Ground leveling construction method and leveling structure based on removable rigid reference

Abstract

The present application relates to a kind of ground leveling construction methods based on removable rigid reference, comprising the following steps: S1. composite elevation reference is established;S2. continuous rigid rib strip forming;S3. saturation scraping;S4. hierarchical maintenance.The present application uses "removable rigid mold" to form rib strip, reference straightness is guaranteed by ruler rather than artificial feeling, flatness is stably controlled at ≤0.5mm / 2m, more than 5 times higher than traditional process;When leveling structure is >50mm, before the surface hardening of first leveling layer, micro-locked structure is formed by scratching, interlayer bonding strength is increased from ≤0.5MPa of pure chemical bonding to ≥1.2MPa of mechanical locking, completely eliminates delamination and hollowing, and enhances bonding performance;Realize "thin layer fast hardening+thick layer composite", and the construction efficiency is increased by more than 40%;Industrialization replication: all parameters, such as ruler length, standing time, scratching parameter, curing cycle, etc., can be quantified, quality is not affected by worker experience, and is suitable for precision finishing batch construction.

Description

Technical Field

[0001] This invention relates to the field of ground base treatment technology in building decoration engineering, specifically to a ground leveling construction method and leveling structure based on a removable rigid reference. Background Technology

[0002] In interior decoration, floor leveling is a necessary preliminary step for laying wood flooring, tiles, epoxy flooring, and other finishing materials. The current mainstream leveling method is the "mortar spot screed method," which involves first setting several cement mortar spots on the ground as elevation control points. After the spots harden, mortar is then laid between them and leveled with a screed.

[0003] However, this method has the following inherent drawbacks: Point-based benchmarks cannot control linear accuracy: Since the mortar spots are discrete points, the scraper will bend and deform between two points, causing the middle area of ​​the leveling layer to sink, and the flatness error is usually 5-10mm, which cannot meet the requirement of ≤2mm for wood flooring.

[0004] The self-deformation of wet mortar strips leads to the failure of the benchmark: the wet mortar strips applied directly will deform due to their own weight and shrinkage before hardening. Even if they are flush with the elevation line at the time, they may deviate after hardening.

[0005] Thick-layer construction inevitably leads to cracking: When the thickness of a single construction exceeds 50mm, the hydration heat of the cement mortar is concentrated and the shrinkage stress is large, making it very easy to produce through cracks; while if the interface treatment is not properly handled in layered construction, it is easy to produce interlayer voids.

[0006] Therefore, there is an urgent need for a new leveling process that can provide a continuous high-precision benchmark and solve the problem of thick-layer cracking. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention aims to provide a ground leveling construction method and leveling structure based on a removable rigid reference, thereby solving the technical problems of insufficient accuracy of point references, self-deformation of wet reinforcement, and easy cracking of thick layers in the prior art, and achieving a high-quality leveling structure with flatness ≤2mm / 2m, no through cracks, and resistance to hollowing.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first objective of this invention is to provide a ground leveling construction method based on a removable rigid reference, comprising the following steps: S1. Establish composite elevation benchmark: Plot the finished surface elevation line around the wall, and plot multiple parallel screed position lines at preset intervals on the ground. Set multiple elevation control mortar spots on the screed position lines and calibrate the top surface of the mortar spots to be flush with the elevation line. S2. Forming of continuous rigid screed strips: Lay screed mortar along the screed position line, use a rigid ruler with a length covering both ends of the mortar spots at the screed position line, press it across the top surface of the mortar spots, press down and scrape off excess mortar, let it stand until the screed mortar initially sets to form a continuous screed strip, then remove the rigid ruler and perform curing. S3. Saturated leveling: Lay leveling mortar between adjacent hardened screed strips, use a screed bar that matches the length of the screed strips, make its two ends fit tightly against the top surface of the two screed strips, and scrape it in one direction until the surface of the leveling mortar is flush with the top surface of the screed strips. S4. Graded curing: After leveling and before initial setting, rub and smooth the surface, and determine the curing cycle according to the designed leveling layer thickness for moisturizing curing.

[0009] Specifically, the construction method also includes treating the ground base before step S1, which includes cleaning the base, checking the base for hollow areas or sand, and wetting the base. If hollow areas larger than 0.1㎡ are found, the hollow areas need to be removed down to the solid base and then repaired with cement mortar. If the base is sandy, an interface agent needs to be applied and allowed to dry before proceeding with subsequent construction.

