阅读说明：本技术 一种喷射砂浆/混凝土用速凝剂的制备方法 (Preparation method of accelerator for spraying mortar/concrete ) 是由 钱珊珊 王子明 郑春扬 黄春满 胡阳成 甘杰忠 于 2020-11-27 设计创作，主要内容包括：本发明公开了一种喷射砂浆/混凝土用速凝剂的制备方法,速凝剂包括有机组分、无机组分硫酸铝、引发剂以及还原剂；其中有机组份以聚合物单体添加到水泥中,在引发剂和还原剂共同作用下聚合形成高分子网络结构；无机组分硫酸铝能够促进水泥快速水化形成无机网络结构；从而形成的有机-无机互穿网络结构使水泥基材料快速增稠,达到强粘附和速凝、硬化的特性,有效降低喷射砂浆/混凝土的回弹量。本方法制备的速凝剂与各种水泥适应性良好,且高效环保。通过聚合反应与水泥水化反应形成有机-无机互穿网络结构从而提高喷射砂浆/混凝土韧性的有机聚合物-无机复合速凝剂。(The invention discloses a preparation method of an accelerator for spraying mortar/concrete, wherein the accelerator comprises an organic component, an inorganic component, aluminum sulfate, an initiator and a reducing agent; wherein the organic component is added into cement by polymer monomer, and is polymerized to form a macromolecular network structure under the combined action of an initiator and a reducing agent; the inorganic component aluminum sulfate can promote the cement to be quickly hydrated to form an inorganic network structure; the formed organic-inorganic interpenetrating network structure enables the cement-based material to be thickened rapidly, achieves the characteristics of strong adhesion, quick setting and hardening, and effectively reduces the rebound quantity of the sprayed mortar/concrete. The accelerator prepared by the method has good adaptability to various cements, and is efficient and environment-friendly. The organic polymer-inorganic composite accelerator can improve the toughness of the sprayed mortar/concrete by forming an organic-inorganic interpenetrating network structure through a polymerization reaction and a cement hydration reaction.)

1. A preparation method of an accelerator for spraying mortar/concrete is characterized by comprising the following steps: the accelerator comprises an organic component, an inorganic component, namely aluminum sulfate, an initiator and a reducing agent; wherein the organic component is added into cement by polymer monomer, and is polymerized to form a macromolecular network structure under the combined action of an initiator and a reducing agent; the inorganic component aluminum sulfate can promote the cement to be quickly hydrated to form an inorganic network structure; the formed organic-inorganic interpenetrating network structure enables the cement-based material to be thickened rapidly, achieves strong adhesion and quick setting, achieves the characteristics of strong adhesion and quick setting, and effectively reduces the rebound quantity of the sprayed mortar/concrete.

2. The method for preparing the accelerator for sprayed mortar/concrete according to claim 1, wherein the method comprises the following steps: the accelerator comprises the following specific components in parts by weight:

3. the method for preparing the accelerator for sprayed mortar/concrete according to claim 1, wherein the method comprises the following steps: the synthesis method of the polymer monomer comprises the following steps: the structure is simplified as R₁[CH(O)CH₂]₂The diepoxy organic compound has a structure formula of R₂NH₂Carrying out amino-epoxy ring-opening polymerization reaction on the primary amine to obtain a polymer monomer; the polymer monomer contains a large amount of alkylene, and the structure simple formula is as follows:wherein R is₁Is an alkylene, ether or phenyl derivative, R₂Is unsaturated olefin group, and n is more than or equal to 2.

4. The method for preparing the accelerator for sprayed mortar/concrete according to claim 3, wherein the method comprises the following steps: the weight average molecular weight of the polymer monomer is 400-5000 g/mol.

5. The method for preparing the accelerator for sprayed mortar/concrete according to claim 3, wherein the method comprises the following steps: the diepoxy organic matter is one or the combination of more than two of 1, 3-diglycidyl ether glycerol, 3-diepoxybutane, diepoxy- (+) -1, 3-butadiene-D6, 4' -diepoxy diphenyl sulfone, diepoxy diphenyl, 1,2,5, 6-diepoxy hexane, propylene glycol diglycidyl ester, diglycidyl ether, 1, 4-butanediyl diglycidyl ether, ethylene glycol diglycidyl ether and neopentyl glycol-1, 4-butanediyl diglycidyl ether.

