Environment-friendly mortar and preparation method thereof

Abstract

According to the environment-friendly mortar and the preparation method thereof, construction waste recycled aggregate is used as a core raw material, acrylate latex powder, wood fiber, xanthan gum and graphene oxide are introduced for modification, the performance of the mortar is improved due to introduction of multiple components, and the environment-friendly mortar is green, low in carbon and wide in application range. According to the formula, waste resource utilization is achieved through the recycled aggregate, and the compressive strength of the mortar is improved to 35-40 MPa in combination with the nanometer enhancement effect of graphene oxide; the freezing resistance of a polymer network formed by the acrylate latex powder is remarkably improved, and the mass loss rate is only 2.5-2.9% after a freezing and thawing cycle at the temperature of-30 DEG C to 30 DEG C. And the construction performance is optimized through synergism of the wood fibers and the xanthan gum, and the operable time is prolonged. The method reduces the carbon emission of a unit product, realizes green production while maintaining high performance, and is suitable for the fields of building heat preservation, repair and reinforcement and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building technology, in particular to an environmentally friendly mortar and a preparation method thereof. BACKGROUND

[0002] As an indispensable basic material in the field of construction, mortar plays a crucial role in various construction projects. It is a mixture prepared by mixing cementitious materials (such as cement, lime, etc.), fine aggregates, and water in appropriate proportions, and is widely used in masonry, plastering, repairing, and other construction processes. In masonry engineering, mortar serves as the bonding agent between bricks, stones, and other building blocks, firmly connecting them together to form a stable building structure, ensuring the overall strength and stability of the building. In plastering construction, mortar can level the surface of walls, floors, and other surfaces, improving the aesthetics and comfort of the building, and also plays a certain role in waterproofing, fireproofing, and thermal insulation. With the continuous development of building technology and the increasing requirements of building, the types and performance of mortar are also constantly enriched and improved to meet the needs of different projects. For example, in order to adapt to the construction of high-rise buildings and large infrastructure, high-strength and high-durability mortar has emerged; in order to meet the requirements of green building and environmental protection, environmentally friendly and energy-saving mortar has gradually gained market favor.

[0003] Although existing mortar has been widely used in the field of construction, there are still many problems to be solved in terms of environmental protection and performance. In terms of environmental protection, traditional mortar produces a large amount of pollutants during production and use. On the one hand, the extraction and processing of raw materials often cause serious environmental pollution, such as the emission of a large amount of carbon dioxide, dust, and other pollutants during cement production, which damages the atmospheric environment. On the other hand, some mortars may contain harmful chemical substances, such as formaldehyde, benzene, and other volatile organic compounds, which can be volatilized into the air during construction, causing harm to the health of construction workers, and also having a long-term impact on indoor environmental quality. In terms of performance, the stability and durability of existing mortar need to be improved. Some mortars are prone to delamination, segregation, and other phenomena during construction, resulting in uneven quality of the mortar, affecting the construction effect and building quality. Moreover, in the long-term use process, mortar is easily affected by external environmental factors, such as temperature changes, humidity changes, chemical corrosion, etc., which may cause cracking, peeling, and other problems, shortening the service life of the building and increasing the maintenance cost. In addition, the construction performance of existing mortar needs to be optimized, such as the poor flowability of some mortars, which makes it difficult to meet the requirements of complex construction processes, affecting the construction efficiency and quality. Therefore, it is of great practical significance to develop a mortar with excellent environmental performance, stable performance, and convenient construction.

[0004] Therefore, it has important practical significance to develop an environmentally friendly mortar with excellent environmental performance, stable performance and simple preparation process. SUMMARY

[0005] The present application aims to provide an environmentally friendly mortar and a preparation method thereof to solve the problems in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions: The present application provides an environmentally friendly mortar and a preparation method thereof, which is prepared by the following steps: 40-60 parts by weight of cement substitute, 120-150 parts by weight of recycled aggregate, 0.5-1.5 parts by weight of wood fiber, 0.1-0.3 parts by weight of xanthan gum, 2-5 parts by weight of acrylate emulsion powder, 0.01-0.1 parts by weight of graphene oxide, and 40-60 parts by weight of water are put into a conical double screw mixer and stirred uniformly for 50 minutes to obtain the mortar.

