White cement admixture and method for its production

Abstract

The application discloses a white cement admixture and a preparation method thereof. The white cement admixture comprises the following raw materials in percentage by mass: grinding aid component: 5-10%; reinforcing component: 10-15%; dispersing component: 0.1-0.3%; anti-cracking component: 0.5-1%; durability improving component: 0.1-0.5%; and the balance is a carrier. The white cement admixture is added into the white cement as a grinding aid, can improve the yield of the white cement, reduce the power consumption, and can greatly improve a series of problems in the application process of the white cement, such as low early strength, easy cracking, poor construction and the like, and significantly improve the comprehensive performance of the white cement as a decorative material.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of cement admixtures, and particularly relates to a white cement admixture and a preparation method thereof. BACKGROUND

[0002] White cement, also known as white portland cement, is a hydraulic cementitious material made of portland cement clinker with a low content of iron oxide, a proper amount of gypsum and a mixing material meeting the requirements. White portland cement has the characteristics of high whiteness, bright color and high strength, and is widely used in building decoration engineering, such as wall painting, white floor, sculpture modeling and white concrete terrazzo products, and is often used to produce white or colored concrete products.

[0003] The main difference between white cement and ordinary portland cement is the content of iron oxide in the cement. The content of iron oxide in white cement is very low, while the content of iron oxide in ordinary portland cement clinker is high. The color of the hardened cement is mainly caused by Fe2O3. With the change of the content of Fe2O3, the color of the cement clinker is different. In order to ensure the whiteness of white cement, the content of Fe2O3 in white cement should be controlled to be less than 0.5%. In addition, considering the strength requirement of white cement, the control of KH value of white cement clinker is not much different from that of ordinary cement, but the control of SM value is quite different from that of ordinary cement. The SM value of the pre-decomposition kiln of white cement is controlled at about 5 or even higher, which leads to a great difference in grindability between white cement clinker and ordinary portland cement clinker. The conventional cement grinding aid cannot meet the grinding and production requirements of white cement.

[0004] There are also problems of long setting time, low early strength, large shrinkage and deformation, and poor weather resistance in the use of white cement. It is of great significance to solve the defects in the use of white cement to ensure the advantages of white cement as a decorative material. SUMMARY

[0005] To solve the above technical problems, the present application provides a white cement admixture and a preparation method thereof. The white cement admixture is added to white cement as a grinding aid, which can improve the yield of white cement, reduce power consumption, and greatly improve the problems of low early strength, easy cracking and poor construction in the application process of white cement, and significantly improve the comprehensive performance of white cement as a decorative material.

[0006] The technical scheme adopted by the present application is as follows:

[0007] A white cement admixture, comprising the following raw materials in mass percentage:

[0008] Grinding component: 5%-10%;

[0009] Reinforcing component: 10%-15%;

[0010] Dispersing component: 0.1%-0.3%;

[0011] Anti-cracking component: 0.5%-1%;

[0012] Durability improving component: 0.1%-0.5%;

[0013] The rest is a carrier.

[0014] Further, the grinding aid component is a compound of an alcohol amine and a polyol ester in a mass ratio of 2-5:1; the alcohol amine is the main grinding aid component, and the polyol ester is the auxiliary grinding aid component; the two components are used together to ensure good adaptability of the white cement raw material under fluctuation.

[0015] The reinforcing component is an aluminum salt, an aluminate, or a calcium salt.

[0016] The dispersing component is a polycarboxylic acid water reducer or a naphthalene water reducer.

[0017] The anti-cracking component is a compound of a cellulose ether and a starch ether in a mass ratio of 4-7:1; in the compound, the cellulose ether plays a water-retaining role, and the starch ether improves the construction performance of the white cement; the water-retaining and construction performance improving effects of the compound are better than those of a single component, but considering the cost factor, the starch ether does not need to be added too much due to its own performance, and therefore, the cellulose ether and the starch ether are controlled in a mass ratio of 4-7:1.

[0018] The durability improving component is a siloxane substance.

[0019] The alcohol amine is at least one of triethanolamine and triisopropanolamine, and preferably triethanolamine.

[0020] The polyol ester is at least one of a polyol phosphate and glycerol triacetate, and preferably glycerol triacetate.

