A kind of antifreeze concrete and preparation method thereof

Abstract

This invention discloses an antifreeze concrete and its preparation method, comprising the following raw materials in parts by weight: cement: 300-400 parts; fly ash: 70-80 parts; sand: 600-700 parts; aggregate: 1000-1100 parts; water-reducing agent: 5-10 parts; water: 130-150 parts; air-entraining agent: 1.5-2.5 parts; modified basalt fiber: 50-80 parts; polyacrylonitrile fiber: 20-30 parts; hydroxyethyl cellulose: 10-20 parts; wherein the modified basalt fiber is prepared by modifying basalt fiber with ethanol, nitric acid, polyacrylate, and hydrazine hydrate. This application has the effect of improving the freeze-thaw resistance of concrete.

Description

Technical Field

[0001] The invention relates to the field of concrete, and in particular to frost-resistant concrete and a preparation method thereof. Background Art

[0002] Concrete is a general term for engineering composite materials that are made of aggregates bonded together by cementitious materials. Generally speaking, concrete refers to cement as a cementitious material, sand and stone as aggregates, and water in a certain proportion, and the resulting cement concrete is mixed and can be widely used in civil engineering.

[0003] As one of the most common and important building materials, concrete is now widely used in various fields. There are concretes with different functional properties on the market for different applications. For example, concrete used in cold areas is generally made by adding air entraining agents to the concrete so that the concrete can be used normally in cold areas and has anti-freeze properties.

[0004] With respect to the above-mentioned related technologies, the inventors have found that in cold regions, in addition to being easily melted by deicing salt or snow-melting agents on the surface of concrete, concrete is also easily damaged during the freezing and thawing process. Summary of the invention

[0005] In order to improve the freeze-thaw resistance of concrete, the present application provides a freeze-resistant concrete and a preparation method thereof.

[0006] In the first aspect, the present application provides an antifreeze concrete adopting the following technical solution:

[0007] A frost-resistant concrete is made of the following raw materials in parts by weight:

[0008] Cement: 300-400 parts;

[0009] Fly ash: 70-80 parts;

[0010] Sand: 600-700 parts;

[0011] Stone: 1000-1100 parts;

[0012] Water reducing agent: 5-10 parts;

[0013] Water: 130-150 parts;

[0014] Air entraining agent: 1.5-2.5 parts;

[0015] Modified basalt fiber: 50-80 parts;

[0016] Polyacrylonitrile fiber: 20-30 parts;

[0017] Hydroxyethyl cellulose: 10-20 parts;

[0018] The modified basalt fiber is prepared by modifying basalt fiber, ethanol, nitric acid, polyacrylate and hydrazine hydrate.

[0019] By adopting the above technical scheme, the present application adds air entraining agent to the concrete raw materials, introduces pores into the concrete, increases the activity space of water during freezing and swelling, and the air bubbles can buffer the pressure generated when the water inside the concrete freezes and thaws, reduce the concrete cracking caused by excessive pressure, and thus improve the anti-freeze performance of the concrete; at the same time, the present application also adds modified basalt fiber, polyacrylonitrile fiber and hydroxyethyl cellulose, wherein the basalt fiber is modified by ethanol, nitric acid, polyacrylate, and hydrazine hydrate, so that the modified basalt fiber is closely mixed with the polyacrylate, has good mechanical properties and chemical stability, improves the workability of the concrete mixture, improves the fluidity of the concrete, gives full play to the adhesion of the polyacrylate, makes the sand and stone of the concrete raw materials closely connected together, and a variety of fibers are mixed and distributed in the concrete mixture, which improves the bonding strength in the concrete, makes it difficult for cracks to occur in the concrete, and thus greatly improves the anti-freeze and thaw performance of the concrete.

[0020] Preferably, the preparation method of the modified basalt is as follows: 20-40 parts by weight of basalt fiber are soaked in 40-50 parts by weight of ethanol and 40-50 parts by weight of nitric acid solution in sequence, and then rinsed and dried to obtain dry basalt fiber; after mixing and stirring the dry basalt fiber with 10-20 parts by weight of polyacrylate, 5-10 parts by weight of hydrazine hydrate are added, heated and stirred, and the modified basalt fiber is obtained after washing and drying; the weight ratio of the basalt fiber, polyacrylate and hydrazine hydrate is 1:(0.5-0.6):(0.15-0.2).

