阅读说明：本技术 一种厚层水泥基自流平砂浆及其施工方法 (Thick-layer cement-based self-leveling mortar and construction method thereof ) 是由 范树景 张庆 葛师鋆 于 2021-06-10 设计创作，主要内容包括：本发明公开了一种厚层水泥基自流平砂浆,以重量份计,包括以下组分：硫铝酸盐水泥80-100份,普通硅酸盐水泥100-200份,细砂100-150份,减水剂2-3份,消泡剂0.5-1.5份,可再分散乳胶粉5-8份,膨胀剂1-2份,功能填料80-120份；所述功能填料为核壳结构纤维材料,所述核壳结构纤维材料的核层材料为石墨烯改性的聚乙烯醇纤维,壳层材料为纳米氧化钛增强的聚丙烯腈纤维。本发明还公开了该砂浆的制备方法。本发明提供的自流平砂浆在保证良好流动性的前提下,力学性能得到明显改善。(The invention discloses a thick-layer cement-based self-leveling mortar which comprises the following components in parts by weight: 80-100 parts of sulphoaluminate cement, 100-200 parts of ordinary portland cement, 100-150 parts of fine sand, 2-3 parts of a water reducing agent, 0.5-1.5 parts of a defoaming agent, 5-8 parts of redispersible latex powder, 1-2 parts of an expanding agent and 80-120 parts of a functional filler; the functional filler is a core-shell structure fiber material, the core layer material of the core-shell structure fiber material is graphene modified polyvinyl alcohol fiber, and the shell layer material is nano titanium oxide reinforced polyacrylonitrile fiber. The invention also discloses a preparation method of the mortar. On the premise of ensuring good fluidity, the self-leveling mortar provided by the invention has obviously improved mechanical properties.)

1. The thick-layer cement-based self-leveling mortar is characterized by comprising the following components in parts by weight: comprises the following components:

80-100 parts of sulphoaluminate cement, 100-200 parts of ordinary portland cement, 100-150 parts of fine sand, 2-3 parts of a water reducing agent, 0.5-1.5 parts of a defoaming agent, 5-8 parts of redispersible latex powder, 1-2 parts of an expanding agent and 80-120 parts of a functional filler;

the functional filler is a core-shell structure fiber material, the core layer material of the core-shell structure fiber material is graphene modified polyvinyl alcohol fiber, and the shell layer material is nano titanium oxide reinforced polyacrylonitrile fiber.

2. A thick layer cement based self-levelling mortar according to claim 1, wherein: the fine sand is river sand with the average grain diameter of 0.15-0.35 mm.

3. A thick layer cement based self-levelling mortar according to claim 1, wherein: the water reducing agent is polycarboxylate water reducing agent.

4. A thick layer cement based self-levelling mortar according to claim 1, wherein: the defoaming agent is an organic silicon defoaming agent.

5. A thick layer cement based self-levelling mortar according to claim 1, wherein: the redispersible latex powder is one of vinyl acetate-ethylene copolymer rubber powder and vinyl acetate-ethylene versatate copolymer.

6. A thick layer cement based self-levelling mortar according to claim 1, wherein: the swelling agent is magnesium oxide.

7. A thick layer cement based self-levelling mortar according to claim 1, wherein: the preparation method of the functional filler comprises the following steps:

(1) dispersing nano titanium oxide in a DMF solvent, adding polyacrylonitrile powder, stirring and mixing to prepare a shell spinning solution, placing polyvinyl alcohol powder in deionized water, adding graphene, stirring and dispersing to prepare a nuclear layer spinning solution;

(2) and respectively placing the prepared shell layer spinning solution and the prepared core layer spinning solution in coaxial electrostatic spinning equipment for electrostatic spinning to prepare the functional filler.

8. A thick layer cement based self-levelling mortar according to claim 7, wherein: in the step (1), the mass ratio of the nano titanium oxide to the polyacrylonitrile powder to the graphene to the polyethanol powder is 1: 10: (1-2): 15.

