Mortar replacement method for historical building wall

Abstract

The invention relates to a mortar replacement method for a historical building wall, and aims to improve the stability and durability of the wall while protecting the integrity and historical value of a building structure. The method comprises the steps of construction preparation, material preparation, stripping of an existing painting layer on the inner side of a wall, brickwork joint cleaning, old brickwork joint surface treatment, new mortar preparation, new mortar pouring, manual joint pressing, secondary joint pouring through a joint pressing machine in cooperation with manual work and the like. Particularly, according to the method, the crack digging depth is accurately controlled, and customized tools are used, so that damage to the wall is reduced; the bonding strength between the new mortar and the old mortar is enhanced by spraying water to wet a wall body and spraying an adhesion agent; the best material proportion is determined through laboratory testing, and the mortar quality is ensured; and the construction efficiency is improved by utilizing modern construction equipment. In addition, according to the method, the cut depth is accurately calculated through a main tensile stress theory and a contact area formula, the shear resistance of the wall is ensured, the service life is prolonged, and the style and appearance of a historical building are maintained.

Description

Technical Field

[0001] The invention relates to the technical field of ancient building repair, and in particular to a mortar replacement method for a wall of a historical building. Background Art

[0002] In the field of historical building protection and restoration, the wall is an important part of the building structure, and its stability and durability are directly related to the safety and service life of the entire building. Traditional methods of repairing the walls of historical buildings often have many shortcomings, such as low construction efficiency, significant damage to the original structure, and insufficient stability of the repaired walls. Especially in the key link of mortar replacement, how to effectively replace the weathered or damaged old mortar while maintaining the integrity and historical style of the wall structure is a major challenge in the restoration of historical buildings.

[0003] Traditional mortar replacement methods usually adopt full replacement or partial replacement, which often require the removal of a large amount of original wall materials. Not only is the construction difficult and costly, but it also causes irreversible damage to the original style and structural integrity of historical buildings. In addition, traditional methods also have obvious limitations in terms of bonding between new and old mortars and improving the shear resistance of walls, and cannot meet the requirements of modern building protection.

[0004] Although there have been some improvement measures for the above problems, such as using specific interface agents to enhance the bonding between new and old mortars, or using specific construction equipment to improve construction efficiency, these measures are often scattered and lack systematic solutions. Therefore, a new method of replacing mortar in the walls of historical buildings is needed, which can protect the original appearance and structural integrity of historical buildings while improving the stability and durability of the walls, extending the service life of the buildings, and ensuring the efficiency and safety of construction.

[0005] The present invention is based on the above background and aims to provide a method that can systematically solve the problem of mortar replacement of walls of historical buildings. By precisely controlling the depth of the cracks, optimizing the material ratio, enhancing the adhesion between new and old mortars, and improving construction efficiency, the present invention can achieve effective protection and restoration of the walls of historical buildings. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes a mortar replacement method for the wall of a historical building, which is implemented by the following technical solutions:

[0007] A mortar replacement method for a historical building wall comprises the following steps:

[0008] Step 1: Construction preparation: Construction equipment entry test, the equipment at least includes electric caulking gun, manual seam cutting custom tools, spray gun, seam cleaning brush, seam blowing gun, seam pressing knife, mixer, seam pressing machine, copper wire;

[0009] Step 2: Material preparation: The materials include cement, fine sand, interface agent and additives;

[0010] Step 3: Stripping the existing plaster layer on the inner side of the wall: Use a customized manual grooving tool to grooving the existing plaster layer on the inner side of the wall. The grooving depth is: the grooving depth of the upper brick is h, and the grooving depth of the lower brick is H, where: H>h;

[0011] Step 4: Clean the brick joints: Use a joint cleaning brush to clean the residual mortar in the brick joints, and then use a joint blowing gun to clean the residual mortar particles and dust in the brick joints;

[0012] Step 5: Treatment of old brick joints: Wet the wall with water and spray the interface agent on the brick joints with a spray gun;

[0013] Step 6, preparing new mortar: adding cement, fine sand, additives and water into a mixer in proportion to prepare new mortar;

[0014] Step 7: Pour new mortar: Use an electric grouting gun to grout the brick joints;

[0015] Step 8: Use a seam pressing knife to manually press the seam once;

[0016] Step 9. Use a seam pressing machine in combination with manual secondary caulking and insert copper wire.

[0017] Furthermore, the preparation of the new mortar in step six further comprises the following steps:

[0018] a) Add cement, fine sand, additives and water into the mixer in the optimum proportions determined by laboratory tests;

[0019] b) Stir until the mortar is uniform in color. The stirring time should be controlled within 3 to 5 minutes to ensure sufficient mixing.

