阅读说明：本技术 一种湿拌砂浆外加剂及其制备方法 (Wet-mixed mortar additive and preparation method thereof ) 是由 陈云松 潘呈恭 杨涛 程茗燊 刘洋 于 2020-05-26 设计创作，主要内容包括：一种湿拌砂浆外加剂,包括以下重量百分比的组分组成：减水剂：1-5％,保水剂：0.1-1.0％,保塑时间调节剂：5-15％,引气剂：1-4％,粘度调节剂：0.1-0.3％,余量为水。本发明湿拌砂浆外加剂通过合理配置各原料组分,所得到的外加剂可以有效的增加砂浆的施工性、耐久性、增加砂浆的保塑时间至12-48h、改善抹灰砂浆容易出现的空鼓、开裂等问题,同时可有效提高砂浆的保水率,并使粘结强度和抗压强度明显增强,施工性能好,适用于推广应用。(The wet-mixed mortar admixture comprises the following components in percentage by weight: water reducing agent: 1-5%, water-retaining agent: 0.1-1.0%, plastic-retaining time regulator: 5-15%, air entraining agent: 1-4%, viscosity modifier: 0.1-0.3 percent of the total weight of the composition and the balance of water. The wet-mixed mortar additive disclosed by the invention has the advantages that through reasonable configuration of the raw material components, the obtained additive can effectively increase the workability and durability of the mortar, increase the plastic retention time of the mortar to 12-48h, improve the problems of hollowing, cracking and the like easily caused by plastering the mortar, effectively improve the water retention rate of the mortar, obviously enhance the bonding strength and the compressive strength, have good construction performance and are suitable for popularization and application.)

1. The wet-mixed mortar admixture is characterized by comprising the following components:

1-5 wt% of a water reducing agent;

0.1-1 wt% of water-retaining agent;

5-15 wt% of plastic-retaining time regulator;

1-4 wt% of an air entraining agent;

0.1-0.3 wt% of a viscosity modifier;

the balance of water;

the water reducing agent is a solution of polycarboxylic acid III type concrete slump retaining agent, the solid content is 40%, the water retaining agent is a mixture of hydroxypropyl methyl cellulose, hydroxypropyl starch ether and redispersible latex powder, and the mass ratio of the hydroxypropyl methyl cellulose to the hydroxypropyl starch ether to the redispersible latex powder is 6-6.5: 2.5-3: 0.5-1, the plastic-retaining time regulator is one or a mixture of several of white sugar, sodium gluconate, sodium citrate monohydrate and tartaric acid, the air-entraining agent is one or a mixture of several of fatty alcohol-polyoxyethylene ether sodium sulfate, sodium dodecyl sulfate and triterpene saponin, the viscosity regulator is a solution of a high molecular compound polymerized by taking N, N-dimethylacrylamide, acrylamide and acrylic acid as monomers, the solid content is 18-22%, and the mass ratio of the N, N-dimethylacrylamide, the acrylamide and the acrylic acid is 5-10: 0-10: 30-40, the molecular weight of the high molecular compound is 100000-300000.

2. The wet-mix mortar admixture according to claim 1, comprising the following components:

3 wt% of a water reducing agent;

0.5 wt% of a water retaining agent;

8 wt% of plastic-retaining time regulator;

3 wt% of an air entraining agent;

0.2 wt% of a viscosity modifier;

the balance being water.

3. The wet mix mortar admixture according to claim 1, wherein the viscosity modifier is prepared by the steps of:

1) taking 30-40 parts by weight of acrylic acid, 5-10 parts by weight of N, N-dimethylacrylamide, 0-10 parts by weight of acrylamide, 0.1-1 part by weight of chain transfer agent, 1-5 parts by weight of initiator and 160-200 parts by weight of water, wherein the initiator is 30 wt% of aqueous hydrogen peroxide solution and ascorbic acid;

2) dissolving acrylic acid with water to obtain a solution A, dissolving N, N-dimethylacrylamide with water to obtain a solution B, dissolving acrylamide with water to obtain a solution C, and dissolving a chain transfer agent and ascorbic acid with water to obtain a chain transfer agent solution;

3) heating the solution A to 45-50 ℃ under the stirring condition, adding aqueous hydrogen peroxide solution, keeping the temperature and stirring, simultaneously dropwise adding the solution B, the solution C and the chain transfer agent solution, and finishing dropping within 2-4 h;

4) and (5) keeping the temperature to react until the reaction is finished, and adjusting the pH to 6-8 to obtain the viscosity regulator.

