Method for repairing sprayed mortar finishing

Abstract

The present invention relates to a method for repairing a sprayed mortar finishing. Structural layers of an outer wall, from inside to outside, are successively: a base layer, a pricking-up layer, a bonding layer, and a finishing layer. The base layer comprises a brick base layer and a concrete base layer. The pricking-up layer is made of cement mortar and mixed mortar. The repairing method comprises the following steps: (1) using a tool to remove the finishing layer and the pricking-up layer on the outer wall, then removing loose bricks on the base layer to expose a solid wall, and filling a void; (2) using the cement mortar to prick up the brick base layer, using the mixed mortar to prick up the concrete base layer, compacting and smoothing the rough surface, scoring, and watering and curing; (3) after watering and wetting bottom layer mortar that has undergone curing in step (2), scraping plain cement mortar; (4) spraying cement dough from one end of the wall surface to form cement lumps until the cement lumps cover the whole wall surface; and (5) watering and curing solidified cement lumps obtained in step (4), and completing repairing. The repairing method of the present invention can meet the special decoration requirements of the outer wall.

Description

A repair method for slurry-throwing finish Technical Field

[0001] The present invention relates to the technical field of decoration, in particular to a repair method for a slurry-throwing finish. Background Art

[0002] Throwing slurry on exterior walls was a rough-surface decorative technique popular in early 20th-century cities like Shanghai and Tianjin. Alone or in combination with other finishing materials, it created a rich, contrasting exterior finish. In the 1900s, this technique was commonly found on buildings like Western-style buildings and mansions, but was later replaced by stone-like wall finishes like water-brushed stone. Due to its age, intact examples of this technique are now rare, and this traditional craft has been lost. Investigations have revealed only sporadic discoveries of similar finishes on the exterior walls of individual historic buildings.

[0003] Therefore, the existing exterior wall slurry finishing methods cannot achieve good repair and aesthetic effects, and a new method needs to be developed.

[0004] Summary of the Invention

[0005] The technical problem to be solved by the present invention is that the existing exterior wall slurry finishing method has a general repair effect, a poor texture, and low compressive strength. In view of the defects in the existing technology, a slurry finishing repair method is provided.

[0006] In order to solve the above technical problems, the present invention provides a method for repairing a mortar-throwing finish, wherein the structural layers of the exterior wall are, from the inside to the outside, a base layer, a roughening layer, a bonding layer, and a finishing layer, wherein the base layer includes a brick base layer and a concrete base layer, and the material of the roughening layer is cement mortar and mixed mortar;

[0007] The repair method comprises the following steps:

[0008] (1) Use tools to remove the finishing layer and roughening layer of the exterior wall, then remove the loose bricks at the base to expose the solid wall and fill the voids;

[0009] (2) Use cement mortar to roughen the brick base, and use mixed mortar to roughen the concrete base, compact and flatten the rough surface, scratch it, and water it for maintenance;

[0010] (3) After watering and moistening the base ash after curing in step (2), scrape the cement mortar;

[0011] (4) Throwing the cement-containing lump from one end of the wall to form a cement lump until it covers the entire wall;

[0012] (5) The cement lumps solidified in step (4) are watered and maintained to complete the repair.

[0013] The repair method provided by the present invention has the following characteristics: the particle size of the lumps formed after repair is generally 42 to 50 mm, the density is moderate, there are no visible gaps between the lumps, there is no stacking, the lumps are evenly distributed, the sizes are consistent, each one is blooming, and the color is close to cement color.

[0014] Preferably, the tool in step (1) is a steel chisel.

[0015] In this method, a steel chisel is used to remove weathered, cracked, or peeling surface layers and roughened layers. The edges should be chiseled gently to avoid damaging the adjacent intact surface layers. Weathered and loose bricks in the base layer are further removed until a solid wall is exposed. The chiseled holes are filled and leveled with whole bricks. Any remaining plaster is removed and moistened with water.

[0016] Preferably, in the cement mortar in step (2), the mass ratio of cement to yellow sand is 1:3.

[0017] Preferably, the mass ratio of cement, lime paste and yellow sand in the mixed mortar in step (2) is 1:0.5:3.

[0018] Preferably, the curing time in step (2) is 1 to 2 days.

[0019] Preferably, the cement mortar in step (3) is prepared by mixing Portland cement and water in a mass ratio of 1:0.4.

[0020] Preferably, the cement material in step (4) comprises water, cement, yellow sand and optionally paper fiber ash.

[0021] Preferably, the cement lumps formed by the cement material have a diameter of 42 to 50 mm.

[0022] Preferably, the mass ratio of water, cement, paper reinforced ash and yellow sand is (0.5-0.7):1:(0.5-2.5):(2-3), or the mass ratio of water, cement and yellow sand is (0.5-0.7):1:(2-3).