[0020] Furthermore, the treatment of the old brick joint surface in step 5 further includes the following steps:

[0021] a) Spray water on the wall to moisten it and ensure that the humidity of the wall is suitable for the adhesion of the interface agent;

[0022] b) Use a spray gun to spray the interface agent, ensuring that the interface agent evenly covers the brick joints to enhance the bonding strength between the new and old mortars.

[0023] Furthermore, the preparation of the new mortar in step 6 also includes laboratory testing including:

[0024] a) consistency test to determine the fluidity of the mortar;

[0025] b) Apparent density test to determine the mass per unit volume of mortar;

[0026] c) Separation test to assess the uniformity of the mortar;

[0027] d) Water retention test to determine the stability of the internal components of the mortar mixture during transportation and storage;

[0028] e) Setting time test to determine the setting time of mortar and ensure the construction window.

[0029] Furthermore, the stripping of the existing paint layer on the inner side of the wall in step 3 also includes:

[0030] The contact area S between the mortars is determined by the following formula:

[0031] τ x =f v0 -μσ y ;

[0032] Among them, τ x is the shear stress, f v0 is the shear strength along the crack (i.e., cohesion c), μ is the friction coefficient, σ y is the normal stress in the y-axis direction;

[0033] The contact area S is calculated by the following formula:

[0034] S=τ x / σ y .

[0035] Furthermore, the depth h of the upper brick seam in step 3 is determined by the following formula:

[0036] h=σ1 / f t ;

[0037] Where h is the filling depth, σ1 is the principal tensile stress, and f t is the tensile strength of the mortar.

[0038] Furthermore, the depth H of the lower brick seam in step 3 is determined by the following formula:

[0039]

[0040] Among them: h is the depth of the upper brick joint, H is the depth of the lower brick joint, S is the contact area, L is the width of the brick joint, and l is the height of the brick joint.

[0041] The mortar replacement method for the walls of historical buildings of the present invention has the following significant beneficial effects:

[0042] (1) The construction method of retaining the old mortar and filling with new mortar can cure the defects on the basis of ensuring the basic stability of the walls of historical buildings. The weathered old mortar on the surface is removed, and the inclined surface is used as the contact surface between the new and old mortars to ensure that the contact surface can meet the shear-compression composite stress borne by the masonry. At the same time, the depth of the joint is limited to ensure that the new and old mortars can meet the design requirements of the main tensile stress. This not only realizes the replacement of the old mortar, but also ensures the quality of the newly injected mortar, better preserves the overall image of the original historical building wall, reduces the impact of repairs on it, extends the service life of the historical building wall, and maintains the style of the historical building.

[0043] (2) By precisely controlling the depth of the grouting and using customized tools, this method can minimize damage to the walls of historical buildings and maintain their original structural integrity and historical value. By stripping off the existing plaster layer and replacing it with new mortar, this method enhances the stability and durability of the wall and extends the service life of the building. By spraying water to wet the wall and spraying the interface agent, this method ensures good bonding between the new and old mortars, improving the overall strength and crack resistance of the wall. The new mortar is prepared by the optimal ratio determined by laboratory tests, and laboratory tests of consistency, apparent density, stratification, water retention and setting time are carried out to ensure the quality of the mortar and the construction effect. By using modern construction equipment such as electric grouting guns and seam presses, this method improves construction efficiency while reducing the risk and labor intensity of manual operation. By accurately calculating the grouting depth through the principal tensile stress theory and the contact area formula, this method can reasonably determine the grouting depth according to the actual stress conditions of the wall and avoid excessive damage to the wall structure. By calculating the shear stress and contact area, this method can specifically enhance the shear resistance of the wall, especially to protect the safety of the building structure under natural disasters such as earthquakes. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the implementation modes of the present application, the drawings required for use in the description of the implementation modes will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0045] Figure 1 It is a schematic diagram of the existing plaster layer on the inner side of the wall of the present invention.

[0046] Figure 2 It is a schematic diagram of the existing cracks in the plaster layer on the inner side of the wall of the present invention.

[0047] Figure 3 This is a schematic diagram of the treatment of old brick joints according to the present invention.

[0048] Figure 4Schematic diagram of the completion of mortar replacement on the wall of a historic building.

[0049] Description of reference numerals:

[0050] 100-existing plaster layer, 101-upper bricks, 102-lower bricks, 103-interface agent, 104-new mortar. DETAILED DESCRIPTION

[0051] The following description of the embodiments will help the public better understand the present invention, but the specific embodiments given by the applicant cannot and should not be regarded as limitations on the technical solutions of the present invention. Any changes to the definitions of components or technical features, or formal rather than substantive changes to the overall structure should be regarded as the scope of protection defined by the technical solutions of the present invention.