[0007] As a preferred technical solution of the present application, the cement substitute comprises the following preparation steps: Step one, the following raw materials are weighed by weight parts: fly ash 50-60 parts by weight, mineral powder 30-40 parts by weight, cement 10-20 parts by weight, and water 40-60 parts by weight.

[0008] Step two, the weighed fly ash, mineral powder and cement are sequentially added to a forced mixer and stirred at a speed of 50-60 rpm for 20-35 minutes until uniformly mixed to obtain a fly ash and mineral powder mixture.

[0009] Step three, 40-60 parts by weight of water is slowly added to the fly ash and mineral powder mixture under stirring for 30 minutes to control the fluidity to 180-220 mm and the pH value to 9-11 to obtain the cement substitute.

[0010] As a preferred technical solution of the present application, the recycled aggregate comprises the following preparation steps: S1. Building waste pretreatment: collect building waste such as waste concrete and bricks, remove impurities such as wood, plastic and steel, and use a jaw crusher to crush the waste into block-shaped objects with a particle size of 50-80 mm.

[0011] S2. Primary screening and impurity removal: separate the block-shaped objects with a particle size of 50-80 mm using a 70 mm aperture vibrating screen, remove residual steel using a magnetic separator, and separate light impurities using a wind separator to obtain aggregate smaller than 70 mm.

[0012] S3. The following reinforcing agents are weighed by weight parts and mixed: 5-8 parts by weight of 30% sodium silicate solution, 1-2 parts by weight of polyvinyl alcohol, 90-95 parts by weight of water, the mixed solution is sprayed to the surface of 1000 parts by weight of aggregate, and is cured for 12-24 hours to obtain reinforced aggregate.

[0013] S4. Secondary screening and shaping: the reinforced aggregate is shaped using an impact crusher to reduce the corners, and then placed in a vibrating screen with a pore size of 20 mm for grading, to obtain recycled aggregate less than 20 mm.

[0014] As a preferred technical solution of the present application, the particle size of the graphene oxide is 100-250 nm.

[0015] As a preferred technical solution of the present application, the stirring speed in step two is 50-60 rpm.

[0016] As a preferred technical solution of the present application, the flow degree of the cement substitute in step three is controlled to be 180-220 mm, and the pH value is 9-11.

[0017] As a preferred technical solution of the present application, the particle size of the block in S1 is 50-80 mm.

[0018] Compared with the prior art, the present application has the following beneficial effects: 1. In terms of environmental performance, the mortar uses environmentally friendly raw materials, significantly reducing the emission of harmful substances from the source. Compared with traditional mortar, the volatile harmful gases in the production and use process are very small, the harm to the health of construction personnel is significantly reduced, and the pollution to the surrounding environment is also reduced, which is in line with the current concept of green building and sustainable development, and provides strong support for creating an environmentally friendly building environment.

[0019] 2. In terms of performance, the environmentally friendly mortar has excellent bonding strength and durability. It can tightly combine with various substrates to form a stable connection, effectively ensuring the safety and stability of the building structure. Moreover, the mortar has excellent crack resistance and impermeability, which can effectively prevent water penetration and crack generation, prolong the service life of the building, and reduce the maintenance cost in the later period.

[0020] 3. In terms of construction application, the preparation method is simple and easy to operate, the raw materials are easy to obtain and the cost is controllable, which is conducive to large-scale production and promotion. At the same time, the mortar has good construction operability, whether it is hand painting or mechanical spraying, it can be uniformly attached, the construction efficiency is high, and the construction period can be greatly shortened. In addition, the drying time is moderate, which will not affect the construction continuity due to too fast drying, nor will it delay the project progress due to slow drying. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present application.

