Color-adjustable anti-efflorescence high-performance cement-based pointing agent for ancient building restoration and preparation method thereof

Abstract

The application discloses a color-adjustable alkali bleeding resistant high-performance cement-based pointing agent for ancient building repair and a preparation method thereof, and belongs to the technical field of building materials. The pointing agent is composed of cement 60-150 parts, sand 800-1000 parts, water reducing agent 0.1-0.6 parts, cellulose ether 0.1-0.5 parts, waterproof agent 2-6 parts, thickening agent 0.1-10 parts, inorganic pigment 0.1-5 parts, glue powder 2-4 parts and water, and the water-material ratio is 0.2-0.24. The pointing agent meets the requirements of GB / T 41081-2021 'Ceramic Tile Filling Agent' cement-based CG1 level, meets the pointing and masonry performance requirements of GB / T 25181-2019 'Ready-mixed Mortar', and is suitable for ancient building fair-faced brick wall repair, antique masonry pointing and traditional style building protection and the like, and solves the problems of easy alkali bleeding, unadjustable color, difficult to balance strength and alkali bleeding resistance and insufficient durability of the existing ancient building pointing agent.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a color-adjustable, efflorescence-resistant, high-performance cement-based grout for the restoration of ancient buildings and its preparation method. Background Technology

[0002] For grouting exposed brick walls in historical buildings, the grouting material must match the color of the original masonry, adhere firmly, and not effloresce, crack, or stain the brick surface over a long period. Cement-based grouting agents, with cement, mineral admixtures, aggregates, and functional additives as the main components and supplemented with inorganic pigments, have good compatibility with sintered bricks and old blue bricks. They can be applied using traditional techniques and are an ideal material for the restoration of ancient buildings. However, existing grouts generally have the following problems: (1) Severe efflorescence: Cement hydration produces a large amount of Ca(OH)2, which migrates to the surface to form white precipitates, polluting the surface of the clear bricks and damaging the historical appearance; (2) Fixed and unadjustable color: It is difficult to match the traditional colors of old bricks such as gray, bluish-gray, and light brown, and the repair marks are obvious; (3) It is difficult to balance strength and efflorescence resistance: High-strength grouts use a large amount of cement, and the risk of efflorescence is high; low-alkali formulas are prone to insufficient strength and shrinkage cracking; (4) Insufficient durability: Under long-term rainwater erosion, dry and wet cycles, and freeze-thaw action, it is easy to powder, fall off, and leach alkali; (5) Efflorescence is divided into primary efflorescence and secondary efflorescence: Primary efflorescence is formed by the migration and precipitation of Ca(OH)2 from cement hydration; Secondary efflorescence is formed by the intrusion of external water and the dissolution of soluble salts, which migrate to the surface with the evaporation of water and are deposited, which is the most prominent disease of ancient building grouting. Currently, most commercially available grouts meet basic anti-efflorescence requirements, but their anti-efflorescence stability is poor under long-term wet and dry cycles, and they cannot meet the stringent usage requirements of historical buildings. Summary of the Invention

[0003] To overcome the above-mentioned shortcomings of the prior art, the main objective of this invention is to provide a color-adjustable, high-performance cement-based grout for the restoration of ancient buildings that resists efflorescence, thereby solving the problems of easy efflorescence, unadjustable color, difficulty in balancing strength and efflorescence resistance, and insufficient durability of existing ancient building grouts.

[0004] Another objective of this invention is to provide a method for preparing the aforementioned anti-efficiency high-performance cement-based grout for the restoration of ancient buildings, which is simple in process and can be mass-produced.

[0005] Another objective of this invention is to provide the application of the color-adjustable, efflorescence-resistant, high-performance cement-based grout for the restoration of ancient buildings in the grouting repair and style preservation of exposed brick walls and antique-style masonry in historical buildings.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a color-adjustable, high-performance cement-based grout for the restoration of ancient buildings, which is composed of the following components in the indicated weight ratios: 60-150 parts cement, 800-1000 parts sand, 0.1-0.6 parts water-reducing agent, 0.1-0.5 parts cellulose ether, 2-6 parts waterproofing agent, 0.1-10 parts thickener, 0.1-5 parts inorganic pigment, 2-4 parts adhesive powder, and water, wherein the water-to-material ratio is 0.20-0.24.

[0008] Preferably, the cement is white silicate cement.

[0009] Preferably, the sand is white quartz sand or clean river sand with a particle size of 80-120 mesh.

[0010] Preferably, the water-reducing agent is a melamine water-reducing agent.

[0011] Preferably, the cellulose ether is hydroxypropyl methylcellulose ether with a viscosity of 25,000-45,000 mPa·s.