[0021] The reinforcing component is any one or more of polyaluminum sulfate, sodium aluminate, sodium metaaluminate, and glycerol calcium phosphate, and preferably sodium metaaluminate.

[0022] The polycarboxylic acid water reducer is a polycarboxylic acid water reducer synthesized from isopentenyl alcohol polyoxyethylene ether; the polycarboxylic acid water reducer and the naphthalene water reducer are both in powder form.

[0023] The cellulose ether is any one or more of methyl cellulose ether, ethyl cellulose ether, and hydroxypropyl methyl cellulose ether, and preferably hydroxypropyl methyl cellulose ether.

[0024] The starch ether is at least one of carboxymethyl starch ether or hydroxypropyl starch ether, preferably hydroxypropyl starch ether.

[0025] The durability improving component is at least one of polydimethylsiloxane, fluorosilicone, ethylene glycol siloxane, preferably polydimethylsiloxane.

[0026] The carrier is talc or calcium carbonate powder, preferably calcium carbonate powder with fineness greater than 800 mesh.

[0027] The present application also provides a preparation method of the white cement admixture, which comprises the following steps: adding a formulation amount of carrier into a stirrer, starting stirring, then adding a grinding aid component into the stirrer and stirring for 20-30 min, and then sequentially adding a crack resistance component, a strength component, a dispersing component and a durability improving component into the stirrer and stirring for 30-40 min, to obtain the white cement admixture.

[0028] The specific application method of the white cement admixture is as follows: the white cement admixture is added in an amount of 0.3-0.5% of the mass of cement during the grinding process of the white cement.

[0029] During the grinding process of the white cement, due to the high content of silica and low content of iron oxide in the clinker used, the easy grindability of the white cement is different from that of ordinary Portland cement, and due to the low content of C4AF and C3A, the early hydration of the white cement is slow, the flexural strength is low, and the shrinkage rate after hydration and hardening is large, which leads to the phenomenon that the decorative surface of the white cement often cracks in the application of building decoration; and the surface of the white cement is rough, which leads to uneven wall surface after painting, and other problems; in addition, the white cement is easily affected by external humidity and air temperature, although the hardness is very large after painting, but it is easy to dry and crack after a period of time, and other problems.

[0030] The inventors find that the ordinary Portland cement grinding aid is directly applied to the white cement production process, the effect of improving the hourly output of white cement is far less than that of ordinary Portland cement, and the conventional grinding aid cannot meet the demand of the grinding performance of white cement. Moreover, due to the low C4AF content of white cement clinker, when the material is ground to a certain fineness, the material has increased cohesion, and the polyol material used in the conventional grinding aid is more likely to adsorb particles due to the multiple hydroxyl groups, resulting in micro-fine powder agglomeration; in addition, different alcohol amines also have selective adaptability, the inventors find that triethanolamine or triisopropanolamine with a symmetrical structure of multi-branched alcohol hydroxyl is more suitable for grinding and dispersing of white cement, and the selection of polyol ester material compound with the alcohol amine has more excellent performance for grinding and dispersing of white cement. The addition of aluminum salt or aluminate material in the invention can accelerate the early hydration of white cement, improve the early strength of white cement, and improve the flexural strength of white cement; the polycarboxylate superplasticizer is the latest generation of superplasticizer product, which is widely used in cement concrete due to its high water-reducing rate, low dosage, and good slump retention performance. After the introduction of the water-reducing component, the water consumption of white cement in the use process can be greatly reduced, thereby effectively reducing the shrinkage cracking phenomenon caused by hydration and environmental influence, and improving the density of white cement, thereby improving the strength thereof. The cellulose ether is a high molecular compound with ether structure made of cellulose, which has water retention, thickening, leveling, film forming, and bonding multiple functions in cement mortar. The application of the cellulose ether in white cement can not only ensure the controllable hydration of white cement without rapid hydration shrinkage cracking, but also improve the construction performance of white cement by compounding with starch ether, so that the finish of white cement is more smooth and beautiful. The structure of polydimethylsiloxane contains a repeating unit of silicon-oxygen bond, which usually has a linear or branched chain structure. This polymer has excellent high and low temperature resistance, excellent chemical stability, and low surface tension. The silicon-oxygen bond provides flexibility and flexibility, and the aminopropyl group increases its hydrophilicity and guminess. The application of the polydimethylsiloxane in white cement can not only eliminate the air bubbles in white cement products and increase the strength, but also effectively improve the weather resistance of white cement as a decorative material. The carrier is not only a carrier for various effective components, but also a kind of white superfine powder, which can improve the whiteness of white cement, and also improve the bonding performance and construction performance of white cement.