[0022] Reference herein to“an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase“an embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that the embodiments described herein are merely examples from among a great variety of embodiments that can be claimed as falling within the scope of the present application.

[0023] The recycled aggregate is usually obtained by crushing, screening and other processes of waste concrete, bricks and other construction waste. From the perspective of resource recycling, it greatly reduces the accumulation of construction waste, reduces the occupation of land resources and pollution to the environment. In terms of professional mechanism, the waste concrete and bricks in construction waste have certain strength and stability. After reasonable treatment, they can be used as aggregate in mortar, which not only can replace part of natural aggregate and reduce the exploitation of natural sandstone resources, but also can improve the air permeability and sound absorption performance of mortar to some extent, so that the mortar can meet the functional requirements of building and be more in line with the development concept of green environmental protection.

[0024] Graphene oxide has a unique two-dimensional nanostructure, and its surface contains a large number of oxygen-containing functional groups such as hydroxyl and carboxyl groups. These functional groups enable graphene oxide to chemically react with active ingredients in cement substitutes, forming chemical bonds. During the mixing process, graphene oxide is uniformly dispersed in the mortar system, and its high specific surface area can effectively adsorb cement hydration products, promote the hydration reaction of cement, and accelerate the early strength development of cement stone. At the same time, the nano-sheet structure of graphene oxide can form a reinforced network structure inside the mortar, which can effectively disperse stress and prevent crack propagation when the mortar is subjected to external force, thereby improving the mechanical properties such as compressive strength and flexural strength of the mortar and enhancing the stability of the building structure.

[0025] The addition of wood fiber and xanthan gum significantly improves the workability of the mortar. Wood fiber has a high aspect ratio and good flexibility, forming a three-dimensional random support system in the mortar. During the mixing process, wood fiber can prevent the sedimentation and segregation of solid particles in the mortar, maintaining the uniformity of the mortar. At the same time, the water absorption of wood fiber can form a moisturizing film on the surface of the mortar, reducing water evaporation and prolonging the workable time of the mortar, allowing the construction personnel to have enough time to perform troweling, leveling and other operations, and improving the construction quality. Xanthan gum is a high-performance water-soluble polymer, which has unique rheological properties. In the mortar, xanthan gum can increase the viscosity of the mortar and improve its fluidity and thixotropy. When the mortar is subjected to shear force, its viscosity decreases and its fluidity increases, making it easier to operate; when the shear force disappears, the viscosity of the mortar quickly recovers, maintaining a certain shape and preventing the mortar from flowing and falling, further improving the construction efficiency.

[0026] The introduction of acrylic ester latex powder optimizes the durability of the mortar. Acrylic ester latex powder forms a continuous polymer film in the mortar, which has good flexibility and adhesion. During the hardening process of the mortar, the polymer film can fill the micro-pores and cracks in the cement stone, prevent the intrusion of water, oxygen and harmful ions, and reduce the corrosion phenomena such as corrosion of steel bars and carbonization of concrete. At the same time, the polymer film can also improve the adhesion between the mortar and the base layer, and enhance the anti-stripping ability of the mortar. In addition, the addition of acrylic ester latex powder can also improve the freeze-thaw resistance of the mortar. In cold regions, after several freeze-thaw cycles, the mortar can still maintain good integrity and strength, thereby prolonging the service life of the building and reducing the maintenance cost in the later period.

[0027] Example one:

[0028] The present application provides an environmentally friendly mortar and a preparation method thereof, which is prepared by the following steps: 50 parts by weight of cement substitute, 135 parts by weight of recycled aggregate, 1.0 parts by weight of wood fiber, 0.2 parts by weight of xanthan gum, 3.5 parts by weight of acrylic ester latex powder, 0.05 parts by weight of graphene oxide, and 50 parts by weight of water are put into a conical double screw mixer and stirred uniformly, the stirring time is 50 minutes, and the mortar is obtained.

