Masonry hole rapid layering repair composite material and method based on solid waste

Abstract

The invention discloses a masonry hole rapid layering repairing composite material and method based on solid waste, and belongs to the technical field of building material repairing and solid waste recycling. The composite material is composed of 10-30 parts of alpha-ethyl cyanoacrylate (ECA) and 1-30 parts of alkaline solid waste powder, such as combustion ash powder CAP and alkaline residue powder SRP. The repairing method comprises the steps that after holes are cleaned, a layering process is adopted, an alkaline powder layer with the thickness of 2-3 mm is firstly filled, then ECA is poured to infiltrate the holes and initiate second-level curing, and operation is cycled till the holes are filled. According to the invention, high alkalinity of industrial solid waste is utilized to initiate rapid polymerization of ECA, and the solid waste is used as a reinforcing filler; by optimizing the layering thickness, the technical problems of incomplete internal curing, concentrated heat release, generation of pores and layering and the like during large-volume repair are effectively solved, and ultra-rapid forming, high early strength, excellent interface bonding performance and overall compactness of the prosthesis are realized. The method is simple in process, green, economical, high in field adaptability and particularly suitable for rapid in-situ repair of cement-based materials and red brick masonry.

Description

Technical Field

[0001] This invention relates to the interdisciplinary field of building material repair and solid waste resource utilization, and in particular to a material and method for rapid, efficient, and high-strength in-situ repair of surface holes and defects in building masonry (such as cement-based materials, red bricks, etc.) by using industrial alkaline solid waste and ethyl α-cyanoacrylate composite through a layered injection process. Background Technology

[0002] Masonry structures, especially concrete and brick structures, are prone to localized damage such as voids and spalling during long-term service due to factors such as load, environmental erosion, and freeze-thaw cycles. This damage not only affects structural safety and durability but also the building's aesthetics. For emergency repairs and the preservation of historical buildings, there is an urgent need for an in-situ repair technology that can quickly solidify, immediately bear load, and is easy to implement.

[0003] Ethyl α-cyanoacrylate (ECA), an instant adhesive (commonly known as 502 glue), is renowned for its rapid room-temperature anionic polymerization initiated by trace amounts of moisture, resulting in extremely fast curing and high bond strength. However, its direct use in building structure repair has significant drawbacks: 1) Pure ECA, after curing, exhibits a linear polymer structure, leading to high brittleness, poor impact resistance, and poor toughness; 2) It has limited penetration and filling capabilities into porous substrates, easily forming weak interfacial zones; 3) Its bulk strength is insufficient to withstand structural loads; 4) When used in large quantities, the concentrated exothermic polymerization may lead to thermal degradation or even the generation of large amounts of irritating fumes.

[0004] Meanwhile, many industrial processes, such as ammonia-soda alkali production and biomass combustion, generate large amounts of alkaline solid waste (such as solid reactive alkali (SRP) residue and carbonaceous alkali (CAP) ash). These wastes are rich in alkaline components such as CaO and CaCO3, have high pH values, and their storage occupies land and poses environmental risks. If they can be utilized at a high value, it can alleviate environmental pressure and create economic benefits. Theoretically, such alkaline substances can be used as initiators for ECA polymerization, but currently there are no mature technologies or reports on using solid waste systems as initiators and reinforcing fillers for ECA and applying them to building structure repair.

[0005] Therefore, developing a composite material and its supporting construction method that can synergistically utilize industrial solid waste, overcome the defects of pure ECA materials, and achieve high-strength repair of building masonry holes at low or even normal temperatures within seconds has significant technological advancements, environmental benefits, and engineering application value. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a composite material and method for in-situ repair of holes in building masonry, characterized by extremely fast curing rate, high early strength, excellent interfacial bonding performance, simple construction process, and environmental friendliness. This material utilizes industrial alkaline solid waste as a key component, achieving the green goal of "treating waste with waste."

[0007] Another objective of this invention is to provide a method for applying the above-mentioned composite material, particularly through an innovative "layered infusion" process, to solve the problems of incomplete internal curing, bubble formation, and delamination of ECA caused by exothermic polymerization and oxygen inhibition during large-volume repairs, thereby ensuring that the repair body is dense, homogeneous, and has excellent mechanical properties.

