CN111423177A - Dry-mixed mortar and production process thereof - Google Patents

Abstract

The invention discloses dry powder mortar and a production process thereof, relating to the technical field of building materials; the dry powder mortar is prepared from the following mortar raw materials in parts by weight: 20-30 parts of cement, 5-15 parts of fly ash and 45-55 parts of fine sand, wherein the mortar raw material also comprises a mortar additive, and the mortar additive is prepared from the following additive raw materials in parts by weight: 0.3-3 parts of polyacrylamide, 0.05-0.4 part of air entraining agent, 4-10 parts of zeolite powder and 0.2-0.8 part of defoaming agent; it has the advantages of excellent workability; the production process of the dry powder mortar comprises the following steps: preparing an additive, mixing materials, preparing mortar and the like; the production process of the dry powder mortar has the advantage of being convenient for improving the strength performance.

Description

Dry-mixed mortar and production process thereof

Technical Field

The invention relates to the technical field of building material production, in particular to dry powder mortar and a production process thereof.

Background

Mortar is a building material made of sand and a cementing material in a certain proportion, and is widely applied in the fields of building exterior wall treatment, indoor decoration and the like. The traditional building mortar is mixed on site at construction site, and the mortar mixed on site has poor quality stability, poor crack resistance and impermeability and easily causes the problems of wall surface cracking, crust formation, leakage and the like due to low metering accuracy of each component, unreasonable fine aggregate grading, difficult additive application and the like. Therefore, dry mortar prepared in advance is increasingly used.

The patent with the publication number of CN101838129B discloses dry powder mortar, which is prepared from the following raw materials in parts by weight: 12-25% of cement, 3-4% of fly ash, 32-50% of yellow sand, 32-50% of sodium silicate casting used sand, 2.7-3.4% of mortar thickening powder and 0-0.05% of additive. The dry-mixed mortar is prepared by mixing the raw materials of fly ash, cement, sodium silicate casting old sand and the like, and can be used by adding water in a construction site.

However, since the dry mortar is generally used without good stirring and pulping equipment, especially the dry mortar for interior decoration often has no good stirring tool, the dry mortar is required to have excellent workability so as to facilitate the use of the dry mortar in the construction process.

Application publication No. CN110482940A discloses a sand-free light self-leveling dry powder mortar, which comprises the following components in percentage by weight: 70-75% of cement, 5-10% of fly ash, 5-10% of ground limestone, 8-12% of perlite, 1.5-3% of redispersible latex powder, 0.3-0.5% of methyl cellulose ether, 0.4-0.6% of air entraining agent and 0.5-1% of water reducing agent. The application document improves the workability of the dry-mixed mortar and improves the leveling performance of the dry-mixed mortar by adding the air entraining agent into the dry-mixed mortar.

However, because the air entraining agent is added in the technical scheme, the strength of the dry powder mortar after construction can be reduced to a certain extent, and if the dry powder mortar with excellent workability and good strength performance can be prepared, the dry powder mortar has better market value.

Disclosure of Invention

Aiming at the defects in the prior art, the first purpose of the invention is to provide the dry powder mortar with excellent workability, which has the advantage of good strength performance.

A second object of the present invention is to provide a construction process of dry mortar convenient for improving strength properties, which has advantages of facilitating improvement of strength properties.

In order to achieve the first object, the invention provides the following technical scheme: the dry powder mortar is characterized by being prepared from the following mortar raw materials in parts by weight: 20-30 parts of cement, 5-15 parts of fly ash and 45-55 parts of fine sand, wherein the mortar raw material also comprises a mortar additive, and the mortar additive is prepared from the following additive raw materials in parts by weight: 0.3-3 parts of polyacrylamide, 0.05-0.4 part of air entraining agent, 4-10 parts of zeolite powder and 0.2-0.8 part of defoaming agent.

By adopting the technical scheme, the air entraining agent is added into the dry powder mortar, so that the friction resistance among the raw materials of the dry powder mortar can be reduced, and the workability of the dry powder mortar is improved; the zeolite powder has a higher specific surface area, and can increase the contact area among materials, improve the adhesive force of the materials and improve the strength performance of the dry-mixed mortar; the zeolite powder contains a certain pore channel structure, bubbles can be generated in the process of adding water and stirring in construction, the addition of the defoaming agent can eliminate the bubbles generated in the process of adding water and stirring in construction, and the improvement of the strength performance of the dry-mixed mortar is facilitated.