[0029] The cement substitute comprises the following preparation steps: Step one, the following raw materials are weighed by weight parts: fly ash 55 parts by weight, mineral powder 35 parts by weight, cement 15 parts by weight, and water 50 parts by weight.

[0030] Step two, the weighed fly ash, mineral powder and cement are sequentially added to a forced mixer, and stirred at a speed of 55 rpm for 28 minutes until uniformly mixed, to obtain a fly ash-mineral powder mixture.

[0031] Step three, slowly add 50 parts by weight of water to the fly ash and mineral powder mixture under stirring, stir for 30 minutes, control the fluidity to be 200mm, and the pH value to be 10, to obtain the cement substitute.

[0032] The recycled aggregate comprises the following preparation steps: S1. Building waste pretreatment: collect building waste such as waste concrete and bricks, remove impurities such as wood, plastic and steel bars, and use a jaw crusher to crush the waste into block-shaped objects with a particle size of 65mm.

[0033] S2. Primary screening and impurity removal: use a vibrating screen with a pore size of 70mm to separate block-shaped objects with a particle size of 50-80mm, use a magnetic separator to remove residual steel bars, and use a wind separator to separate light impurities, to obtain aggregate smaller than 70mm.

[0034] S3. Weigh the following reinforcing agents by weight parts and mix them: 6.5 parts by weight of 30% sodium silicate solution, 1.5 parts by weight of polyvinyl alcohol, 92 parts by weight of water, spray the mixed solution onto the surface of 1000 parts by weight of aggregate, and let it stand for 18 hours, to obtain reinforced aggregate.

[0035] S4. Secondary screening and shaping: use an impact crusher to shape the reinforced aggregate, reduce the corners, and then grade it on a vibrating screen with a pore size of 20mm, to obtain recycled aggregate smaller than 20mm.

[0036] Example two:

[0037] The present application provides an environmentally friendly mortar and a preparation method thereof, which is prepared by the following steps: putting 40 parts by weight of cement substitute, 120 parts by weight of recycled aggregate, 0.5 parts by weight of wood fiber, 0.1 parts by weight of xanthan gum, 2 parts by weight of acrylate emulsion powder, 0.01 parts by weight of graphene oxide, and 40 parts by weight of water into a conical double-screw mixer and stirring uniformly for 50 minutes, to obtain the mortar.

[0038] The cement substitute comprises the following preparation steps: Step one, weigh the following raw materials by weight parts: fly ash 50 parts by weight, mineral powder 30 parts by weight, cement 10 parts by weight, and water 40 parts by weight.

[0039] Step two, add the weighed fly ash, mineral powder and cement into a forced mixer in turn, stir at a speed of 50 rpm for 20 minutes until they are mixed uniformly, to obtain a fly ash and mineral powder mixture.

[0040] Step three, slowly add 40 parts by weight of water to the fly ash and mineral powder mixture under stirring, stir for 30 minutes, control the fluidity to be 180mm, and the pH value to be 9, to obtain the cement substitute.

[0041] The recycled aggregate comprises the following preparation steps: S1. Building waste pretreatment: Collecting waste concrete, bricks and other building wastes, removing wood, plastic, steel bars and other impurities, and crushing the wastes into block-shaped objects with a particle size of 50-80 mm using a jaw crusher.

[0042] S2. Primary screening and impurity removal: Separating the block-shaped objects with a particle size of 50-80 mm using a vibrating screen with a pore size of 70 mm, removing residual steel bars using a magnetic separator, and separating light impurities using an air separator to obtain aggregate with a particle size of 0-70 mm.