9. a thick layer cement based self-levelling mortar according to claim 7, wherein: in the step (2), the electrostatic spinning conditions are as follows: the liquid feeding speed is 0.75-0.85ml/h, the distance from a spinning nozzle to a receiver is 15-18cm, the spinning voltage is 8-15kV, and the spinning temperature is 30 ℃.

10. A method of constructing a thick layer cementitious self-levelling screed according to any one of claims 1 to 9 which includes the steps of:

firstly, repairing, polishing, cleaning and airing a base layer; carrying out interface treatment on the base layer by using an interface agent, and carrying out the next procedure after the interface agent is dried; mixing the prepared cement-based self-leveling mortar and water, uniformly stirring to prepare slurry, controlling the water-material ratio to be 0.15-0.25:1, pouring the prepared slurry into a base surface, automatically paving and leveling by using the slurry, defoaming by using a defoaming roller, then using a spatula to assist in leveling, maintaining for 10-40h under natural conditions, and then polishing to obtain the cement-based self-leveling mortar.

Technical Field

The invention relates to the field of building materials, in particular to thick-layer cement-based self-leveling mortar and a construction method thereof.

Background

The ground system is an important part of the building and provides a comfortable place for people to live and work. With the rapid development of national economy, ground materials are rapidly changed, the requirements on building processes are gradually improved, the traditional mortar ground is easy to crack and ash, the flatness is difficult to meet the requirements, and the self-leveling materials can improve the problems, so that the self-leveling materials have a very wide prospect. The self-leveling mortar adopts organic substances or inorganic substances as cementing materials, and fine sand, additives and additives are added to achieve the mortar with high fluidity, good working performance and higher strength. In a short time, the self-leveling mortar can automatically level under the action of self weight so as to meet the requirement of accurate leveling. Generally speaking, the floor mat can be used as a cushion layer below a floor decorative layer to provide a precise leveling layer for a floor surface layer, and decorative layers such as carpets, floor tiles, wood floors, PVC floors and the like can be paved on the cushion layer; meanwhile, the self-leveling mortar can also be used as a surface layer and is directly worn and impacted by external force, so that the self-leveling mortar is required to have higher performances such as wear resistance, strength, hardness and the like.

The cement-based self-leveling material is a ground material capable of leveling by flowing under the self-weight, has the advantages of high fluidity, self-leveling property, quick construction, low labor intensity and the like, is commonly used for ground engineering of large markets, schools, houses, parking lots, marine docks and the like, and has huge market potential. The flatness difference of the leveling layer and the filling part of the ground engineering is large, the flatness difference is from several millimeters to several centimeters, and thick-layer mortar is needed for paving. At present, cement-based self-leveling mortar has higher strength, better water resistance and wear resistance than gypsum-based self-leveling mortar, is commonly used in a thin layer process below 10mm, is easy to crack when applied to a thick layer ground with the thickness of more than 20mm, and is easy to separate and bleed when applied to large-particle aggregates. Furthermore, the strength of thick-bed cement-based self-leveling mortars also needs to be further improved.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the invention provides thick-layer cement-based self-leveling mortar and a construction method thereof, aiming at the defects in the prior art, the invention adopts graphene modified polyvinyl alcohol fiber as a core-shell material, adopts nano titanium oxide reinforced polyacrylonitrile fiber as a shell material to form core-shell structure fiber, and adds the core-shell structure fiber into a mortar matrix for modification, thereby effectively improving the mechanical property of the mortar on the premise of not influencing the fluidity of the mortar.

In order to solve the technical problems, the technical scheme of the invention is as follows:

the thick-layer cement-based self-leveling mortar comprises the following components in parts by weight:

80-100 parts of sulphoaluminate cement, 100-200 parts of ordinary portland cement, 100-150 parts of fine sand, 2-3 parts of a water reducing agent, 0.5-1.5 parts of a defoaming agent, 5-8 parts of redispersible latex powder, 1-2 parts of an expanding agent and 80-120 parts of a functional filler;

the functional filler is a core-shell structure fiber material, the core layer material of the core-shell structure fiber material is graphene modified polyvinyl alcohol fiber, and the shell layer material is nano titanium oxide reinforced polyacrylonitrile fiber.