Preferably, the mortar additive is prepared from the following additive raw materials in parts by weight: 1.5-2.5 parts of polyacrylamide, 0.1-0.3 part of air entraining agent, 6-9 parts of zeolite powder and 0.4-0.6 part of defoaming agent.

By adopting the technical scheme, the dry powder mortar with better workability and strength performance is prepared by using better raw material proportion, and the market competitiveness of the product is improved.

Preferably, the air entraining agent is a sodium abietate air entraining agent.

By adopting the technical scheme, the sodium abietate air entraining agent is added, so that uniformly distributed micro bubbles are generated in the process of adding water into the mortar and stirring, the surface tension of the water in the mortar is reduced, and the workability of the mortar is improved, thereby improving the dispersibility of each component in the mortar, improving the construction efficiency and improving the market competitiveness of products.

Preferably, the defoamer is a polydimethylsiloxane defoamer.

By adopting the technical scheme, the polydimethylsiloxane defoaming agent is added into the dry powder mortar, so that bubbles generated in the process of adding water and stirring the dry powder mortar in construction can be eliminated, the adverse effect of the bubbles on the strength of the dry powder mortar is reduced, and the improvement of the strength performance of the dry powder mortar is facilitated.

Preferably, the mortar additive also comprises 1-4 parts by weight of calcium bentonite.

By adopting the technical scheme, the calcium bentonite is added into the dry powder mortar, the calcium bentonite has certain thixotropy, the system viscosity can be reduced in the process of adding water and stirring in the dry powder mortar construction, the dispersity of each material in the mortar is improved, the product strength is improved, and after the mortar is smeared on construction positions such as a wall body, the calcium bentonite also improves the product viscosity, improves the adhesive force of the mortar, improves the product strength performance and improves the product market competitiveness.

Preferably, the zeolite powder has a particle size of 1-150 μm, and the zeolite powder has a specific surface area of 300-800 square meters per gram.

By adopting the technical scheme, the zeolite powder with small particle size and large specific surface area is used, so that the zeolite powder can be uniformly dispersed in the dry powder mortar, the large specific surface area zeolite powder can improve the contact area with other components, improve the bonding strength among the components and improve the specific surface area of the dry powder mortar.

In order to achieve the second object, the invention provides the following technical scheme: a production process of dry powder mortar comprises the following steps:

(1) preparing an additive: weighing zeolite powder, adding an air entraining agent, polyacrylamide and a defoaming agent, uniformly stirring, and grinding to obtain a mortar additive;

(2) mixing materials: weighing fine sand, fly ash and cement according to a set proportion, uniformly mixing, and grinding to prepare mortar powder;

(3) preparing mortar: and adding the mortar additive into the mortar powder, and uniformly stirring to obtain the dry powder mortar.

By adopting the technical scheme, the air entraining agent, the defoaming agent and the polyacrylamide are added into the zeolite powder with small particle size, the raw materials such as the air entraining agent, the defoaming agent and the like are uniformly dispersed in the zeolite powder through a grinding process, and then the zeolite powder is mixed with the mortar powder, so that the dispersion degree of the additive raw materials in the dry powder mortar is favorably improved, the workability and the strength performance of the dry powder mortar are favorably improved, and the market competitiveness of products is favorably improved.

Preferably, the particle size of the mortar additive is 0.5-180 μm, and the particle size of the mortar powder is 5-320 μm.

By adopting the technical scheme, the mortar additive and the mortar powder with proper particle size are used, so that the dispersity of each component in the dry powder mortar is improved, the product strength is improved, and the product market competitiveness is improved.

In summary, the invention includes at least one of the following beneficial technical effects:

1. the air entraining agent is added into the dry powder mortar, so that the frictional resistance among the raw materials of the dry powder mortar can be reduced, the workability is improved, but the air entraining agent can reduce the strength of the dry powder mortar to a certain extent, the contact area among the components is increased by adding the zeolite powder with small particle size and high specific surface area, the bonding strength among the components is improved, the strength performance of the dry powder mortar is improved, the defoaming agent is added to eliminate bubbles generated in the process of adding water into the dry powder mortar for stirring, the adverse effect of the bubbles on the strength of the dry powder mortar is reduced, and the strength performance of the dry powder mortar is improved.