[0008] To achieve the above objectives, the present invention adopts the following specific technical solution:

[0009] I. Composite Materials

[0010] A composite material for rapid curing and in-situ repair of holes in building masonry, which is made from the following raw materials by mass parts through a contact-initiated polymerization reaction:

[0011] Ethyl α-cyanoacrylate: 10-30 parts;

[0012] Alkaline solid waste powder: 1 to 30 parts.

[0013] The alkaline solid waste powder is at least one of combustion ash (CAP) and alkali slag powder (SRP). Preferably, the median particle size D of the combustion ash is... 50 ≤ 20μm; the particle size of the alkaline residue powder is ≤ 0.5mm.

[0014] Furthermore, the pH value of the alkaline solid waste powder is preferably between 8.00 and 13.00. In addition to CAP and SRP, it may also be selected from one or more mixtures of granulated blast furnace slag, cement clinker, gypsum powder, clay, carbide slag, steel slag, lime powder, and red mud.

[0015] Furthermore, when using both combustion ash powder and alkaline slag powder simultaneously, the preferred mass ratio is 2:5 to 1:10. This ratio range provides a good balance between initiation activity, filling effect, and cost.

[0016] II. Repair Methods

[0017] A method for in-situ repair of holes in building masonry using the aforementioned composite material, wherein the masonry includes, but is not limited to, hardened cement-based materials (concrete, mortar) and red bricks. The method includes the following steps:

[0018] 1. Surface preparation: Thoroughly clean loose material, dust, and standing water from the holes or defective areas to be repaired. For porous substrates such as red brick, wipe the hole walls with a slightly damp cloth to provide a small amount of moisture and remove loose dust, but ensure there is no standing water.

[0019] 2. Layered filling and grouting:

[0020] a. Filling with powder: Fill the treated holes with a layer of the alkaline solid waste powder, and control the thickness of each layer of powder to be between 2 and 3 mm using a scraper or other tools. This thickness is a key optimization parameter of this invention.

[0021] b. Liquid injection: Ethyl α-cyanoacrylate is uniformly added dropwise or poured onto the powder layer to ensure that the liquid fully wets the powder.

[0022] c. Wait for curing: Ethyl α-cyanoacrylate rapidly initiates a polymerization reaction upon contact with alkaline powder, and curing into a hard solid is usually observed within 10-20 seconds. Wait for the reaction of this layer to be basically completed.

[0023] 3. Cycle and Completion: Repeat steps 2a and 2b to perform the next layer of powder filling and monomer infusion. Continue this cycle until the pores are completely filled with the repair material, ultimately forming a robust, defect-free, hardened composite material repair.

[0024] 4. Surface treatment (optional): After the repair has fully cured, if there are slight bumps on the surface, you can use fine sandpaper to sand it to make it blend smoothly with the surrounding original substrate surface.

[0025] The significant beneficial effects of this invention are:

[0026] 1. Ultra-fast curing and high strength: Utilizing the high alkalinity and microporous structure of industrial solid waste, ECA polymerization is efficiently initiated in seconds, resulting in composite materials with high early strength and the ability to quickly restore structural load-bearing capacity. The compressive strength recovery rate of the repaired specimens can exceed 100%.

[0027] 2. Excellent interfacial bonding performance: The polymer formed in situ forms a tight mechanical interlock and possible chemical bond with solid waste powder and masonry substrate (cement hydration products or bricks). The failure mode is often matrix failure rather than interfacial debonding.

[0028] 3. Revolutionary Restoration Quality: The "layered infusion" process (controlling the thickness of each layer to 2-3 mm) is one of the core innovations of this invention. It ensures that: a) each layer of ECA monomer can fully impregnate the powder and react completely, avoiding incomplete internal curing, porosity, and delamination caused by excessive thickness in a single infusion; b) the exothermic reaction of each layer is mild and controllable, avoiding concentrated heat release that leads to material thermal degradation and violent smoke, thus improving construction safety and final material performance; c) the layers are tightly bonded, making the macroscopic restoration a complete whole.