[0031] The white cement admixture of the present application can not only improve the yield of white cement and reduce the power consumption, but also greatly improve the early strength, reduce cracking, and improve the construction performance of white cement in the application process, thereby significantly improving the comprehensive performance of white cement as a decorative material.

[0032] Compared with the prior art, the present application has the following beneficial effects:

[0033] 1.The white cement admixture provided by the present application is applied to the production process of white cement, can effectively disperse white cement particles, solve the problem of agglomeration after white cement is ground to a certain fineness, and further improve the hourly output of white cement, reduce power consumption, and thus reduce the production cost of white cement. And the product has good adaptability, and still has excellent grinding and dispersing effect under the fluctuation of white cement clinker and mixed materials.

[0034] 2.The white cement admixture provided by the present application is compounded with water reducing agent, water retaining agent, anti-cracking agent and components that can improve the durability of white cement, which significantly improves the problems of long setting time, low early strength, large shrinkage deformation and poor weather resistance of white cement as a decorative material, and improves the comprehensive performance of white cement as a decorative material. In the application process of white cement, the white cement admixture provided by the present application can improve the breaking strength and early strength of white cement, effectively solve the problems of easy cracking and difficult construction of white cement as a finish, and at the same time improve the durability of white cement decorative material.

[0035] 3.The dosage of the white cement admixture of the present application in white cement is 0.2%-0.5%, which can be adjusted according to different raw materials in the production process of white cement to achieve the best effect.

[0036] 4.The preparation method of the white cement strength admixture of the present application is simple, the raw materials are easy to obtain, and it is green and environmentally friendly. DETAILED DESCRIPTION

[0037] The present application provides a white cement admixture, which comprises the following raw materials in mass percentage:

[0038] Grinding component: 5%-10%;

[0039] Enhancing component: 10%-15%;

[0040] Dispersing component: 0.1%-0.3%;

[0041] Anti-cracking component: 0.5%-1%;

[0042] Durability improving component: 0.1%-0.5%;

[0043] The balance is the carrier.

[0044] Further, the grinding component is a composite of alcohol amine and polyol ester in a mass ratio of 2-5:1; the alcohol amine is at least one of triethanolamine and triisopropanolamine, preferably triethanolamine; and the polyol ester is at least one of polyol phosphate and glycerol triacetate, preferably glycerol triacetate.

[0045] The reinforcing component is any one or more of polyaluminum sulfate, sodium aluminate, sodium metaaluminate, or calcium glycerophosphate, preferably sodium metaaluminate.

[0046] The dispersing component is a polycarboxylic acid water reducer or a naphthalene water reducer; the polycarboxylic acid water reducer is a polycarboxylic acid water reducer synthesized from isopentenyl alcohol polyoxyethylene ether; both the polycarboxylic acid water reducer and the naphthalene water reducer are in powder form.

[0047] The anti-cracking component is a compound of cellulose ether and starch ether in a mass ratio of 4-7:1; the cellulose ether is any one or more of methyl cellulose ether, ethyl cellulose ether, and hydroxypropyl methyl cellulose ether, preferably hydroxypropyl methyl cellulose ether; the starch ether is at least one of carboxymethyl starch ether and hydroxypropyl starch ether, preferably hydroxypropyl starch ether.

[0048] The durability-improving component is at least one of polydimethylsiloxane, fluorosilicone, and ethylene glycol siloxane, preferably polydimethylsiloxane.

[0049] The carrier is talc powder or calcium carbonate powder, preferably calcium carbonate powder with a fineness of more than 800 mesh.

[0050] The application also provides a preparation method of the white cement admixture, which comprises the following steps: adding a formula amount of carrier into a stirrer, starting stirring, then adding a formula amount of anti-cracking component, reinforcing component, dispersing component, and durability-improving component into the stirrer in sequence, and stirring for 30-40 min to obtain the white cement admixture.

[0051] The application will be described in detail below with reference to the examples.

[0052] In the following examples, the test materials and reagents, etc. can be obtained from commercial channels unless otherwise specified.

