, NH₄Or a monovalent or divalent metal selected from groups Ia, IIa, IIIa, Ib, IIb, IVb, VIb, VIIb or VIIIb of the periodic Table of the elements, and if M is a divalent metal a second equivalent of R-SO is present₃And wherein preferably M is selected from H, NH₄Li, Na, K, MgX, CaX or NiX, where X ═ RSO₃And wherein R is selected from H, NH₂OH or from a hydrocarbon chain having 1 to 18C atoms, which may be substituted by N and/or O and/or which may be linear or branched and/or which may contain one or more unsaturated bonds and/or cycloaliphatic and/or aromatic groups.

2. Additive according to claim 1, characterized in that the at least one retarder S is selected from sugar acids, saccharides, sugar alcohols, hydroxycarboxylic acids, phosphates, phosphonates, borates and amines.

3. Additive according to any one of claims 1-2, characterized in that at least one retarder S is gluconic acid or one of its metal salts, preferably an alkali metal salt, in particular S is sodium gluconate.

4. Additive according to any one of claims 1 to 3, characterized in that the at least one modifier R of the general formula (I) is selected from the group consisting of methanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, naphthalenesulfonic acid, sodium tetrapropylbenzenesulfonate, sodium dodecylbenzenesulfonate, sulfamic acid, N-cyclohexyl-2-aminoethanesulfonic acid, taurine and sulfanilic acid.

5. Additive according to any one of claims 1 to 4, characterized in that the molar ratio of the at least one retarder S to the at least one modifier R is from 1:2 to 1:450mol/mol, preferably from 1:10 to 1:400mol/mol, more preferably from 1:20 to 1:300 mol/mol.

6. A cement-based binder comprising

a) At least one canasite-based clinker,

b) at least one retarder S selected from calcium complexing agents, and

c) at least one regulator R of the general formula (I)

Wherein M is H, NH₄Or a monovalent or divalent metal selected from groups Ia, IIa, IIIa, Ib, IIb, IVb, VIb, VIIb or VIIIb of the periodic Table of the elements, and if M is a divalent metal a second equivalent of R-SO is present₃And wherein preferably M is selected from H, NH₄Li, Na, K, MgX, CaX or NiX, where X ═ RSO₃And wherein R is selected from H, NH₂OH or from a hydrocarbon chain having 1 to 18C atoms, which may be substituted by N and/or O and/or which may be linear or branched and/or which may contain one or more unsaturated bonds and/or cycloaliphatic and/or aromatic groups.

7. Cement-based binder according to claim 6, characterised in that the clinker contains 5-95 w%, preferably 10-80 w%, more preferably 20-70 w% of colemanite, each based on the total dry weight of the clinker.

8. Cement-based binder according to claim 6 or 7, characterized in that the at least one retarder S is selected from sugar acids, saccharides, sugar alcohols, hydroxycarboxylic acids, phosphates, phosphonates, borates and amines.

9. Cement-based binder according to claim 6 or 7, characterized in that it comprises 5-99 w% clinker, 0.01-2 w% sodium gluconate, and 0.1-6 w% of at least one modifier R of formula (I).

10. A cementitious mixture comprising the cementitious binder of any one of claims 6 to 9, said cementitious mixture further comprising:

a) the amount of water is controlled by the amount of water,

b) optionally an aggregate, and

c) optionally one or more further additives selected from: plasticizers, superplasticizers, shrinkage reducers, air entrainers, degassing agents, stabilizers, viscosity modifiers, water reducers, accelerators, retarders, water resistance agents, strength enhancing additives, fibers, foaming agents, pigments, and steel deactivators.

11. A method for controlling early stage hydration reactions in cement or cement-based mixtures, comprising the steps of:

a) providing a clinker or cement-based mixture based on tialite,

b) providing at least one retarder S selected from calcium complexing agents,

c) providing at least one regulator R of the general formula (I),

d) the water is provided to the patient in a water supply,

e) optionally providing an aggregate material, optionally with a binder,

f) optionally providing other additives, and

g) mixing a) to f) in any given order.

12. Method according to claim 11, characterized in that at least one retarder S and at least one regulator R are provided as separate components during any step of mixing.

13. Method according to claim 11, characterized in that the at least one retarder S and the at least one regulator R are provided as a one-component premix during any step of mixing.

14. Use of at least one modifier R of the general formula (I) for controlling early hydration reactions of clinker, cement or cement-based mixtures,

wherein M is H, NH₄Or a monovalent or divalent metal selected from groups Ia, IIa, IIIa, Ib, IIb, IVb, VIb, VIIb or VIIIb of the periodic Table of the elements, and if M is a divalent metal a second equivalent of R-SO is present₃And wherein preferably M is selected from H, NH₄Li, Na, K, MgX, CaX or NiX, where X ═ RSO₃And wherein R is selected from H, NH₂OH or from a hydrocarbon chain having 1 to 18C atoms, which may be substituted by N and/or O and/or which may be linear or branched and/or which may contain one or more unsaturated bonds and/or cycloaliphatic and/or aromatic groups.

15. Use according to claim 14, characterized in that the clinker, cement or cement-based mixture is based on tialite.

16. Use according to any one of claims 14-15, characterized in that the clinker, cement or cement-based mixture contains a retarder S.

17. Use of an additive according to any one of claims 1 to 5 as a grinding aid in the production of cement-based binders, preferably of cements based on tialite.

18. Shaped article, in particular a building or a part of a building, obtainable by curing a cement-based binder or a cement-based mixture according to any one of claims 6-10.

Technical Field

The present invention belongs to the field of additives, in particular a combination of retarders and regulators for the hydration reaction of cement-based binders, in particular cements comprising clinker based on canasite (Ye' elimite). The invention also relates to a cement-based binder comprising said additive. Furthermore, the invention relates to the use of such an additive in clinker comprising xonotlite and/or cement-based binders and to a method for controlling the hydration reactions at an early stage of cement comprising xonotlite-based clinker.

Background

Construction cements commonly comprisePortland Cement (OPC) or based on OPC clinker. Such cements are described in EN 197-1. In the production of OPC, sintering and grinding consume a large amount of energy, and thus a large amount of CO is released per ton of cement₂. For reducing CO for cement producers₂Efforts to discharge include the use of OPC alternatives based on clinker requiring less energy to produce. One such alternative is to use a cement comprising a xonotlite-based clinker.

During cement production, clinker is ground and appropriate amounts of calcium sulfate and other performance modifiers are typically added. Thus, the tialite-based cement may achieve similar workability and similar or even better compressive strength as OPC-based cements. However, the tialite-based cements show significantly faster setting than OPC. In order to ensure a sufficiently long workability for practical use, it is necessary to delay the setting of cement-based mixtures comprising a belite-based cement.