[0021] By adopting the above technical scheme, the basalt fiber is firstly immersed in ethanol and nitric acid in sequence to destroy the smooth surface of the basalt fiber, so that the concrete mixture can have a larger contact area and meshing degree with the basalt fiber, thereby improving the freeze-thaw resistance of the concrete; the basalt fiber is then mixed with polyacrylate and hydrazine hydrate to increase the roughness and chemical reaction activity of the basalt fiber surface, improve the bonding degree between the basalt fiber and the concrete mixture, and then make the modified basalt fiber bond more stably with other raw materials, thereby improving the freeze-thaw resistance of the concrete; when the basalt fiber, polyacrylate and hydrazine hydrate are in a specific weight ratio, the modified basalt fiber can effectively reduce the porosity in the concrete, so that the concrete has better compactness, thereby improving the slump of the concrete.

[0022] Preferably, the hydrazine hydrate is pretreated hydrazine hydrate, and the pretreatment method of the pretreated hydrazine hydrate is: 20-40 parts by weight of hydrazine hydrate and 10-20 parts by weight of guar gum are mixed and heated for 1-2 hours, and then washed and dried to obtain the pretreated hydrazine hydrate.

[0023] By adopting the above technical scheme, the present application pre-treats hydrazine hydrate and mixes hydrazine hydrate with guar gum, so that the bonding performance of the pre-treated hydrazine hydrate is stronger, and it can be evenly dispersed on the surface of basalt fiber, thereby improving the bonding performance of modified basalt fiber and further improving the freeze-thaw resistance of concrete.

[0024] Preferably, the hydroxyethyl cellulose is modified hydroxyethyl cellulose, and the preparation method of the modified hydroxyethyl cellulose is: after mixing 10-20 parts by weight of nano-silicon dioxide and 20-30 parts by weight of propylene glycol, 5-10 parts by weight of toluene diisocyanate are added, heated and stirred in a water bath, and then 10-20 parts by weight of hydroxyethyl cellulose and 5-10 parts by weight of dimethyl methylphosphonate are added, stirred, and then cooled to room temperature to obtain the modified hydroxyethyl cellulose; the weight ratio of the nano-silicon dioxide, toluene diisocyanate, hydroxyethyl cellulose and dimethyl methylphosphonate is (0.8-1):(0.5-0.7):1:(1-1.2).

[0025] By adopting the above technical scheme, the present application modifies hydroxyethyl cellulose, and toluene diisocyanate and dimethyl methylphosphonate fully attach nano-silicon dioxide to the surface of hydroxyethyl cellulose with good bonding effect. The modified hydroxyethyl cellulose can be more evenly dispersed in the concrete mixture, thereby improving the compactness inside the concrete, and further improving the frost resistance of the concrete; when nano-silicon dioxide, toluene diisocyanate, hydroxyethyl cellulose and dimethyl methylphosphonate are in a specific weight ratio, in addition to improving the freeze-thaw resistance of the concrete, the nano-silicon dioxide attached to the hydroxyethyl cellulose can fill the capillary channels blocked inside the concrete, reduce the water absorption of the concrete, and improve the anti-penetration performance of the concrete.

[0026] Preferably, the weight ratio of the modified basalt fiber, polyacrylonitrile fiber and modified hydroxyethyl cellulose is (2.8-3):1:(0.44-0.48).

[0027] By adopting the above technical scheme, when modified basalt fiber, polyacrylonitrile fiber and modified hydroxyethyl cellulose are in a specific weight ratio, the fluidity of the concrete mixture can be improved, and a variety of fibers are attached to the surface of the concrete mixture, delaying the generation of cracks on the surface and inside of the concrete, improving the density of the concrete, and thereby improving the freeze-thaw resistance and anti-penetration ability of the concrete.

[0028] Preferably, the water reducing agent includes one of sodium lignin sulfonate, calcium lignin sulfonate and magnesium lignin sulfonate.

[0029] Preferably, the air entraining agent includes one or more of fatty alcohol polyoxyethylene ether, fatty alcohol polyoxyethylene sulfonate sodium, triterpene saponin, and rosin soap.

