Ice-blocking concrete material, application, and ice-blocking construction method for foundation pit sidewalls

Abstract

The present invention relates to the technical field of ice prevention for foundation pits, and in particular, to an ice-preventing concrete material, its application, and a method for constructing ice prevention for the side walls of foundation pits. The ice-preventing concrete material includes concrete and ice-preventing particles, and the ice-preventing particles are obtained by mixing silicate cement, chloride salts, ammonium salts, lignin, and water; the chloride salt is one of calcium chloride, magnesium chloride, potassium chloride, ferric chloride, and aluminum chloride, and the ammonium salt is one of urea, ammonium nitrate, and triethanolammonium. The present invention prevents the formation of ice hanging on the side walls of foundation pits through the slow dissolution and penetration principle of ammonium salts and chloride salts, thereby avoiding safety accidents caused by ice hanging falling; the concrete and ice-preventing particles can be mixed evenly, so that they can be effectively applied or sprayed on the side walls of foundation pits, and the preparation is simple, the degree of structural corrosion is small, the pollution to the soil is small, and it has the characteristics of economy, safety, and environmental protection.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation pit ice prevention, and in particular to an ice-preventing concrete material, its application and a foundation pit sidewall ice-preventing construction method. Background Art

[0002] Due to factors such as rain, snow, and foundation pit leakage, the sidewalls of foundation pits are subject to repeated freezing and thawing during winter construction in northern China, forming dense icicles near the supports. Falling icicles can easily injure people, posing a safety hazard. Rail transit foundation pits typically have narrow spans and deep depths, ranging from 15-25 meters wide and 15-30 meters deep. These support layers are numerous and located far from the excavation surface, making manual removal difficult.

[0003] Existing asphalt pavement materials in the highway industry offer snow-melting and ice-blocking properties. These materials utilize vehicle load and penetration to melt and break ice, preventing freezing. However, they lack effective pressure on the sidewalls of foundation pits, making them unsuitable for use on these surfaces. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an ice-blocking concrete material, its application and an ice-blocking construction method for a foundation pit side wall.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] The invention provides ice-blocking particles obtained by mixing Portland cement, chloride salt, ammonium salt, lignin and water; the chloride salt is one of calcium chloride, magnesium chloride, potassium chloride, ferric chloride and aluminum chloride; the ammonium salt is one of urea, ammonium nitrate and triethanolammonium.

[0007] Furthermore, the chloride salt is calcium chloride, the ammonium salt is urea, and the lignin is calcium lignin sulfonate; and the mass ratio of the Portland cement, the calcium chloride, the urea, and the calcium lignin sulfonate is 4-8:1-8:1-3:1-2.

[0008] Furthermore, the mass of water is 60% to 80% of the total mass of the Portland cement.

[0009] Furthermore, the particle size of the ice-blocking particles is 1-4 mm.

[0010] The present invention provides an ice-blocking concrete material, comprising concrete and the ice-blocking particles described above; wherein the components of the concrete include aggregate; the ice-blocking particles account for 1% to 5% of the total mass of the ice-blocking concrete material, and the ice-blocking particles account for 1.4% to 7.4% of the total mass of the ice-blocking particles and the aggregate.

[0011] Furthermore, the ice-blocking concrete material is a sprayed material or a plastered material.

[0012] Furthermore, the ice-blocking concrete material is a sprayed material, and its specific composition and mass fractions are 4 parts of the ice-blocking particles and 96 parts of the concrete; the aggregate in the concrete includes sand and gravel; the specific composition and mass fractions of the concrete are 22 parts of cement, 34 parts of sand, 30 parts of gravel, 9 parts of water, and 1 part of water glass.

[0013] Furthermore, the lowest ice-blocking temperature of the ice-blocking concrete material is -15°C.

[0014] The present invention provides an application of the ice-blocking concrete material as described above in ice-blocking construction of foundation pit side walls, wherein the foundation pit side walls are underground continuous walls or pile hole cast-in-place pile side walls.

[0015] The present invention provides an ice-blocking construction method for foundation pit side walls. When the foundation pit side walls are underground continuous walls, after setting a structural waterproof layer and before setting an underground continuous wall support frame, the ice-blocking concrete material is evenly applied to the surface of the underground continuous wall; when the foundation pit side walls are pile hole cast-in-place pile side walls, the concrete material is used to perform mesh spraying on the pile hole cast-in-place pile side walls so that the ice-blocking concrete material is evenly sprayed on the pile hole cast-in-place pile side wall surfaces.