It is common practice to use retarders in cement and cement-based mixtures, such as in the preparation of ready-mix concrete. Retarders extend the set time and increase the open time of cement-based mixtures, thus allowing for longer workability, which can be used for, for example, transportation, mixing, pumping, placement, compaction, or molding. Retarders known in the art include sugars and sugar-like substances (e.g., gluconate), lignosulfonate, citric acid, tartaric acid, phosphonate and/or boric acid and salts thereof.

One disadvantage of the retarders of the prior art is that, in addition to delaying the setting of the cement-based mixture, they also delay the setting of the mixture and thus reduce the compressive strength after 28 days in the early and adverse cases. This delay in curing is disadvantageous because it also extends the time until the working position can be released. Another disadvantage of many set retarders is that when used in combination with the superplasticizers of cement-based binders, especially in combination with the commonly used polycarboxylate ethers (PCEs), these set retarders can cause the mixture to harden, resulting in reduced workability.

Boric acid and borax (disodium tetraborate) are common set retarders for Calcium Sulfoaluminate (CSA) cement because they effectively retard setting, but have less effect on setting after 1 day than other set retarders. Thus, the early strength and ultimate compressive strength of the cured CSA-based material are not reduced to a degree relevant to practical use. Boric acid and borax are also considered useful cement retarders for clinkers containing a sulfoaluminite-based clinker. However, the use of boric acid or borax poses serious environmental, health and safety (EHS) problems, as borates can impair fertility or the fetus.

It is therefore advantageous to combine the retarders of the prior art with a modifier, such as an accelerator, to ensure that the compressive strength is fully developed early and after the cement-based mixture has set for 28 days.

US7326920(Kerneos) discloses a set accelerator for OPC comprising calcium aluminate as accelerator and additionally boric acid and/or a salt of boric acid as retarder. The EHS problem associated with the use of boric acid has not been solved. In addition, calcium aluminates tend to reduce the workability of cement-based mixtures.

WO2008/089481(Ceratech) discloses a combination of salts of citric acid and boric acid as an accelerator/retarder combination for hydratable cements containing pozzolanic materials. The EHS problem associated with the use of boric acid has not been solved. In addition, the use is limited to pozzolanic materials.

DE10009834(MBT) discloses combinations of phosphonoalkyl carboxylic acids and carboxylic acids as retarders for CSA cements. Such phosphonoalkyl carboxylic acids may have a deleterious effect on processability, especially when combined with a PCE plasticizer.

US8361220(Construction Research & Technology) discloses the use of sodium gluconate as a retarder in a cement-based binder also containing PCE. Sodium gluconate does not increase the viscosity of cement-based mixtures containing such binders. However, sodium gluconate is known to significantly reduce the compressive strength of early cement-based binders.

None of the examples of the prior art are useful combinations of retarders and conditioners for cement containing a belite-based clinker. In particular, it is not known that the modifier can be used in combination with known retarders for cements comprising clinkers based on tialite and can ensure that the early development of a suitable compressive strength, which has little or even improved workability, and which can be safely handled.

Thus, there is a need for additives, in particular a combination of a retarder and a modifier, to control the early hydration reactions of cement-based binders, in particular cements comprising a tialite-based clinker, and which do not have the above-mentioned drawbacks.

Summary of The Invention

It is an object of the present invention to provide additives, especially combinations of retarders and regulators, for cement-based binders, especially for cement comprising a belite-based clinker, to control early hydration reactions.

It is another object of the present invention to provide cement-based binders and cement-based mixtures comprising a combination of additives, especially retarders and regulators, for cement-based binders, especially for cements comprising a sulfoalite-based clinker, to control early hydration reactions.

It is another object of the present invention to provide a method for controlling early hydration reactions of cement or cement-based admixtures, especially for cement or cement-based admixtures comprising a tialite-based clinker.

It has surprisingly been found that the additive according to claim 1 is a suitable combination of retarder and regulator agents suitable for use in cement-based binders and/or cement-based mixtures, in particular cements comprising a sulfoalite-based clinker, to control early hydration reactions.

The object of the present invention is therefore an additive for cement-based binders, in particular for cements comprising a xonotlite-based clinker, to control early hydration reactions, comprising

a) At least one retarder S selected from calcium complexing agents,

b) at least one regulator R of the general formula (I),

wherein M is H, NH₄Or a monovalent or divalent metal selected from groups Ia, IIa, IIIa, Ib, IIb, IVb, VIb, VIIb or VIIIb of the periodic Table of the elements, and if M is a divalent metal a second equivalent of R-SO is present₃And wherein preferably M is selected from H, NH₄Li, Na, K, MgX, CaX or NiX, where X ═ RSO₃And are and

wherein R is selected from H, NH₂OH or from a hydrocarbon chain having 1 to 18C atoms, which may be substituted by N and/or O and/or which may be linear or branched and/or which may contain one or more unsaturated bonds and/or cycloaliphatic and/or aromatic groups.

It was found that the additives of the invention, in particular the combination of retarder and conditioning agent, can increase the open time or induction period of a cement or cement-based mixture comprising a tialite-based clinker after addition of the mixing water. The extension of the open time helps to facilitate the transport, mixing, pumping, placing, compacting or shaping of the cement-based mixture comprising the tialite-based clinker.

Another advantage of the inventive additive, especially the combination of retarder and modifier, is that it increases the workability of cement-based mixtures comprising cement containing a belite-based clinker. Thus, the initial spreading flow or initial slump of the cement-based mixture is increased by the addition of the additive of the present invention. When the additive of the present invention is used in a cement-based mixture that additionally contains a PCE-based superplasticizer, the initial extensional flow is the same or increased. In addition, a higher extended flow retention of the cement-based mixture comprising the additive of the invention is achieved, i.e. a less reduction of the extended flow in at least 60 minutes after addition of the mixing water, when compared to the reference.

In addition, it was found that the combination of the additives of the present invention, in particular the set retarder and the modifier, does not delay the setting of cement-based mixtures comprising cement comprising a tialite-based clinker to a level relevant for practical use. Thus, the additives of the present invention do not increase the final setting time and do not reduce the early compressive strength of the cement-based mixture containing such additives as compared to the reference. In particular, the compressive strength of the cement-based mixture comprising the additive of the invention is increased or not reduced to a level relevant for practical use compared to the reference when measured 24 hours, preferably 16 hours, more preferably 8 hours after the addition of the mixing water.

Furthermore, by using the additive of the invention, in particular the combination of retarder and conditioner, it is possible to avoid the use of boric acid or borax, which are harmful to health, as a cement-based binder, in particular a retarder for cement comprising a clinkers based on tialite.

Finally, the use of a combination of set retarder and conditioner according to the invention may result in less exudation of a cement-based mixture comprising the set retarder and conditioner combination.

Other aspects of the invention are the subject of other independent claims. Particularly preferred embodiments of the invention are the subject matter of the dependent claims.