[0030] Preferably, the length of the polyacrylonitrile fiber is 10-20 mm.

[0031] By adopting the above technical scheme, the present application adopts the above-mentioned water reducer and air entraining agent to effectively improve the freeze-thaw resistance of concrete, while controlling the length of polyacrylonitrile fiber so that the polyacrylonitrile fiber can be filled in the gaps in the concrete mixture, thereby improving the freeze resistance of concrete.

[0032] In a second aspect, the present application provides a method for preparing frost-resistant concrete using the following technical solution:

[0033] A method for preparing frost-resistant concrete comprises the following steps:

[0034] Cement, modified basalt fiber, polyacrylonitrile fiber and hydroxyethyl cellulose are mixed and stirred, and then sand, stone and water are added and stirred evenly to obtain a premix;

[0035] A water reducing agent and an air entraining agent are added to the premix, and the mixture is stirred evenly to obtain the antifreeze concrete.

[0036] By adopting the above technical scheme, the raw materials of the antifreeze concrete are mixed evenly in steps, and then admixtures such as water reducing agent and air entraining agent are added, so that concrete with better anti-freeze and thaw effect can be produced.

[0037] In summary, this application has the following beneficial technical effects:

[0038] 1. The present application adds air entraining agent to the concrete raw materials, introduces pores into the concrete, increases the activity space of water during freezing and swelling, and the air bubbles can buffer the pressure generated when the water inside the concrete freezes and thaws, reduce the concrete cracking caused by excessive pressure, and thus improve the anti-freeze performance of the concrete; at the same time, the present application also adds modified basalt fiber, polyacrylonitrile fiber and hydroxyethyl cellulose, wherein the basalt fiber is modified by ethanol, nitric acid, polyacrylate, and hydrazine hydrate, so that the modified basalt fiber is closely mixed with the polyacrylate, has good mechanical properties and chemical stability, improves the workability of the concrete mixture, improves the fluidity of the concrete, gives full play to the adhesion of the polyacrylate, makes the sand and stone of the concrete raw materials closely connected together, and a variety of fibers are mixed and distributed in the concrete mixture, which improves the bonding strength in the concrete, makes it difficult for cracks to occur inside the concrete, and thus greatly improves the anti-freeze and thaw performance of the concrete.

[0039] 2. The present application modifies hydroxyethyl cellulose, and toluene diisocyanate and dimethyl methylphosphonate fully attach nano-silica to the surface of hydroxyethyl cellulose with good bonding effect. The modified hydroxyethyl cellulose can be more evenly dispersed in the concrete mixture, thereby improving the compactness inside the concrete, and further improving the frost resistance of the concrete. When nano-silica, toluene diisocyanate, hydroxyethyl cellulose and dimethyl methylphosphonate are in a specific weight ratio, in addition to improving the freeze-thaw resistance of the concrete, the nano-silica attached to the hydroxyethyl cellulose can fill the capillary channels blocked inside the concrete, reduce the water absorption of the concrete, and improve the anti-penetration performance of the concrete.

[0040] 3. When modified basalt fiber, polyacrylonitrile fiber and modified hydroxyethyl cellulose are in a specific weight ratio, the fluidity of the concrete mixture can be improved. Various fibers are attached to the surface of the concrete mixture, delaying the generation of cracks on the surface and inside of the concrete, improving the density of the concrete, and thus improving the freeze-thaw resistance and anti-penetration ability of the concrete. DETAILED DESCRIPTION

[0041] The present application is further described in detail below in conjunction with embodiments and comparative examples.

[0042] Preparation Example

[0043] Preparation Example 1

[0044] A preparation method of modified hydroxyethyl cellulose:

[0045] 10 kg of nano-silica and 20 kg of propylene glycol were mixed and ultrasonically vibrated for 2 hours, and then 5 kg of toluene diisocyanate was added and heated in a water bath at 60° C. and stirred for 4 hours. Then 10 kg of hydroxyethyl cellulose and 5 kg of dimethyl methylphosphonate were added and stirred for 30 minutes, and then cooled to room temperature to obtain modified hydroxyethyl cellulose.

