Environment-friendly high-toughness C30 desert sand hydraulic concrete and preparation method thereof

Abstract

The invention belongs to the technical field of concrete, and particularly relates to environment-friendly high-toughness C30 desert sand hydraulic concrete and a preparation method thereof, and the environment-friendly high-toughness C30 desert sand hydraulic concrete is prepared from the following raw materials in parts by weight: 330-350 parts of cement, 100-110 parts of fly ash, 500-600 parts of aggregate, 10-15 parts of an efficient soil mud activity excitation composite water reducing agent, 0.1-0.5 part of an air entraining agent, 1-10 parts of steel fiber and 150-200 parts of water. Wherein the aggregate comprises medium broken stone, small broken stone and modified desert sand, and the modified desert sand is prepared by the following steps: S1, preparing polyglycolic acid modified polyacrylate; and S2, preparing the polyglycolic acid modified polyacrylate loaded desert sand, namely the modified desert sand. According to the environment-friendly high-toughness C30 desert sand hydraulic concrete disclosed by the invention, the compressive strength and tensile strength of the hydraulic concrete can be improved, the toughness of the hydraulic concrete is enhanced, the compactness and impermeability of the concrete are improved, the service life is prolonged, and the concrete has certain environmental protection property.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete, and specifically relates to an environmentally friendly high-toughness C30 desert sand hydraulic concrete and a preparation method thereof. Background Art

[0002] Hydraulic concrete is a type of concrete specially designed to withstand the effects of water and to ensure the durability of buildings under long-term normal working conditions. It is a necessary material for buildings that are frequently used or periodically subjected to water in water conservancy projects. It is widely used in water conservancy projects such as water conservancy hubs, hydropower stations, embankment projects and port projects, and has unique properties and important application value. Hydraulic concrete has the characteristics of high strength, impermeability, durability and corrosion resistance. It can withstand greater pressure and tension, effectively prevent water penetration, and can remain stable for a long time in harsh environments. However, traditional hydraulic concrete often has low toughness and is prone to cracking under the erosion of salt and water stains, which reduces its service life.

[0003] In the prior art, the building aggregates of hydraulic concrete mainly include sand, gravel, machine-made sand and gravel, etc. The global consumption of sand and gravel resources is about 40 billion to 60 billion tons per year, and the over-exploitation of sand and gravel resources has become an urgent problem to be solved. Desert sand mainly comes from weathering and erosion, which makes the size and shape of sand particles different. These sand particles usually have a rounded shape, and the particle size is usually between 0.1mm-2mm, which makes desert sand have good fluidity and plasticity. However, the smaller particle size of desert sand also causes the hydraulic concrete added with desert sand to have problems such as easy cracking, poor toughness and poor durability. Therefore, it is of great significance to develop a hydraulic concrete with environmental protection and high toughness and a preparation method thereof. Summary of the invention

[0004] The purpose of the present invention is to provide an environmentally friendly high-toughness C30 desert sand hydraulic concrete and a preparation method thereof. Desert sand is loaded on polyglycolic acid-modified polyacrylate as one of the aggregates and mixed with other components to obtain the environmentally friendly high-toughness C30 desert sand hydraulic concrete.

[0005] The technical problem to be solved by the present invention is that hydraulic concrete is easy to crack, has poor toughness and poor durability.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] An environmentally friendly high-toughness C30 desert sand hydraulic concrete comprises the following raw materials, measured by weight: 330-350 parts of cement, 100-110 parts of fly ash, 500-600 parts of aggregate, 10-15 parts of high-efficiency soil mud activity stimulating composite water reducing agent, 0.1-0.5 parts of air entraining agent, 1-10 parts of steel fiber and 150-200 parts of water.

[0008] The aggregate includes medium crushed stone, small crushed stone and modified desert sand, wherein the mass ratio of the medium crushed stone, small crushed stone and modified desert sand is 5:7:8. The crushed stone is sieved through a 2.5-mesh sieve to obtain the medium crushed stone; and the small crushed stone is sieved through a 100-mesh sieve to obtain the small crushed stone.