Detailed Description

The term "tialite" as used in the context of the present invention refers to a composition of approximately Ca₄Al₆O₁₂(SO₄) Calcium sulfoaluminate. Described in the Strunz classification as group 7.BC.15 (see International mineralogy Association published IMA/CNMNC mineral name List).

The term "clinker" as used in the context of the present invention refers to a material made by sintering a raw material such as limestone, clay, sand, bauxite, fly ash, etc. in a kiln. The choice of raw materials and the detailed sintering procedure depend on the type of clinker to be produced. In the context of the present invention, clinker may also be referred to as hydraulic binder. When mixed with water, the clinker reacts in a so-called hydration reaction, first forming a cement paste, which then solidifies to form a solid hydrate or hydrate phase.

The clinker of the invention is based on tialite. "based on tialite" in the context of the present invention means that the content of tialite in the clinker is 3-95 w%, preferably 5-95%, more preferably 10-80 w%, in particular 20-70 w%, each based on the total dry weight of the clinker. It is possible and also preferred in the context of the present invention that the clinker of the present invention also contains one or more other materials than tialite. Such other minerals are preferably included in a total amount of 97-5 w%, preferably 95-5 w%, more preferably 90-20 w%, especially 80-30 w%, each based on the total dry weight of the clinker. Such other minerals are selected from alite, belite, wollastonite, calcite, wollastonite, aluminates, sulfates and ferrites, for example tetra calcium aluminium ferrite. The clinker of the present invention is preferably produced by sintering suitable raw materials at a temperature not exceeding 1350 ℃.

"cement" or "cement-based binder" as used in the context of the present invention refers to a material containing at least one chalcopyrite-based clinker. The cement referred to in the present invention preferably has a content of at least 5 w%, preferably at least 15 w%, more preferably at least 50 w%, especially at least 80 w% of at least one tialite based clinker, each based on the total dry weight of the cement. In one embodiment, the cement consists of at least 95 w% clinker based on the total dry weight of the cement.

According to certain embodiments, it is possible for the cement of the invention to additionally contain other clinkers than those based on tialite clinkers. Such other clinker may be any known to the person skilled in the art, such as OPC. The content of clinker other than the belite based clinker in the cement of the invention may vary between 0.5 and 85 w%, if present, based on the total dry weight of the cement.

In an advantageous embodiment, the cement additionally contains up to 40 w%, preferably up to 35 w%, in particular up to 20 w%, of calcium sulphate, each based on the total dry weight of the cement. The calcium sulfate may be present in the form of calcium sulfate hemihydrate, calcium sulfate dihydrate, and/or anhydrite.

It is possible and in some cases also preferred that the cement also contains one or more latent hydraulic binders (e.g. slag), pozzolanic binders (e.g. fly ash) and/or non-hydraulic binders (gypsum plaster, anhydrite or white lime). According to an embodiment, the cement of the invention may contain 1-95 w%, preferably 5-80 w%, especially 10-20 w%, of latent hydraulic and/or pozzolanic binder, each based on the total dry weight of the cement.

Additionally, the cement of the present invention may contain a cement modifier selected from the group consisting of grinding aids, strength modifiers, activators, accelerators, plasticizers and superplasticizers. During the grinding process, the cement modifier may be ground together with the clinker. They can likewise be incorporated into the ground clinker.

"cementitious mixture" as used in the context of the present invention refers to a mixture comprising at least one cement or cement-based binder as described above. It is possible and also preferred in the context of the present invention that the cement-based mixture additionally contains an aggregate. It advantageously also contains additives common in the mortar and/or concrete industry, such as plasticizers and/or superplasticizers, shrinkage reducers, air entraining and/or degassing agents, stabilizers, viscosity modifiers, water reducers, accelerators, retarders, water-proofing agents, strength-enhancing additives, fibers, foaming agents, pigments, corrosion inhibitors, etc. It may be advantageous to mix two or more of the above additives in a cement-based mixture. The cement-based mixture of the invention may additionally contain some or all of the mixing water.

In the context of the present invention, a "retarder" is an additive for a cement-based binder and/or a cement-based mixture that delays the hydration reaction of the cement-based binder and/or cement-based mixture after the addition of mixing water compared to a reference without the addition of any such additive. In particular, the retarder affects the early hydration reactions in such a way that: increasing the induction period of the cement-based mixture, increasing the final set time, and decreasing the setting expressed in terms of achieving compressive strength. In the standard EN 934-2:2012-08 in table 8 describes the set retarder in more detail. One advantage of using set retarders may be, for example, that they may allow the mixed concrete to be transported to the construction site longer.

In the context of the present invention, a "conditioner" is an additive for cement-based binders and/or cement-based mixtures which, when used in combination with a retarder, counteracts the retarding effect of the retarder on the final setting time and on the setting after addition of water.

Thus, the effect of the at least one modifier R of the invention is preferably that the cement or cement-based mixture containing the combination of at least one retarder S and the at least one modifier R has the same or slightly reduced open time, the same or reduced final set time and the same or increased plateau height of the cumulative heat flow curve compared to the same cement-based mixture comprising only the at least one retarder S without the at least one modifier R.

It is also preferred that the effect of the at least one modifier R of the invention is that a cement or cement-based mixture containing a combination of at least one retarder S and the at least one modifier R has an increased open time, a moderately increased final set time, and a strongly increased plateau height of the cumulative heat flow curve compared to the same cement-based mixture containing only the at least one retarder S without the at least one modifier R.

In the context of the present invention, the term "identical" means that the respective values do not vary by more than 5%.

The term "early" refers to the period of time of the cement or cement-based mixture shortly after the addition of the mixing water. Preferably, early in the context of the present invention means that the cement-based mixture does not exceed 24 hours, preferably does not exceed 20 hours, in particular does not exceed 16 hours after the addition of the mixing water.

In the context of the present invention, the term "setting" refers to the hydration process of a cement or cement-based mixture starting from the addition of mixing water. Setting is completed once the cement-based mixture has completely lost its plasticity and is sufficiently cured to take the shape of the mold in which it was cast. A measure of the final setting time is the time elapsed from the mixing of the cement or cement-based mixture with the mixing water until the cumulative heat flow curve has reached the plateau (pateau) (fig. 1 and 3). In the context of the present invention, the term "open time" or "induction period" refers to the time after the addition of mixing water to the cement or cement-based mixture during which the workability of the mixture is not significantly changed from the initial one. A measure of the open time is the time elapsed from the mixing of the cement or cement-based mixture with the mixing water until the heat flow curve first starts to increase (fig. 2 and 4).