[0046] Preparation Example 2

[0047] A preparation method of modified hydroxyethyl cellulose:

[0048] 20 kg of nano-silica and 30 kg of propylene glycol were mixed and ultrasonically vibrated for 2 hours, and then 10 kg of toluene diisocyanate was added and heated in a water bath at 60° C. and stirred for 4 hours. Then 20 kg of hydroxyethyl cellulose and 10 kg of dimethyl methylphosphonate were added and stirred for 30 minutes, and then cooled to room temperature to obtain modified hydroxyethyl cellulose.

[0049] Preparation Example 3

[0050] A method for preparing modified hydroxyethyl cellulose is different from Preparation Example 2 in that the input amount of nano-silicon dioxide is 12 kg, the input amount of toluene diisocyanate is 8 kg, the input amount of hydroxyethyl cellulose is 15 kg, and the input amount of dimethyl methylphosphonate is 16 kg.

[0051] Preparation Example 4

[0052] A method for preparing modified hydroxyethyl cellulose is different from Preparation Example 2 in that the input amount of nano-silicon dioxide is 15 kg, the input amount of toluene diisocyanate is 10 kg, the input amount of hydroxyethyl cellulose is 15 kg, and the input amount of dimethyl methylphosphonate is 18 kg.

[0053] Example

[0054] Example 1

[0055] A method for preparing frost-resistant concrete comprises the following steps:

[0056] 30kg of cement, 5kg of modified basalt fiber, 2kg of polyacrylonitrile fiber and 1kg of hydroxyethyl cellulose were put into a mixer and mixed at a temperature of 70°C and a speed of 250r / min for 1min, and then 60kg of sand, 100kg of stone and 13kg of water were added into the mixer and mixed for 3min to obtain a premix;

[0057] 0.5 kg of magnesium lignin sulfonate water reducer and 0.15 kg of fatty alcohol polyoxyethylene ether air entraining agent were added into the premix, and the mixture was stirred evenly to obtain frost-resistant concrete.

[0058] The preparation method of the modified basalt fiber is as follows: 20 kg of basalt fiber is first soaked in 40 kg of ethanol for 6 hours, then ultrasonically treated for 30 minutes, then ultrasonically treated in 40 kg of nitric acid solution at a temperature of 90°C for 10 minutes, then rinsed, and dried at a temperature of 60°C to obtain dry basalt fiber; the dry basalt fiber is mixed with 10 kg of polyacrylate at a speed of 60 r / min and stirred for 20 minutes, then 5 kg of hydrazine hydrate is added, heated to 80°C and stirred for 120 minutes, and then dried at 60°C after washing to obtain the modified basalt fiber.

[0059] Example 2

[0060] A method for preparing frost-resistant concrete comprises the following steps:

[0061] 40kg of cement, 8kg of modified basalt fiber, 3kg of polyacrylonitrile fiber and 2kg of hydroxyethyl cellulose were put into a mixer and mixed for 1min at a temperature of 70°C and a speed of 250r / min, and then 70kg of sand, 110kg of stone and 15kg of water were added into the mixer and mixed for 3min to obtain a premix;

[0062] 1 kg of calcium lignin sulfonate water reducer and 0.25 kg of sodium fatty alcohol polyoxyethylene sulfonate air entraining agent were added to the premix, and the mixture was stirred evenly to obtain frost-resistant concrete.

[0063] The preparation method of the modified basalt fiber is as follows: 20 kg of basalt fiber is first soaked in 40 kg of ethanol for 6 hours, then ultrasonically treated for 30 minutes, then ultrasonically treated in 40 kg of nitric acid solution at a temperature of 90°C for 10 minutes, then rinsed, and dried at a temperature of 60°C to obtain dry basalt fiber; the dry basalt fiber is mixed with 10 kg of polyacrylate at a speed of 60 r / min and stirred for 20 minutes, then 5 kg of hydrazine hydrate is added, heated to 80°C and stirred for 120 minutes, and then dried at 60°C after washing to obtain the modified basalt fiber.