[0016] The beneficial effects of the present invention are:

[0017] (1) The ice-blocking particles of the present invention prevent the formation of ice hanging on the side walls of the foundation pit through the slow dissolution and penetration principle of ammonium salts and chloride salts, thereby avoiding safety accidents caused by ice hanging falling;

[0018] (2) The ice-blocking particles of the present invention are simple to prepare, have little corrosion to structures, and cause little soil pollution. They are economical, safe, and environmentally friendly.

[0019] (3) The ice-blocking concrete material of the present invention can be mixed evenly with concrete and ice-blocking particles, thereby being effectively applied or sprayed on the sidewall of the foundation pit;

[0020] (4) The ice-blocking concrete material of the present invention can be used in the construction of the side walls of foundation pits, so that the side walls of foundation pits have an ice-blocking effect, filling the gap in the existing technology for ice-blocking technology for the side walls of foundation pits.

[0021] (5) The ice-blocking construction method for the foundation pit side wall of the present invention is simple to operate, low in cost, effective, and easy to promote. DETAILED DESCRIPTION

[0022] The following describes the principles and features of the present invention. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0023] The ice-blocking particles of the present invention are obtained by mixing silicate cement, chloride salt, ammonium salt, lignin and water; the chloride salt is one of calcium chloride, magnesium chloride, potassium chloride, ferric chloride and aluminum chloride; the ammonium salt is one of urea, ammonium nitrate and triethanolammonium.

[0024] The ice-blocking particles of this invention contain a certain proportion of water-soluble salts such as chloride and ammonium salts. They primarily prevent the formation of ice on the side walls of foundation pits through the slow dissolution and penetration of salts, thereby preventing accidents caused by ice falling. Furthermore, the material is simple to prepare, causes minimal structural corrosion, and contributes to minimal soil pollution, making it economical, safe, and environmentally friendly.

[0025] The ice-blocking granules of the present invention have a water-soluble, slow-dissolving skeleton structure formed from silicate cement, while lignin exhibits certain water permeability and water-soluble slow-dissolving properties. To achieve safety and environmental protection, the chloride salt does not contain sodium chloride. Furthermore, the main ice-blocking substances and their proportions can be adjusted within a certain range depending on the outdoor temperature range during winter construction. Lignin also has a certain ice-blocking effect, while also reducing the water consumption required to produce the ice-blocking granules and providing a certain anti-corrosion effect.

[0026] Preferably, in order to achieve a good ice-blocking effect, the amount of ammonium salt added is not less than 20% of the total salts of chloride salts and ammonium salts.

[0027] Preferably, the chloride salt is calcium chloride, the ammonium salt is urea, and the lignin is calcium lignin sulfonate (lignocalcium); wherein the mass ratio of Portland cement, calcium chloride, urea and calcium lignin sulfonate is 4-8:1-8:1-3:1-2.

[0028] Preferably, the mass of water is 60% to 80% of the total mass of Portland cement, calcium chloride, urea and calcium lignin sulfonate; using this mass percentage of water can achieve uniform mixing of the components and ensure the formation of stable particles.

[0029] Preferably, the particle size of the ice-blocking particles is 1 to 4 mm; ice-blocking particles in this particle size range can be well mixed with concrete to form ice-blocking concrete materials; if the particle size is too small, the ice-blocking effect is easily reduced; if the particle size is too large, it cannot be evenly mixed with concrete, and even cannot form a usable concrete material, resulting in uneven ice-blocking effect or even unusable concrete material.

[0030] The ice-blocking concrete material of the present invention comprises concrete and the ice-blocking particles as described above; wherein the components of the concrete include aggregate; the ice-blocking particles account for 1% to 5% of the total mass of the ice-blocking concrete material, and the mass of the ice-blocking particles is 1.4% to 7.4% of the mass of the aggregate.