[0052] In this application, unless otherwise clearly specified or limited, the terms "installation", "connection", "fixation" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements, or it can be only surface contact, or surface contact connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0053] Embodiment 1:

[0054] A mortar replacement method for a historical building wall comprises the following steps:

[0055] Step 1: Construction preparation: Construction equipment entry test, the equipment at least includes electric caulking gun, manual seam cutting custom tools, spray gun, seam cleaning brush, seam blowing gun, seam pressing knife, mixer, seam pressing machine, copper wire;

[0056] Step 2: Material preparation: The materials include cement, fine sand, interface agent 103, and additives;

[0057] Step 3: Stripping the existing plaster layer 100 on the inner side of the wall: Use a customized manual grooving tool to grooving the existing plaster layer 100 on the inner side of the wall. The grooving depth is: the grooving depth of the upper brick 101 is h, and the grooving depth of the lower brick 102 is H, where: H>h;

[0058] By precisely controlling the depth of the cracks and using customized tools, the method can minimize damage to the walls of the historic building, maintaining its original structural integrity and historical value. By stripping off the existing plaster layer 100 and replacing it with new mortar 104, the method enhances the stability and durability of the wall and extends the service life of the building.

[0059] Step 4: Clean the brick joints: Use a joint cleaning brush to clean the residual mortar in the brick joints, and then use a joint blowing gun to clean the residual mortar particles and dust in the brick joints;

[0060] Step 5: Treatment of old brick joints: Wet the wall with water and spray the interface agent 103 on the brick joints with a spray gun;

[0061] By spraying water to wet the wall and spraying the interface agent 103, the method ensures good bonding between the new and old mortars, thereby improving the overall strength and crack resistance of the wall.

[0062] Step 6, preparing new mortar 104: adding cement, fine sand, additives and water into a mixer according to proportion to prepare new mortar 104;

[0063] Step 7, pouring new mortar 104: using an electric grouting gun to grout the brick joints;

[0064] Step 8: Use a seam pressing knife to manually press the seam once;

[0065] Step 9. Use a seam pressing machine in combination with manual secondary caulking and insert copper wire.

[0066] By utilizing modern construction equipment such as electric caulking guns and seam presses, this method improves construction efficiency while reducing the risks and labor intensity of manual operations.

[0067] The preparation of the new mortar 104 further includes the following steps:

[0068] a) Add cement, fine sand, additives and water into the mixer in the optimum proportions determined by laboratory tests;

[0069] b) Stir until the mortar is uniform in color. The stirring time should be controlled within 3 to 5 minutes to ensure sufficient mixing.

[0070] Among them, the treatment of old brick joints also includes the following steps:

[0071] a) Spray water on the wall to moisten it and ensure that the humidity of the wall is suitable for the adhesion of the interface agent 103;

[0072] b) Use a spray gun to spray the interface agent 103, ensuring that the interface agent 103 evenly covers the brick joints to enhance the bonding strength between the new and old mortars.

[0073] Among them, the preparation of the new mortar 104 also includes laboratory tests including:

[0074] a) consistency test to determine the fluidity of the mortar;

[0075] b) Apparent density test to determine the mass per unit volume of mortar;

[0076] c) Separation test to assess the uniformity of the mortar;

[0077] d) Water retention test to determine the stability of the internal components of the mortar mixture during transportation and storage;

[0078] e) Setting time test to determine the setting time of mortar and ensure the construction window.

[0079] The new mortar 104 was prepared according to the optimal ratio determined by laboratory tests, and laboratory tests on consistency, apparent density, stratification, water retention and setting time were carried out to ensure the quality of the mortar and the construction effect.

[0080] The stripping of the existing paint layer 100 on the inner side of the wall also includes:

[0081] The contact area S between the mortars is determined by the following formula:

[0082] τ x =f v0 --μσ y ;

[0083] Among them, τ x is the shear stress, f v0 is the shear strength along the crack (i.e., cohesion c), μ is the friction coefficient, σ y is the normal stress in the y-axis direction;

[0084] The contact area S is calculated by the following formula:

[0085] S=τ x / σ y .

[0086] By calculating the shear stress and contact area, this method can specifically enhance the shear resistance of the wall, especially to protect the safety of the building structure under natural disasters such as earthquakes.

[0087] The depth h of the crack of the upper brick 101 is determined by the following formula:

[0088] h=σ1 / f t ;

[0089] Where h is the filling depth, σ1 is the principal tensile stress, and f t is the tensile strength of the mortar.

[0090] The depth of the cutout is accurately calculated through the principal tensile stress theory and the contact area formula. This method can reasonably determine the depth of the cutout according to the actual stress conditions of the wall and avoid excessive damage to the wall structure.

[0091] The depth H of the crack of the lower brick 102 is determined by the following formula:

[0092]

[0093] Wherein: h is the depth of the joint of the upper brick 101, H is the depth of the joint of the lower brick 102, S is the contact area, L is the width of the brick joint, and l is the height of the brick joint.