[0064] Example 3

[0065] A method for preparing frost-resistant concrete comprises the following steps:

[0066] 35 kg of cement, 6.5 kg of modified basalt fiber, 2.5 kg of polyacrylonitrile fiber and 1.5 kg of hydroxyethyl cellulose were put into a mixer and mixed for 1 min at a temperature of 70°C and a speed of 250 r / min. Then 6.5 kg of sand, 105 kg of stone and 14 kg of water were added into the mixer and mixed for 3 min to obtain a premix;

[0067] 0.75 kg of sodium lignin sulfonate water reducer and 0.2 kg of triterpenoid saponin air entraining agent were added to the premix, and the mixture was stirred evenly to obtain frost-resistant concrete.

[0068] The preparation method of the modified basalt fiber is as follows: 20 kg of basalt fiber is first soaked in 40 kg of ethanol for 6 hours, then ultrasonically treated for 30 minutes, then ultrasonically treated in 40 kg of nitric acid solution at a temperature of 90°C for 10 minutes, then rinsed, and dried at a temperature of 60°C to obtain dry basalt fiber; the dry basalt fiber is mixed with 10 kg of polyacrylate at a speed of 60 r / min and stirred for 20 minutes, then 5 kg of hydrazine hydrate is added, heated to 80°C and stirred for 120 minutes, and then dried at 60°C after washing to obtain the modified basalt fiber.

[0069] Example 4

[0070] A method for preparing frost-resistant concrete, which is different from Example 3 in that the raw materials for preparing modified basalt are different: 40 kg of basalt fiber is first soaked in 50 kg of ethanol for 6 hours and then ultrasonically treated for 30 minutes, then ultrasonically treated in 50 kg of nitric acid solution at a temperature of 90° C. for 10 minutes and then rinsed, and dried at a temperature of 60° C. to obtain dry basalt fiber; the dry basalt fiber is mixed with 20 kg of polyacrylate at a speed of 60 r / min and stirred for 20 minutes, and then 10 kg of hydrazine hydrate is added, heated to 80° C. and stirred for 120 minutes, and then washed and dried at 60° C. to obtain modified basalt fiber.

[0071] Example 5

[0072] A method for preparing frost-resistant concrete is different from Example 3 in that the input amount of the modified basalt raw materials is different, the input amount of basalt fiber is 30 kg, the input amount of polyacrylate is 16 kg, and the input amount of hydrazine hydrate is 5 kg.

[0073] Example 6

[0074] A method for preparing frost-resistant concrete is different from Example 3 in that the input amount of the modified basalt raw materials is different, the input amount of basalt fiber is 30 kg, the input amount of polyacrylate is 18 kg, and the input amount of hydrazine hydrate is 6 kg.

[0075] Example 7

[0076] A method for preparing frost-resistant concrete, which is different from Example 6 in that hydrazine hydrate is pretreated, wherein the pretreatment method of hydrazine hydrate is: 20 kg of hydrazine hydrate and 10 kg of guar gum are stirred evenly at a temperature of 70° C. for 2 hours, and then washed and dried at 60° C. to obtain pretreated hydrazine hydrate.

[0077] Example 8

[0078] A method for preparing frost-resistant concrete, which is different from Example 6 in that hydrazine hydrate is pretreated, wherein the pretreatment method of hydrazine hydrate is: 40 kg of hydrazine hydrate and 20 kg of guar gum are stirred evenly at a temperature of 70° C. for 2 hours, and then washed and dried at 60° C. to obtain pretreated hydrazine hydrate.

[0079] Example 9

[0080] A method for preparing frost-resistant concrete, which is different from Example 8 in that an equal amount of hydroxyethyl cellulose is replaced by the modified hydroxyethyl cellulose prepared in Preparation Example 1.

[0081] Example 10

[0082] A method for preparing frost-resistant concrete, which is different from Example 8 in that an equal amount of hydroxyethyl cellulose is replaced by the modified hydroxyethyl cellulose prepared in Preparation Example 2.

[0083] Embodiment 11

[0084] A method for preparing frost-resistant concrete, which is different from Example 8 in that an equal amount of hydroxyethyl cellulose is replaced by modified hydroxyethyl cellulose prepared in Preparation Example 3.

[0085] Example 12

[0086] A method for preparing frost-resistant concrete, which is different from Example 8 in that an equal amount of hydroxyethyl cellulose is replaced by modified hydroxyethyl cellulose prepared in Preparation Example 4.