In the context of the present invention, the term "setting" in connection with cement or cement-based mixtures means that the process of hydration continues after setting is completed until the final compressive strength of the cement-based mixture is obtained. The compressive strength of the cement-based mixture will increase during the curing process. The compressive strength of cement-based mixtures can be measured on prisms with dimensions 40X 160mm according to EN 12390-1 to 12390-4. Alternatively, the compressive strength may be calculated from the height of the plateau of the cumulative heat flow curve after calibration.

Thus, a cementitious mixture containing the combination of at least one set retarder S and at least one setting agent R also has increased compressive strength at an early stage as compared to the same cementitious mixture containing at least one set retarder S without at least one setting agent R.

In the context of the present invention, the term "controlling the hydration reaction" refers to controlling the setting and curing of the cement or cement-based mixture as described above. The control is expressed in terms of the effect on open time, final set time, compressive strength, which can be calculated from the plateau height of the cumulative heat flow curve, the extensional fluidity, and the retention of the extensional fluidity.

In the context of the present invention, the "cumulative heat flow curve" is a measure of the amount of heat released by a hydrated cement-based mixture over time. In the context of the present invention, the term "heat flow curve" relates to the first derivative of the cumulative heat flow curve (see fig. 2 and 4 as examples). The heat flow curve can be measured according to the isothermal procedure described in the standard ASTM C1702-17. For the present invention, the heat flow curves were measured on TAM AIR from TM Instruments and I-CAL 4000 from Calmetrix. The cumulative heat flow curve is calculated from the heat flow curve by integration using software default parameters.

Fig. 1 and 3 show examples of cumulative heat flow curves. The energy released per gram of cement in a hydrated cement-based mixture is plotted against the time after addition of mixing water. Open time, final set time, and plateau height are labeled for each curve. The open time is the first inflection point of the cumulative heat flow curve. In the context of the present invention, final coagulation is measured on the cumulative thermal flow curve as the time at which the increase in energy measured every 12 minutes becomes less than 0.1J/g. The plateau height is the energy released per gram of cement at the final set time. Fig. 2 and 4 show examples of heat flow curves. The power per gram of cement in a hydrated cement-based mixture is plotted against the time after addition of mixing water. The initial peak between 0 and 1 hour is due to the mixing process and is negligible.

It has surprisingly been found that the combination of at least one retarder S selected from calcium complexing agents and at least one modifier R of general formula (I) is effective in extending the open time while modifying the setting and/or curing of a cement or cement-based mixture comprising a belite-based clinker.

Wherein M is H, NH₄Or a monovalent or divalent metal selected from groups Ia, IIa, IIIa, Ib, IIb, IVb, VIb, VIIb or VIIIb of the periodic Table of the elements, and if M is a divalent metal a second equivalent of R-SO is present₃And wherein preferably M is selected from H, NH₄Li, Na, K, MgX, CaX or NiX, where X ═ RSO₃And are and

wherein R is selected from H, NH₂OH or from a hydrocarbon chain having 1 to 18C atoms, which may be substituted by N and/or O and/or which may be linear or branched and/or which may contain one or more unsaturated bonds and/or cycloaliphatic and/or aromatic groups.

In particular, the open time of a cement or cement-based mixture containing at least one set retarder S and at least one setting retarder R is increased by at least 15% when compared to a reference that does not contain any set retarder S and setting retarder R.

At the same time, the final set time increased by no more than 75% compared to the reference without any retarder and regulator, and decreased compared to the reference with only retarder S and no regulator R. In addition, the cumulative heat flow curve for the cement or cement-based mixture containing at least one set retarder S and at least one set retarder R has the same or an increased plateau height as compared to a reference that does not contain any set retarder S and set retarder R or as compared to a reference that does contain only set retarder S and no set retarder R.

As the plateau height of the cumulative heat flow curve of the cement or cement-based mixture containing at least one setting retarder S and at least one modifier R increases, the compressive strength of the corresponding cement or cement-based mixture of the invention increases after 4h, 6h or 8h of curing at 23 ℃/50% r.h. compared to the compressive strength of a reference without the additive of the invention.

Another advantage of the combination of at least one retarder S selected from calcium complexing agents and at least one modifier R of general formula (I) is that it does increase the workability of cement-based mixtures containing said compounds and containing cement comprising a clinkers based on tialite. Thus, the initial extended fluidity of the cementitious mixture of the invention is the same or better, and the retention of extended fluidity is better within the first 60 minutes after the addition of the mixing water, even if the cementitious mixture additionally contains PCE, compared to the reference without the addition of any set retarder S and conditioner R.

Accordingly, a first aspect of the present invention is to provide an additive, in particular a combination of at least one retarder S and at least one modifier R, comprising or essentially consisting of a combination of at least one retarder S and at least one modifier R, for a cement-based binder and/or a cement-based mixture comprising a tialite-based clinker.

At least one retarder S of the additive of the invention is chosen from calcium complexing agents. The calcium complexing agent may be any chemical substance capable of forming a complex with calcium ions. According to an embodiment, the at least one retarder S of the present invention is selected from sugar acids, sugars, sugar alcohols, hydroxycarboxylic acids, phosphates (phosphates), phosphonates (phosphonates), borates (borates) and amines.

In the context of the present invention, a "sugar acid" is a monosaccharide having a carboxyl group. It may belong to any of the classes of aldonic acids, ketonic acids (ulosonac acids), uronic acids or aldaric acids. Preferably, it is an aldonic acid. Examples of sugar acids useful in the context of the present invention include, but are not limited to, glyceric acid, xylonic acid, gluconic acid, ascorbic acid, neuraminic acid, glucuronic acid, galacturonic acid, iduronic acid, tartaric acid, mucic acid, and glucaric acid. Sugar acids may exist in the free acid form or in the salt form. According to an embodiment, the salt of a sugar acid may be a salt with a metal of group Ia, IIa, Ib, IIb, IVb, VIIIb of the periodic table of the elements. Preferred salts of sugar acids are the salts of alkali and alkaline earth metals, iron, cobalt, copper or zinc. Particularly preferred are salts with monovalent metals such as lithium, sodium and potassium.

In the context of the present invention, a "sugar" is a carbohydrate with an aldehyde group. In a particularly preferred embodiment, the sugar belongs to the class of mono-or disaccharides. Examples of sugars include, but are not limited to, glyceraldehyde, threose, erythrose, xylose, lyxose, ribose, arabinose, allose, altrose, glucose, mannose, gulose, idose, galactose, talose, fructose, sorbose, lactose, maltose, sucrose, lactulose, trehalose, cellobiose, chitobiose, isomaltose, palatinose, mannobiose, raffinose, and xylobiose.

In the context of the present invention, a "sugar alcohol" is a polyol derivable from a saccharide by a redox reaction. Thus, sugar alcohols belong to the class of alditols. Examples of sugar alcohols include, but are not limited to, ethylene glycol, glycerol, diglycerol, threitol, erythritol, pentaerythritol, dipentaerythritol, xylitol, ribitol, arabitol, sorbitol, sorbitan, isosorbide, mannitol, dimeritol, fruitol, iditol, inositol, succulent lactitol, maltitol, isomalt, maltotriose, maltotetraitol, and polyglucitol.