[0094] The construction method of retaining the old mortar and filling the new mortar 104 can treat the defects on the basis of ensuring the basic stability of the walls of the historical buildings. The weathered old mortar on the surface can be removed. At the same time, the inclined surface is used as the contact surface between the new and old mortars, which ensures that the contact surface can meet the shear-compression composite stress of the masonry. At the same time, the depth of the joint is limited to ensure that the new and old mortars can meet the design requirements of the main tensile stress. This not only realizes the replacement of the old mortar, but also ensures the quality of the newly injected mortar, better preserves the overall image of the original historical building wall, reduces the impact of repairs on it, extends the service life of the historical building wall, and maintains the style of the historical building.

[0095] Those skilled in the art should understand that those skilled in the art can implement variations by combining the prior art and the above embodiments, which will not be described in detail here. Such variations do not affect the essential content of the present invention, and will not be described in detail here.

[0096] The above describes the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes, which does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention are still within the scope of protection of the technical solutions of the present invention.

Claims

1. A mortar replacement method for a historical building wall, characterized in that: The following steps are involved: Step 1: Construction preparation: Construction equipment entry test, the equipment at least includes electric caulking gun, manual seam cutting custom tools, spray gun, seam cleaning brush, seam blowing gun, seam pressing knife, mixer, seam pressing machine, copper wire; Step 2: Material preparation: The materials include cement, fine sand, interface agent (103), and additives; Step 3: Stripping the existing plaster layer (100) on the inner side of the wall: Use a customized manual grooving tool to grooving the existing plaster layer (100) on the inner side of the wall, the grooving depth is: the grooving depth of the upper brick (101) is h, and the grooving depth of the lower brick (102) is H, wherein: H>h; Step 4: Clean the brick joints: Use a joint cleaning brush to clean the residual mortar in the brick joints, and then use a joint blowing gun to clean the residual mortar particles and dust in the brick joints; Step 5: Treatment of old brick joints: Wetting the wall with water, and spraying an interface agent (103) on the brick joints with a spray gun; Step 6, preparing new mortar (104): adding cement, fine sand, additives and water into a mixer in proportion to prepare new mortar (104); Step 7, pouring new mortar (104): using an electric grouting gun to grout the brick joints; Step 8: Use a seam pressing knife to manually press the seam once; Step 9. Use a seam pressing machine in combination with manual secondary caulking and insert copper wire.

2. The mortar replacement method for the wall of a historical building as claimed in claim 1, characterized in that: The step 6 of preparing the new mortar (104) further includes the following steps: a) Add cement, fine sand, additives and water into the mixer in the optimum proportions determined by laboratory tests; b) Stir until the mortar is uniform in color. The stirring time should be controlled within 3 to 5 minutes to ensure sufficient mixing.

3. The mortar replacement method for the wall of a historical building as claimed in claim 1, characterized in that: The treatment of the old brick joint surface in step 5 also includes the following steps: a) Spray water on the wall to moisten it, ensuring that the humidity of the wall is suitable for the adhesion of the interface agent (103); b) Use a spray gun to spray the interface agent (103) to ensure that the interface agent (103) evenly covers the brick joints to enhance the bonding strength between the new and old mortars.

4. The mortar replacement method for the wall of a historical building as claimed in claim 1, characterized in that: After preparing the new mortar (104) in step 6, laboratory tests are also performed, including: a) consistency test to determine the fluidity of the mortar; b) Apparent density test to determine the mass per unit volume of mortar; c) Separation test to assess the uniformity of the mortar; d) Water retention test to determine the stability of the internal components of the mortar mixture during transportation and storage; e) Setting time test to determine the setting time of mortar and ensure the construction window.

5. The mortar replacement method for the wall of a historic building as claimed in claim 1, characterized in that: The step 3 of stripping the existing paint layer (100) on the inner side of the wall further includes: The contact area S between the mortars is determined by the following formula: τx=fv0-μσy; Among them, τx is the shear stress, fv0 is the shear strength along the crack (i.e., cohesion c), μ is the friction coefficient, and σy is the normal stress in the y-axis direction; The contact area S is calculated by the following formula: S = τx / σy.

6. The mortar replacement method for the wall of a historical building according to claim 5, characterized in that: In step 3, the depth h of the crack of the upper brick (101) is determined by the following formula: h = σ1 / ft; Where h is the filling depth, σ1 is the principal tensile stress, and ft is the tensile strength of the mortar.

7. The mortar replacement method for the wall of a historical building according to claim 6, characterized in that: In step 3, the depth H of the hollowing of the lower brick (102) is determined by the following formula: Wherein: h is the depth of the upper brick (101), H is the depth of the lower brick (102), S is the contact area, L is the width of the brick joint, and l is the height of the brick joint.

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