[0087] Embodiment 13

[0088] A method for preparing frost-resistant concrete, which is different from Example 12 in that, in the step of preparing the frost-resistant concrete, the input amount of modified basalt fiber is 7 kg, the input amount of polyacrylonitrile fiber is 2.5 kg, and the input amount of modified hydroxyethyl cellulose prepared in Preparation Example 4 is 1.1 kg.

[0089] Embodiment 14

[0090] A method for preparing frost-resistant concrete, which is different from Example 12 in that, in the step of preparing the frost-resistant concrete, the input amount of modified basalt fiber is 7.5 kg, the input amount of polyacrylonitrile fiber is 2.5 kg, and the input amount of modified hydroxyethyl cellulose prepared in Preparation Example 4 is 1.2 kg.

[0091] Embodiment 15

[0092] A method for preparing frost-resistant concrete, which is different from Example 14 in that an equal amount of the modified hydroxyethyl cellulose prepared in Preparation Example 4 is replaced by hydroxyethyl cellulose.

[0093] Comparative Example

[0094] Comparative Example 1

[0095] A method for preparing frost-resistant concrete, which is different from Example 1 in that an equal amount of modified basalt fiber is replaced with commercially available basalt fiber.

[0096] Comparative Example 2

[0097] A method for preparing frost-resistant concrete, which is different from Example 1 in that an equal amount of polyacrylonitrile fibers are replaced with polyacrylamide fibers.

[0098] Comparative Example 3

[0099] A method for preparing frost-resistant concrete, which is different from Example 1 in that an equal amount of hydroxyethyl fiber is replaced by modified basalt fiber.

[0100] Comparative Example 4

[0101] A method for preparing frost-resistant concrete, which is different from Example 1 in that no polyacrylonitrile fiber is added.

[0102] Comparative Example 5

[0103] A method for preparing frost-resistant concrete, which is different from Example 1 in that hydroxyethyl cellulose is not added.

[0104] Performance level test:

[0105] Freeze-thaw resistance: The concrete prepared in Examples 1-15 and Comparative Examples 1-5 was cut into concrete blocks of 10 cm×10 cm×10 cm, and the quick freezing method in GB / T50082-2009 "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete" was used. The concrete was taken out and immersed in water at 24°C, with the water surface 20 mm higher than the test block. It was taken out after 4 days. At the end of freezing and thawing, the center temperature of the specimen was controlled at -17±2°C and 8±2°C, respectively; each freeze-thaw cycle was completed within 2.5 to 4 hours, and the time used for thawing was not less than 1 / 4 of the entire freeze-thaw cycle. After 150 freeze-thaw cycles, the corresponding test blocks were taken out, the surface of the test blocks was wiped dry with a wet cloth, and the compressive strength was measured.

[0106] Slump: According to GB / T50080-2016 "Standard for Test Methods for Performance of Ordinary Concrete Mixtures", the slump test was performed on the concrete prepared in Examples 1-15 and Comparative Examples 1-5.

[0107] Water penetration resistance: The water penetration depth of standard test blocks made of the concrete prepared in Examples 1-15 and Comparative Examples 1-5 was tested by the step-by-step pressure method in accordance with GB / T50082-2009 "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete".

[0108]

[0109]

[0110] According to the data comparison of Examples 1-4 and Comparative Examples 1-5, the present application modifies the basalt fiber, increases the roughness and chemical reaction activity of the basalt fiber surface, improves the bonding degree between the basalt fiber and the concrete mixture, and thereby enables the modified basalt fiber to bond more stably with other raw materials, thereby improving the freeze-thaw resistance of the concrete.

[0111] According to the data comparison of Example 4 and Examples 5-8, when basalt fiber, polyacrylate and hydrazine hydrate are in a specific weight ratio, the modified basalt fiber can effectively reduce the porosity in the concrete, so that the concrete has better compactness, thereby reducing the slump loss of the concrete.

[0112] According to the data comparison of Example 8 and Examples 9-12, when nano-silica, toluene diisocyanate, hydroxyethyl cellulose and dimethyl methylphosphonate are in a specific weight ratio, in addition to improving the freeze-thaw resistance of concrete, the nano-silica attached to hydroxyethyl cellulose can fill the capillary channels blocked inside the concrete, reduce the water absorption of the concrete, and improve the anti-penetration performance of the concrete.