[0053] In the examples, the specific techniques or conditions not specified are all performed according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0054] Example 1

[0055] A white cement admixture is composed of the following raw materials in the following weight percentages: triethanolamine 3.75%, glycerol triacetate 1.25%, sodium metaaluminate 10%, polycarboxylic acid water reducer 0.1%, methyl cellulose ether 0.42%, carboxymethyl starch ether 0.08%, polydimethylsiloxane 0.1%, and the rest is calcium carbonate powder.

[0056] The preparation method of the white cement admixture comprises the following steps:

[0057] 1) Weigh each raw material by percentage of weight;

[0058] 2) Mix triethanolamine with glyceryl triacetate to prepare grinding aid component mixture A;

[0059] 3) Mix hydroxypropyl methylcellulose with starch ether to prepare anti-cracking component mixture B;

[0060] 4) Weigh the formula amount of lime powder into the stirrer, start stirring, then add the grinding aid component mixture A into the stirrer and stir for 20-30 min, then add the formula amount of anti-cracking component mixture B, polyaluminum sulfate, polycarboxylic acid water reducer, and polydimethylsiloxane into the stirrer in sequence, stir for 30-40 min, to obtain a white cement admixture.

[0061] Example 2

[0062] A white cement admixture, which is composed of the following raw materials by weight percentage: triisopropanolamine 6%, glyceryl triacetate 2%, polyaluminum sulfate 12%, polycarboxylic acid water reducer 0.2%, hydroxypropyl methylcellulose 0.67%, hydroxypropyl starch ether 0.13%, ethylene glycol siloxane 0.3%, and the balance is lime powder.

[0063] The process parameters in the preparation process are the same as those in Example 1.

[0064] Example 3

[0065] A white cement admixture, which is composed of the following raw materials by weight percentage: triethanolamine 7.5%, glyceryl triacetate 2.5%, sodium metaaluminate 15%, polycarboxylic acid water reducer 0.3%, hydroxypropyl methylcellulose 0.83%, carboxymethyl starch ether starch ether 0.17%, polydimethylsiloxane 0.5%, and the balance is lime powder.

[0066] The process parameters in the preparation process are the same as those in Example 1.

[0067] Example 4

[0068] A white cement admixture, which is composed of the following raw materials by weight percentage: triethanolamine 3.75%, polyol phosphate 1.25%, sodium metaaluminate 13%, polycarboxylic acid water reducer 0.3%, hydroxypropyl methylcellulose 0.58%, hydroxypropyl starch ether 0.12%, fluorosilicone 0.5%, and the balance is lime powder.

[0069] The process parameters in the preparation process are the same as those in Example 1.

[0070] Example 5

[0071] A white cement admixture, which is composed of the following raw materials in percentage by weight: triisopropanolamine 6%, glycerol triacetate 2%, calcium glycerophosphate 15%, polycarboxylic acid water reducing agent 0.3%, hydroxypropyl methyl cellulose ether 0.83%, carboxymethyl starch ether 0.17%, ethylene glycol siloxane 0.3%, and the rest is calcium lime powder.

[0072] The process parameters in the preparation process are the same as those in Example 1.

[0073] Example 6

[0074] A white cement admixture, which is composed of the following raw materials in percentage by weight: triisopropanolamine 6%, glycerol triacetate 2%, calcium glycerophosphate 15%, polycarboxylic acid water reducing agent 0.3%, hydroxypropyl methyl cellulose ether 0.83%, carboxymethyl starch ether 0.17%, ethylene glycol siloxane 0.3%, and the rest is calcium lime powder.

[0075] The process parameters in the preparation process are the same as those in Example 1.

[0076] Comparative Example 1

[0077] A white cement admixture, which is composed of the following raw materials in percentage by weight: triisopropanolamine 6%, glycerol triacetate 2%, calcium glycerophosphate 15%, polycarboxylic acid water reducing agent 0.3%, hydroxypropyl methyl cellulose ether 0.83%, carboxymethyl starch ether 0.17%, ethylene glycol siloxane 0.3%, and the rest is calcium lime powder.

