CN111732364A - Early strength agent for concrete prefabricated member and preparation method thereof - Google Patents
Early strength agent for concrete prefabricated member and preparation method thereof Download PDFInfo
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- CN111732364A CN111732364A CN201911275830.4A CN201911275830A CN111732364A CN 111732364 A CN111732364 A CN 111732364A CN 201911275830 A CN201911275830 A CN 201911275830A CN 111732364 A CN111732364 A CN 111732364A
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- early strength
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
- C04B40/0028—Aspects relating to the mixing step of the mortar preparation
- C04B40/0039—Premixtures of ingredients
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/10—Accelerators; Activators
- C04B2103/14—Hardening accelerators
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The invention discloses an early strength agent for a concrete prefabricated part and a preparation method thereof, wherein the early strength agent comprises the following components: soluble calcium salt, soluble silicon salt, anionic dispersant, nonionic dispersant, thickening agent and water; the preparation method comprises the following steps: carrying out composite reaction on soluble calcium salt, soluble silicon salt, anionic dispersant, nonionic dispersant and thickening agent in aqueous solution to generate organic doped calcium silicate hydrate gel suspension, namely the early strength agent for the concrete prefabricated part. According to the invention, the anionic and nonionic composite dispersing agents are used for dispersing the calcium silicate hydrate gel particles, so that a better dispersing effect can be provided; and the thickening agent is added into the early strength agent, so that the coalescence among hydrated calcium silicate gel particles is reduced, and the stability is further improved.
Description
Technical Field
The invention relates to the technical field of early strength agents, in particular to an early strength agent for a concrete prefabricated part and a preparation method thereof.
Background
The concrete has the advantages of low price, strong bearing capacity, high durability and the like, and is the building material with the largest usage in the world at present. With the development of high-speed rail and subway construction in China, the concrete prefabricated part becomes an important development direction of the concrete industry in China, and higher requirements are put forward on the early strength and the form removal time of concrete. The traditional chloride early strength agent contains chloride ions, and sulfate inorganic early strength agent contains alkali, so that the application has limitation, and the development of a novel early strength agent with excellent performance is urgently needed.
The hydrated calcium silicate is a main product of cement hydration and plays an important role in the strength development and the durability of concrete; therefore, calcium silicate hydrate is added into concrete as a seed crystal to induce the hydration product to separate out and crystallize more quickly, and the early strength effect is remarkable.
At present, the preparation method of the early strength agent by using calcium silicate hydrate as a crystal nucleus mainly adopts a silicate solution and a calcium salt solution to carry out a composite reaction in a dispersing agent, and the dispersing agent is mostly an anionic dispersing agent. Chinese patent CN105330194B discloses a nano suspension concrete early strength agent and a preparation method thereof, wherein a nano early strength agent is prepared by dispersing soluble calcium salt and silicate through polycarboxylic acid, and the early strength agent can be stably stored for 75 days when the solid content is 10.0%; the solid content is 20.0%, and the product can be stored stably for 45 days. The lower solid content can increase the transportation cost, and the shorter storage stable period can limit the popularization and the application of the early strength agent; therefore, the development of the early strength agent with high solid content and good storage stability has great application prospect.
Disclosure of Invention
Aiming at the problems of good early strength effect and poor storage stability of the existing calcium silicate hydrate seed crystal early strength agent suspension, the invention provides the early strength agent for the concrete prefabricated part and the preparation method thereof, wherein the preparation method is simple, the early strength effect is good, the solid content is high, and the storage stability is good.
The invention discloses an early strength agent for a concrete prefabricated member, which comprises the following components in percentage by weight: soluble calcium salt, soluble silicon salt, anionic dispersant, nonionic dispersant, thickening agent and water.
As a further improvement of the invention, the water-soluble polymer is prepared by mixing, by weight percent,
the soluble calcium salt is 2.5-20%;
the soluble silicate accounts for 2.4-10%;
the anionic dispersant accounts for 1.0 to 10 percent;
the non-ionic dispersant accounts for 0.4 to 4.0 percent;
0.01 to 0.1 percent of thickening agent;
the balance being water.
In a further improvement of the invention, the soluble calcium salt is calcium nitrate tetrahydrate, and the soluble silicon salt is anhydrous sodium metasilicate.