[0009] The high-efficiency soil activity stimulating composite water reducing agent comprises one or more of calcium lignin sulfonate, sodium lignin sulfonate and magnesium lignin sulfonate.

[0010] The air entraining agent includes one or more of rosin-based air entraining agents, alkylbenzene sulfonate-based air entraining agents and saponin-based air entraining agents.

[0011] Further, the modified desert sand is prepared by the following steps:

[0012] S1. Ultrasonic dispersion of polyglycolic acid in 20 wt% acetone solution, placing in a stainless steel polytetrafluoroethylene lined reactor, adding polyacrylate, stirring, then adding benzoyl peroxide and stannous octoate, controlling the temperature at 70°C-90°C, reacting for 2h-5h, cooling to room temperature, filtering, washing, and drying to obtain polyglycolic acid modified polyacrylate;

[0013] S2. Wash the desert sand, dry it, and sieve it through a 200-mesh sieve. Put the polyglycolic acid-modified polyacrylate and desert sand into a mixer, add dimethylsiloxane dropwise, control the temperature at 40°C-60°C, add water and stir for 10min-50min until it becomes a paste, cool to room temperature, filter, discard the filtrate, wash, and evaporate the water to obtain polyglycolic acid-modified polyacrylate-loaded desert sand, i.e., modified desert sand.

[0014] In the step S1, the mass ratio of polyglycolic acid to benzoyl peroxide is (10-15):(1-2); the volume ratio of acetone, polyacrylate and stannous octoate is (40-50):(10-15):(1-3).

[0015] In step S2, the mass ratio of desert sand to polyglycolic acid modified polyacrylate is (4-6):(3-4); the volume ratio of dimethylsiloxane to water is (3-5):(10-30).

[0016] The preparation method of environmentally friendly high-toughness C30 desert sand hydraulic concrete comprises the following steps:

[0017] Cement, fly ash, high-efficiency water reducing agent, air entraining agent and steel fiber are weighed in parts by weight and mixed evenly to obtain a mixture; medium crushed stone, small crushed stone and modified desert sand are mixed evenly in a mass ratio of 5:7:8 to prepare aggregate; the mixture and aggregate are put into a concrete mixer; corresponding parts by weight of water are added and stirred evenly to obtain environmentally friendly and high-toughness C30 desert sand hydraulic concrete.

[0018] Beneficial effects of the present invention:

[0019] 1. In this technical solution, polyglycolic acid and polyacrylate are grafted and polymerized to form a three-dimensional framework with a cross-linked network structure. Desert sand is used as fine aggregate and adsorbed inside the framework through electrostatic action. It effectively improves the compressive strength and tensile strength of hydraulic concrete and enhances the toughness of hydraulic concrete. At the same time, polyglycolic acid has good flexibility and ductility, thereby improving the crack resistance and fatigue resistance of hydraulic concrete, improving the density and impermeability of concrete, and extending the service life.

[0020] 2. In this technical solution, desert sand, as a natural resource, is widely available and low in cost. It can be used in combination with polyglycolic acid-modified polyacrylate to reduce the production cost of hydraulic concrete. At the same time, polyglycolic acid and polyacrylate are both degradable materials, which will not cause serious pollution to the environment after use, and help achieve the goals of environmental protection and sustainable development. In addition, from the perspective of construction, polyglycolic acid-modified polyacrylate has good fluidity, which can improve the construction performance of concrete, increase the slump and expansion of concrete, and make concrete easier to mix, transport and pour. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0022] Example 1

[0023] Modified desert sand is prepared by the following steps:

[0024] S1. Ultrasonic dispersion of 10 g polyglycolic acid in 40 mL 20 wt% acetone solution was placed in a stainless steel polytetrafluoroethylene lined reactor, 10 mL polyacrylate was added, stirred, and then 1 g benzoyl peroxide and 1 mL stannous octoate were added, the temperature was controlled at 80°C, the reaction was carried out for 3 h, cooled to room temperature, filtered, washed, and dried to obtain polyglycolic acid modified polyacrylate;

[0025] S2. Wash the desert sand, dry it, and sieve it through a 200-mesh sieve. Put 30 g of polyglycolic acid-modified polyacrylate and 40 g of desert sand into a mixer, add 3 mL of dimethylsiloxane, control the temperature at 50°C, add 10 mL of water and stir for 50 minutes until it becomes a paste, cool to room temperature, filter, discard the filtrate, wash, and evaporate the water to obtain polyglycolic acid-modified polyacrylate-loaded desert sand, i.e., modified desert sand.

[0026] Example 2

[0027] Modified desert sand is prepared by the following steps:

[0028] S1. Ultrasonic dispersion of 12.5 g polyglycolic acid in 45 mL 20 wt% acetone solution was placed in a stainless steel polytetrafluoroethylene lined reactor, and 12.5 mL polyacrylate was added, stirred, and then 1.5 g benzoyl peroxide and 2 mL stannous octoate were added, the temperature was controlled at 80°C, the reaction was carried out for 3 h, cooled to room temperature, filtered, washed, and dried to obtain polyglycolic acid modified polyacrylate;

[0029] S2. Wash the desert sand, dry it, and sieve it through a 200-mesh sieve. Put 35 g of polyglycolic acid-modified polyacrylate and 50 g of desert sand into a mixer, add 4 mL of dimethylsiloxane, control the temperature at 50°C, add 20 mL of water and stir for 40 minutes until it becomes a paste, cool to room temperature, filter, discard the filtrate, wash, and evaporate the water to obtain polyglycolic acid-modified polyacrylate-loaded desert sand, i.e., modified desert sand.

[0030] Example 3

[0031] Modified desert sand is prepared by the following steps:

[0032] S1. Ultrasonic dispersion of 15 g polyglycolic acid in 50 mL 20 wt% acetone solution was placed in a stainless steel polytetrafluoroethylene lined reactor, 15 mL polyacrylate was added, stirred, and then 2 g benzoyl peroxide and 3 mL stannous octoate were added, the temperature was controlled at 80°C, the reaction was carried out for 3 h, cooled to room temperature, filtered, washed, and dried to obtain polyglycolic acid modified polyacrylate;

[0033] S2. Wash the desert sand, dry it, and sieve it through a 200-mesh sieve. Put 40 g of polyglycolic acid-modified polyacrylate and 60 g of desert sand into a mixer, add 5 mL of dimethylsiloxane, control the temperature at 50°C, add 30 mL of water and stir for 30 minutes until it becomes a paste, cool to room temperature, filter, discard the filtrate, wash, and evaporate the water to obtain polyglycolic acid-modified polyacrylate-loaded desert sand, i.e., modified desert sand.

[0034] Example 4

[0035] The preparation method of environmentally friendly high-toughness C30 desert sand hydraulic concrete comprises the following steps:

[0036] 330 parts of cement, 100 parts of fly ash, 10 parts of high-efficiency water reducing agent, 0.1 part of air entraining agent and 1 part of steel fiber were weighed and mixed uniformly to obtain a mixture, and medium gravel, small gravel and the modified desert sand prepared in Example 1 were mixed uniformly in a mass ratio of 5:7:8 to prepare aggregate, and 500 parts of the mixture and aggregate were put into a concrete mixer, and 150 parts of water in corresponding weight parts were added and stirred uniformly to obtain environmentally friendly high-toughness C30 desert sand hydraulic concrete.