Preferably, the fine sand is river sand having an average particle size of 0.15 to 0.35 mm.

Preferably, in the above technical solution, the water reducing agent is a polycarboxylate water reducing agent.

Preferably, the defoaming agent is a silicone defoaming agent.

Preferably, the redispersible latex powder is one of vinyl acetate-ethylene copolymer rubber powder and vinyl acetate-ethylene versatate copolymer.

Preferably, in the above aspect, the swelling agent is magnesium oxide.

Preferably, the preparation method of the functional filler comprises the following steps:

(1) dispersing nano titanium oxide in a DMF solvent, adding polyacrylonitrile powder, stirring and mixing to prepare a shell spinning solution, placing polyvinyl alcohol powder in deionized water, adding graphene, stirring and dispersing to prepare a nuclear layer spinning solution;

(2) and respectively placing the prepared shell layer spinning solution and the prepared core layer spinning solution in coaxial electrostatic spinning equipment for electrostatic spinning to prepare the functional filler.

Preferably, in the step (1), the mass ratio of the nano titanium oxide to the polyacrylonitrile powder to the graphene to the polyethanol powder is 1: 10: (1-2): 15.

preferably, in the step (2), the electrostatic spinning conditions are as follows: the liquid feeding speed is 0.75-0.85ml/h, the distance from a spinning nozzle to a receiver is 15-18cm, the spinning voltage is 8-15kV, and the spinning temperature is 30 ℃.

In order to better solve the technical problems, the invention also discloses a construction method of the thick-layer cement-based self-leveling mortar, which comprises the following steps:

firstly, repairing, polishing, cleaning and airing a base layer; carrying out interface treatment on the base layer by using an interface agent, and carrying out the next procedure after the interface agent is dried; mixing the prepared cement-based self-leveling mortar and water, uniformly stirring to prepare slurry, controlling the water-material ratio to be 0.15-0.25:1, pouring the prepared slurry into a base surface, automatically paving and leveling by using the slurry, defoaming by using a defoaming roller, then using a spatula to assist in leveling, maintaining for 10-40h under natural conditions, and then polishing to obtain the cement-based self-leveling mortar.

The interface agent is prepared by mixing emulsion and water according to the mass ratio of 1:6-9, wherein the emulsion can be EVA emulsion or SBR emulsion.

Due to the adoption of the technical scheme, the invention has the beneficial effects that:

according to the invention, a certain amount of functional filler is added into mortar, the functional filler is a core-shell structure fiber material, a core layer material of the core-shell structure fiber material is graphene modified polyvinyl alcohol fiber, and a shell layer material is nano titanium oxide reinforced polyacrylonitrile fiber. The length-diameter ratio of the functional filler prepared by the method is 10-15: 1. The functional filler prepared by the invention has excellent performance and good bonding force with a mortar matrix, and can effectively improve the mechanical property of the mortar on the premise of not influencing the fluidity of the mortar, and the mortar provided by the invention can be constructed to a thickness of more than 40mm at one time.

Detailed Description

The invention is further illustrated by the following examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Example 1

Dispersing 1g of nano titanium oxide in 50ml of DMF solvent, adding 10g of polyacrylonitrile powder, stirring and mixing to prepare a shell spinning solution, putting 15g of polyvinyl alcohol powder in 50ml of deionized water, adding 1g of graphene, stirring and dispersing to prepare a core-shell spinning solution;

respectively placing the prepared shell layer spinning solution and the prepared core layer spinning solution in coaxial electrostatic spinning equipment for electrostatic spinning to prepare a functional filler; the electrostatic spinning conditions are as follows: the liquid feed speed was 0.75ml/h, the distance from the spinneret to the receiver was 15cm, the spinning voltage was 8kV, and the spinning temperature was 30 ℃.

According to the weight parts, 80 parts of sulphoaluminate cement, 200 parts of ordinary portland cement, 100 parts of fine sand, 2 parts of polycarboxylate water reducing agent, 0.5 part of organic silicon defoamer, 5 parts of vinyl acetate and ethylene copolymer rubber powder, 1 part of magnesium oxide and 80 parts of functional filler are added into a stirrer to be stirred and mixed uniformly to prepare the cement-based self-leveling mortar.