[0012] Preferably, the waterproofing agent is organosilicon powder.

[0013] Preferably, the thickener is sodium alginate.

[0014] Preferably, the pigment is an inorganic mineral pigment.

[0015] Preferably, the adhesive powder is EVA adhesive powder.

[0016] A second aspect of the present invention provides a method for preparing the color-adjustable, anti-efflorescence high-performance cement-based grout for the restoration of ancient buildings, wherein the water content is 20%-24% of the total weight of the dry materials, comprising the following steps:

[0017] S1. Accurately weigh various raw materials such as cement, sand, water-reducing agent, cellulose ether, waterproofing agent, thickener, inorganic pigment and adhesive powder according to the weight ratio;

[0018] S2. Mix the raw materials from step S1 evenly to make dry material;

[0019] S3. Pour water into the dry material and stir for at least 180 seconds until the slurry is uniform.

[0020] A third aspect of the present invention provides the application of the color-adjustable, efflorescence-resistant, high-performance cement-based grout for the restoration of ancient buildings in the grouting repair and style protection of exposed brick walls and antique-style masonry in historical buildings.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] I. This invention reduces alkali source formation and lowers the risk of primary efflorescence by using a low cement content and compounding with mineral admixtures; it also reduces the risk of secondary efflorescence by using an organosilicon waterproofing agent to block external moisture intrusion and internal salt migration; and it achieves precise and adjustable grout color by combining a white cementitious system with inorganic pigments to match the appearance of exposed brickwork. Despite low cement content, it still meets the requirements of high strength, low shrinkage, high water retention, and easy construction, making it particularly suitable for grouting exposed brick walls in historical buildings.

[0023] II. The product of this invention can meet the requirements of GB / T 41081-2021 "Ceramic Tile Grout" Cement-based CG1 grade, and also meets the grouting and masonry performance requirements of GB / T 25181-2019 "Premixed Mortar". It is suitable for engineering occasions such as the repair of fair-faced brick walls of ancient buildings, grouting of antique masonry, and protection of traditional style buildings.

[0024] III. The color-adjustable high-performance cement-based grout for the restoration of ancient buildings has the following technical advantages: (1) Low carbon and low alkali: low cement consumption and significantly reduced carbon emissions; (2) Super strong anti-efficiency: no visible efficiency marks or powdering after 30 anti-efficiency cycles, far exceeding conventional standard requirements; (3) Color-adjustable: based on a white cementitious system, inorganic pigments are used for color adjustment, which can accurately match the traditional color tone of fair-faced bricks; (4) High performance: 28d compressive strength ≥15MPa, meeting the grouting strength requirements of ancient buildings; (5) Construction compatibility: consistency 70-80mm, high water retention, no cracking, no dripping, compatible with traditional grouting techniques; (6) High durability: stain resistant, weather resistant, frost resistant, and does not powder, fall off, or contaminate the brick surface after long-term use. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The following embodiment proposes a color-adjustable, high-performance cement-based grout for the restoration of ancient buildings, which is composed of the following components in the indicated weight ratios: 60-150 parts cement, 800-1000 parts sand, 0.1-0.6 parts water-reducing agent, 0.1-0.5 parts cellulose ether, 2-6 parts waterproofing agent, 0.1-10 parts thickener, 0.1-5 parts inorganic pigment, 2-4 parts adhesive powder, and water, with a water-to-material ratio of 0.2-0.24.

[0027] In some embodiments, the cement is white silicate cement.

[0028] In some embodiments, the sand is white quartz sand or clean river sand with a particle size of 80-120 mesh.

[0029] In some embodiments, the water-reducing agent is a melamine water-reducing agent.

[0030] In some embodiments, the cellulose ether is hydroxypropyl methylcellulose ether with a viscosity of 25,000-45,000 mPa·s.

[0031] In some embodiments, the waterproofing agent is silicone powder.

[0032] In some embodiments, the thickener is sodium alginate.

[0033] In some embodiments, the pigment is an inorganic mineral pigment.

[0034] In some embodiments, the adhesive powder is EVA adhesive powder.

[0035] The following embodiments present a method for preparing the above-mentioned color-adjustable anti-efflorescence high-performance cement-based grout for the restoration of ancient buildings, wherein the water content is 20%-24% of the total dry material weight, and includes the following steps:

[0036] S1. Accurately weigh various raw materials such as cement, sand, water-reducing agent, cellulose ether, waterproofing agent, thickener, inorganic pigment and adhesive powder according to the weight ratio;

[0037] S2. Mix the raw materials from step S1 evenly to make dry material;

[0038] S3. Pour water into the dry material and stir for at least 180 seconds until the slurry is uniform.

