Ultrafine grouting material for repairing concrete slits in high and cold environment as well as preparation method and application of superfine grouting material

Abstract

The invention discloses a superfine grouting material for repairing concrete slits in a high and cold environment as well as a preparation method and application of the superfine grouting material. The superfine grouting material for repairing the concrete slits in the high and cold environment is prepared from the following raw materials in parts by weight: 4000 to 8000 parts of sulphoaluminate cement clinker, 500 to 1000 parts of dihydrate gypsum, 500 to 1000 parts of ordinary Portland cement, 200 to 1000 parts of silica fume, 200 to 1000 parts of limestone powder, 1000 to 2000 parts of slag, 1 to 5 parts of lithium carbonate, 20 to 30 parts of boric acid, 20 to 30 parts of polycarboxylate superplasticizer, 1 to 10 parts of thickener, 10 to 80 parts of calcium formate and 3500 to 4000 parts of water. The grouting material does not contain aggregate and can enter cracks with the size smaller than 0.05 mm, and extension of extremely narrow cracks is prevented; in addition, the grouting material is directly mixed with water with the temperature lower than 5 DEG C in a cold environment, the operable time is long, and preset compression resistance and breaking strength can be achieved within one day.

Description

Technical Field

[0001] The invention belongs to the field of grouting repair and reinforcement, and particularly relates to an ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment, and a preparation method and application thereof. Background Art

[0002] There are a large number of engineering projects with high altitudes, deep valleys, and long-term low temperatures in cold plateau areas. Grouting materials have been widely used for emergency reinforcement of strata and water plugging and leak plugging measures at this stage, but most of the existing grouting materials are only suitable for normal temperature conditions. Due to the low temperature of the shallow surface layer of the plateau, and the fact that the rock joints and fissures are rich in melted snow water from the top of the mountains and low-temperature water seeping from the ice lake at the foot of the mountain, the temperature of grouting construction is at a relatively low level. Low temperature affects the early strength development of conventional grouting materials, making it difficult to achieve the same effect at normal temperature. Summary of the invention

[0003] The invention provides an ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment, a preparation method and an application thereof, aiming to achieve rapid repair of extremely narrow cracks in a high-cold environment.

[0004] Based on this, the present invention provides the following technical solutions:

[0005] The first aspect of the present invention provides an ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment. The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment is composed of the following raw materials in parts by weight: 4000-8000 parts of sulphoaluminate cement clinker, 500-1000 parts of dihydrate gypsum, 500-1000 parts of ordinary Portland cement, 200-1000 parts of silica fume, 200-1000 parts of limestone powder, 1000-2000 parts of slag, 1-5 parts of lithium carbonate, 20-30 parts of boric acid, 20-30 parts of polycarboxylic acid water reducer, 1-10 parts of thickener, 10-80 parts of calcium formate, and 3500-4000 parts of water.

[0006] In combination with the first aspect of the present invention, in some embodiments, the water-to-cement ratio of the ultra-fine grouting material for repairing narrow cracks in concrete in an alpine environment is 0.3-0.4; preferably, the water-to-cement ratio of the ultra-fine grouting material for repairing narrow cracks in concrete in an alpine environment is 0.35.

[0007] In conjunction with the first aspect of the present invention, in some embodiments, the temperature of the water is 1-5°C.

[0008] In combination with the first aspect of the present invention, in some embodiments, the content of calcium formate is 50 parts.

[0009] In conjunction with the first aspect of the present invention, in some implementation modes:

[0010] The Fe2O3 content in the sulphoaluminate cement clinker is not less than 5wt%; and / or,

[0011] The CaO content in the slag is not less than 40wt%; and / or,

[0012] The ordinary Portland cement is labeled PO 42.5; and / or,

[0013] The CaSO4·2H2O content in the dihydrate gypsum is not less than 97%; and / or,

[0014] The CaCO3 content of the limestone powder is not less than 95%; and / or,

[0015] The specific surface area of ​​the silica fume is not less than 21000m 2 / kg; and / or,

[0016] The thickener is hydroxypropyl methylcellulose; and / or,

[0017] The polycarboxylate water reducer is one of Sika, BASF and Clariant.