Example 2

Dispersing 1g of nano titanium oxide in 50ml of DMF solvent, adding 10g of polyacrylonitrile powder, stirring and mixing to prepare a shell spinning solution, putting 15g of polyvinyl alcohol powder in 50ml of deionized water, adding 2g of graphene, stirring and dispersing to prepare a core-shell spinning solution;

respectively placing the prepared shell layer spinning solution and the prepared core layer spinning solution in coaxial electrostatic spinning equipment for electrostatic spinning to prepare a functional filler; the electrostatic spinning conditions are as follows: the liquid feed speed was 0.85ml/h, the distance from the spinneret to the receiver was 18cm, the spinning voltage was 15kV, and the spinning temperature was 30 ℃.

100 parts of sulphoaluminate cement, 200 parts of ordinary portland cement, 150 parts of fine sand, 3 parts of polycarboxylate water reducing agent, 1.5 parts of organic silicon defoamer, 8 parts of vinyl acetate-ethylene copolymer rubber powder, 2 parts of magnesium oxide and 120 parts of functional filler are added into a stirrer to be stirred and mixed uniformly to prepare the cement-based self-leveling mortar.

Example 3

Dispersing 1g of nano titanium oxide in 50ml of DMF solvent, adding 10g of polyacrylonitrile powder, stirring and mixing to prepare a shell spinning solution, putting 15g of polyvinyl alcohol powder in 50ml of deionized water, adding 1.5g of graphene, stirring and dispersing to prepare a core-shell spinning solution;

respectively placing the prepared shell layer spinning solution and the prepared core layer spinning solution in coaxial electrostatic spinning equipment for electrostatic spinning to prepare a functional filler; the electrostatic spinning conditions are as follows: the liquid feed rate was 0.75ml/h, the distance from the spinneret to the receiver was 16cm, the spinning voltage was 10kV, and the spinning temperature was 30 ℃.

According to the weight parts, 90 parts of sulphoaluminate cement, 120 parts of ordinary portland cement, 100 parts of fine sand, 2 parts of polycarboxylate water reducing agent, 1 part of organic silicon defoamer, 5 parts of vinyl acetate and ethylene copolymer rubber powder, 1 part of magnesium oxide and 80 parts of functional filler are added into a stirrer to be uniformly stirred and mixed to prepare the cement-based self-leveling mortar.

Example 4

Dispersing 1g of nano titanium oxide in 50ml of DMF solvent, adding 10g of polyacrylonitrile powder, stirring and mixing to prepare a shell spinning solution, putting 15g of polyvinyl alcohol powder in 50ml of deionized water, adding 2g of graphene, stirring and dispersing to prepare a core-shell spinning solution;

respectively placing the prepared shell layer spinning solution and the prepared core layer spinning solution in coaxial electrostatic spinning equipment for electrostatic spinning to prepare a functional filler; the electrostatic spinning conditions are as follows: the liquid feed speed was 0.85ml/h, the distance from the spinneret to the receiver was 18cm, the spinning voltage was 15kV, and the spinning temperature was 30 ℃.

According to the weight parts, 85 parts of sulphoaluminate cement, 120 parts of ordinary portland cement, 110 parts of fine sand, 2 parts of polycarboxylate water reducing agent, 1 part of organic silicon defoamer, 7 parts of vinyl acetate and ethylene copolymer rubber powder, 2 parts of magnesium oxide and 100 parts of functional filler are added into a stirrer to be uniformly stirred and mixed to prepare the cement-based self-leveling mortar.

Example 5

Dispersing 1g of nano titanium oxide in 50ml of DMF solvent, adding 10g of polyacrylonitrile powder, stirring and mixing to prepare a shell spinning solution, putting 15g of polyvinyl alcohol powder in 50ml of deionized water, adding 1g of graphene, stirring and dispersing to prepare a core-shell spinning solution;

respectively placing the prepared shell layer spinning solution and the prepared core layer spinning solution in coaxial electrostatic spinning equipment for electrostatic spinning to prepare a functional filler; the electrostatic spinning conditions are as follows: the liquid feeding speed was 0.85ml/h, the distance from the spinneret to the receiver was 18cm, the spinning voltage was 8kV, and the spinning temperature was 30 ℃.