[0078] The preparation method of the white cement admixture comprises the following steps:

[0079] 1) The raw materials are weighed in percentage by weight;

[0080] 2) The hydroxypropyl methyl cellulose ether and the starch ether are mixed to prepare a crack resistance component mixture;

[0081] 3) The formula amount of calcium lime powder is weighed and added to a stirrer, and then the formula amount of the crack resistance component mixture, sodium metaaluminate, polycarboxylic acid water reducing agent, and polydimethylsiloxane are sequentially added to the stirrer after the stirring is started, and the stirring is performed for 30-40 min to obtain the white cement admixture.

[0082] Comparative Example 2

[0083] A white cement admixture, which is composed of the following raw materials in percentage by weight: triisopropanolamine 6%, glycerol triacetate 2%, calcium glycerophosphate 15%, polycarboxylic acid water reducing agent 0.3%, hydroxypropyl methyl cellulose ether 0.83%, carboxymethyl starch ether 0.17%, ethylene glycol siloxane 0.3%, and the rest is calcium lime powder.

[0084] The preparation method of the white cement admixture comprises the following steps:

[0085] 1) The raw materials are weighed in percentage by weight;

[0086] 2) Triethanolamine and glyceryl triacetate are mixed to prepare a grinding aid mixture;

[0087] 3) Weigh the amount of lime powder according to the formula and add it into the mixer. After starting the mixer, add the grinding aid mixture into the mixer and stir for 20-30 minutes. Then, add the amount of sodium aluminate, polycarboxylate superplasticizer and polydimethylsiloxane according to the formula into the mixer in sequence and stir for 30-40 minutes to obtain the white cement admixture.

[0088] Comparative Example 3

[0089] A white cement admixture is composed of the following raw materials in weight percentages: 2.5% triethanolamine, 0.5% glyceryl triacetate, 0.08% polycarboxylate superplasticizer, 0.2% hydroxypropyl methyl cellulose ether, 0.1% carboxymethyl starch ether, and the balance being lime powder;

[0090] The method for preparing the white cement admixture includes the following steps:

[0091] 1) Weigh each raw material according to its weight percentage;

[0092] 2) Triethanolamine and glyceryl triacetate are mixed to prepare grinding aid component mixture A;

[0093] 3) Hydroxypropyl methyl cellulose ether and starch ether are mixed to prepare crack-resistant component mixture B;

[0094] 4) Weigh out the amount of lime powder according to the formula and add it into the mixer. After starting the mixer, add the grinding aid component mixture A into the mixer and stir for 20-30 minutes. Then, add the crack-resistant component mixture B and the polycarboxylate superplasticizer according to the formula into the mixer in sequence and stir for 30-40 minutes to obtain the white cement admixture.

[0095] Comparative Example 4

[0096] The rest is the same as in Example 1, except that the triacetylglycerol in the raw materials is replaced with triethanolamine of the same weight.

[0097] Comparative Example 5

[0098] The rest is the same as in Example 1, except that the carboxymethyl starch ether in the raw materials is replaced with an equal weight of methyl cellulose ether.

[0099] Test case

[0100] The white cement admixtures prepared in Examples 1-6 and Comparative Examples 1-5 of this invention were used in... Grinding tests were conducted in a standard cement test mill with the following material proportions: white cement clinker (80%) + gypsum (4.0%) + slag (10%) + limestone (6%). The cement specific surface area was controlled at 340 ± 10 m². 2The grinding aid performance of the admixture was detected according to the grinding aid performance test method of GB / T 26748-2011 Cement Grinding Aid; the whiteness was detected according to the whiteness test method of GB / T 2015-2005 White Portland Cement; the white cement mortar strength was detected according to GB / T 17671-1999 Cement Mortar Strength Test Method (ISO Method); and the dry shrinkage rate of the white cement mortar was detected according to JC / T 603-2004 Cement Mortar Dry Shrinkage Test Method.

[0101] The test results are as follows:

[0102] The blank sample is cement without the admixture, and the other tests are tests of adding the admixture of each embodiment and the comparative example of the present application. The cement discharged from the mill is detected for the related performance, the dosage of the white cement admixture and the test results are shown in Table 1.