[0029] 4. Green and environmentally friendly with low cost: It makes extensive use of industrial solid waste as functional filler, realizing the high-value resource utilization of waste, reducing material costs, and conforming to the concept of green and sustainable development.

[0030] 5. Extremely simple construction and strong on-site adaptability: The material system is simple, and the construction only requires two steps of "filling powder-injection". No complicated equipment or electricity is required, making it particularly suitable for on-site rapid construction, emergency repairs, and the protection of historical buildings.

[0031] 6. Wide range of applications: Successfully applied to various common masonry materials such as cement-based materials and red bricks, expanding the applicable scenarios of the technology. Attached Figure Description

[0032] Figure 1 This is a schematic diagram illustrating the application of the composite material of the present invention in the repair of holes in cement-based and red brick masonry.

[0033] Figure 2 This refers to the temperature change during the repair process of the composite repair materials in Examples 1 and 2 of this invention.

[0034] Figure 3 These are SEM images of the composite repair materials from Examples 1 and 2 of this invention.

[0035] Figure 4 This is a diagram showing the compressive strength results of the specimen after the composite material of the present invention repaired the hole in the cement-based material.

[0036] Figure 5 This is a diagram showing the interface bonding effect of the repair body after the composite material of the present invention repairs the pores in the cement-based material.

[0037] Figure 6 These are images illustrating the difference in repair effects between delamination and non-delamination when using the composite material of this invention to repair pores in cement-based materials.

[0038] Figure 7 This is a schematic diagram of the rapid layered repair method for masonry holes based on solid waste according to the present invention. Detailed Implementation

[0039] The following is in conjunction with the appendix Figure 1-7The present invention will be further described in detail with reference to the embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0040] Example 1: In-situ repair of holes in cement mortar test blocks

[0041] Repair objects and materials:

[0042] Repair object: Cement-based test block (30mm × 30mm × 30mm) cured for 28 days, with a cylindrical hole of 6mm in diameter and 12mm in depth drilled in the center of one surface.

[0043] Raw materials: Ethyl α-cyanoacrylate (ECA) liquid; combustion ash powder (CAP, D) 50 ≈13μm); Alkali residue powder (SRP, D 50 ≈300μm).

[0044] Repair operation:

[0045] 1. Clean the hole: Use compressed air and an air blower to thoroughly remove dust from the hole.

[0046] 2. Powder premixing: Mix the dried CAP and SRP powder evenly at a mass ratio of 1:5.

[0047] 3. Layered repair:

[0048] a. Use a small tool to fill the bottom of the hole with a layer of mixed alkaline powder, controlling the thickness to be about 2.5 mm.

[0049] b. Use a dropper to draw up the ECA monomer and add it evenly to the powder layer until the powder is fully wetted.

[0050] c. The system was observed to solidify into a hard white solid within approximately 15 seconds.

[0051] d. Repeat step ac, filling and grouting layer by layer until the holes are completely filled. Approximately 6 layers in total.

[0052] 4. Surface treatment: After the restoration has fully cured (about 2 minutes later), gently sand the slightly raised surface with fine sandpaper to make it flush with the surface of the test block.

[0053] Performance verification:

[0054] Curing speed: Each layer cures in less than 15 seconds.

[0055] Mechanical properties: The compressive strength of the repaired specimen was tested, and its strength recovery rate (strength after repair / strength of intact specimen) exceeded 100%.

[0056] Failure mode: In the stress test, failure mostly occurred in the cement mortar matrix itself, rather than inside the repair or at the repair-matrix interface, proving that the repair has high strength and excellent interfacial bonding.

[0057] Example 2: In-situ repair of holes on the surface of red brick walls

[0058] Repair objects and materials:

[0059] Object to be repaired: A bare red brick wall with a roughly conical hole (approximately 25mm in diameter and 15mm in depth) formed by weathering and peeling on the surface.

[0060] Raw materials: Ethyl α-cyanoacrylate (ECA) liquid; Alkali residue powder (SRP, particle size ≤0.5mm).