[0031] It should be noted that there are many types of concrete formulas, and the water-cement ratio and sand ratio of concrete vary greatly depending on different strength requirements and specific usage conditions. In actual use, those skilled in the art can make adjustments according to actual needs. However, no matter what specific formula of concrete is used to prepare the ice-blocking concrete material of the present invention, it is necessary to replace a part of the corresponding graded aggregate with the ice-blocking particles of the present invention. After the replacement, the mass of the ice-blocking particles accounts for 1% to 5% of the total mass of the ice-blocking concrete material. The corresponding graded aggregate refers to an aggregate whose particle size is similar to the particle size of the ice-blocking particles of the present invention. For example, if ice-blocking particles with a particle size of 4 mm are used, the corresponding aggregate of about 4 mm in the concrete is subtracted.

[0032] By subtracting a portion of the original concrete aggregate and replacing it with the ice-blocking particles of the present invention, a usable ice-blocking concrete material can be formed after mixing. Directly adding ice-blocking particles to a complete concrete formula can easily affect the concrete skeleton structure and significantly affect the concrete strength.

[0033] Preferably, the ice-blocking concrete material is a sprayed material or a plastered material.

[0034] Preferably, the ice-blocking concrete material is a sprayed material, and its specific composition and mass fractions are 4 parts of ice-blocking particles and 96 parts of concrete; the aggregate in the concrete includes sand and gravel; the specific composition and mass fractions of the concrete are 22 parts of cement, 34 parts of sand, 30 parts of gravel, 9 parts of water, and 1 part of water glass.

[0035] Preferably, the lowest ice-blocking temperature of the ice-blocking concrete material is -15°C.

[0036] The ice-blocking concrete material of the present invention is used in ice-blocking construction of foundation pit side walls, where the foundation pit side walls are underground continuous walls or pile hole cast-in-place pile side walls.

[0037] The ice-blocking construction method for foundation pit side walls of the present invention comprises the following steps: when the foundation pit side walls are underground continuous walls, after setting a structural waterproof layer and before setting an underground continuous wall support frame, ice-blocking concrete material is evenly applied to the surface of the underground continuous wall; when the foundation pit side walls are pile hole cast-in-place pile side walls, concrete material is used to carry out mesh spraying on the pile hole cast-in-place pile side walls, so that the ice-blocking concrete material is evenly sprayed on the pile hole cast-in-place pile side wall surfaces.

[0038] It should be noted that when used as anti-icing plastering material, it is generally not necessary to add water glass, while water glass is added more frequently in sprayed concrete materials. Other accelerators can also be used instead of water glass.

[0039] The construction method of the present invention can provide the side walls of the foundation pit with a good ice-blocking effect, effectively preventing safety accidents caused by falling ice.

[0040] The present invention is illustrated below by means of specific examples.

[0041] Example 1

[0042] The ice-blocking particles in this embodiment consist of Portland cement, calcium chloride, urea, and wood calcium in a ratio of 4:1:3:1. The water-to-binder ratio (water-to-cement ratio) is between 0.6 and 0.8. These particles are mixed to form solid particles with a diameter of less than 4 mm. In the concrete mix, these particles replace 4% of the total mass of graded aggregate to produce the ice-blocking concrete material. This ice-blocking concrete material is specifically a shotcrete material, which is directly mixed and sprayed into concrete during use.

[0043] The material composition of the ice-blocking concrete of this embodiment and the mass fraction of each component are: 4 parts of ice-blocking particles, 22 parts of cement, 34 parts of sand, 30 parts of crushed stone, 9 parts of water, and 1 part of water glass.

[0044] Example 2

[0045] The composition ratio of the ice-blocking particles in this embodiment is Portland cement: calcium chloride: urea: wood calcium = 8:5:3:2. The rest is the same as in Example 1.

[0046] Example 3

[0047] The composition ratio of the ice-blocking particles in this embodiment is Portland cement: calcium chloride: urea: wood calcium = 8:8:1:2. The rest is the same as in Example 1.

[0048] Comparative Example 1

[0049] This comparative example is concrete containing ice-blocking particles, and its composition is the same as that of Example 1, except that the ice-blocking particles in Example 1 are replaced with aggregates of the same grade.

[0050] The materials of Examples 1 to 3 and Comparative Example 1 were made into test blocks. After each test block was placed in an environment of -5°C, -10°C, and -15°C for 12 hours, a spray test was performed on the surface of each test block, and the freezing condition was tested at regular intervals. The test results are shown in Table 1.

[0051] It can be seen from the test results in Table 1 that the test blocks of Examples 1 to 3 did not condense ice or had poor condensation effects, while the surface of the test block of Comparative Example 1 was frozen and frozen firmly, indicating that the embodiments have obvious ice-blocking effects in a certain temperature environment below 0°C.