[0043] S3. Weighing the following reinforcing agents by weight parts and mixing: 5 parts by weight of a 30% sodium silicate solution, 1 part by weight of polyvinyl alcohol, 90 parts by weight of water, spraying the mixed solution onto the surface of 1000 parts by weight of aggregate, and curing for 12 hours to obtain reinforced aggregate.

[0044] S4. Secondary screening and shaping: Shaping the reinforced aggregate using an impact crusher to reduce the corners, and then grading it using a vibrating screen with a pore size of 20 mm to obtain recycled aggregate with a particle size of 0-20 mm.

[0045] Example Three:

[0046] The application provides an environmentally friendly mortar and a preparation method thereof, which is prepared by the following steps: putting 60 parts by weight of a cement substitute, 150 parts by weight of recycled aggregate, 1.5 parts by weight of wood fiber, 0.3 parts by weight of xanthan gum, 5 parts by weight of acrylate emulsion powder, 0.1 parts by weight of graphene oxide and 60 parts by weight of water into a conical double-screw mixer, uniformly stirring for 50 minutes to obtain the mortar.

[0047] The cement substitute comprises the following preparation steps: Step one, weighing the following raw materials by weight parts: 60 parts by weight of fly ash, 40 parts by weight of mineral powder, 20 parts by weight of cement and 60 parts by weight of water.

[0048] Step two, adding the weighed fly ash, mineral powder and cement into a forced mixer in sequence, stirring at a speed of 60 rpm for 35 minutes until the mixture is uniform, to obtain a fly ash-mineral powder mixture.

[0049] Step three, slowly adding 60 parts of water to the fly ash-mineral powder mixture under stirring, stirring for 30 minutes, controlling the fluidity to be 220 mm and the pH value to be 11, to obtain the cement substitute.

[0050] The recycled aggregate comprises the following preparation steps: S1. Building waste pretreatment: Collecting waste concrete, bricks and other building wastes, removing wood, plastic, steel bars and other impurities, and crushing the wastes into block-shaped objects with a particle size of 50-80 mm using a jaw crusher.

[0051] S2. Primary screening and impurity removal: Use a 70mm aperture vibrating screen to separate the 50-80mm block material, use a magnetic separator to remove residual steel bars, and a wind separator to separate light impurities, to obtain aggregate less than 70mm.

[0052] S3. Weigh the following reinforcing agents by weight parts and mix: 8 parts by weight of 30% sodium silicate solution, 2 parts by weight of polyvinyl alcohol, 95 parts by weight of water, spray the mixed solution onto the surface of 1000 parts by weight of aggregate, and let it stand for 24 hours, to obtain reinforced aggregate.

[0053] S4. Secondary screening and shaping: Use an impact crusher to shape the reinforced aggregate and reduce the corners, then place it in a vibrating screen with an aperture of 20mm for grading, to obtain recycled aggregate less than 20mm.

[0054] Comparative Example One: The difference from Example One is that the environmentally friendly mortar prepared does not use recycled aggregate.

[0055] Comparative Example Two: The difference from Example One is that the environmentally friendly mortar prepared does not use acrylic ester latex powder.

[0056] Comparative Example Three: The difference from Example One is that the environmentally friendly mortar prepared does not use wood fiber and xanthan gum.

[0057] The compressive strength of the mortar prepared in Examples One, Two, Three and Comparative Examples One, Two, Three was tested according to the GB / T25181-2019 standard, and the frost resistance (-30°C~30°C) of the mortar prepared in Examples One, Two, Three and Comparative Examples One, Two, Three was tested according to the GB / T20473-2006 standard.