6. The method for preparing the accelerator for sprayed mortar/concrete according to claim 3, wherein the method comprises the following steps: the primary amine is one or the combination of more than two of allylamine, p-vinylaniline, m-vinylaniline, 3-methyl-2-butenylamine, 3-butenylamine and 4-pentenylamine.

7. The method for preparing the accelerator for sprayed mortar/concrete according to claim 2, wherein the method comprises the following steps: the initiator is one or the combination of two of sodium persulfate and potassium persulfate.

8. The method for preparing the accelerator for sprayed mortar/concrete according to claim 2, wherein the method comprises the following steps: the reducing agent is N, N, N ', N' -tetramethyl ethylenediamine.

9. The method for preparing the accelerator for sprayed mortar/concrete according to claim 2, wherein the method comprises the following steps: the initiator and the reducing agent are alkali-resistant redox composite initiation systems.

Technical Field

The invention relates to the field of building materials, in particular to a preparation method of an accelerator for spraying mortar/concrete.

Background

The sprayed mortar/concrete has been widely used in the fields of tunnel engineering, underground engineering, hydraulic tunnels, revetment support, water conservancy and hydropower, mine tunnels, engineering repair and the like. The alkali-free (low) accelerator represented by an aluminum sulfate type used in the accelerator has the advantages of low 28d strength loss, no alkali and chlorine, safety, environmental protection, high durability and the like, but has the problems of large mixing amount, unstable adaptability to cement, other additives and working environments, unstable set accelerating time, large rebound loss and the like which need to be solved.

The prior art application number is EP0946451B1 with the name: SOLIDIFYING AND HARDENING ACCELERATOR FOR HYDRAULIC BINDERS, discloses a liquid ACCELERATOR which can be easily mixed into concrete with aluminum hydroxide, aluminum salt and organic carboxylic acid as main components, but has a problem of instability in solution. The invention with the application number of US8075688B2 is named as: an Aqueous accelerator mixture is disclosed, which uses alumina, sulfuric acid, fluoride, magnesium silicate or kaolin as a stabilizing agent, and uses magnesium silicate or kaolin to absorb water and expand to increase the viscosity of the system so as to improve the stability of the solution system, so that the solution can be well dispersed in concrete and the coagulation is promoted. The invention with the application number of US9242904B2 is named as: aqueous precursors of polymer-modified setting acids and use of the same in the construction industry, disclosed a accelerator of aluminum salt, aluminate, alkali metal silicate modified by various forms (liquid, solid or powder) of polymer vinyl acetate or its copolymer, the polymer vinyl acetate increases the viscosity of the system to achieve the simultaneous stable existence of various polymers and accelerator components in solution.

The polymer monomer is fused into the cement paste, intermolecular and intramolecular polymerization of the polymer monomer is carried out under the action of the initiator-reducing agent to form a network structure, so that the concrete/mortar is tackified, the adhesion of the sprayed mortar/concrete is increased, the rebound loss is reduced, the sprayed mortar/concrete is prevented from falling off due to gravity, the once spraying thickness is increased, the interval time between spraying layers is shortened, and the polymer monomer has nitrogen and hydroxyl groups, is similar to an alcohol amine structure, can accelerate cement hydration and shorten the initial setting time. The cement is continuously hydrated from the beginning of adding water to form a large amount of crystals and colloid hydration products to be solidified, and the crystals and the colloid hydration products form an organic-inorganic composite network structure together with polymer monomers, so that the combination between interfaces of the hydration products is improved, and the breaking strength is improved. The accelerator disclosed by the invention is good in adaptability to a water reducing agent, and has no adverse effect on the 28d strength of concrete.

Disclosure of Invention

1. The technical problem to be solved is as follows:

aiming at the technical problems, the invention provides a preparation method of an accelerator for sprayed mortar/concrete, and the accelerator prepared by the method is an organic polymer accelerator which is efficient and environment-friendly, has good adaptability with various cements, and forms an organic-inorganic interpenetrating network structure with the cement through polymerization reaction so as to improve the toughness of the sprayed concrete.

2. The technical scheme is as follows:

a preparation method of an accelerator for spraying mortar/concrete is characterized by comprising the following steps: the accelerator comprises an organic component, an inorganic component, namely aluminum sulfate, an initiator and a reducing agent; wherein the organic component is added into cement by polymer monomer, and is polymerized to form a macromolecular network structure under the combined action of an initiator and a reducing agent; the inorganic component aluminum sulfate can promote the cement to be quickly hydrated to form an inorganic network structure; the formed organic-inorganic interpenetrating network structure enables the cement-based material to be thickened rapidly, achieves strong adhesion and quick setting, achieves the characteristics of strong adhesion and quick setting, and effectively reduces the rebound quantity of the sprayed mortar/concrete.