[0018] A second aspect of the present invention provides a method for repairing concrete cracks in a high-cold environment, comprising:

[0019] Under natural conditions, the ultra-fine grouting material for repairing narrow cracks in high-cold environments concrete is mixed into slurry;

[0020] Inject the slurry into the cracks of concrete or rock and allow to cure naturally for one day.

[0021] In conjunction with the second aspect of the present invention, in some embodiments, the temperature of the natural environment is -5 to 5°C.

[0022] In conjunction with the second aspect of the present invention, in some embodiments, the width of the crack is less than 1 mm.

[0023] In conjunction with the second aspect of the present invention, in some embodiments, the temperature of the water does not exceed 5°C.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] 1. Compared with existing cement-based repair materials, the grouting material provided by the present invention does not contain aggregates, can enter cracks with a size of less than 0.05 mm, and prevent the expansion of extremely narrow cracks.

[0026] 2. The grouting material provided by the present invention can be directly mixed with water at a temperature of less than 5° C. in a cold environment, which also slows down the increase in viscosity of the slurry and provides a longer operable time in a cold environment.

[0027] 3. The grouting material provided by the present invention has a fast hydration speed. After being injected into the cracks under pressure, it can reach the predetermined compressive and flexural strengths within 1 day in a cold environment, and can then be coated with a waterproof coating or other protective coatings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the present invention will be described in detail below in conjunction with the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor.

[0029] Figure 1 This is a diagram showing the mechanism of action of each component of ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment;

[0030] Figure 2 The solidification and demoulding conditions of the grouting materials of Examples 1 to 4 and Comparative Example 1 under -3 to 3°C environmental conditions;

[0031] Figure 3 The solidification and demoulding conditions of the grouting material of Comparative Example 10 under -3 to 3°C environmental conditions;

[0032] Figure 4 The fluidity development curve of the grouting materials of Examples 1 to 4 and Comparative Example 1 within 1 hour under -3 to 3°C environmental conditions;

[0033] Figure 5 It is the expansion rate development curve of the grouting materials of Examples 1 to 4 and Comparative Example 1 at 28 days of age under -3 to 3°C environmental conditions. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] For simplicity, the present invention only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unclearly recorded range; and any lower limit can be combined with other lower limits to form an unclearly recorded range. Similarly, any upper limit can be combined with any other upper limit to form an unclearly recorded range. In addition, although not clearly recorded, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unclearly recorded range.

[0036] It should be noted that, in the description of the present invention, unless otherwise specified, "above" and "below" are inclusive numbers, and the meaning of "multiple" in "one or more" is two or more. Relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements.

[0037] In the description of the present invention, the description with reference to the terms "any embodiment / method", "one embodiment / method", "some embodiments / methods", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, without contradiction.

[0038] The above summary of the invention of the present invention is not intended to describe each disclosed embodiment or each implementation in the present invention. The following description more specifically illustrates exemplary embodiments. These embodiments can be used in various combinations. In each example, the enumeration is only used as a representative group and should not be interpreted as exhaustive.

[0039] Ultra-fine grouting materials for repairing narrow cracks in concrete in high-cold environments:

[0040] As described in the background technology, the existing grouting materials have a slow hydration rate and slow strength growth in severe cold environments. In order to increase the strength growth rate of the grouting materials, warm water is added in the field to increase the hydration rate of cement, but the addition of warm water shortens the operable time of the grouting materials, and may even make the grouting materials too viscous and too fluid, making it impossible to smoothly enter the slits, and placing high operational requirements on construction personnel. In addition, general grouting materials are added with aggregates, and the presence of aggregates can improve the compressive strength and flexural strength of the grouting materials, but at the same time, it also makes it impossible for the grouting materials to enter the slits. Although omitting aggregates can make it possible for the grouting materials to enter the slits, it will reduce the strength of the grouting materials and increase the shrinkage rate, resulting in poor repair effects on the slits.