4. The wet-mixed mortar admixture according to claim 3, wherein the mass ratio of the aqueous hydrogen peroxide solution to the ascorbic acid in the step 1) is 3: 1.

5. the wet-mix mortar admixture according to claim 3, wherein the chain transfer agent is mercaptoethanol.

6. The wet-mixed mortar admixture according to claim 3, wherein the step 1) is carried out by taking 35 parts by weight of acrylic acid, 5 parts by weight of N, N-dimethylacrylamide, 5 parts by weight of acrylamide, 0.1 part by weight of chain transfer agent, 2 parts by weight of initiator, and 175 parts by weight of water.

7. The wet-mixed mortar admixture according to claim 3, wherein the mass ratio of the water of the solution of acrylic acid, N-dimethylacrylamide and acrylamide in the step 2) is 25: 3: 5.

8. the wet-mixed mortar admixture and the preparation method thereof according to claim 3, wherein the dropping time of the solution B, the solution C and the chain transfer agent solution in the step 3) is 3 hours, and the heat preservation reaction time in the step 4) is 1-3 hours.

9. The method for preparing a wet-mix mortar admixture according to claim 1 or 2, characterized by comprising the steps of:

1) taking materials according to a proportion;

2) adding 70% of water in the formula into a container, adding a water reducing agent, and stirring;

3) adding a viscosity regulator, and stirring;

4) adding a plastic-retaining time regulator, and stirring;

5) heating to 60-70 deg.C, adding water-retaining agent, and stirring;

6) cooling to room temperature, adding an air entraining agent, and stirring;

7) and adding the rest water in the formula, and stirring to obtain the wet-mixed mortar additive.

10. The method according to claim 9, wherein the stirring time in step 2) is 5 to 10min, the stirring time in step 3) is 5 to 10min, the stirring time in step 4) is 5 to 10min, the stirring time in step 5) is 10 to 20min, the stirring time in step 6) is 10 to 15min, and the stirring time in step 7) is 5 to 10 min.

Technical Field

The invention relates to the field of building materials, in particular to a wet-mixed mortar additive and a preparation method thereof.

Background

With the increasing concern of people on environmental problems, the urban construction process is accelerated, and a large amount of dust generated in the construction process also becomes one of the main sources of urban environmental pollutants. According to statistics, construction dust accounts for 23% of dust emission of urban areas, wherein the dust emission of site-use cement, sand and stone accounts for 36% of the total construction dust. When the traditional building mortar is stirred on site, a closed operation site is not provided generally, and the air quality is seriously influenced. Particularly, in haze weather in most areas of the country since 2013, people pay more attention to dust pollution in ecological environment protection. Compared with commercial mortar, the field stirring mortar also has a large number of technical defects, such as poor mortar workability, large shrinkage, unstable strength, poor impermeability and the like. In view of the problems, governments in various places have also issued documents that band the field mortar stirring with the ready-mixed mortar. Therefore, how to improve the performance parameters of the ready-mixed mortar is a problem to be solved urgently by the technical personnel in the field.

Disclosure of Invention

One of the purposes of the invention is to provide a wet-mixed mortar admixture which can effectively increase the workability and durability of mortar, prolong the opening time of the mortar to 12-48h and effectively improve the problems of hollowing, cracking and the like easily caused by plastering mortar, aiming at the defects of the prior art.

The invention also aims to provide the preparation method of the wet-mixed mortar admixture, which has the advantages of simple and convenient preparation process and mild process parameters and is suitable for industrial processing production.

The technical scheme for realizing one purpose of the invention is as follows: the wet-mixed mortar admixture comprises the following components:

1-5 wt% of a water reducing agent;

0.1-1 wt% of water-retaining agent;

5-15 wt% of plastic-retaining time regulator;

1-4 wt% of an air entraining agent;

0.1-0.3 wt% of a viscosity modifier;

the balance of water;

the water reducing agent is a solution of polycarboxylic acid III type concrete slump retaining agent, the solid content is 40%, the water retaining agent is a mixture of hydroxypropyl methyl cellulose, hydroxypropyl starch ether and redispersible latex powder, and the mass ratio of the hydroxypropyl methyl cellulose to the hydroxypropyl starch ether to the redispersible latex powder is 6-6.5: 2.5-3: 0.5-1, the plastic-retaining time regulator is one or a mixture of several of white sugar, sodium gluconate, sodium citrate monohydrate and tartaric acid, the air-entraining agent is one or a mixture of several of fatty alcohol-polyoxyethylene ether sodium sulfate, sodium dodecyl sulfate and triterpene saponin, the viscosity regulator is a solution of a high molecular compound polymerized by taking N, N-dimethylacrylamide, acrylamide and acrylic acid as monomers, the solid content is 18-22%, and the mass ratio of the N, N-dimethylacrylamide, the acrylamide and the acrylic acid is 5-10: 0-10: 30-40, the molecular weight of the high molecular compound is 100000-300000.