Further, the concrete components of the accelerator comprise the following components in parts by weight:

further, the synthesis method of the polymer monomer comprises the following steps: the structure is simplified as R₁[CH(O)CH₂]₂The diepoxy organic compound has a structure formula of R₂NH₂Of primary amine (A) to (B)Performing amino-epoxy ring-opening polymerization reaction to obtain a polymer monomer; the polymer monomer contains a large amount of alkylene, and the structure simple formula is as follows:wherein R is₁Is an alkylene, ether or phenyl derivative, R₂Is unsaturated olefin group, n is more than or equal to 2; the molecular structure of the polymer monomer contains nitrogen and hydroxyl, is similar to the structure of alcohol amine, and has an early strength effect.

Further, the weight average molecular weight of the polymer monomer is 400-5000 g/mol.

Further, the diepoxy organic matter is one or the combination of more than two of 1, 3-diglycidyl ether glycerol, 3-diepoxybutane, diepoxy- (+) -1, 3-butadiene-D6, 4' -diepoxy diphenyl sulfone, diepoxy diphenyl, 1,2,5, 6-diepoxy hexane, propylene glycol diglycidyl ester, diglycidyl ether, 1, 4-butanediyl diglycidyl ether, ethylene glycol diglycidyl ether and neopentyl glycol-1, 4-butanediyl diglycidyl ether.

Further, the primary amine is one or the combination of more than two of allylamine, p-vinylaniline, m-vinylaniline, 3-methyl-2-butenylamine, 3-butenylamine and 4-pentenylamine.

Further, the initiator is one or two of sodium persulfate and potassium persulfate.

Further, the reducing agent is N, N, N ', N' -tetramethylethylenediamine.

Further, the initiator and the reducing agent are alkali-resistant redox composite initiation systems.

3. Has the advantages that:

the preparation method of the accelerating agent for spraying mortar/concrete adopts the technical scheme that polymer monomers are blended into cement slurry and subjected to polymerization reaction under the action of an initiator-reducing agent to form a high-molecular network structure. The inorganic component makes the cement hydrate quickly to form an inorganic network structure, and the organic-inorganic interpenetrating network structure shortens the initial setting time of the cement. Nitrogen and activity in late stage organic matterThe existence of a sexual group-OH can be combined with Ca in a cement hydration product²⁺，Mg²⁺，Al³⁺Hydrogen bonds and complexation are generated, the chemical bonding between the organic matter and the multivalent cations is mutually interpenetrated with the self-crosslinked network of the organic matter, the combination between interfaces is improved, and the breaking strength is improved; the polymer film is filled around the hydration products and on the surface of the aggregate in the interface transition period, so that the combination between the hydration products and the interface area of the cement paste and the aggregate is enhanced, and the pores are filled, thereby having the enhancement effect.

Detailed Description

A preparation method of an accelerator for spraying mortar/concrete is characterized by comprising the following steps: the accelerator comprises an organic component, an inorganic component, namely aluminum sulfate, an initiator and a reducing agent; wherein the organic component is added into cement by polymer monomer, and is polymerized to form a macromolecular network structure under the combined action of an initiator and a reducing agent; the inorganic component aluminum sulfate can promote the cement to be quickly hydrated to form an inorganic network structure; the formed organic-inorganic interpenetrating network structure enables the cement-based material to be thickened rapidly, achieves strong adhesion and quick setting, achieves the characteristics of strong adhesion and quick setting, and effectively reduces the rebound quantity of the sprayed mortar/concrete.

Further, the concrete components of the accelerator comprise the following components in parts by weight:

further, the synthesis method of the polymer monomer comprises the following steps: the structure is simplified as R₁[CH(O)CH₂]₂The diepoxy organic compound has a structure formula of R₂NH₂Carrying out amino-epoxy ring-opening polymerization reaction on the primary amine to obtain a polymer monomer; the polymer monomer contains a large amount of alkylene, and the structure simple formula is as follows:wherein R is₁Is an alkylene, ether or phenyl derivative, R₂Is unsaturated olefin group, n is more than or equal to 2; molecular junction of the polymer monomerThe structure contains nitrogen and hydroxyl, is similar to the structure of alcohol amine, and has early strength.

Further, the weight average molecular weight of the polymer monomer is 400-5000 g/mol.