[0041] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided by the present invention is composed of the following raw materials in parts by weight: 4000-8000 parts of sulphoaluminate cement clinker, 500-1000 parts of dihydrate gypsum, 500-1000 parts of ordinary Portland cement, 200-1000 parts of silica fume, 200-1000 parts of limestone powder, 1000-2000 parts of slag, 1-5 parts of lithium carbonate, 20-30 parts of boric acid, 20-30 parts of polycarboxylate water reducer, 1-10 parts of thickener, 10-80 parts of calcium formate, and 3500-4000 parts of water.

[0042] The grouting material of the present invention does not add aggregate, so the grouting material can enter the slit; at the same time, the grouting material of the present invention uses cold water, so the operation time is long; the grouting material of the present invention is compounded with six cementitious materials, namely, sulphoaluminate cement clinker, dihydrate gypsum, ordinary Portland cement, silica fume, limestone powder, and slag, so that the grouting material has good fluidity and fast hydration speed in a cold environment, and the 1-day flexural strength and compressive strength can meet the requirements, and then the grouting device can be removed, and waterproof and UV-proof coatings can be constructed. At the same time, the grouting material has the advantage of micro-expansion in volume, which can avoid shrinkage cracks in the slit repair part.

[0043] In the grouting material of the present invention, sulphoaluminate cement and ordinary silicate cement have the effect of promoting each other's hydration; dihydrate gypsum provides raw materials for the hydration of sulphoaluminate cement, which can accelerate the hydration reaction and the coagulation of the grouting material; silica fume has a small particle size, a large specific surface area, and extremely strong surface activity. After mixing with cement materials, the volcanic ash effect and micro-aggregate effect can make the slurry structure more compact; slag has stable chemical components, which can replace the fly ash widely used in traditional grouting materials, reduce the shrinkage of the slurry during the hydration process, and effectively improve the stability of the slurry; calcium formate can improve the crystal morphology of the main hydration products, improve the skeleton strength of the grouting material, and thus further improve the overall strength. In addition, the present invention incorporates a large proportion of mineral waste residues such as silica fume and slag into the grouting material, which promotes the conversion and utilization of industrial waste.

[0044] The water-cement ratio of the ultrafine grouting material for repairing narrow cracks in concrete in a high-cold environment is controlled to be 0.3-0.4; preferably, the water-cement ratio of the ultrafine grouting material for repairing narrow cracks in concrete in a high-cold environment is 0.35. This water-cement ratio can ensure that the grouting material has high fluidity and high strength, and avoid large shrinkage of the grouting material. The water-cement ratio of the ultrafine grouting material for repairing narrow cracks in concrete in a high-cold environment is controlled to be 5-8:1.

[0045] The role of calcium formate in the grouting material of the present invention is to serve as an additional early strength agent for cement. Preferably, the content of calcium formate is 50 parts. The present invention also attempts to add aluminum sulfate and triethanolamine, which are also cement early strength agents, and tests the initial fluidity of the grouting material and the strength after solidification for 1 day. As shown in Table 1, the early compressive strength of concrete is insufficient after aluminum sulfate and triethanolamine replace calcium formate.

[0046] The Fe2O3 content in the sulphoaluminate cement clinker used in the embodiment of the present invention is 5wt%, the CaO content in the slag is 40wt%, the ordinary Portland cement is PO 42.5 slag, the CaSO4·2H2O content in the dihydrate gypsum is 97wt%, the CaCO3 content in the limestone powder is 95wt%, and the specific surface area of ​​the silica fume is 21000m 2 / kg, the thickener is hydroxypropyl methylcellulose, the polycarboxylate water reducer is Sika, BASF or Clariant can also be used. In order to ensure that the test results are not lower than the results listed in the embodiments of the present invention, the material property values ​​selected by those skilled in the art should not be lower than the values ​​selected by the present invention, that is:

[0047] The Fe2O3 content in the sulphoaluminate cement clinker is not less than 5wt%; and / or,

[0048] The CaO content in the slag is not less than 40wt%; and / or,

[0049] Ordinary Portland cement with the designation PO 42.5; and / or,

[0050] The CaSO4·2H2O content in the dihydrate gypsum is not less than 97wt%; and / or,

[0051] The CaCO3 content in the limestone powder is not less than 95wt%; and / or,

[0052] The specific surface area of ​​silica fume is not less than 21000m 2 / kg; and / or,

[0053] The thickener is hydroxypropyl methylcellulose; and / or,

[0054] Polycarboxylate water reducer is one of the products from Sika, BASF and Clariant.

[0055] Methods for repairing narrow cracks in concrete in high-cold environments:

[0056] The invention provides a method for repairing narrow cracks in concrete in a high-cold environment, comprising:

[0057] Under natural conditions, the ultra-fine grouting material for repairing narrow cracks in high-cold environments concrete is mixed into slurry;

[0058] Inject the slurry into the cracks of concrete or rock and allow to cure naturally for one day.

[0059] In conjunction with the second aspect of the present invention, in some embodiments, the temperature of the natural environment is -5 to 5°C.

[0060] In conjunction with the second aspect of the present invention, in some embodiments, the width of the crack is less than 1 mm. Preferably, the width of the crack is less than 0.5 mm; further, the width of the crack is less than 0.1 mm.

[0061] In conjunction with the second aspect of the present invention, in some embodiments, the temperature of water used in the grouting material is 1-5°C.

[0062] Example

[0063] Below, the embodiment of the present invention is described. The embodiment described below is exemplary, is only used to explain the present invention, and cannot be interpreted as limiting the present invention. If no specific technology or conditions are indicated in the embodiment, the technology or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments is not indicated, they are all conventional products that can be obtained commercially.

[0064] Embodiment 1:

[0065] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this embodiment is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylate water reducer, 10 parts of hydroxypropyl methylcellulose, 30 parts of calcium formate, and 3500 parts of 3°C water.

[0066] The preparation method of the ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment comprises the following specific steps:

[0067] First, sulphoaluminate cement clinker, dihydrate gypsum, ordinary Portland cement, silica fume, limestone powder and slag are mixed to obtain component A; then lithium carbonate, boric acid, polycarboxylic acid water reducer and hydroxypropyl methylcellulose are mixed to obtain component B; finally, calcium formate is dissolved in water to obtain component C. Component A is placed in a mixer and stirred at low speed for 1-3 minutes to mix evenly, and component B is evenly added to the mixing pot while stirring. After stirring, keep the mixer stirring at low speed, and slowly pour component C into the mixing pot at a uniform speed and stir for 30 seconds before stopping stirring. Use a scraper to scrape off the slurry deposited on the bottom of the mixing pot to ensure that there is no block deposition and attachment on the surface of the mixing pot. Finally, stir quickly for 1-2 minutes to fully mix the slurry to obtain the grouting material.

[0068] Embodiment 2:

[0069] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this embodiment is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylate water reducer, 10 parts of hydroxypropyl methylcellulose, 50 parts of calcium formate, and 3500 parts of 3°C water.

[0070] The preparation method of the ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment comprises the following specific steps:

[0071] First, sulphoaluminate cement clinker, dihydrate gypsum, ordinary Portland cement, silica fume, limestone powder and slag are mixed to obtain component A; then lithium carbonate, boric acid, polycarboxylic acid water reducer and hydroxypropyl methylcellulose are mixed to obtain component B; finally, calcium formate is dissolved in water to obtain component C. Component A is placed in a mixer and stirred at low speed for 1-3 minutes to mix evenly, and component B is evenly added to the mixing pot while stirring. After stirring, keep the mixer stirring at low speed, and slowly pour component C into the mixing pot at a uniform speed and stir for 30 seconds before stopping stirring. Use a scraper to scrape off the slurry deposited on the bottom of the mixing pot to ensure that there is no block deposition and attachment on the surface of the mixing pot. Finally, stir quickly for 1-2 minutes to fully mix the slurry to obtain the grouting material.