[0103] Table 1 White cement performance test results

[0104]

[0105]

[0106] As can be seen from the test results in Table 1, compared with the blank sample, the whiteness of the white cement of each of embodiments 1-6 after adding the admixture is improved; the fineness reduction of 45 μm is more than 2 percentage points; the 3d compressive strength of the cement is increased by at least 2.5 Mpa, and the highest is increased by 3.7 Mpa; the 28d compressive strength is increased by at least 2.8 Mpa, and the highest is increased by 4.5 Mpa; and the 28d dry shrinkage rate is obviously reduced, the lowest is reduced by 0.02%, and the highest is reduced by 0.028%.

[0107] In the comparative example 1, the whiteness and fineness of the cement do not change much without adding the grinding component; in the comparative example 2, the dry shrinkage rate of the white cement does not change much with the low content of the effective component and without adding the anti-cracking component; in the comparative example 3, the strength and anti-dry shrinkage performance of the white cement do not change much with the low content of the effective component, and without adding the strengthening component and the durability improving component. In the comparative example 4, the whiteness of the white cement is reduced, and the fineness does not change much after replacing the glycerol triacetate with triethanolamine of the same weight; in the comparative example 5, the whiteness of the white cement is reduced, the fineness is obviously increased, and the 3d compressive strength is slightly reduced after replacing the carboxymethyl starch ether with methyl cellulose ether of the same weight, which has certain influence on the grinding and strengthening effect of the white cement.

[0108] In summary, the white cement admixture of the present application can effectively improve the grinding efficiency of the white cement, reduce the fineness of the white cement, and improve the whiteness of the white cement in the production and application of the white cement with a mixing amount of 0.2%-0.5% in the material. The white cement admixture can improve the mortar strength of the white cement and significantly reduce the shrinkage of the white cement, thereby effectively solving the problems of easy cracking and difficult construction of the white cement as a decorative material, and improving the durability of the white cement decorative material.

[0109] The above detailed description of the white cement admixture and the preparation method thereof in the reference examples is illustrative rather than limiting, and several examples can be listed within the limited range, and thus the changes and modifications without departing from the overall concept of the present application shall fall within the protection scope of the present application.

Claims

1. A white cement admixture, characterized in that, Including the following percentages by weight of raw materials: Grinding aid components: 5%-10%; Reinforcing components: 10%-15%; Dispersed component: 0.1%-0.3%; Crack-resistant component: 0.5%-1%; Components that improve durability: 0.1%-0.5%; The remaining space serves as a carrier; The grinding aid component is a complex composed of alkanolamines and polyol esters in a mass ratio of 2 to 5:

1. The reinforcing component is an aluminum salt, aluminate, or calcium salt; The dispersing component is a polycarboxylic acid water-reducing agent or a naphthalene-based water-reducing agent; The anti-cracking component is a complex composed of cellulose ether and starch ether in a mass ratio of 4~7:1; The durability-enhancing component is a siloxane-based substance; The polyol esters are at least one of polyol phosphates and triacetic acid esters; The durability-enhancing component is at least one of polydimethylsiloxane, fluorosiloxane, and ethylene glycol siloxane.

2. The white cement admixture according to claim 1, characterized in that, The alkanolamine is at least one of triethanolamine and triisopropanolamine.

3. The white cement admixture according to claim 1, characterized in that, The reinforcing component is any one or more of polyaluminum sulfate, sodium aluminate, sodium metaaluminate, and calcium glycerophosphate.

4. The white cement admixture according to claim 1, characterized in that, The polycarboxylic acid water-reducing agent is a polycarboxylic acid water-reducing agent synthesized from isopentenyl alcohol polyoxyethylene ether; both the polycarboxylic acid water-reducing agent and the naphthalene-based water-reducing agent are in powder form.

5. The white cement admixture according to claim 1, characterized in that, The cellulose ether is any one or more of methyl cellulose ether, ethyl cellulose ether, and hydroxypropyl methyl cellulose ether; the starch ether is at least one of carboxymethyl starch ether or hydroxypropyl starch ether.

6. The white cement admixture according to claim 1, characterized in that, The carrier is talc or lime powder.

7. The method for preparing the white cement admixture according to any one of claims 1-6, characterized in that, The preparation method includes the following steps: adding the carrier of the formula amount into the mixer, starting the mixer, adding the grinding aid component into the mixer and stirring for 20-30 minutes, and then sequentially adding the crack-resistant component, reinforcing component, dispersing component and durability-improving component of the formula amount into the mixer and stirring for 30-40 minutes to obtain the white cement admixture.

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