[0010] Specifically, in step S1, the spacing of the screeds is determined according to the size of the ground to be laid, and the spacing is less than or equal to the effective working length of the screed.

[0011] Specifically, in step S2, the rigid ruler is an aluminum alloy ruler with a length ≥ 2m and its own straightness error ≤ 0.5mm / 2m; the straightness error of the formed continuous punch strip is ≤ 1mm / 2m.

[0012] Specifically, in step S2, the initial setting time of the screed mortar is controlled at 45-60 minutes, and the standing time is 15-25 minutes; the curing is specifically: moist curing for 24 hours until the strength of the screed strip reaches more than 70% of its design strength.

[0013] Specifically, in step S3, the leveling mortar has a higher fluidity than the screed mortar, and its laying thickness is 5-10mm higher than the top surface of the screed strip. During the leveling process, the depressions need to be filled with mortar immediately and then leveled again. Step S3 also includes a step of using a trowel to perform a secondary finishing before the leveling layer is fully set, in order to improve the surface density.

[0014] Specifically, in step S3, when the design leveling layer thickness is >50 mm, the first layer should be ≤30 mm thick, and roughening treatment should be performed on the surface of the first leveling layer before it hardens. After it is fully set, the second layer should be laid up to the top elevation of the screed strip.

[0015] Specifically, in step S4, when the leveling layer thickness is ≤50mm, the curing period is ≥7 days; when the leveling layer thickness is >50mm or during winter construction, the curing period is ≥14 days. During the curing period, cover with wet burlap sacks or plastic film and sprinkle water 2-3 times a day.

[0016] Specifically, the screed mortar comprises cement, sand, and water, with a cement-to-sand volume ratio of 1:2.5; the leveling mortar comprises cement, sand, and water, with a cement-to-sand volume ratio of 1:3; wherein the cement is selected from non-lumpy 325-grade or 425-grade ordinary Portland cement, the sand is medium sand with a fineness modulus of 2.3-3.0, and the mud content after removing impurities and large particles is no more than 3%; the slump of the leveling mortar is 10-20 mm greater than that of the screed mortar.

[0017] The second objective of this invention is to provide a leveling structure, which is obtained by the construction method described above.

[0018] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: 1. Significantly improved precision: The punching strip is formed using a "removable rigid mold". The reference straightness is guaranteed by a straightedge rather than by human touch, and the flatness is stably controlled at ≤2mm / 2m, which is more than 5 times better than the traditional process; 2. Innovative composite structure to eliminate hollow areas and cracks: When the leveling structure thickness is >50mm, a roughening treatment is performed on the surface of the first leveling layer before hardening to form a micro-interlocking structure. This significantly increases the interlayer bonding strength from ≤0.5MPa for purely chemical bonding to ≥1.2MPa for mechanical interlocking, completely eliminating delamination and hollow areas, and enhancing overall bonding performance and reliability. This method achieves a technological innovation of "thin-layer rapid hardening + thick-layer composite," improving overall construction efficiency by more than 40%. 3. The process can be industrially replicated: All key process parameters in this invention, such as the length and accuracy of the straightedge, the settling time, the timing and depth of roughening, and the curing cycle, can be quantified and controlled, so that the construction quality is no longer subject to the personal experience of workers, ensuring the stability and consistency of project quality, and is especially suitable for batch construction of fine decoration. Detailed Implementation

[0019] The present invention will be further described below with reference to embodiments.

[0020] The key points of quality control in this invention are as follows: 1. Flatness: Use a 2m straightedge to check. The gap between the straightedge and the ground should be ≤3mm (requirement for tile flooring) and ≤2mm (requirement for wood flooring), and the gap should be evenly distributed with no local protrusions. 2. Elevation deviation: The deviation between the finished ground surface and the elevation line is ≤5 mm (within the entire house), and the deviation between two adjacent points on the same straight line is ≤2 mm; 3. Hollow area rate: When lightly tapping the leveling layer with a small hammer, the hollow area is ≤200 cm² (single hollow area), and the total number of hollow areas in the whole house is ≤2 (if used for wood flooring base, hollow areas are strictly prohibited). 4. Appearance quality: The surface is free from cracks, sanding, peeling, and exposed reinforcement (exposed reinforcement strips). The inside and outside corners are square (checked with a right angle ruler, deviation ≤ 3 mm).