In the context of the present invention, a "hydroxycarboxylic acid" is a carboxylic acid which additionally comprises an OH-moiety within the same molecule. Examples of hydroxycarboxylic acids include, but are not limited to, malic acid, citric acid, isocitric acid, tartronic acid, mandelic acid, salicylic acid, and lactic acid. The hydroxycarboxylic acids may be present in the form of the free acids or in the form of salts. According to an embodiment, the salt of a hydroxycarboxylic acid may be a salt with ammonium or with a metal of groups Ia, IIa, Ib, IIb, IVb, VIIIb of the periodic table of the elements. Preferred salts of hydroxycarboxylic acids are alkali metal salts, alkaline earth metal salts or ammonium salts.

In the context of the present invention, a "phosphate" is a derivative of phosphoric acid. The phosphate may be free phosphoric acid, an oligomer of phosphoric acid, and/or a polymer of phosphoric acid, such as a diphosphate, a triphosphate, a tetraphosphate, and the like. The phosphate may be present in a protonated, partially deprotonated or fully deprotonated state. They may also be fluorinated. Examples of suitable phosphates are trisodium ortho-phosphate and tetrasodium pyrophosphate, sodium hexametaphosphate and disodium fluorophosphate. It is also possible that "phosphate" refers to an ester of phosphoric acid or one of its oligomers. Phosphate esters include, but are not limited to, mixed esters with the above-mentioned hydroxycarboxylic and/or sugar acids, mixed esters with carboxylic acids, especially with fatty acids, alkyl esters, aryl esters, esters with polyalkylene glycols.

The term "phosphonate" likewise relates to mono-, di-, tri-, tetra-, penta-or hexaphosphonic acids, and oligomers and/or esters thereof. Preferably, the phosphonate carries an organofunctional group. The phosphonate may be present in a protonated, partially deprotonated or fully deprotonated state. Examples of suitable phosphonates are 1-hydroxyethylidene-1, 1-diphosphonic acid, 2-phosphinobutane-1, 2, 4-tricarboxylic acid, 3-aminopropylphosphonic acid, aminotri (methylenephosphonic acid) and diethylenetriaminepenta (methylenephosphonic acid).

In the context of the present invention "borate" is preferably boric acid, a salt of boric acid or borax.

In the context of the present invention, "amine" preferably relates to polyamines containing two or more amino groups. Useful polyamines are aliphatic, cycloaliphatic, heterocyclic and/or aromatic polyamines. Particularly useful polyamines are, for example, ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, isophoronediamine, polyaminoalcohols such as aminoethylethanolamine, tetra (hydroxyethyl) ethylenediamine, polyaminocarboxylates such as iminodisuccinic acid, ethylenediaminetetraacetic acid, ethylenediamine disuccinic acid or polyaspartic acid, in the form of the free acids or in the form of their salts, in particular in the form of their sodium salts.

It is possible and in some cases preferred to use mixtures of different calcium complexing agents S. Preferably, the at least one retarder S is selected and dosed in such a way that the workability of the cement or cement-based mixture of the invention is not reduced.

In a particularly preferred embodiment, the retarder S of the additive of the invention is a sugar acid or an alkali metal salt of a sugar acid. In particular, the sugar acid is gluconic acid or an alkali metal salt of gluconic acid. In particular, the retarder S is sodium gluconate with a purity of at least 90%, preferably 95%, most preferably 99%. One advantage of using sodium gluconate as the at least one retarder S is that this will prevent the cement-based mixture of the invention from hardening after the addition of mixing water. The amount of sodium gluconate used should be at least 0.05 w%, based on the total dry weight of the clinker, to prevent hardening of the cement-based mixture.

At least one regulator R of the additive according to the invention has the general formula (I)

Wherein M is H, NH₄Or a monovalent or divalent metal selected from groups Ia, IIa, IIIa, Ib, IIb, IVb, VIb, VIIb or VIIIb of the periodic Table of the elements, and if M is a divalent metal a second equivalent of R-SO is present₃And wherein preferably M is selected from H, NH₄Li, Na, K, MgX, CaX or NiX, where X ═ RSO₃And are and

wherein R is selected from H, NH₂OH or from a hydrocarbon chain having 1 to 18C atoms, which may be substituted by N and/or O and/or which may be linear or branched and/or which may contain one or more unsaturated bonds and/or cycloaliphatic and/or aromatic groups.

In a preferred embodiment, M is selected from H, NH₄、Li. Na, K, MgX, CaX or NiX, wherein X ═ RSO₃Most preferably H, NH₄Li or Na.

R is preferably selected from alkyl of 1 to 8 carbon atoms, especially from methyl, ethyl, propyl or butyl, most preferably methyl, or from unsubstituted or substituted aryl, especially from phenyl, tolyl, naphthyl, 4-aminophenyl or 4-alkylphenyl. Also preferably, R is amino or alkyl substituted with at least one nitrogen atom.

In a preferred embodiment of the invention, R is methyl. In another preferred embodiment of the invention, R is amino.

Examples of the at least one regulator R of formula (I) include, but are not limited to, sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid and naphthalenesulfonic acid, sulfonates such as sodium tetrapropylenebenzenesulfonate and sodium dodecylbenzenesulfonate, sulfamic acid and salts thereof (also referred to as sulfamates), sulfamic acids such as aminomethanesulfonic acid, N-cyclohexyl-2-aminoethanesulfonic acid, taurine and sulfanilic acid. In a preferred embodiment, the at least one regulator R of the general formula (I) is methanesulfonic acid or sulfamic acid or a mixture of methanesulfonic acid and sulfamic acid.

Suitable molar ratios of the at least one retarder S to the at least one regulator R are from 1:2 to 1:450mol/mol, preferably from 1:10 to 1:400mol/mol, more preferably from 1:20 to 1:300 mol/mol. The molar ratio of the at least one retarder S to the at least one modifier R is 1: 1mol/mol means that for 1mol of all retarders S, 1mol of all regulators R is present. Molar ratios higher than those defined above will result in a decrease in the retardation properties of the additive.

The additive of the present invention may contain one or more other materials commonly used in the concrete additive art. These materials may be plasticizers and/or superplasticizers, shrinkage reducers, air entraining and/or degassing agents, stabilizers, viscosity modifiers, water reducers, accelerators, set retarders, water-resistant agents, strength enhancing additives, foaming agents, pigments, fillers, corrosion inhibitors, detergents, solvents, and/or water.