[0037] Example 5

[0038] The preparation method of environmentally friendly high-toughness C30 desert sand hydraulic concrete comprises the following steps:

[0039] 340 parts of cement, 105 parts of fly ash, 12.5 parts of high-efficiency water reducing agent, 0.3 parts of air entraining agent and 5.5 parts of steel fiber were weighed and mixed uniformly to obtain a mixture; medium gravel, small gravel and the modified desert sand prepared in Example 2 were mixed uniformly in a mass ratio of 5:7:8 to prepare aggregate; 550 parts of the mixture and aggregate were put into a concrete mixer; 175 parts of water in corresponding weight parts were added and stirred uniformly to obtain environmentally friendly high-toughness C30 desert sand hydraulic concrete.

[0040] Example 6

[0041] The preparation method of environmentally friendly high-toughness C30 desert sand hydraulic concrete comprises the following steps:

[0042] 350 parts of cement, 110 parts of fly ash, 15 parts of high-efficiency water reducing agent, 0.5 parts of air entraining agent and 10 parts of steel fiber were weighed and mixed uniformly to obtain a mixture, and medium gravel, small gravel and the modified desert sand prepared in Example 3 were mixed uniformly in a mass ratio of 5:7:8 to prepare aggregate, and 600 parts of the mixture and aggregate were put into a concrete mixer, and 200 parts of water in corresponding weight parts were added and stirred uniformly to obtain environmentally friendly high-toughness C30 desert sand hydraulic concrete.

[0043] Comparative Example 1

[0044] 330 parts of cement, 100 parts of fly ash, 10 parts of high-efficiency water reducing agent, 0.1 parts of air entraining agent and 1 part of steel fiber are weighed by weight and mixed evenly to obtain a mixture, and medium crushed stone, small crushed stone and untreated desert sand are mixed evenly in a mass ratio of 5:7:8 to prepare aggregate, and 500 parts of the mixture and aggregate are put into a concrete mixer, and 150 parts of water by corresponding weight are added and stirred evenly.

[0045] Comparative Example 2

[0046] 330 parts of cement, 100 parts of fly ash, 10 parts of high-efficiency water reducing agent, 0.1 parts of air entraining agent and 1 part of steel fiber are weighed by weight and mixed evenly to obtain a mixture, medium crushed stone and small crushed stone are mixed evenly in a mass ratio of 5:7:8 to prepare aggregate, and desert sand is not used. 500 parts of the mixture and aggregate are put into a concrete mixer, and 150 parts of water by corresponding weight are added and stirred evenly.

[0047] The anti-permeability performance of Examples 4-6 and Comparative Examples 1-2 was tested according to GB / T 50082-2009 "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete". Six pieces were randomly selected from Examples 4-6 and Comparative Examples 1-2 for sample testing. The sample delivery time was June 11, 2021. The results are shown in Table 1:

[0048] Table 1. Test results of anti-seepage performance of Examples 4-6 and Comparative Examples 1-2

[0049]

[0050] The abrasion resistance of Examples 4-6 and Comparative Examples 1-2 was tested according to SL 352-2006 "Test Procedure for Hydraulic Concrete". Three pieces were randomly selected from each of Examples 4-6 and Comparative Examples 1-2 for sample testing. The sample delivery time was June 15, 2021. The underwater steel ball method was used for the detection method. The results are shown in Table 2:

[0051] Table 2. Test results of anti-abrasion performance of Examples 4-6 and Comparative Examples 1-2

[0052]

[0053] As shown in Table 1, when the water pressure is 1.3 MPa, the 6 test pieces of Examples 4-6 did not seep water, the 5 test pieces of Comparative Example 1 saw water, and the 6 test pieces of Comparative Example 2 saw water, indicating that the anti-seepage performance of Examples 4-6 is good. As shown in Table 2, the average abrasion resistance of Examples 4-6 is 14.83 h / (kg / m), which is better than the abrasion resistance of Comparative Examples 1-2. It shows that the environmentally friendly high-toughness C30 desert sand hydraulic concrete obtained by loading desert sand with polyglycolic acid modified polyacrylate as one of the aggregates and mixing it with other components has good anti-seepage performance and toughness, and the use of polyglycolic acid modified polyacrylate to load desert sand has certain environmental protection.