As a further improvement of the invention, the anionic dispersant is polycarboxylic acid, and the molecular weight is 3000-70000; the non-ionic dispersing agent is polyethylene diamine and has a molecular weight of 600-70000.
As a further improvement of the invention, the thickener is a welan gum.
The invention also discloses a preparation method of the early strength agent for the concrete prefabricated member, which comprises the following steps:
and carrying out composite reaction on the soluble calcium salt, the soluble silicon salt, the anionic dispersant, the nonionic dispersant and the thickening agent in an aqueous solution to generate an organic doped calcium silicate hydrate gel suspension, namely the early strength agent for the concrete prefabricated part.
As a further improvement of the invention, the method comprises the following steps:
respectively preparing the soluble calcium salt, the soluble silicon salt and the thickening agent into aqueous solutions;
adding the anionic dispersant, the nonionic dispersant, the thickener aqueous solution and water into a reaction vessel, and setting a preset reaction temperature and a preset stirring rate;
and (3) simultaneously dripping a soluble calcium salt solution and a soluble silicon salt solution into the reaction container, and obtaining the early strength agent for the concrete prefabricated part after the reaction is finished.
In a further improvement of the invention, the mass concentration of the soluble calcium salt solution is 50-70%, the mass concentration of the soluble silicon salt solution is 5-25%, and the mass concentration of the thickening agent aqueous solution is 0.3-5%.
As a further improvement of the invention, the reaction temperature is 20-90 ℃, and the stirring speed is 100-800 rpm; stirring for 0.5-2 h, keeping stirring, dripping the soluble calcium salt solution and the soluble silicon salt solution for 1-48 h, and continuously stirring for reaction for 0.5-2 h after dripping is finished.
As a further improvement of the invention, the particle size of the calcium silicate hydrate gel in the early strength agent for the concrete precast member is 150 nm-400 nm.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, the anionic and nonionic composite dispersing agents are used for dispersing the calcium silicate hydrate gel particles, so that a better dispersing effect can be provided; and the thickening agent is added into the early strength agent, so that the coalescence among hydrated calcium silicate gel particles is reduced, and the stability is further improved.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
The invention is described in further detail below:
the invention provides an early strength agent for a concrete prefabricated member, which comprises the following raw materials: soluble calcium salt, soluble silicon salt, anionic dispersant, nonionic dispersant, thickening agent and water; wherein the content of the first and second substances,
according to the weight percentage, the weight percentage of the alloy is,
2.5 to 20 percent of soluble calcium salt;
2.4 to 10 percent of soluble silicate;
1.0 to 10 percent of anionic dispersant;
0.4 to 4.0 percent of nonionic dispersant;
0.01 to 0.1 percent of thickening agent;
the balance being water.
In the above early strength agent for a concrete preform,
the soluble calcium salt is calcium nitrate tetrahydrate, and the soluble silicon salt is anhydrous sodium metasilicate; as a further improvement of the invention, the anionic dispersant is polycarboxylic acid, and the molecular weight is 3000-70000; the non-ionic dispersing agent is polyethylene diamine with the molecular weight of 600-70000; the thickening agent is welan gum.
The invention also provides a preparation method of the early strength agent for the concrete prefabricated member, which comprises the following steps:
carrying out composite reaction on soluble calcium salt, soluble silicon salt, anionic dispersant, nonionic dispersant and thickening agent in aqueous solution to generate organic doped calcium silicate hydrate gel suspension, namely the early strength agent for the concrete prefabricated part.
In particular to a method for preparing a high-performance nano-silver alloy,
respectively preparing soluble calcium salt, soluble silicon salt and a thickening agent into aqueous solution; wherein, the mass concentration of the soluble calcium salt solution is 50-70%, the mass concentration of the soluble silicon salt solution is 5-25%, and the mass concentration of the thickening agent aqueous solution is 0.3-5%;
adding an anionic dispersant, a nonionic dispersant, a thickener aqueous solution and water into a reaction vessel, and setting a preset reaction temperature and a preset stirring rate; wherein, the reaction vessel can adopt a three-mouth bottle, the reaction temperature is 20-90 ℃, and the stirring speed is 100-800 rpm;
stirring for 0.5-2 h, keeping stirring, simultaneously dropwise adding a soluble calcium salt solution and a soluble silicate solution into the reaction container, and obtaining the early strength agent for the concrete prefabricated part after the reaction is finished; wherein, the time for dripping the soluble calcium salt solution and the soluble silicon salt solution is 1-48 h, and the stirring reaction is continued for 0.5-2 h after the dripping is finished; the grain diameter of the hydrated calcium silicate gel in the prepared early strength agent for the concrete prefabricated part is 150 nm-400 nm.