[0023] Preferably, the mass ratio of water, cement, paper reinforced ash and yellow sand is 0.7:1:0.5:2;

[0024] Preferably, the mass ratio of water, cement, paper reinforced ash and yellow sand is 0.5:1:1:3;

[0025] Preferably, the mass ratio of water, cement and yellow sand is 0.5:1:2.5;

[0026] Preferably, the mass ratio of water, cement and yellow sand is 0.5:1:2.8.

[0027] In the present invention, the selected materials are developed and screened through the following process.

[0028] In order to restore the historical appearance of the slurry finish in its original form, sampling and analysis must first be carried out, which is divided into four steps: the first step is preliminary exploration, which involves a detailed exploration of the building's exterior finish; the second step is sampling and marking / data collection, which involves randomly taking 20-30 samples from each facade, marking and recording them, and then sending them for inspection; the third step is laboratory analysis, measurement, and data processing; and the fourth step is experimental data comparison / data analysis.

[0029] The measured data includes sphere density and sphere diameter. Density, the number of spheres within a fixed unit area, is a key factor influencing the appearance of the product. The overall requirement is to ensure a uniform and aesthetically pleasing sphere layout with an appropriate density. From all samples, 8-10 samples with relatively uniform craftsmanship and appearance were selected. Ten spheres were randomly selected from each sample for particle size analysis. Based on the comprehensive measurement and analysis results, the average particle size of the samples was 4.21 cm.

[0030] Material analysis revealed that the original mortar layer consisted of SiO2, calcium carbonate, calcium bicarbonate, hydrated calcium aluminosilicate, and a small amount of calcium bicarbonate (a carbonization product). Combined with observations of on-site samples, the base layer was determined to be paper reinforced ash, while the mortar layer was composed of water, cement, and yellow sand.

[0031] Therefore, through further research, it was determined that the material composition of the slurry is water, cement, yellow sand and optionally paper fiber ash.

[0032] Preferably, step (4) further includes a repair process after the cement lumps cover the entire wall surface;

[0033] Preferably, the repairing process is: using cement lumps to apply paint to uneven areas or areas not covered by cement lumps to cover the wall surface; and then tying the cement lumps apart.

[0034] During the slurrying process, the ash ball is kneaded into a ball and evenly slurried from one end of the wall. The application should be consistent in force and angle, and the lumps should be evenly distributed, uniform in size, and each one should form a single layer. During the repair process, unformed lumps can be pricked open with a wire brush or bamboo broom. Maintenance should be continued after final setting, at least three times daily.

[0035] The implementation of the present invention has the following beneficial effects:

[0036] The repair method provided by the present invention has the characteristics of easy operation, strong adaptability, good stability, rich texture of the finished product, and natural beauty. The standard value of the cube compressive strength reaches above 5.3MPa, which has high strength and can meet the special decoration requirements of the exterior walls of historical buildings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG1 shows a situation in which the cavity is repaired with cement mortar after the damaged surface layer and loose bricks are removed in Example 1 of the present invention;

[0038] FIG2 is a diagram of the roughening, compaction, flattening and scratching of the rough surface using cement mortar in Example 1 of the present invention;

[0039] FIG3 shows the situation of scraping cement slurry after the bottom ash is moistened in Example 1 of the present invention;

[0040] FIG4 is a diagram showing a situation in which water, cement, paper reinforced ash and yellow sand in a mass ratio of 0.7:1:0.5:2 are mixed and rolled into a ball and then thrown onto a wall by hand in Example 1 of the present invention.

[0041] FIG5 is a diagram showing a wall surface with uneven cement lumps being coated with elastic paint to cover the wall surface in Example 1 of the present invention. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] Example 1

[0044] This embodiment provides a method for repairing a slurry-sprayed surface, comprising the following steps:

[0045] (1) Use tools to remove the surface layer and rough layer of the exterior wall, then remove the bricks of the brick base to expose the wall and fill the voids;

[0046] (2) Use cement mortar to roughen the brick base, and use mixed mortar to roughen the concrete base. Compact and smooth the rough surface, scratch it, and water it for 2 days.

[0047] (3) After watering and moistening the base ash after curing in step (2), scrape the cement mortar;

[0048] (4) A lump containing cement material, which is a mixture of water, cement, paper reinforced ash, and yellow sand in a mass ratio of 0.7:1:0.5:2, is thrown from one end of the wall to form cement lumps until the entire wall is covered. The formed lumps have a diameter of 45±3 mm, a moderate density, and a granular feel.

[0049] (5) For areas that are uneven or not covered by cement lumps, use cement lumps to apply paint and cover the wall surface; then pry the cement lumps apart and sprinkle water on the cement lumps that have solidified in step (4) to complete the repair.

[0050] The specific process is detailed in Figures 1 to 5.