2. According to the invention, the air entraining agent, the defoaming agent and the polyacrylamide are added into the zeolite powder with small particle size and high specific surface area, and then the zeolite powder is ground to prepare the mortar additive, so that the components such as the defoaming agent, the air entraining agent and the like are uniformly dispersed in the mortar additive, the dispersion degree of each component in the mortar is improved, the workability and the strength performance of the dry powder mortar are improved, and the market competitiveness of the product is improved;

3. according to the invention, the calcium bentonite with thixotropic property is added into the dry powder mortar, so that the viscosity of a system can be reduced, the workability of the mortar is improved and the dispersity of each component is improved in the process of adding water into the dry powder mortar and stirring, and after the product is smeared on a construction position, the calcium bentonite can improve the viscosity of the system, the adhesive force of the product, the strength performance of the product and the market competitiveness of the product.

Detailed Description

Examples

The present invention will be described in further detail below.

The raw materials involved in the present invention are all commercially available, and specifications and sources of the respective components are shown in table 1.

TABLE 1 specification and sources of raw materials for the components

Component (Kg)	Specification of	Manufacturer/origin
			Cement	P·042.5	Sichuan
Fly ash	Class I	Sichuan
			Fine sand	Fineness modulus of 1.6-2.2	Sichuan
Polyacrylamide	Cationic type	Consolidation of Henan
			Sodium abietate air entraining agent	Superior product	Zhengzhou Henan
Zeolite powder	Clinoptilolite	Xinyang of Henan province
			Polydimethylsiloxane defoaming agent	Food grade	Zhengzhou Henan
Calcium bentonite	The passing rate of 200 meshes is more than or equal to 95 percent	Hebei stone house
			Sodium dodecyl sulfate air entraining agent	The active matter content is more than or equal to 95 percent	Yunnan Kunming
Polyether type defoaming agent	Polyether modified silicon, technical grade	Guandong Dongguan

Example 1: a production process of dry powder mortar comprises the following steps:

(1) preparing an additive: sieving zeolite powder with a sieve with the aperture of 1 mu m and 150 mu m, weighing 7.5Kg of zeolite powder with the particle size of 1 mu m-150 mu m, wherein the specific surface area of the zeolite powder is 550 square meters per gram, adding 0.2Kg of sodium abietate air entraining agent, 2Kg of polyacrylamide, 0.5Kg of polydimethylsiloxane antifoaming agent and 2.5Kg of calcium bentonite, stirring uniformly, grinding, sieving with a sieve with the aperture of 0.5 mu m and 180 mu m, selecting particles with the aperture of 0.5 mu m-180 mu m, and preparing the mortar additive;

(2) mixing materials: weighing 50Kg of fine sand, 10Kg of fly ash and 25Kg of cement, uniformly mixing, grinding, sieving by using screens with the aperture of 5 mu m and 320 mu m, and selecting materials with the particle size of 5 mu m-320 mu m to prepare mortar powder;

(3) preparing mortar: and adding the mortar additive into the mortar powder, and uniformly stirring to obtain a dry powder mortar product.

Example 2

Example 2 differs from example 1 in that example 2 does not have calcium bentonite added and otherwise remains the same as example 1.

Example 3

Example 3 differs from example 1 in that zeolite powder with a particle size of 150 μm to 350 μm was selected in example 3, and the rest was the same as example 1.

Example 4

Example 4 differs from example 1 in that example 4 uses a mortar powder with a particle size of 1 μm to 500. mu.m, all the other things remaining the same as example 1.

Example 5

Example 5 differs from example 1 in that example 5 uses a sodium dodecyl sulphate air entraining agent instead of a sodium abietate air entraining agent, all otherwise in accordance with example 1.

Example 6

Example 6 differs from example 1 in that example 6 uses a polyether defoamer in place of the polydimethylsiloxane defoamer and otherwise remains the same as example 1.

Example 7

Example 7 differs from example 1 in that the amount of zeolite powder used in example 7 was reduced from 7.5Kg to 4Kg, all other things remaining the same as in example 1.

Example 8

Example 8 differs from example 1 in that the amount of zeolite powder used in example 8 was reduced from 7.5Kg to 5.8Kg, all other things remaining the same as in example 1.

Examples 9 to 16

Examples 9-16 differ from example 1 in the amounts of starting materials added and the process parameters of examples 9-16.