[0113] According to the data comparison of Examples 12-15, it can be obtained that when the modified basalt fiber, polyacrylonitrile fiber and modified hydroxyethyl cellulose are in a specific weight ratio, the fluidity of the concrete mixture can be improved, and a variety of fibers are attached to the surface of the concrete mixture, delaying the occurrence of cracks on the surface and inside of the concrete, improving the density of the concrete, and thereby improving the freeze-thaw resistance and anti-penetration ability of the concrete.

Claims

1. A frost-resistant concrete, characterized in that: The invention is made of the following raw materials in parts by weight: Cement: 300-400 parts; Fly ash: 70-80 parts; Sand: 600-700 parts; Stone: 1000-1100 parts; Water reducing agent: 5-10 parts; Water: 130-150 parts; Air entraining agent: 1.5-2.5 parts; Modified basalt fiber: 50-80 parts; Polyacrylonitrile fiber: 20-30 parts; Hydroxyethyl cellulose: 10-20 parts; The modified basalt fiber is prepared by modifying basalt fiber, ethanol, nitric acid, polyacrylate and hydrazine hydrate; The preparation method of the modified basalt fiber comprises: soaking 20-40 parts by weight of basalt fiber in 40-50 parts by weight of ethanol and 40-50 parts by weight of nitric acid solution in sequence, and then washing and drying to obtain dry basalt fiber; mixing and stirring the dry basalt fiber with 10-20 parts by weight of polyacrylate, adding 5-10 parts by weight of hydrazine hydrate, heating and stirring, washing and drying to obtain the modified basalt fiber; the weight ratio of the basalt fiber, polyacrylate and hydrazine hydrate is 1: (0.5-0.6): (0.15-0.2); The hydrazine hydrate is pretreated hydrazine hydrate, and the pretreatment method of the pretreated hydrazine hydrate is: 20-40 parts by weight of hydrazine hydrate and 10-20 parts by weight of guar gum are mixed and heated for 1-2 hours, and then washed and dried to obtain the pretreated hydrazine hydrate; The hydroxyethyl cellulose is modified hydroxyethyl cellulose. The preparation method of the modified hydroxyethyl cellulose is as follows: after mixing 10-20 parts by weight of nano silicon dioxide and 20-30 parts by weight of propylene glycol, 5-10 parts by weight of toluene diisocyanate are added, heated and stirred in a water bath, and then 10-20 parts by weight of hydroxyethyl cellulose and 5-10 parts by weight of dimethyl methylphosphonate are added, stirred, and then cooled to room temperature to obtain the modified hydroxyethyl cellulose.

2. The frost-resistant concrete according to claim 1, characterized in that: The weight ratio of the nano silicon dioxide, toluene diisocyanate, hydroxyethyl cellulose and dimethyl methylphosphonate is (0.8-1): (0.5-0.7): 1: (1-1.2).

3. The frost-resistant concrete according to claim 1, characterized in that: The weight ratio of the modified basalt fiber, polyacrylonitrile fiber and modified hydroxyethyl cellulose is (2.8-3):1:(0.44-0.48).

4. The frost-resistant concrete according to claim 1, characterized in that: The water reducing agent includes one of sodium lignin sulfonate, calcium lignin sulfonate and magnesium lignin sulfonate.

5. The frost-resistant concrete according to claim 1, characterized in that: The air entraining agent includes one or more of fatty alcohol polyoxyethylene ether, fatty alcohol polyoxyethylene sodium sulfonate, triterpene saponin, and rosin soap.

6. The frost-resistant concrete according to claim 1, characterized in that: The length of the polyacrylonitrile fiber is 10-20 mm.

7. A method for preparing frost-resistant concrete, used for preparing the frost-resistant concrete according to any one of claims 1 to 6, characterized in that: The following steps are involved: Cement, modified basalt fiber, polyacrylonitrile fiber and hydroxyethyl cellulose are mixed and stirred, and then sand, stone and water are added and stirred evenly to obtain a premix; A water reducing agent and an air entraining agent are added to the premix, and the mixture is stirred evenly to obtain the antifreeze concrete.

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