The invention has the advantages that:
according to the invention, the anionic and nonionic composite dispersing agents are used for dispersing the calcium silicate hydrate gel particles, so that a better dispersing effect can be provided; and the thickening agent is added into the early strength agent, so that the coalescence among hydrated calcium silicate gel particles is reduced, and the stability is further improved.
Example 1
The invention provides a preparation method of an early strength agent for a concrete prefabricated part, which comprises the following steps:
weighing 50.0g of calcium nitrate tetrahydrate and 50.0g of water to prepare a 50.0% aqueous solution, weighing 15.0g of sodium metasilicate and 85.0g of water to prepare a 15.0% aqueous solution, and weighing 1.0g of welan gum and 99.0g of water to prepare a 1.0% aqueous solution;
adding 30.0g of anionic dispersant, 3.0g of nonionic dispersant, 3.0g of thickener solution and 58.0g of water into a 500ml three-necked bottle in sequence, setting the temperature to be 60 ℃ and the stirring speed to be 400 rpm;
after stirring for 1 hour, simultaneously dropwise adding 84.6g of calcium nitrate solution and 121.4g of sodium silicate solution, keeping stirring, and controlling the dropwise adding speed to ensure that the dropwise adding time is 24 hours; and continuously stirring for 1h after the dropwise addition is finished, and then slowly cooling to room temperature to obtain the early strength agent.
Example 2
The invention provides a preparation method of an early strength agent for a concrete prefabricated part, which comprises the following steps:
weighing 66.0g of calcium nitrate tetrahydrate and 34.0g of water to prepare a 66.0% aqueous solution, weighing 22.0g of sodium metasilicate and 78.0g of water to prepare a 22.0% aqueous solution, and weighing 1.0g of welan gum and 99.0g of water to prepare a 1.0% aqueous solution;
adding 24.0g of anionic dispersant, 9.0g of nonionic dispersant, 3.0g of thickener solution and 142.9g of water into a 500ml three-necked bottle in sequence, setting the temperature to be 40 ℃ and the stirring speed to be 300 rpm;
after stirring for 0.5h, simultaneously dropwise adding 75.1g of calcium nitrate solution and 46.0g of sodium silicate solution, keeping stirring, and controlling the dropwise adding speed so that the dropwise adding time is 12 h; and continuously stirring for 1h after the dropwise addition is finished, and then slowly cooling to room temperature to obtain the early strength agent.
Example 3
The invention provides a preparation method of an early strength agent for a concrete prefabricated part, which comprises the following steps:
weighing 50.0g of calcium nitrate tetrahydrate and 50.0g of water to prepare a 50.0% aqueous solution, weighing 15.0g of sodium metasilicate and 85.0g of water to prepare a 15.0% aqueous solution, and weighing 0.5g of welan gum and 99.5g of water to prepare a 0.5% aqueous solution;
sequentially adding 6.0g of anionic dispersant, 1.0g of nonionic dispersant, 50.0g of thickener solution and 174.3g of water into a 500ml three-necked bottle, setting the temperature to be 25 ℃ and the stirring speed to be 300 rpm;
stirring for 1h, then simultaneously dropwise adding 28.2g of calcium nitrate solution and 40.5g of sodium silicate solution, keeping stirring, and controlling the dropwise adding speed to ensure that the dropwise adding time is 2 h; and continuously stirring for 0.5h after the dropwise addition is finished, and then slowly cooling to room temperature to obtain the early strength agent.
The solids content and stability of the samples of the above examples are shown in Table 1.