The amounts of the starting materials used in examples 9 to 16 are shown in Table 2, and the process parameters for examples 9 to 16 are shown in Table 3.

TABLE 2 addition of the starting materials of examples 9 to 16

TABLE 3 parameters in the procedure of examples 9-16

Comparative example

Comparative example 1

Comparative example 1 differs from example 1 in that comparative example 1 does not have the zeolite powder, sodium rosin acid air entraining agent, and polydimethylsiloxane defoamer, all in keeping with example 1.

Comparative example 2

Comparative example 2 differs from example 1 in that comparative example 2 does not have the addition of zeolite powder and polydimethylsiloxane defoamer and otherwise remains the same as example 1.

Comparative example 3

Comparative example 3 differs from example 1 in that comparative example 3 does not have zeolite powder added, and otherwise remains the same as example 1.

Comparative example 4

Comparative example 4 differs from example 1 in that comparative example 4 does not have the addition of a polydimethylsiloxane defoamer and otherwise remains the same as example 1.

Performance detection

The dry mortar prepared in examples 1 to 15 and comparative examples 1 to 4 were sampled and prepared according to JGJ/T70-2009 "standard for basic performance test method of building mortar", and subjected to a consistency test, a water retention test and a cubic compressive strength test, with the test results shown in table 4.

TABLE 4 comparison table of performance test results of different dry powder mortar products

In the comparative example 1, under the experimental condition that the air entraining agent, the zeolite powder and the defoaming agent are not added at the same time, the prepared dry powder mortar product has good compressive strength, but poor consistency and water retention, poor workability, no contribution to market popularization of the product and poor market competitiveness of the product. Comparative example 2 in the absence of zeolite powder and defoamer, the dry mortar product prepared in comparative example 2 has good consistency and water retention, and excellent workability, which should be due to the addition of air-entraining agent, but the dry mortar prepared in comparative example 2 has lower compressive strength and poor compressive performance because no zeolite and defoamer are added. In the comparative example 3, the prepared dry powder mortar product has good consistency and water retention property and excellent workability without adding zeolite powder, but has low compressive strength and poor compressive property, and is not beneficial to market popularization of the product. Comparative example 4 no defoamer was added, and the prepared dry powder mortar product was good in consistency and water retention, excellent in workability, 23.4MPa in compressive strength, and not good in compressive property, and was not favorable for market promotion of the product.

Comparing the experimental results of the example 1 and the comparative examples 1 to 4, it can be seen that, in the process of preparing the dry-mixed mortar, the sodium abietate air-entraining agent, the zeolite powder and the polydimethylsiloxane defoaming agent are added, and under the combined action of the three factors, the dry-mixed mortar sample prepared in the example 1 has good consistency and water retention, excellent workability, good compressive strength, excellent compressive performance and good product market competitiveness.

Comparing the experimental results of example 1 and example 2, in example 2, the dry mortar sample prepared without adding calcium bentonite has better consistency and water retention, excellent workability and reduced strength performance. However, the dry mortar prepared in example 2 has better strength properties than those of comparative examples 1 to 4. Therefore, the preferable scheme of the invention is to add calcium bentonite.

Compared with the experimental results of the embodiment 1 and the embodiment 3, the embodiment 3 selects the zeolite powder with larger particle size, and the prepared dry-mixed mortar sample has better consistency and water retention property, excellent workability and reduced strength property. However, the dry mortar prepared in example 3 has better strength properties than those of comparative examples 1 to 4. Therefore, the preferred scheme of the invention is to use zeolite powder with the particle size of 1-150 μm.

Comparing the experimental results of example 1 and example 4, example 4 uses mortar powder with wider particle size distribution range, and the prepared dry powder mortar sample has little difference in consistency, reduced water retention and reduced strength performance. Therefore, the preferred embodiment of the present invention is to use mortar powder with a particle size of 5 μm to 320 μm.

Comparing the experimental results of the embodiment 1 and the embodiment 5, the embodiment 5 selects different types of air-entraining agents, and the prepared dry-mixed mortar sample has good consistency and water retention, excellent workability and reduced strength performance. However, the dry mortar product prepared in example 5 has better compression resistance than the comparative examples 1 to 4. Therefore, the preferable scheme of the invention is to use the sodium abietate air entraining agent.