[0039] Example 1

[0040] This embodiment proposes a basic gray-white grouting agent, the raw material composition by weight is as follows: 100 parts white silicate cement, 900 parts sand, 0.2 parts cellulose ether, 0.5 parts water-reducing agent, 4 parts organosilicon powder, 4 parts sodium alginate, 2 parts adhesive powder, and 200 parts water.

[0041] Example 2

[0042] This embodiment proposes a high-strength bluish-gray grout, the raw material composition by weight is: 60 parts white silicate cement, 940 parts sand, 0.3 parts cellulose ether, 0.5 parts water-reducing agent, 4 parts organosilicon powder, 4 parts adhesive powder, and 200 parts water.

[0043] Example 3

[0044] This embodiment proposes a color-adjustable antique-style grout, the raw material composition by weight is as follows: 120 parts white silicate cement, 880 parts sand, 0.2 parts cellulose ether, 0.5 parts water-reducing agent, 4 parts organosilicon powder, 2 parts inorganic pigment, 2 parts adhesive powder, and 210 parts water.

[0045] The performance of the grout prepared in Examples 1-3 above was tested, and the results are shown in Table 1.

[0046] Table 1: Performance Test Results of Grout

[0047]

[0048] As shown in Table 1, the color-adjustable antique-style grout prepared in Example 3 has the characteristics of low carbon and low alkali, super strong resistance to efflorescence, and adjustable color. Its 28-day compressive strength is ≥15MPa, which meets the grouting strength requirements of ancient buildings. It has high water retention, does not crack or drip, is resistant to stains, weathering, and freezing. It does not powder, fall off, or contaminate the brick surface after long-term use. It is suitable for the repair of fair-faced brick walls of ancient buildings, grouting of antique masonry, and protection projects of traditional style buildings.

[0049] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A color-adjustable, efflorescence-resistant, high-performance cement-based grout for the restoration of ancient buildings, characterized in that... It consists of the following components in the indicated weight ratios: 60-150 parts cement, 800-1000 parts sand, 0.1-0.6 parts water-reducing agent, 0.1-0.5 parts cellulose ether, 2-6 parts waterproofing agent, 0.1-10 parts thickener, 0.1-5 parts inorganic pigment, 2-4 parts adhesive powder, and water, with a water-to-material ratio of 0.2-0.

24.

2. The color-adjustable, efflorescence-resistant, high-performance cement-based grout for ancient building restoration according to claim 1, characterized in that, The cement is white silicate cement.

3. The color-adjustable, efflorescence-resistant, high-performance cement-based grout for ancient building restoration according to claim 1, characterized in that, The sand is white quartz sand or clean river sand with a particle size of 80-120 mesh.

4. The color-adjustable, efflorescence-resistant, high-performance cement-based grout for the restoration of ancient buildings according to claim 1, characterized in that, The water-reducing agent is a melamine water-reducing agent.

5. The color-adjustable, efflorescence-resistant, high-performance cement-based grout for the restoration of ancient buildings according to claim 1, characterized in that, The cellulose ether is hydroxypropyl methylcellulose ether with a viscosity of 25,000-45,000 mPa·s.

6. The color-adjustable, efflorescence-resistant, high-performance cement-based grout for the restoration of ancient buildings according to claim 1, characterized in that, The waterproofing agent is silicone powder.

7. The color-adjustable, efflorescence-resistant, high-performance cement-based grout for the restoration of ancient buildings according to claim 1, characterized in that, The thickener is sodium alginate.

8. The color-adjustable, efflorescence-resistant, high-performance cement-based grout for the restoration of ancient buildings according to claim 1, characterized in that, The pigment is an inorganic mineral pigment, and the adhesive powder is EVA adhesive powder.

9. A method for preparing the color-adjustable, efflorescence-resistant, high-performance cement-based grout for the restoration of ancient buildings as described in any one of claims 1 to 8, characterized in that, The amount of water added should be 20%-24% of the total weight of the dry materials, and the process includes the following steps: S1. Accurately weigh various raw materials such as cement, sand, water-reducing agent, cellulose ether, waterproofing agent, thickener, inorganic pigment and adhesive powder according to the weight ratio; S2. Mix the raw materials from step S1 evenly to make dry material; S3. Pour water into the dry material and stir for at least 180 seconds until the slurry is uniform.

10. The application of the color-adjustable, efflorescence-resistant, high-performance cement-based grouting agent for the restoration of ancient buildings as described in any one of claims 1 to 8 in the grouting repair and style protection of exposed brick walls and antique masonry in historical buildings.

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