TABLE 1 sample solids content and stability
| Sample (I) | Solid content (%) | Stability of |
| Example 1 | 20.7 | More than or equal to half a year |
| Example 2 | 19.5 | More than or equal to half a year |
| Example 3 | 6.5 | More than or equal to half a year |
Application example
The early strength performance of the early strength agent was evaluated using the mortar mix ratios shown in table 2.
TABLE 2 mortar mix proportion
| Reference cement (g) | Common mineral powder (g) | Classifying sand (g) | Water (g) | Water reducing agent (g) |
| 810 | 90 | 1340 | 250 | 5 |
According to the mixing proportion shown in the table 2, the mortar test piece is formed, the early strength agent is doped according to the solid content of the early strength agent accounting for 0.4 percent of the mortar adhesive material, and the water content of the early strength agent is deducted, so that the water-adhesive ratio is ensured to be consistent. The molded mortar was cured under standard conditions, and the strength data of the mortar are shown in table 3.
TABLE 3 mortar Strength test results
| Group of | Mixing amount | 16h breaking strength (MPa) | 16h compressive strength (MPa) |
| Example 1 | 0.4％ | 5.7 | 23.2 |
| Example 2 | 0.4％ | 5.5 | 24.3 |
| Example 3 | 0.4％ | 5.4 | 24.1 |
| Comparative example | 0 | 0.5 | 7.9 |
As can be seen from Table 3, the early strength agent provided by the invention can obviously improve the flexural strength and the compressive strength of the mortar, the flexural strength is improved by 11 times in 16 hours, and the compressive strength is improved by 3 times.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. An early strength agent for a concrete prefabricated member, comprising: soluble calcium salt, soluble silicon salt, anionic dispersant, nonionic dispersant, thickening agent and water.
2. The early strength agent for concrete preforms claimed in claim 1, wherein, in terms of weight percentage,
the soluble calcium salt is 2.5-20%;
the soluble silicate accounts for 2.4-10%;
the anionic dispersant accounts for 1.0 to 10 percent;
the non-ionic dispersant accounts for 0.4 to 4.0 percent;
0.01 to 0.1 percent of thickening agent;
the balance being water.
3. The early strength agent for concrete preforms claimed in claim 1, wherein the soluble calcium salt is calcium nitrate tetrahydrate and the soluble silicon salt is anhydrous sodium metasilicate.
4. The early strength agent for the concrete preform as claimed in claim 1, wherein the anionic dispersant is a polycarboxylic acid having a molecular weight of 3000 to 70000; the non-ionic dispersing agent is polyethylene diamine and has a molecular weight of 600-70000.
5. An early strength agent for a concrete preform according to claim 1, wherein the thickener is a welt gum.
6. A method for preparing an early strength agent for a concrete preform as claimed in any one of claims 1 to 5, comprising:
and carrying out composite reaction on the soluble calcium salt, the soluble silicon salt, the anionic dispersant, the nonionic dispersant and the thickening agent in an aqueous solution to generate an organic doped calcium silicate hydrate gel suspension, namely the early strength agent for the concrete prefabricated part.
7. The method of claim 6, comprising:
respectively preparing the soluble calcium salt, the soluble silicon salt and the thickening agent into aqueous solutions;
adding the anionic dispersant, the nonionic dispersant, the thickener aqueous solution and water into a reaction vessel, and setting a preset reaction temperature and a preset stirring rate;
and (3) simultaneously dripping a soluble calcium salt solution and a soluble silicon salt solution into the reaction container, and obtaining the early strength agent for the concrete prefabricated part after the reaction is finished.
8. The method according to claim 7, wherein the soluble calcium salt solution has a mass concentration of 50 to 70%, the soluble silicon salt solution has a mass concentration of 5 to 25%, and the aqueous thickener solution has a mass concentration of 0.3 to 5%.
9. The process according to claim 6, wherein the reaction temperature is 20 ℃ to 90 ℃ and the stirring rate is 100rpm to 800 rpm; stirring for 0.5-2 h, keeping stirring, dripping the soluble calcium salt solution and the soluble silicon salt solution for 1-48 h, and continuously stirring for reaction for 0.5-2 h after dripping is finished.
10. The method according to claim 6, wherein the calcium silicate hydrate gel in the early strength agent for the concrete preform has a particle size of 150nm to 400 nm.
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