[0054] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means 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 representation of the above terms does 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.

[0055] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. An environmentally friendly high-toughness C30 desert sand hydraulic concrete, characterized in that: The following raw materials are included by weight: 330-350 parts of cement, 100-110 parts of fly ash, 500-600 parts of aggregate, 10-15 parts of high-efficiency soil activity stimulating composite water reducing agent, 0.1-0.5 parts of air entraining agent, 1-10 parts of steel fiber and 150-200 parts of water.

2. The environmentally friendly high-toughness C30 desert sand hydraulic concrete according to claim 1 is characterized in that: The aggregate includes medium crushed stone, small crushed stone and modified desert sand, wherein the mass ratio of medium crushed stone, small crushed stone and modified desert sand is 5:7:

8. The crushed stone is sieved through a 2.5-mesh sieve to obtain medium crushed stone; and is sieved through a 100-mesh sieve to obtain small crushed stone.

3. The environmentally friendly high-toughness C30 desert sand hydraulic concrete according to claim 1 is characterized in that: The high-efficiency soil activity stimulating composite water reducing agent comprises one or more of calcium lignin sulfonate, sodium lignin sulfonate and magnesium lignin sulfonate.

4. The environmentally friendly high-toughness C30 desert sand hydraulic concrete according to claim 1, characterized in that: The air entraining agent includes one or more of rosin-based air entraining agents, alkylbenzene sulfonate-based air entraining agents and saponin-based air entraining agents.

5. The environmentally friendly high-toughness C30 desert sand hydraulic concrete according to claim 1 is characterized in that: Modified desert sand is prepared by the following steps: S1. Ultrasonic dispersion of polyglycolic acid in 20 wt% acetone solution, placing in a stainless steel polytetrafluoroethylene lined reactor, adding polyacrylate, stirring, then adding benzoyl peroxide and stannous octoate, controlling the temperature at 70°C-90°C, reacting for 2h-5h, cooling to room temperature, filtering, washing, and drying to obtain polyglycolic acid modified polyacrylate; S2. Wash the desert sand, dry it, and sieve it through a 200-mesh sieve. Put the polyglycolic acid-modified polyacrylate and desert sand into a mixer, add dimethylsiloxane dropwise, control the temperature at 40°C-60°C, add water and stir for 10min-50min until it becomes a paste, cool to room temperature, filter, discard the filtrate, wash, and evaporate the water to obtain polyglycolic acid-modified polyacrylate-loaded desert sand, i.e., modified desert sand.

6. The environmentally friendly high-toughness C30 desert sand hydraulic concrete according to claim 5, characterized in that: In step S1, the mass ratio of polyglycolic acid to benzoyl peroxide is (10-15):(1-2); the volume ratio of acetone, polyacrylate and stannous octoate is (40-50):(10-15):(1-3).

7. The environmentally friendly high-toughness C30 desert sand hydraulic concrete according to claim 5, characterized in that: In step S2, the mass ratio of desert sand to polyglycolic acid modified polyacrylate is (4-6):(3-4); the volume ratio of dimethylsiloxane to water is (3-5):(10-30).

8. A method for preparing the environmentally friendly high-toughness C30 desert sand hydraulic concrete according to any one of claims 1 to 7, characterized in that: The following steps are involved: Cement, fly ash, high-efficiency water reducing agent, air entraining agent and steel fiber are weighed in parts by weight and mixed evenly to obtain a mixture; medium crushed stone, small crushed stone and modified desert sand are mixed evenly in a mass ratio of 5:7:8 to prepare aggregate; the mixture and aggregate are put into a concrete mixer; corresponding parts by weight of water are added and stirred evenly to obtain environmentally friendly and high-toughness C30 desert sand hydraulic concrete.

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