[0058] Table 1

[0059] The experimental results according to Table 1 show that the mechanical properties of the mortar prepared in Comparative Example 1 decrease obviously, and the compressive and flexural strengths are lower than those in Example 1, which indicates that the recycled aggregate plays a significant role in improving the strength and optimizing the internal structure of the mortar; in Comparative Example 2, no acrylic ester latex powder is added, and the durability of the mortar is greatly reduced, and the impermeability and freeze-thaw resistance are weakened, which shows that the polymer film formed by the acrylic ester latex powder is crucial for preventing harmful substances from entering and enhancing the resistance to environmental erosion; in Comparative Example 3, after the wood fiber and xanthan gum are removed, the working performance of the mortar becomes poor, the mortar is easy to separate during stirring, the workable time is shortened, and the construction difficulty is increased, which shows that the two components are crucial for improving the uniformity of the mortar and extending the workable time. In summary, the components in Example 1 work together to give the environment-friendly mortar good mechanical properties, durability and working performance, and none of them can be omitted.

[0060] The above merely illustrates the specific embodiments of the present application, but the technical features of the present application are not limited thereto. Any simple change, equivalent replacement or modification made on the basis of the present application to solve the basically same technical problem and realize the basically same technical effect shall be included in the protection scope of the present application.

Claims

1. A method for preparing environmentally friendly mortar, characterized in that, The mortar is prepared by the following steps: 40-60 parts by weight of cement substitute, 120-150 parts by weight of recycled aggregate, 0.5-1.5 parts by weight of wood fiber, 0.1-0.3 parts by weight of xanthan gum, 2-5 parts by weight of acrylic latex powder, 0.01-0.1 parts by weight of graphene oxide, and 40-60 parts by weight of water are added to a conical double-helix mixer and stirred evenly for 50 minutes to obtain mortar.

2. The method for preparing an environmentally friendly mortar according to claim 1, characterized in that, The cement substitute is prepared by the following method: Step 1: Weigh the following raw materials according to their weight proportions: 50-60 parts by weight of fly ash, 30-40 parts by weight of mineral powder, 10-20 parts by weight of cement, and 40-60 parts by weight of water; Step 2: Add the weighed fly ash, mineral powder, and cement to a forced mixer in sequence, and mix for 20-35 minutes until uniformly mixed to obtain a fly ash and mineral powder mixture. Step 3: While stirring, slowly add 40-60 parts by weight of water to the powdered lime and mineral powder mixture, stir for 30 minutes, and obtain the cement substitute.

3. The method for preparing an environmentally friendly mortar according to claim 1, characterized in that, The recycled aggregate is prepared by the following method: S1. Construction waste pretreatment: Collect waste concrete and brick construction waste, remove wood, plastic and steel bars, and crush the waste with a jaw crusher to obtain block material; S2. Primary screening and impurity removal: Use a 70mm vibrating screen to separate lumps, use a magnetic separator to remove residual steel bars, and use an air separator to separate light impurities to obtain aggregates smaller than 70mm. S3. Weigh and mix the following reinforcing agents according to the following weight parts: Weigh 5-8 parts by weight of sodium silicate solution with a mass solubility of 30%, 1-2 parts by weight of polyvinyl alcohol, and 90-95 parts by weight of water to obtain a mixture. Spray the mixture onto the surface of 1000 parts by weight of aggregate and let it stand for 12-24 hours to obtain reinforced aggregate. S4. Secondary screening and shaping: The reinforced aggregate is shaped using an impact crusher to reduce sharp edges, and then placed on a vibrating screen with a 20mm aperture for grading to obtain recycled aggregate smaller than 20mm.

4. The method for preparing an environmentally friendly mortar according to claim 1, characterized in that, The graphene oxide has a particle size of 100-250 nm.

5. The method for preparing an environmentally friendly mortar according to claim 2, characterized in that, The stirring speed in step two is 50-60 rpm.

6. The method for preparing an environmentally friendly mortar according to claim 2, characterized in that, The cement substitute in step three has a flowability of 180-220 mm and a pH value of 9-11.

7. The method for preparing an environmentally friendly mortar according to claim 3, characterized in that, The particle size of the blocky material in S1 is 50-80 mm.

8. An environmentally friendly mortar, characterized in that, It can be prepared using any one of methods 1-7.

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