Preferably, the wet-mixed mortar admixture comprises the following components:

3 wt% of a water reducing agent;

0.5 wt% of a water retaining agent;

8 wt% of plastic-retaining time regulator;

3 wt% of an air entraining agent;

0.2 wt% of a viscosity modifier;

the balance being water.

The viscosity regulator is prepared by the following steps:

1) taking 30-40 parts by weight of acrylic acid, 5-10 parts by weight of N, N-dimethylacrylamide, 0-10 parts by weight of acrylamide, 0.1-1 part by weight of chain transfer agent, 1-5 parts by weight of initiator and 160-200 parts by weight of water, wherein the initiator is 30 wt% of aqueous hydrogen peroxide solution and ascorbic acid;

2) dissolving acrylic acid with water to obtain a solution A, dissolving N, N-dimethylacrylamide with water to obtain a solution B, dissolving acrylamide with water to obtain a solution C, and dissolving a chain transfer agent and ascorbic acid with water to obtain a chain transfer agent solution;

3) heating the solution A to 45-50 ℃ under the stirring condition, adding aqueous hydrogen peroxide solution, keeping the temperature and stirring, simultaneously dropwise adding the solution B, the solution C and the chain transfer agent solution, and finishing dropping within 2-4 h;

4) and (5) keeping the temperature to react until the reaction is finished, and adjusting the pH to 6-8 to obtain the viscosity regulator.

Preferably, the mass ratio of the aqueous hydrogen peroxide solution to the ascorbic acid in the step 1) is 3: 1.

preferably, the chain transfer agent is mercaptoethanol.

Preferably, step 1) takes 35 parts by weight of acrylic acid, 5 parts by weight of N, N-dimethylacrylamide, 5 parts by weight of acrylamide, 0.1 part by weight of chain transfer agent, 2 parts by weight of initiator, and 175 parts by weight of water.

Preferably, the mass ratio of the solution of acrylic acid, N-dimethylacrylamide and water of acrylamide in the step 2) is 25: 3: 5.

preferably, the dropping time of the solution B, the solution C and the chain transfer agent solution in the step 3) is 3 hours, and the holding time in the step 4) is 1-3 hours.

The second technical scheme for realizing the aim of the invention is as follows:

the preparation method of the wet-mixed mortar admixture comprises the following steps:

1) taking materials according to a proportion;

2) adding 70% of water in the formula into a container, adding a water reducing agent, and stirring;

3) adding a viscosity regulator, and stirring;

4) adding a plastic-retaining time regulator, and stirring;

5) heating to 60-70 deg.C, adding water-retaining agent, and stirring;

6) cooling to room temperature, adding an air entraining agent, and stirring;

7) and adding the rest water in the formula, and stirring to obtain the wet-mixed mortar additive.

Preferably, the stirring time in the step 2) is 5-10min, the stirring time in the step 3) is 5-10min, the stirring time in the step 4) is 5-10min, the stirring time in the step 5) is 10-20min, the stirring time in the step 6) is 10-15min, and the stirring time in the step 7) is 5-10 min.

Adopt above-mentioned technical scheme to have following beneficial effect:

1. in the wet-mixed mortar admixture, the added water reducing agent is a polycarboxylic acid III type concrete slump retaining agent, so that the plastic retaining time of the wet-mixed mortar can be effectively prolonged, the wet-mixed mortar admixture also has certain air entraining and retarding performances, the water reducing rate can meet the use requirement of the mortar, the bleeding phenomenon in the early stage of the mortar is avoided, and the construction performance of the mortar is improved. If the content of the water reducing agent is too low, the 2h consistency loss rate of the mortar is larger, if the content of the water reducing agent is too high, the water reducing rate of a mortar additive is too high, so that sufficient water cannot be added into a mortar system, along with the prolonging of the standing time of the mortar, the hydration heat is increased and the water is consumed, the mortar becomes dry in a short time, loses plasticity and cannot be normally used; the water retaining agent that adds is used for showing the water retention effect that strengthens the mortar, play the effect of extension wet-mixed mortar engineering time, if the content of water retaining agent is low excessively, then can't form one deck polymer film at the mortar skin, reduce the water retention effect, if the content of water retaining agent is too high, then can lead to mortar viscosity great, be unfavorable for the workman and plaster the construction, also can reduce the compressive strength of mortar simultaneously, the water retaining agent is by hydroxypropyl methyl cellulose, hydroxypropyl starch ether, but the redispersibility emulsion powder is 6-6.5 according to the mass ratio: 2.5-3: 0.5-1, wherein the hydroxypropyl methyl cellulose and the hydroxypropyl starch ether have synergistic effect, so that the water retention effect can be obviously enhanced, and the redispersible latex powder is matched, so that the sag resistance of the mortar can be effectively improved, the phenomena of hollowing, separation and the like of the mortar are reduced, if the content of each component is too low, the unqualified conditions such as poor water retention effect of wet-mixed mortar, low tensile bonding strength and the like can be caused, and if the content of each component is too high, the mortar has low consistency, and meanwhile, the mortar is not solidified for a long time after being put on the wall, so that the construction efficiency is reduced; the added plastic-retaining time regulator is a main material for regulating the mortar setting time, if the content of the plastic-retaining time regulator is too low, the mortar is solidified in a short time, the requirement of a worker for long-time use cannot be met, if the content is too high, the mortar is subjected to hollowing, and the mortar has no strength; the added air entraining agent is used for reducing the volume weight of the mortar and improving the workability of the mortar, if the content of the air entraining agent is too low, the volume weight of the mortar is too large, the mortar is difficult to construct by workers, and the mortar falls off after being smeared on a wall, and if the content of the air entraining agent is too high, the strength of the mortar is too low, so that the standard requirement cannot be met; the N, N-dimethylacrylamide and the amide group of acrylamide in the added viscosity regulator have strong hydration effect besides adsorption capacity, a hydration film is thickened by being adsorbed on cement particles, the water retention capacity is strong, the surface tension of mortar can be effectively reduced, the viscosity and the consistency of the mortar are maintained, if the content of the viscosity regulator is too low, the effect of regulating the viscosity of the mortar cannot be reflected, and if the content of the viscosity regulator is too high, the condition of low consistency of the mortar can be caused.

2. The wet-mixed mortar additive provided by the invention is added according to 1-3% of the using amount of the cementing material in the mortar proportion, so that the construction property and the durability of the mortar can be effectively increased, the opening time of the mortar is prolonged to 12-48h, the problems of hollowing, cracking and the like easily caused by plastering the mortar can be effectively solved, the water retention rate of the mortar can be improved, the bonding strength and the compressive strength of the mortar are obviously enhanced, the construction performance is good, and the wet-mixed mortar additive is suitable for popularization and application.

3. The water-retaining agent is prepared by mixing hydroxypropyl methyl cellulose, hydroxypropyl starch ether and redispersible latex powder, wherein the viscosity of the hydroxypropyl methyl cellulose is 100000 mPa.s, in order to ensure the uniformity of the mortar admixture, the dispersion can be ensured to be completed only at 60-70 ℃, but the viscosity is not generated at the moment, and the viscosity is generated only when the temperature is reduced to 40 ℃ or below, so that the use requirement is met.

The following is a further description with reference to specific examples.

Detailed Description

In the invention, the source of the used material and the viscosity regulator are self-made; hydroxypropyl methylcellulose, hydroxypropyl starch ether and redispersible emulsion powder are all produced by Gomes chemical Co.Ltd.

The preparation process of the viscosity regulator comprises the following steps:

weighing 5.5g of N, N-dimethylacrylamide, dissolving in 12g of deionized water, and uniformly stirring to obtain a solution B for later use; weighing 2.5g of acrylamide in 10g of deionized water, and uniformly stirring to obtain a solution C for later use; weighing 0.5g of mercaptoethanol and 0.64gVC, dissolving in 40g of deionized water, and uniformly stirring to obtain a chain transfer agent solution for later use; weighing 32.5g of acrylic acid and 100g of deionized water, putting into a reaction container, heating for dissolving, adding 3g of 30 wt% hydrogen peroxide solution after the temperature reaches 50 ℃, keeping the temperature and stirring for 5min, then beginning to dropwise add the solution B, the solution C and the chain transfer agent solution at a constant speed, finishing dropping for 2.5h, continuing to keep the temperature for reaction for 2h, adding a sodium hydroxide aqueous solution after the reaction is finished, adjusting the pH value of the system to 7.8, and discharging to obtain the product.