[0051] Figure 1 shows the use of cement mortar to repair cavities after removing the damaged surface layer and loose bricks. Figure 2 shows the use of cement mortar to roughen, compact, and roughen the surface. Figure 3 shows the use of cement mortar to apply cement slurry after moistening the base coat. Figure 4 shows the use of water, cement, paper reinforced ash, and yellow sand in a mass ratio of 0.7:1:0.5:2, which is then mixed and rolled into a ball and thrown onto the wall. The cement lumps formed by throwing the slurry are 45±3mm in diameter, have a moderate density, and have a granular feel. Figure 5 shows the application of a spray coating to cover the uneven cement lumps. The unopened cement lumps are pricked open with a tool, and finally, water is sprinkled for curing to complete the repair.

[0052] Example 2

[0053] The repair process of this embodiment is the same as that of Example 1, except that the repair materials are replaced with water, cement, paper reinforced ash and yellow sand in a mass ratio of 0.5:1:1:3.

[0054] Example 3

[0055] The repair process of this embodiment is the same as that of Example 1, except that the repair materials are replaced with water, cement, and yellow sand in a mass ratio of 0.5:1:2.5.

[0056] Example 4

[0057] The repair process of this embodiment is the same as that of Example 1, except that the repair materials are replaced with water, cement, and yellow sand in a mass ratio of 0.5:1:2.8.

[0058] Comparative Example 1

[0059] The repair process of this embodiment is the same as that of Example 1, except that the repair materials are replaced with water, cement, and yellow sand in a mass ratio of 0.5:1:2.0.

[0060] Comparative Example 2

[0061] The repair process of this embodiment is the same as that of embodiment 1, except that the repair materials are replaced with water, cement, and paper reinforced ash in a mass ratio of 0.5:1:1.

[0062] The 28-day compressive strength test results of the mortar-sanding finishing mortar provided in Examples 1-4 above, which were cured under the same conditions, met the strength and durability requirements. The experimental data are shown in Table 1 below:

[0063] Table 1

[0064] The data in the table show that the present invention uses a manual lumpy-throwing process, which is controlled by measurement, analysis, and sampling, to achieve a uniform distribution of lumps, uniform size, and individual blooms. Furthermore, the cement mortar is mixed with 20% paper reinforced ash to ensure tensile strength and adhesion, overcome the shortcomings of shrinkage cracking, and further improve the slurry throwing effect.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for repairing a slurry-throwing surface, characterized in that: The structural layers of the exterior wall are, from inside to outside, base layer, rough layer, bonding layer, and finishing layer. The base layer includes a brick base layer and a concrete base layer. The material of the rough layer is cement mortar and mixed mortar. The repair method comprises the following steps: (1) Use tools to remove the finishing layer and roughening layer of the exterior wall, then remove the loose bricks at the base to expose the solid wall and fill the voids; (2) Use cement mortar to roughen the brick base, use mixed mortar to roughen the concrete base, compact and flatten the rough surface, scratch it, and water it for maintenance; (3) After watering and moistening the bottom mortar after curing in step (2), scrape the cement mortar; (4) Throwing the lump containing cement material from one end of the wall to form a cement lump until it covers the entire wall; (5) Sprinkle water on the cement lumps after solidification in step (4) to complete the repair.

2. The repair method according to claim 1, characterized in that: The tool in step (1) is a steel chisel.

3. The repair method according to claim 1 or 2, characterized in that: In the cement mortar described in step (2), the mass ratio of cement to yellow sand is 1:

3.

4. The repair method according to any one of claims 1 to 3, characterized in that: The mass ratio of cement, lime paste and yellow sand in the mixed mortar in step (2) is 1:0.5:

3.

5. The repair method according to any one of claims 1 to 4, characterized in that: The curing time in step (2) is 1 to 2 days.

6. The repair method according to any one of claims 1 to 5, characterized in that: The cement mortar in step (3) is prepared by mixing silicate cement and water in a mass ratio of 1:0.

4.

7. The repair method according to any one of claims 1 to 6, characterized in that: The cement material in step (4) includes water, cement, yellow sand and optionally paper fiber ash; Preferably, the cement lumps formed by the cement material have a diameter of 42 to 50 mm.

8. The repair method according to claim 7, characterized in that: The mass ratio of water, cement, paper ash and yellow sand is (0.5-0.7):1:(0.5-2.5):(2-3), or the mass ratio of water, cement and yellow sand is (0.5-0.7):1:(2-3); Preferably, the mass ratio of water, cement, paper tendon ash and yellow sand is 0.7:1:0.5:2; Preferably, the mass ratio of water, cement, paper tendon ash and yellow sand is 0.5:1:1:3; Preferably, the mass ratio of water, cement and yellow sand is 0.5:1:2.5; Preferably, the mass ratio of water, cement and yellow sand is 0.5:1:2.

8.

9. The repair method according to any one of claims 1 to 8, characterized in that: Step (4) After the cement lumps cover the entire wall surface, it also includes a repair process; Preferably, the repairing process is: using cement lumps to apply on uneven areas or areas not covered by cement lumps to cover the wall surface; and then ripping the cement lumps apart.

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