[0072] Embodiment 3:

[0073] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this embodiment is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylate water reducer, 10 parts of hydroxypropyl methylcellulose, 100 parts of calcium formate, and 3500 parts of 3°C water.

[0074] The specific steps of the preparation method of the above-mentioned ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment are consistent with those of Example 1.

[0075] Embodiment 4:

[0076] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this embodiment is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylic acid water reducer, 10 parts of hydroxypropyl methylcellulose, 150 parts of calcium formate, and 3500 parts of 3°C water.

[0077] The specific steps of the preparation method of the above-mentioned ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment are consistent with those of Example 1.

[0078] Embodiment 5:

[0079] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this embodiment is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylate water reducer, 10 parts of hydroxypropyl methylcellulose, 200 parts of calcium formate, and 3500 parts of 3°C water.

[0080] The specific steps of the preparation method of the above-mentioned ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment are consistent with those of Example 1.

[0081] Comparative Example 1:

[0082] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this comparative example is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylic acid water reducer, 10 parts of hydroxypropyl methylcellulose, and 3500 parts of 3°C water.

[0083] The preparation method of the above grouting material comprises the following specific steps:

[0084] First, sulphoaluminate cement clinker, dihydrate gypsum, ordinary Portland cement, silica fume, limestone powder and slag are mixed to obtain component A; then lithium carbonate, boric acid, polycarboxylic acid water reducer and hydroxypropyl methylcellulose are mixed to obtain component B; component A is placed in a mixer and stirred at low speed for 1-3 minutes to mix evenly, and component B is evenly added to the mixing pot while stirring. After stirring, keep the mixer stirring at a low speed, and slowly pour water into the mixing pot at a uniform speed and stir for 30 seconds before stopping stirring. Use a scraper to scrape off the slurry deposited on the bottom of the mixing pot to ensure that there is no block deposition and attachment on the surface of the mixing pot. Finally, stir quickly for 1-2 minutes to fully mix the slurry and obtain the grouting material.

[0085] Comparative Example 2:

[0086] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this comparative example is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylic acid water reducer, 10 parts of hydroxypropyl methylcellulose, 10 parts of triethanolamine, and 3500 parts of 3°C water.

[0087] The specific steps of the preparation method of the above-mentioned ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment are consistent with those of Example 1.

[0088] Comparative Example 3:

[0089] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this comparative example is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylic acid water reducer, 10 parts of hydroxypropyl methylcellulose, 20 parts of triethanolamine, and 3500 parts of 3°C water.

[0090] The specific steps of the preparation method of the above-mentioned ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment are consistent with those of Example 1.

[0091] Comparative Example 4:

[0092] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this comparative example is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylic acid water reducer, 10 parts of hydroxypropyl methylcellulose, 40 parts of triethanolamine, and 3500 parts of 3°C water.

[0093] The specific steps of the preparation method of the above-mentioned ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment are consistent with those of Example 1.

[0094] Comparative Example 5:

[0095] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this comparative example is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylic acid water reducer, 10 parts of hydroxypropyl methylcellulose, 60 parts of triethanolamine, and 3500 parts of 3°C water.

[0096] The specific steps of the preparation method of the above-mentioned ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment are consistent with those of Example 1.

[0097] Comparative Example 6:

[0098] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this comparative example is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylic acid water reducer, 10 parts of hydroxypropyl methylcellulose, 50 parts of aluminum sulfate, and 3500 parts of 3°C water.

[0099] The specific steps of the preparation method of the above-mentioned ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment are consistent with those of Example 1.