The additive of the invention may be a one-component premix of at least one retarder S selected from calcium complexing agents and at least one regulator R of the general formula (I) in the proportions described above. In case compounds S and R are liquid, the premix may be obtained by mixing two or more liquid compounds by any method known to the skilled person. The premix thus obtained may be a solution, an emulsion or a multiphase mixture. It may be present in the form of a liquid or paste. It can also be further processed to obtain a solid, for example by spray drying. In the case where compounds S and R are solids, the premix may be obtained by mixing two or more solid compounds by any method known to those skilled in the art. The premix thus obtained may be in the form of a powder or paste. In case at least one of the compounds S and R is a liquid and at least one other compound S and R is a solid, the premix may be obtained by mixing the compounds by any method known to the skilled person or by absorbing at least one liquid on at least one solid. The premix thus obtained may be in the form of a solid, a paste, a dispersion or a solution.

The one-component premixes of the compounds S and R of the invention thus obtained can be stored and stable at temperatures between-10 ℃ and +40 ℃ for at least 1 week. By stable is meant that the effect of the additive on setting and compressive strength changes by 10% or less after storage compared to the same effect before storage.

The one-component additive of the invention obtained by any of the above-described methods may comprise further materials, such as solvents, solubilizers, detergents, emulsifiers and/or anti-settling agents.

The premixed compounds S and R of the present invention may be added to a dry blend of a cement-based binder or cement-based mixture during cement production. They may also be added with the mixing water or shortly after the mixing water.

The additive of the invention can also be provided as two separate components α and β, wherein component α comprises at least one retarder S selected from calcium complexing agents and component β comprises at least one regulator R of the general formula (I). Component a and component β are stored in separate containers or in spatially separated compartments of one container. Both components alpha and beta may be premixed shortly before addition to the cement or cement-based mixture. The premixing may be performed by any method known to those skilled in the art. The premixed components a and β can be added to the dry blend together with or shortly after the mixing of the water. It is likewise possible to meter both components α and β separately to the clinker, cement or cement-based mixture. For example, it is possible, and in some cases preferred, to mix the two components α and β into a dry blend of a cement-based mixture. It is also possible and in some cases preferred to mix only one component α or β into the dry mix and to add the other component α or β together with or shortly after the mixing of the water. Furthermore, one component α or β may be added together with or shortly after the mixing water and the other component α or β at a later stage, for example shortly before or during the standing. Finally, both components α or β can be added together with or shortly after the mixing of the water.

According to an embodiment of the invention, component α is added before component β. For example, component a may be added during the production of clinker or cement, or to a dry blend of cement-based mixtures, and component β may be added shortly before, together with or shortly after the mixing of the water.

Both components α or β of the additive of the invention can preferably be stored and stable for at least 1 week at temperatures between-10 ℃ and +40 ℃. By stable is meant that the effect of the additive on setting and compressive strength changes by 10% or less after storage compared to the same effect before storage.

The two components α or β of the two-component additive according to the invention may, independently of one another, contain materials other than the compounds S and R, such as solvents, solubilizers, detergents, emulsifiers and/or anti-settling agents.

In a second aspect of the invention, there is provided a cement-based binder comprising

a) At least one clinker

b) At least one retarder S selected from calcium complexes

c) At least one regulator R of the general formula (I)

Wherein M is H, NH₄Or a monovalent or divalent metal selected from groups Ia, IIa, IIIa, Ib, IIb, IVb, VIb, VIIb or VIIIb of the periodic Table of the elements, and if M is a divalent metal a second equivalent of R-SO is present₃And wherein preferably M is selected from H, NH₄Li, Na, K, MgX, CaX or NiX, where X ═ RSO₃And wherein R is selected from H, NH₂OH or from a hydrocarbon chain having 1 to 18C atoms, which may be substituted by N and/or O and/or which may be linear or branched and/or which may contain one or more unsaturated bonds and/or cycloaliphatic and/or aromatic groups.

The clinker and cement-based binder are as described above.

The cement-based binder of the invention may be present in the dry state, for example in the form of a powder, or in the form of a mixture with a solvent and/or mixing water having a fluid or pasty consistency. The cement-based binder of the present invention may also be present in a cured state, for example as a shaped body, as a building or as part of a building.

The cement-based binder of the invention comprises 0.01 to 2 w%, preferably 0.025 to 1 w%, especially 0.03 to 0.5 w%, each based on the total dry weight of the cement, of at least one retarder S of the invention and 0.1 to 6 w%, preferably 0.2 to 5 w%, especially 0.25 to 2 w%, each based on the total dry weight of the cement, of at least one modifier R selected from the group consisting of formula (I).

Preferred ratios of the at least one retarder S to the at least one regulator R are from 1:2 to 1:450mol/mol, preferably from 1:10 to 1:400mol/mol, more preferably from 1:20 to 1:300 mol/mol.

Higher doses of the additive of the invention using at least one retarder S and at least one regulator R in any given ratio within the limits as described above may result in longer open times.

According to embodiments of the present invention, the ratio of the at least one retarder S to the at least one regulator R may be adjusted to the dosage of the at least one retarder S. In particular, if the dosage of the at least one retarder S is increased, the ratio of the at least one retarder S to the at least one regulator R can be increased. One preferred ratio of the at least one retarder S to the at least one modifier R is, for example, a ratio between 1:10 and 1:100mol/mol, if the dosage of the at least one retarder S is 0.05 w%, based on the total dry weight of the cement. Another preferred ratio of at least one retarder S to at least one modifier R is, for example, a ratio of at least 1:100mol/mol, if the dose of retarder is at least 0.15 w%, based on the total dry weight of the cement.

A third aspect of the present invention is to provide a cementitious mixture comprising the inventive cementitious binder as described above, and additionally comprising

a) The amount of water is controlled by the amount of water,

b) optionally an aggregate, and

c) optionally one or more other additives selected from plasticizers, superplasticizers, shrinkage reducing agents, air entraining agents, air degassing agents, stabilizers, viscosity modifiers, water reducing agents, accelerators, retarders, water resistance agents, strength enhancing additives, fibers, foaming agents, pigments, and steel deactivators.

The water may be water available at any mixing location, such as distilled water, purified water, tap water, mineral water, spring water, well water, waste water, or salt water. The water is added in a water/cement ratio of 0.1 to 2.0, preferably 0.2 to 1.0, especially 0.25 to 0.6.

The cement-based mixture of the present invention preferably contains an aggregate. The aggregate may be any substance that does not react in the hydration reaction of the clinker. The aggregate may be any aggregate commonly used in cement-based binders. Typical aggregates are, for example, rock, crushed stone, gravel, slag, sand, quartz sand, recycled concrete, glass, perlite or vermiculite. The aggregates useful in the present invention may be of any shape and size typically encountered with such aggregates. Aggregates useful in the present invention are as described in EN12620:2008-07 and EN13139: 2015-07.