Comparing the experimental results of the embodiment 1 and the embodiment 6, the embodiment 6 selects different types of defoaming agents, and the prepared dry mortar sample has good consistency and water retention, excellent workability and reduced strength performance. However, the dry mortar product prepared in example 5 has better strength properties than comparative examples 1 to 4. Therefore, the preferred embodiment of the present invention is to use a polydimethylsiloxane defoamer.

Comparing the experimental results of example 1 and examples 7-8, the amount of zeolite powder used in example 7 and example 8 was reduced from 7.5Kg to 4Kg and 5.8Kg, respectively, and the prepared dry mortar samples had little difference in consistency and water retention, excellent workability, and slightly decreased strength properties. Therefore, the preferable scheme of the invention is that the dosage of the zeolite powder is not less than 6 parts.

The feed amounts of the various materials of examples 9-16 were different and the process parameters were different compared to example 1. Wherein the weight ratio of the raw materials of the embodiments 13-16 is as follows: 20-30 parts of cement, 5-15 parts of fly ash, 45-55 parts of fine sand, 1.5-2.5 parts of polyacrylamide, 0.1-0.3 part of air entraining agent, 6-9 parts of zeolite powder and 0.4-0.6 part of defoaming agent; the dry powder mortar products prepared in the embodiments 13 to 16 have the compressive strength of about 31MPa, good compressive strength and strong market competitiveness. The weight ratio of the raw materials in examples 9-12 is different from that in examples 13-16, and the compressive strength of the prepared dry mortar product is about 30MPa, and the compressive performance is slightly reduced. Therefore, the preferable weight ratio of the raw materials is as follows: 20-30 parts of cement, 5-15 parts of fly ash, 45-55 parts of fine sand, 1.5-2.5 parts of polyacrylamide, 0.1-0.3 part of air entraining agent, 6-9 parts of zeolite powder and 0.4-0.6 part of defoaming agent.

The zeolite powder with the grain size of more than 150 mu m can be crushed to the grain size of not more than 150 mu m and then used, the mortar additive with the grain size of more than 180 mu m can be crushed to the grain size of not more than 180 mu m and then used, and the mortar powder with the grain size of more than 320 mu m can be crushed to the grain size of not more than 320 mu m and then used.

The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.

Claims (8)

1. The dry powder mortar is characterized by being prepared from the following mortar raw materials in parts by weight: 20-30 parts of cement, 5-15 parts of fly ash and 45-55 parts of fine sand, wherein the mortar raw material also comprises a mortar additive, and the mortar additive is prepared from the following additive raw materials in parts by weight: 0.3-3 parts of polyacrylamide, 0.05-0.4 part of air entraining agent, 4-10 parts of zeolite powder and 0.2-0.8 part of defoaming agent.

2. The dry-mixed mortar of claim 1, wherein the mortar additive is prepared from the following raw materials in parts by weight: 1.5-2.5 parts of polyacrylamide, 0.1-0.3 part of air entraining agent, 6-9 parts of zeolite powder and 0.4-0.6 part of defoaming agent.

3. The dry-mixed mortar of claim 2, wherein: the air entraining agent is a sodium abietate air entraining agent.

4. The dry-mixed mortar of claim 2, wherein: the defoaming agent is a polydimethylsiloxane defoaming agent.

5. The dry-mixed mortar of claim 2, wherein: the mortar additive also comprises 1-4 parts by weight of calcium bentonite.

6. The dry-mixed mortar of claim 2, wherein: the particle size of the zeolite powder is 1-150 μm, and the specific surface area of the zeolite powder is 300-800 square meters per gram.

7. A process for the production of a dry-mixed mortar as claimed in any one of claims 1 to 6, characterized in that it comprises the following steps:

(1) preparing an additive: weighing zeolite powder according to a set proportion, adding an air entraining agent, polyacrylamide and a defoaming agent, uniformly stirring, and grinding to prepare a mortar additive;

(2) mixing materials: weighing fine sand, fly ash and cement according to a set proportion, uniformly mixing, and grinding to prepare mortar powder;

(3) preparing mortar: and adding the mortar additive into the mortar powder, and uniformly stirring to obtain the dry powder mortar.

8. The construction method of the dry-mixed mortar according to claim 7, characterized in that: the grain diameter of the mortar additive is 0.5-180 mu m, and the grain diameter of the mortar powder is 5-320 mu m.