[0052] Table 1 Sprinkling freezing situation

[0053]

[0054] Description: 1-not frozen; 2-slightly frozen; 3-soft ice; 4-hard ice.

[0055] Comparative Example 2

[0056] In this comparative example, ice-blocking particles were prepared in the same manner as in Example 1, except that the calcium chloride was completely replaced with an equal amount of urea. That is, the salt component in the ice-blocking particles of this comparative example only contained urea.

[0057] The test of the ice-blocking concrete material of this comparative example found that the ice-blocking concrete material using only urea only has a certain ice-blocking effect above -5°C, but the ice-blocking effect is poor and cannot meet the use requirements.

[0058] Comparative Example 3

[0059] In this comparative example, ice-blocking particles were prepared in the same manner as in Example 1, except that the urea therein was completely replaced by an equal amount of calcium chloride. That is, the salt component in the ice-blocking particles of this comparative example only contained calcium chloride.

[0060] Too high a calcium chloride content will increase the corrosiveness to concrete structures. In actual use, it will cause steel bar corrosion and affect structural safety.

[0061] Comparative Example 4

[0062] In this comparative example, ice-blocking particles were prepared in the same manner as in Example 1, except that urea and calcium chloride were completely replaced by sodium chloride. That is, the salt component in the ice-blocking particles of this comparative example only contained sodium chloride.

[0063] In existing technologies, sodium chloride is commonly used in road de-icing agents. In theory, sodium chloride can prevent ice buildup at lower temperatures. However, sodium chloride is more corrosive than calcium chloride, causing corrosion not only to steel reinforcement but also to the concrete itself. When applied to foundation pit walls, it can damage adjacent structures and even contaminate surrounding soil, impacting the environment.

[0064] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An ice-blocking particle, characterized in that: It is obtained by mixing Portland cement, calcium chloride, urea, lignin and water.

2. The ice-blocking particle according to claim 1, characterized in that: The lignin is calcium lignin sulfonate; the mass ratio of the Portland cement, the calcium chloride, the urea and the calcium lignin sulfonate is 4-8:1-8:1-3:1-2.

3. The ice-blocking particle according to claim 2, characterized in that: The mass of water is 60% to 80% of the total mass of the Portland cement.

4. The ice-blocking particle according to claim 3, characterized in that: The particle size of the ice-blocking particles is 1-4 mm.

5. An ice-blocking concrete material, characterized in that: The ice-blocking concrete material comprises concrete and the ice-blocking particles according to any one of claims 1 to 4; wherein the components of the concrete include aggregate; the ice-blocking particles account for 1% to 5% of the total mass of the ice-blocking concrete material, and the mass of the ice-blocking particles is 1.4% to 7.4% of the mass of the aggregate.

6. The ice-blocking concrete material according to claim 5, characterized in that: The ice-blocking concrete material is a sprayed material or a plastered material.

7. The ice-blocking concrete material according to claim 6, characterized in that: The ice-blocking concrete material is a sprayed material, and its specific composition and mass fractions are: 4 parts of the ice-blocking particles and 96 parts of the concrete; the aggregate in the concrete includes sand and gravel; the specific composition and mass fractions of the concrete are: 22 parts of cement, 34 parts of sand, 30 parts of gravel, 9 parts of water, and 1 part of water glass.

8. The ice-blocking concrete material according to any one of claims 5 to 7, characterized in that: The lowest ice-blocking temperature of the ice-blocking concrete material is -15°C.

9. Use of the ice-blocking concrete material according to any one of claims 5 to 8 in ice-blocking construction of foundation pit side walls, characterized in that: The side walls of the foundation pit are underground continuous walls or side walls of pile holes and cast-in-place piles.

10. A method for ice prevention construction on the side wall of a foundation pit, characterized in that: When the side wall of the foundation pit is an underground continuous wall, after setting the structural waterproof layer and before setting the underground continuous wall support frame, the ice-blocking concrete material according to claim 5 is evenly applied to the surface of the underground continuous wall; when the side wall of the foundation pit is a pile hole cast-in-place pile side wall, the concrete material according to claim 5 is used to carry out mesh spraying on the pile hole cast-in-place pile side wall so that the ice-blocking concrete material is evenly sprayed on the pile hole cast-in-place pile side wall surface.

Images