It may also be advantageous for the cement-based mixture of the invention to further contain one or more additives selected from the group consisting of plasticizers, superplasticizers, shrinkage reducers, air entraining agents, degassing agents, stabilizers, viscosity modifiers, water reducers, accelerators, retarders, water-resistant agents, strength enhancing additives, fibers, foaming agents, pigments and steel deactivators.

It may be particularly advantageous to add a superplasticizer to the cement or cement-based mixture of the present invention. The superplasticizer may be of any kind known to those skilled in the art. A particularly suitable superplasticizer may be a polycarboxylic ether (PCE). Polycarboxylic acid ethers are comb polymers having a polycarboxylic acid backbone and polyalkylene oxide side chains. Such polycarboxylic acid ethers are described, for example, in EP 2468696 (Sika Technology AG).

Superplasticizers, in particular polycarboxylic acid ethers, may be added to the cement or cement-based mixture of the invention in an amount of 0 to 10 w%, preferably 0.010 to 7.5 w%, especially 0.015 to 2.5 w%, calculated as dry weight of superplasticizer, based on the total weight of the cement comprised.

Other suitable superplasticizers include lignosulfonates, polynaphthalenesulfonates, polyamine sulfonates, vinyl copolymers, and polyethylene oxide sulfonates. It may be preferred to add a mixture of different superplasticizers to the cement or cement-based mixture of the present invention.

Thus, the cement or cement-based mixture of the invention preferably contains or consists of:

a) 5-99 w% of at least one clinker,

b) 0.01-2% of at least one retarder S selected from calcium complexing agents,

c)0.1 to 6% by weight of at least one regulator R of the general formula (I)

Wherein M is H, NH₄Or a monovalent or divalent metal selected from groups Ia, IIa, IIIa, Ib, IIb, IVb, VIb, VIIb or VIIIb of the periodic Table of the elements, and if M is a divalent metal a second equivalent of R-SO is present₃And when and whichPreferably M is selected from H, NH₄Li, Na, K, MgX, CaX or NiX, where X ═ RSO₃And wherein R is selected from H, NH₂OH or from a hydrocarbon chain having 1 to 18C atoms, which may be substituted by N and/or O and/or which may be linear or branched and/or which may contain one or more unsaturated bonds and/or cycloaliphatic and/or aromatic groups,

d) 0-10 w% of a superplasticizer,

e) optionally an aggregate, and optionally a filler,

f) optionally water.

A fourth aspect of the invention is to provide a method of regulating the early hydration reaction of a cement or cement-based mixture comprising a tialite-based clinker. In particular, the setting of the cement or cement-based mixture is delayed and thus the open time is increased, while neither the final setting time nor the early compressive strength of the cement or cement-based mixture is changed to a degree relevant for practical use, or if the final setting time is increased, the compressive strength is also increased.

A method of regulating the early hydration reactions of a cement or cement-based mixture comprising a tialite-based clinker comprises the steps of:

a) providing a cement or cement-based mixture comprising a belite-based clinker,

b) providing at least one retarder S selected from calcium complexing agents,

c) providing at least one regulator R of the general formula (I),

d) providing water

e) Optionally providing an aggregate

f) Optionally providing other additives to the composition, such as,

g) mixing a) to f) in any given order.

As mentioned above, the at least one retarder S and the at least one regulator R of the invention can be provided simultaneously as separate components or as a premix. As mentioned above, the at least one retarder S and the at least one regulator R of the invention can likewise be provided as separate components α and β.

According to an embodiment of the invention, at least one retarder S and/or at least one regulator R is mixed with the tialite-based clinker before or after grinding of the clinker. The at least one retarder S and/or the at least one regulator R can be introduced, for example, in small doses into the mill and ground together with the clinker to obtain a homogeneous pulverulent cement. In the context of the present invention, it is preferred to admix only at least one retarder S to the tialite clinker before or after grinding. In addition, other grinding aids known to those skilled in the art for clinker may be used, such as glycols, alkanolamines, amine acetates, aromatic acetates. The homogeneous powdered cement may be stored prior to further mixing. The cement can then, for example, be mixed with additional setting retarders S and with regulators R, provided that the above-mentioned dosages and ratios are met, and then mixed with water and optionally aggregates and optionally further additives. In other words, the clinker or cement can be modified with at least one retarder S, stored and/or transported, and the at least one regulator R is added shortly before, together with or shortly after the mixing water.

In another embodiment of the invention, at least one set retarder S and at least one conditioner R are mixed with a dry mix of cement or cement-based mixture. Blending may be performed by any method known to those skilled in the art. As mentioned above, the at least one retarder S and the at least one regulator R can be mixed together or separately as a premix. However, it is preferred to blend at least one retarder S first, as this will result in a longer open time of the cement-based mixture. The entire mass of the at least one retarder S and the at least one regulator R can be added to the cement-based mixture at once or can be added in several smaller portions. And may subsequently be mixed with water and optionally aggregate and optionally other additives.

In another embodiment of the invention, at least one retarder S and/or at least one modifier R is premixed with the mixing water and then added to the cement or cement-based mixture as described above. It can then, for example, be mixed with further retarders S and/or regulators R, provided that the above-mentioned dosages and ratios are met, and then optionally mixed with aggregates and optionally further additives.

In another embodiment of the invention, the at least one retarder S and/or the at least one regulator R are mixed shortly after adding the mixing water and optionally the aggregate and optionally further additives to the cement or cement-based composition. As mentioned above, the at least one retarder S and the at least one modifier R may be mixed as a premix or separately. Then, for example, it can be mixed with further retarders S and/or regulators R, provided that the above-mentioned dosages and ratios are met. For example, the cement-based mixture may be premixed with the mixing water and the at least one set retarder S. At least one regulator R of the general formula (I) is then admixed in a subsequent stage, for example shortly before or during the setting of the cement-based mixture. Preferably, the incorporation of the at least one regulator R is carried out continuously during the placing, for example by metering and mixing the at least one regulator R in the application head or nozzle.

The method of regulating the hydration reaction according to the invention results in an increase of the open time of the cement or cement-based mixture of at least 15% compared to the open time of the same cement or cement-based mixture without any set retarder S and setting agent R. At the same time, the method results in an increase in the final set time of the cement or cement-based mixture of no more than 75% as compared to a reference that does not contain any set retarder S and regulator R, and a decrease in the final set time of the cement or cement-based mixture as compared to a reference that contains only set retarder S and no regulator R. Furthermore, it results in the same or an increase in the plateau height of the cumulative heat flow curve of the cement or cement-based mixture, compared to a reference that does not contain any retarder S and regulator R or a reference that does contain only retarder S and no regulator R.