[0100] Comparative Example 7:

[0101] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this comparative example is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylic acid water reducer, 10 parts of hydroxypropyl methylcellulose, 100 parts of aluminum sulfate, and 3500 parts of 3°C water.

[0102] The specific steps of the preparation method of the above-mentioned ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment are consistent with those of Example 1.

[0103] Comparative Example 8:

[0104] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this comparative example is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylic acid water reducer, 10 parts of hydroxypropyl methylcellulose, 200 parts of aluminum sulfate, and 3500 parts of 3°C water.

[0105] The specific steps of the preparation method of the above-mentioned ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment are consistent with those of Example 1.

[0106] Comparative Example 9:

[0107] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this comparative example is composed of the following raw materials in parts by weight: 4500 parts of sulphoaluminate cement clinker, 800 parts of dihydrate gypsum, 700 parts of ordinary Portland cement, 1000 parts of silica fume, 1000 parts of limestone powder, 2000 parts of slag, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylic acid water reducer, 10 parts of hydroxypropyl methylcellulose, 300 parts of aluminum sulfate, and 3500 parts of 3°C water.

[0108] The specific steps of the preparation method of the above-mentioned ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment are consistent with those of Example 1.

[0109] Comparative Example 10:

[0110] The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment provided in this comparative example is composed of the following raw materials in parts by weight: 10,000 parts of ordinary Portland cement, 5 parts of lithium carbonate, 30 parts of boric acid, 20 parts of polycarboxylic acid water reducer, 10 parts of hydroxypropyl methylcellulose, and 3,500 parts of 3°C water.

[0111] The preparation method of the ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment comprises the following specific steps:

[0112] First, stir the ordinary Portland cement evenly to obtain component A; then mix lithium carbonate, boric acid, polycarboxylic acid water reducer and hydroxypropyl methylcellulose to obtain component B; place component A in a mixer and stir at low speed for 1-3 minutes to mix evenly, and add component B evenly into the mixing pot while stirring. After stirring, keep the mixer stirring at low speed, and slowly pour water into the mixing pot at a uniform speed and stir for 30 seconds before stopping stirring. Use a scraper to scrape off the slurry deposited on the bottom of the mixing pot to ensure that there is no block deposition and attachment on the surface of the mixing pot. Finally, stir quickly for 1-2 minutes to fully mix the slurry and obtain the grouting material.

[0113] Under -3 to 3°C environmental conditions, the properties of the grouting materials obtained in each embodiment and comparative example were tested. The fluidity was referenced to "GB / T 8077-2012 Test Method for Homogeneity of Concrete Admixtures", the strength was referenced to "GB / T 17671-2021 Test Method for Strength of Cement Mortar (ISO Method)", and the expansion rate was referenced to "JC / T 313-2009 Test Method for Expansion Rate of Expansive Cement". The strength and fluidity test results are shown in Table 1.

[0114] Table 1 Performance test results of grouting materials under -3~3℃ environmental conditions

[0115]

[0116]

[0117] From Table 1, Examples 1 to 5 of the present invention provide ultra-fine grouting materials for repairing narrow cracks in high-cold environments concrete, which are mixed with different contents of calcium formate, that is, the mix ratio of the present invention; Comparative Example 1 is a mix ratio without early strength agent; Comparative Examples 2 to 5 are mix ratios mixed with different contents of triethanolamine; Comparative Examples 6 to 9 are mix ratios mixed with different contents of aluminum sulfate; Comparative Example 10 is a mix ratio containing only ordinary Portland cement;

[0118] Figure 4 The initial fluidity and flexural and compressive strength properties of the grouting materials of Examples 1 to 4 and Comparative Example 1 are shown. By comparing Examples 1 to 4 with Comparative Example 1, it can be seen that the amount of calcium formate has a great influence on the performance of the grouting material, and Example 2 has the best effect.

[0119] Comparison of Example 2 with Comparative Example 10 shows that the curing properties of the grouting material of the present invention and the grouting material made of ordinary Portland cement under low temperature conditions are greatly different.