According to the weight parts, 95 parts of sulphoaluminate cement, 150 parts of ordinary portland cement, 120 parts of fine sand, 3 parts of polycarboxylate water reducing agent, 1 part of organic silicon defoamer, 7 parts of vinyl acetate and ethylene copolymer rubber powder, 2 parts of magnesium oxide and 100 parts of functional filler are added into a stirrer to be uniformly stirred and mixed to prepare the cement-based self-leveling mortar.

Example 6

Dispersing 1g of nano titanium oxide in 50ml of DMF solvent, adding 10g of polyacrylonitrile powder, stirring and mixing to prepare a shell spinning solution, putting 15g of polyvinyl alcohol powder in 50ml of deionized water, adding 1.5g of graphene, stirring and dispersing to prepare a core-shell spinning solution;

respectively placing the prepared shell layer spinning solution and the prepared core layer spinning solution in coaxial electrostatic spinning equipment for electrostatic spinning to prepare a functional filler; the electrostatic spinning conditions are as follows: the liquid feed rate was 0.75ml/h, the distance from the spinneret to the receiver was 16cm, the spinning voltage was 11kV, and the spinning temperature was 30 ℃.

According to the weight parts, 90 parts of sulphoaluminate cement, 150 parts of ordinary portland cement, 130 parts of fine sand, 3 parts of polycarboxylate water reducing agent, 1.5 parts of organic silicon defoamer, 8 parts of vinyl acetate and ethylene copolymer rubber powder, 2 parts of magnesium oxide and 120 parts of functional filler are added into a stirrer to be stirred and mixed uniformly to prepare the cement-based self-leveling mortar.

Comparative example

The functional filler is not added to the cement-based self-leveling mortar, and other conditions are the same as those in example 6.

The performance of the prepared cement-based self-leveling mortar is tested, and the test method and the test result are as follows:

1. compressive strength and flexural strength

And testing the compressive strength and the flexural strength of the mortar according to the JC/T985-2017 standard.

2. Shrinkage rate

The 28d shrinkage was measured using the JC/T985-2017 standard.

3. Degree of fluidity

Testing the fluidity of the mortar according to JC/T985-2017 standard, wherein the specific test method comprises the following steps: a metal hollow cylinder with an inner diameter (30 +/-1) mm and a height (50 +/-1) mm is prevented from being arranged at the center of the test board, mortar is poured into the metal hollow cylinder until the metal hollow cylinder is completely filled, excess mortar is scraped, the metal hollow cylinder is vertically lifted upwards by 50mm to 100mm within 2 seconds, and the sample is kept to flow freely for 10 to 15 seconds. Two perpendicular diameters of the expanded mortar slurry were measured, and the average diameter was taken as the initial fluidity.

And standing the stirred mortar for 20min, stirring at a low speed for 15s, and testing the fluidity by adopting the method, namely testing the fluidity for 20 min.

4. Tensile bond strength

Weighing 1kg of sample according to the proportion, stirring and mixing to obtain slurry, placing a silica gel test mold on a concrete slab forming surface, pouring the prepared slurry into a forming frame, leveling, placing for 24 hours, and then demolding to obtain cement-based self-leveling test pieces with the thickness of 50mm multiplied by 5mm, wherein 10 test pieces are 1 group. And placing the test piece in a standard curing chamber for curing for 27d, removing surface floating slurry by using sand paper, bonding a drawing head on the molding surface of the test piece by using epoxy resin glue, continuously placing for 24h under the standard test condition, testing the tensile bonding strength by using a drawing instrument, and taking the arithmetic average value of the test results of 10 test pieces as the tensile bonding strength.

The test results are shown in table 1.

TABLE 1

From the test results, the self-leveling mortar prepared by the invention has effectively improved mechanical properties on the premise of not influencing the fluidity of the mortar.

Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.