The method of regulating the hydration reaction according to the invention also results in an increase in the compressive strength of the cement or cement-based mixture at an early stage, compared to the same cement or cement-based mixture without any set retarder S and setting agent R. In particular, the method of adjusting the hydration reaction according to the invention results in an increase in the compressive strength of the cement or cement-based mixture after curing at 23 ℃/50% r.h. for 4h or 6h or 8h, compared to the compressive strength of a reference without the additive of the invention.

The method for regulating hydration reactions according to the present invention also results in that the initial spreading fluidity is maintained or increased in the first 60 minutes after the addition of the mixed water, and the retention of the spreading fluidity is increased.

Finally, the method of regulating hydration reactions according to the present invention can reduce the exudation of cement-based mixtures.

The additive of the invention may also be used in a method for delaying the hydration reaction of a cement or cement-based mixture comprising a colemanite-based clinker. In particular, the setting of the cement or cement-based mixture is delayed and thus the open time is increased. Depending on the embodiment, the delay may or may not affect the final set time and/or compressive strength, especially the early compressive strength. The additive of the invention can therefore be used as a retarder, for example as described in standard EN 934-2: 2012-08. The invention also relates to a cement or cement-based mixture comprising a tialite-based clinker, which is retarded by the addition of the additive of the invention.

The following working examples illustrate the invention. This example is not intended to limit the scope of the invention in any way.

Brief description of the drawings

FIG. 1 shows the cumulative heat flow curves for examples M-1, M-7, M-11

FIG. 2 shows the heat flow curves for examples M-1, M-7, M-11

Working examples

The extended fluidity test was carried out according to EN 12350-2 as a measure of the workability of cement-based mixtures. After mixing with the mixing water, the extended fluidity test was performed on each sample at the specified time points. The respective times are given in tables 4 and 6 below.

The compressive strength was measured according to EN 12390-1 to 12390-4 on prisms of dimensions 40X 160 mm.

The heat flow curve was measured in an isothermal process as described in the standard ASTM C1702-17. Examples M1-M19 were measured using TAM AIR from TM Instruments. Examples M20-M33 were measured using I-CAL 4000 from calmetrix. The cumulative heat flow curve is calculated from the heat flow curve by integration using software default parameters.

The open time is the time at the inflection point of the cumulative heat flow curve. Which is measured on the heat flow curve as the time it begins to increase (see fig. 2 and 4; the initial peak is related to the mixing process and is ignored). The final coagulation time was measured on the cumulative thermal flow curve and was the time when the increase in energy measured every 12 minutes became less than 0.1J/g (see fig. 1 and 3). The plateau height is the total energy released from the time of mixing with the mixing water until the final set time is reached.

Table 1 below gives an overview of the chemicals used. All chemicals were used as supplied unless otherwise stated.

TABLE 1 Chemicals used

TABLE 2 Cement compositions (XRD, Rietveld refining)

Phase (C)	wt％
		Sulfoaluminite	29
Belite	46
		Ferrite	4
Calcium sulfate anhydrite	6
		Silica apatite	4
Calcium aluminate	2
		Calcite	1
Amorphous state	8

Example M1-17:

to prepare a cement-based mixture of M1-M17, 100g of cement having the composition shown in Table 2, 50g of mixing water (to produce a w/c ratio of 0.5), and the admixtures given in Table 3 below were mixed on a Heidolph propeller mixer at 1500rpm for 2 minutes.

TABLE 3 examples M1-M17

Comparative examples not according to the invention

Table 4: results of M1-M17

Comparative examples not according to the invention

n.m. not measuring

dnc not cured within 24h

Examples M18-30:

to prepare a cement-based mixture of M18-M30, 265g of CEN reference sand as described in EN 196-1 was added to 100g of cement having the composition shown in table 2. The resulting dry blend was mixed in a Hobart mixer for 1 minute. The amounts of mixed water and additives given in table 5 were then added to give the w/c ratios given in table 5 and mixing was continued for 2 minutes.

TABLE 5 examples M18-M30

Examples	Additive agent	Water (W)	w/c ratio
				M18*	Is free of	40	0.4
M19*	0.35g boric acid	50	0.5
				M20	0.05g of sodium gluconate, 0.5g of sulfamic acid	50	0.5
M21	0.1g of sodium gluconate, 0.7g of sulfamic acid	50	0.5
				M22	0.05g of sodium gluconate, 0.25g of sulfamic acid	50	0.5
M23	0.025g of sodium gluconate, 0.25g of sulfamic acid	50	0.5
				M24	0.1g of sodium gluconate, 1.0g of sulfamic acid	50	0.5
M25	0.15g of sodium gluconate, 1.5g of sulfamic acid	50	0.5
				M26*	PCE of 0.0775g	40	0.4
M27*	0.0775g of PCE, 0.35g of boric acid	40	0.4
				M28	0.0775g of PCE, 0.1g of sodium gluconate, 1.0g of sulfamic acid	40	0.4
M29	0.0775g of PCE, 0.05g of sodium gluconate and 0.5g of sulfamic acid	40	0.4
				M30	0.0775g PCE, 0.05g sodium gluconate, 0.5g methanesulfonic acid	40	0.4

Comparative examples not according to the invention

TABLE 6 results of M18-M30

Comparative example n.m. not according to the invention no measurement was made

TABLE 7 compressive Strength results

No measurement is possible

Comparative examples not according to the invention

As can be seen from the results given in tables 3 to 7 above, the use of the conditioning agent alone, not according to the invention, did not result in an increase in open time. The use of only retarders, not the present invention, results in a significant increase in open time, but the final set time is also greatly increased without increasing the platform height. This is particularly evident in the case of example M12, which is not according to the invention, which does not show sufficient curing within 24 hours.

On the other hand, examples M6-M8, M10, M13-M17, M20-M22, M24 and M29, all according to the invention, show a significantly increased open time and only a moderately increased final set time when compared with reference examples M1 or M18, respectively. At the same time, the platform height according to all these embodiments of the invention is the same or increased compared to the corresponding reference examples. The increase in platform height is associated with higher compressive strength at an early stage. Inventive examples M9 and M23 showed only a modest increase in open time compared to the corresponding reference examples, but an excellent increase in plateau height, and a reduction or only a slight increase in final set time. Finally, inventive examples M25, M28, and M30 showed greatly increased open times relative to the reference example. In these cases, the final setting time is also increased, but this is also accompanied by a strong increase in the plateau height and therefore a higher early compressive strength.

All of the non-inventive examples M5, M19, and M27, which all use only boric acid and are therefore not according to the invention, can be considered as reference comparisons. It is evident from the results given above that the examples according to the invention lead to a more balanced control of hydration at an early stage compared to the reference examples.

As can be seen from the extensional fluidity measurements shown in the above tables 4 and 6, the embodiment according to the present invention has no significantly increased viscosity (because of the apparent decrease in the initial extensional fluidity) compared to the corresponding reference example. In addition, they have the same or better extended fluidity retention in all cases than the corresponding reference examples.