[0021] Example 1 (Standard working conditions, thickness ≤40 mm): A residential living room with an area of ​​35㎡ is to be fitted with solid wood flooring (substrate flatness required ≤2 mm / 2 m). The original floor slab flatness deviation is 8 mm, and the designed leveling thickness is 35 mm.

[0022] This embodiment provides a ground leveling construction method and leveling structure based on a removable rigid reference, including the following steps: S1. Mark a +500mm elevation line on the wall and calculate the finished floor elevation. Mark three screed position lines on the ground at 1.8m intervals and set four elevation control mortar spots on each screed position line. Align the top of the mortar spots with the elevation line. S2. Mix the screed mortar (PO 42.5 cement: medium sand = 1:2.5, water-cement ratio 0.45) and lay it on the designated line. Use a 3m aluminum alloy straightedge (straightness 0.3mm / 3m) to press across the top surface of the mortar patch, press down to form it, and remove the aluminum alloy straightedge after standing for 18 minutes; after curing for 24 hours, the surface of the screed strip should leave no mark when scratched with a fingernail, and the strength should reach more than 70% of the design value; S3. Lay leveling mortar (PO 42.5 cement: sand = 1:3, water-cement ratio 0.5) between adjacent hardened screed strips, 8mm above the top of the screed, and use a 2m screed to screed across the double screeds to level it. S4. After smoothing, press and polish for 1.5 hours. After final setting, cover with a damp burlap sack to maintain moisture for 8 days.

[0023] Test results: The maximum gap between the 2m straightedge and feeler gauge was 1.5mm, with no hollow areas or cracks.

[0024] Example 2 (thick layer condition, thickness 70mm): The original base layer has a large height difference, and the designed leveling thickness is 70mm.

[0025] This embodiment provides a ground leveling construction method and leveling structure based on a removable rigid reference, including the following steps, which are basically the same as those in Embodiment 1. The difference is that in step S3, leveling mortar (PO 42.5 cement: sand = 1:3, water-cement ratio 0.5) is laid between adjacent hardened screed strips. The first layer is 25mm thick, and after rubbing and pressing, it is immediately roughened (a hard plastic brush is used to create a texture 1.5mm deep). After 24 hours of final setting, the second layer of 45mm thick is laid to the top surface of the screed, and then cured for 14 days.

[0026] Test results: The maximum flatness deviation was 1.8mm / 2m; core samples were taken for pull-out tests, and the interlayer tensile strength was 1.35MPa (far exceeding the national standard of 0.5MPa), with no hollow areas or cracks.

[0027] Comparative Example 1 (Thick Layer Condition, Traditional Method): A factory floor renovation project was carried out. The original base layer had a large height difference, and the designed leveling thickness was 70mm.

[0028] This comparative example illustrates a traditional method for leveling ground: First, elevation mortar spots are created, then wet screed strips are manually applied. After hardening, leveling mortar is laid in two layers (the first layer is 35mm, and the second layer is 35mm after a 3-day interval). The two layers are bonded solely by natural wetting, without any surface roughening or other treatments.

[0029] Results of the test: The total construction period was 11 days, significantly longer than that of Example 2 of this invention (estimated at approximately 6-7 days). The measured flatness of the final leveling layer was 6-7 mm / 2m, which does not meet the high-requirement flooring standards. Inspection with a small hammer revealed multiple hollow areas, especially at the interface between the two construction layers. Pull-out tests on samples showed that the interlayer tensile strength was only 0.4-0.6 MPa, with some areas falling below the standard requirements, indicating a risk of hollow areas.

[0030] Comparative Example 2 provides a ground leveling construction method and leveling structure based on a removable rigid reference, which is basically the same as Example 1, except that the rigid guide is not removed in step S2, and the guide is forcibly removed after the mortar has completely hardened.

[0031] Results: The straightedge could not be removed smoothly, damaging the edge of the screed strip; the screed strip was partially damaged, and the flatness decreased significantly (measured ≥4 mm / 2 m); some screed strips broke due to the straightedge being too tightly bonded to the mortar, causing the screed to lose its continuous reference and the leveling failed.

[0032] Comparative Example 3 (roughening treatment omitted in thick layer construction) This comparative example provides a ground leveling construction method and leveling structure based on a removable rigid reference, which is basically the same as Example 2, except that the surface of the first layer of leveling mortar is not roughened and the second layer is laid directly.