Further, the diepoxy organic matter is one or the combination of more than two of 1, 3-diglycidyl ether glycerol, 3-diepoxybutane, diepoxy- (+) -1, 3-butadiene-D6, 4' -diepoxy diphenyl sulfone, diepoxy diphenyl, 1,2,5, 6-diepoxy hexane, propylene glycol diglycidyl ester, diglycidyl ether, 1, 4-butanediyl diglycidyl ether, ethylene glycol diglycidyl ether and neopentyl glycol-1, 4-butanediyl diglycidyl ether.

Further, the primary amine is one or the combination of more than two of allylamine, p-vinylaniline, m-vinylaniline, 3-methyl-2-butenylamine, 3-butenylamine and 4-pentenylamine.

Further, the initiator is one or two of sodium persulfate and potassium persulfate.

Further, the reducing agent is N, N, N ', N' -tetramethylethylenediamine.

Further, the initiator and the reducing agent are alkali-resistant redox composite initiation systems.

Example 1:

the quick-setting admixture for the sprayed mortar/concrete is prepared by the following components in parts by weight: 45 parts of aluminum sulfate, 10 parts of polymer monomer, 1.4 parts of potassium persulfate and 0.5 part of N, N, N ', N' -tetramethyl ethylenediamine.

The structural formula of the polymer monomer isThe weight average molecular weight was 3000 g/mol.

Example 2:

the quick-setting admixture for the sprayed mortar/concrete is prepared by the following components in parts by weight: 40 parts of aluminum sulfate, 5 parts of polymer monomer, 1.2 parts of potassium persulfate and 0.5 part of N, N, N ', N' -tetramethyl ethylenediamine.

The structural formula of the polymer monomer isThe weight average molecular weight was 400 g/mol.

Example 3:

the quick-setting admixture for the sprayed mortar/concrete is prepared by the following components in parts by weight: 45 parts of aluminum sulfate, 8 parts of polymer monomer, 0.8 part of potassium persulfate and 0.5 part of N, N, N ', N' -tetramethyl ethylenediamine.

The structural formula of the polymer monomer isThe weight average molecular weight was 5000 g/mol.

And (3) performance detection:

the reference cement was used, and the main components are shown in Table 1. Examples 1,2 and 3 were tested for setting time, flexural strength and compressive strength according to GBT 35159 and 2017.

Table 1Chemical and mineral compositions of reference cement

Coagulation time test:

pouring 400g of cement and 16g of 4% doping amount of accelerating agent into a stirring pot of a clean slurry stirrer, starting the stirrer to stir at low speed for 10s, stopping stirring, adding 140g of water once, stirring at low speed for 5s, stirring at high speed for 15s, immediately filling into a master mould, inserting and smashing by a knife, slightly vibrating for a plurality of times, scraping redundant clean slurry, trowelling the surface, and performing the whole operation for no more than 50s from the time of adding water. A clotting time test was performed.

And (3) flexural strength and compressive strength test:

pouring 900g of cement and 36g of 4% doping amount accelerator into a stirring pot, starting the stirrer to stir at low speed for 30s until the cement and the accelerator are uniformly mixed, uniformly adding 1350g of standard sand into the stirring pot during the second 30s of low-speed stirring, adding 450g of water, stirring at low speed for 5s, then stirring at high speed for 15s, and finishing the stirring. The mortar is filled into a cement mortar mould as soon as possible for subsequent flexural strength and compressive strength tests

1. Test for setting time

The setting time test is carried out by adding the accelerating agent with the formula of the embodiment 1,2 and 3, the result is shown in the table 2, and the experimental result shows that the accelerating agent of the embodiment can meet the national standard requirement.

TABLE 2 Effect of accelerators on setting time of reference Cement

2. Flexural strength test

The results of the mortar flexural strength test with the addition of the accelerator of the formula of examples 1,2 and 3 are shown in Table 3, and the experimental results show that the accelerator of the examples can improve the early-stage and 28-day flexural strength of the cement.

Table 3 mortar flexural strength test table

3. Test for compressive Strength

The results of the compressive strength test by adding the accelerator with the formula of examples 1,2 and 3 and the accelerator of Tianjin brand as a comparison sample are shown in Table 4, and the experimental results show that the strength of 28 days is not shrunk due to the use of the accelerator, the three accelerators prepared in the examples meet the requirements of national standards, and the index of the retention rate before 28 days is superior to that of the Tianjin brand accelerator.

Table 4: mortar compression strength test

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.