[0120] By comparing Example 2 with Comparative Examples 2 to 5 and Comparative Examples 6 to 9, it can be found that triethanolamine and aluminum sulfate have no beneficial effect on improving the early strength, while calcium formate can improve the early strength of the grouting material.

[0121] Figure 2 and Figure 3 This indicates that the grouting material prepared with ordinary silicate cement cannot solidify under low temperature conditions, while the grouting material provided by the present invention can solidify and demould normally.

[0122] Figure 4 The results show that the fluidity loss of the grouting material provided by the present invention within 1 hour is different from that of the grouting materials containing different calcium formate contents. As the calcium formate content increases, the ability of the grouting material to maintain fluidity first increases and then decreases.

[0123] Figure 5 The expansion rate development curve of the grouting material specimen within the standard age of 28 days is displayed, which illustrates that the expansion rates of grouting materials with different calcium formate contents are different. With the increase of calcium formate content, the expansion rate of the specimen in the stable stage increases first and then decreases.

[0124] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment, characterized by: The ultra-fine grouting material for repairing narrow cracks in concrete in a high-cold environment is composed of the following raw materials in parts by weight: 4000-8000 parts of sulphoaluminate cement clinker, 500-1000 parts of dihydrate gypsum, 500-1000 parts of ordinary Portland cement, 200-1000 parts of silica fume, 200-1000 parts of limestone powder, 1000-2000 parts of slag, 1-5 parts of lithium carbonate, 20-30 parts of boric acid, 20-30 parts of polycarboxylic acid water reducer, 1-10 parts of thickener, 10-80 parts of calcium formate, and 3500-4000 parts of water.

2. The ultra-fine grouting material for repairing narrow cracks in concrete in high-cold environments according to claim 1 is characterized by: The water-to-cement ratio of the ultra-fine grouting material for repairing narrow cracks in concrete in high-cold environments is 0.3-0.

4.

3. The ultra-fine grouting material for repairing narrow cracks in concrete in high-cold environments according to claim 2 is characterized by: The water-to-cement ratio of the ultra-fine grouting material for repairing narrow cracks in concrete in high-cold environments is 0.

35.

4. The ultra-fine grouting material for repairing narrow cracks in concrete in high-cold environments according to claim 1 is characterized by: The water temperature is 1-5°C.

5. The ultra-fine grouting material for repairing narrow cracks in concrete in high-cold environments according to claim 1 is characterized by: The content of calcium formate is 50 parts.

6. The ultra-fine grouting material for repairing narrow cracks in concrete in high-cold environments according to claim 1 is characterized by: The Fe2O3 content in the sulphoaluminate cement clinker is not less than 5wt%; and / or, The CaO content in the slag is not less than 40wt%; and / or, The ordinary Portland cement is labeled PO 42.5; and / or, The CaSO4·2H2O content in the dihydrate gypsum is not less than 97%; and / or, The CaCO3 content of the limestone powder is not less than 95%; and / or, The specific surface area of ​​the silica fume is not less than 21000m 2 / kg; and / or, The thickener is hydroxypropyl methylcellulose; and / or, The polycarboxylate water reducer is one of Sika, BASF and Clariant.

7. A method for repairing narrow cracks in concrete in a high-cold environment, characterized in that: include: Under severe cold temperatures, the ultra-fine grouting material for repairing narrow cracks in high-cold environment concrete according to any one of claims 1 to 6 is mixed into a slurry; Inject the slurry into the cracks of concrete or rock and allow to cure naturally for one day.

8. The method for repairing narrow cracks in concrete in a high-cold environment according to claim 7, characterized in that: The severe cold temperature is -5 to 5℃.

9. The method for repairing narrow cracks in concrete in a high-cold environment according to claim 7, characterized in that: The width of the crack is less than 1mm.

10. The method for repairing narrow cracks in concrete in a high-cold environment according to claim 7, characterized in that: The temperature of the water used for the grouting material is 1 to 5°C.

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