[0033] Results: The interlayer pull-out strength was only 0.6–0.8 MPa; after curing, a knocking test revealed a noticeable hollow sound; core samples showed a smooth interface between the two layers with no mechanical interlocking structure. Therefore, when the design leveling layer thickness is >50 mm, roughening treatment is a key process for forming interlayer mechanical interlocking and preventing hollowness, and cannot be omitted.

[0034] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A ground leveling construction method based on a removable rigid reference, characterized in that, Includes the following steps: S1. Establish composite elevation benchmark: Plot the finished surface elevation line around the wall, and plot multiple parallel screed position lines at preset intervals on the ground. Set multiple elevation control mortar spots on the screed position lines and calibrate the top surface of the mortar spots to be flush with the elevation line. S2. Forming of continuous rigid screed strips: Lay screed mortar along the screed position line, use a rigid ruler with a length covering both ends of the mortar spots at the screed position line, press it across the top surface of the mortar spots, press down and scrape off excess mortar, let it stand until the screed mortar initially sets to form a continuous screed strip, then remove the rigid ruler and perform curing. S3. Saturated leveling: Lay leveling mortar between adjacent hardened screed strips, use a screed bar that matches the length of the screed strips, make its two ends fit tightly against the top surface of the two screed strips, and scrape it in one direction until the surface of the leveling mortar is flush with the top surface of the screed strips. S4. Graded curing: After leveling and before initial setting, rub and smooth the surface, and determine the curing cycle according to the designed leveling layer thickness for moisturizing curing.

2. The construction method according to claim 1, characterized in that, The construction method also includes treating the ground substrate before step S1, in the following order: cleaning the substrate, checking for hollow areas or loose sand, and moistening the substrate; if the area is larger than 0.1m² 2 If there is hollowness, the hollow area needs to be removed down to a solid base layer, and then repaired with cement mortar; if the base layer is sandy, an interface agent needs to be applied, and subsequent construction can be carried out after it dries.

3. The construction method according to claim 1, characterized in that: In step S1, the spacing of the screeds is determined according to the size of the ground to be laid, and the spacing is less than or equal to the effective working length of the screed.

4. The construction method according to claim 1, characterized in that: In step S2, the rigid ruler is an aluminum alloy ruler with a length ≥ 2m and its own straightness error ≤ 0.5mm / 2m; the straightness error of the formed continuous punch strip is ≤ 1mm / 2m.

5. The construction method according to claim 1, characterized in that, In step S2, the initial setting time of the screed mortar is controlled at 45-60 minutes, and the standing time is 15-25 minutes; the curing is specifically: moist curing for 24 hours until the strength of the screed strip reaches more than 70% of its design strength.

6. The construction method according to claim 1, characterized in that, In step S3, the leveling mortar has higher fluidity than the screed mortar, and its laying thickness is 5-10mm higher than the top surface of the screed strip. During the leveling process, the depressions need to be filled with mortar immediately and then leveled again. Step S3 also includes a second finishing step using a trowel before the leveling layer is fully set, in order to improve the surface density.

7. The construction method according to claim 1, characterized in that: In step S3, when the design leveling layer thickness is greater than 50 mm, the first layer should be laid with a thickness of ≤30 mm. The surface of the first leveling layer should be roughened before it hardens. After it is fully set, the second layer should be laid up to the top elevation of the screed strip.

8. The construction method according to claim 1, characterized in that: In step S4, when the leveling layer thickness is ≤50mm, the curing period is ≥7 days; when the leveling layer thickness is >50mm or during winter construction, the curing period is ≥14 days. During the curing period, cover with wet burlap sacks or plastic film and sprinkle water 2-3 times a day.

9. The construction method according to claim 1, characterized in that: The screed mortar comprises cement, sand, and water, with a cement-to-sand volume ratio of 1:2.5; the leveling mortar comprises cement, sand, and water, with a cement-to-sand volume ratio of 1:3; wherein the cement is selected from non-lumpy 325-grade or 425-grade ordinary Portland cement, the sand is medium sand with a fineness modulus of 2.3-3.0, and the mud content after removing impurities and large particles is no more than 3%; the slump of the leveling mortar is 10-20 mm greater than that of the screed mortar.

10. A leveling structure, characterized in that, Obtained by the construction method according to any one of claims 1 to 9.