[0061] Repair operation:

[0062] 1. Hole Cleaning and Wetting: Use a wire brush to remove all loose brick chips and dust from the hole. Wipe the hole walls with a slightly damp, soft cloth to remove loose dust and provide a small amount of moisture to promote initial ECA anchoring, ensuring there is no standing water.

[0063] 2. Layered repair:

[0064] a. Fill the hole with a layer of SRP powder, controlling the thickness to about 2~3mm.

[0065] b. Draw ECA liquid into a syringe and slowly and evenly inject it into the powder layer. Immediately observe the reaction as exothermic and releasing a small amount of white smoke. After about 10-12 seconds, it solidifies into a grayish-white hard solid.

[0066] c. Repeat steps a and b until the hole is completely filled.

[0067] 3. Surface treatment: After curing, gently sand the repaired surface with fine sandpaper to make it transition smoothly with the brick surface.

[0068] Repair results:

[0069] Immediacy: Each repair layer can be supported within 20 seconds, achieving "instant repair".

[0070] Adhesion performance: Tapping the repaired area produces a solid sound with no hollow areas. Scraping the interface with a blade does not remove the repair material, indicating high interface adhesion strength.

[0071] Appearance and durability: The color of the restoration is close to that of the red brick, resulting in good harmony. No cracking, peeling, or powdering was observed after short-term exposure to sun and rain.

[0072] In summary, this invention has successfully developed a rapid repair system based on industrial solid waste and ECA, and through an innovative layered injection process, it has effectively solved the technical challenges of rapid repair of large volumes, providing an efficient, economical, and green innovative solution for building maintenance, reinforcement, and the protection of historical relics.

Claims

1. A composite material for rapid layered repair of masonry voids based on solid waste, characterized in that, It is produced by contact-initiated polymerization of raw materials comprising the following parts by weight: 10-30 parts of ethyl α-cyanoacrylate; 1-30 parts of alkaline solid waste powder; The alkaline solid waste powder is at least one of combustion ash powder (CAP) and alkali slag powder (SRP).

2. The composite material according to claim 1, characterized in that, The median particle size D of the combustion ash powder 50 ≤ 20μm; and / or, the particle size of the alkaline residue powder is ≤ 0.5mm.

3. The composite material according to claim 1, characterized in that, The pH value of the alkaline solid waste powder is between 8.00 and 13.

00.

4. The composite material according to claim 1 or 3, characterized in that, The alkaline solid waste powder also includes one or more of the following: granulated blast furnace slag, cement clinker, gypsum powder, clay, carbide slag, steel slag, lime powder, and red mud.

5. The composite material according to claim 1, characterized in that, When the alkaline solid waste powder contains both combustion ash powder (CAP) and alkali slag powder (SRP), the mass ratio of the combustion ash powder to the alkali slag powder is 2:5 to 1:

10.

6. A method for in-situ repair of voids in building masonry using the composite material as described in any one of claims 1-5, characterized in that, The building masonry includes cement-based materials or red bricks, and the method includes the following steps: (1) Surface treatment: Clean the holes to be repaired, ensuring there are no loose materials or water accumulation; (2) Layered filling and grouting: a. Fill the hole with a layer of the alkaline solid waste powder, controlling the thickness of a single layer of powder to be 2-3 mm; b. Ethyl α-cyanoacrylate is uniformly poured onto the powder layer to ensure it is fully impregnated; c. After the layer has cured, repeat steps a and b to perform powder filling and ECA injection for the next layer; (3) Cycle and completion: Repeat step (2) until the hole is completely filled with the repair material to form an integral repair body.

7. The method according to claim 6, characterized in that, In step (2)b, the ethyl α-cyanoacrylate is polymerized and cured within 20 seconds after contacting the alkaline solid waste powder.

8. The method according to claim 6, characterized in that, For the repair of red brick masonry, in step (1), after cleaning, wipe the hole wall with a slightly damp cloth to provide a small amount of moisture and remove loose dust, and ensure that there is no standing water.

9. The method according to claim 6, characterized in that, After the restoration is fully filled, the process also includes a step of polishing the surface of the restoration to make it flush with the surface of the surrounding substrate.

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