Concrete and concrete guardrail

Abstract

The invention relates to the technical field of concrete materials, in particular to concrete and a concrete guardrail. The concrete is prepared from the following raw materials in parts by weight: 136 to 151 parts of water, 252 to 324 parts of cement, 108 to 36 parts of fly ash, a water reducing agent accounting for 1 percent of the parts of the cement and the fly ash, 1800 to 2000 parts of a gravel mixture with the sand content of 40 to 50 percent and an air entraining agent accounting for 0.015 to 0.025 per mill of the parts of the cement and the fly ash. By adjusting the air entraining agent, the water reducing agent and the water-binder ratio, the anti-freezing performance of the concrete is improved, meanwhile, the compressive strength of the concrete can be guaranteed, and the service life of the concrete in a low-temperature environment is prolonged.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of concrete materials, and specifically to concrete and concrete guardrails. Background Art

[0002] As a building material widely used in buildings and engineering structures, concrete must meet a variety of performance requirements, among which compressive strength is a key factor in determining its service life and maintaining structural integrity. Under constant low temperature, the compressive strength of concrete is improved relative to the compressive strength at room temperature, and it increases significantly with the decrease in temperature and the increase in water content and air content.

[0003] The inventors of the present application found in their research that under the conditions of freeze-thaw cycles, the compressive strength of concrete shows a downward trend to varying degrees, and the degree of damage becomes more serious as the number of freeze-thaw cycles increases, the minimum temperature during the cycle decreases, the water-cement ratio increases, and the environmental moisture content increases. Summary of the invention

[0004] In view of the above problems, the embodiments of the present application provide a kind of concrete and concrete guardrail to solve the above technical problems existing in the prior art.

[0005] In one aspect of an embodiment of the present application, a concrete is proposed, comprising the following raw materials in parts by weight: 136 to 151 parts of water, 252 to 324 parts of cement, 108 to 36 parts of fly ash, 1% of a water reducer based on the cement and fly ash, 1800 to 2000 parts of a sand and gravel mixture having a sand content of 40 to 50%, and 0.015 to 0.025‰ of an air entraining agent based on the cement and fly ash.

[0006] Preferably, the sand and gravel mixture is 1900 parts and the sand content is 46%.

[0007] Preferably, the sand and gravel mixture includes: 874 parts of machine-made sand with a particle size of 0-5 mm, 103 parts of crushed stone with a particle size of 5-10 mm, and 923 parts of crushed stone with a particle size of 5-25 mm.

[0008] Preferably, the fly ash content is 20%.

[0009] Preferably, the air entraining agent accounts for 0.02‰ of the cement and fly ash.

[0010] Preferably, the air entraining agent is hexadecyl dimethyl ethyl ammonium bromide, polyoxyethylene alkyl ether or alkyl sulfate.

[0011] On the other hand of the embodiments of the present application, a concrete guardrail is also proposed, wherein the main body of the concrete guardrail is made of the concrete described in the above embodiments, and the surface of the main body of the concrete guardrail is coated with a waterproof coating, which includes 70 to 100 parts of silicate cement, 70 to 100 parts of quartz sand, 35 to 55 parts of water and a hydrophobic agent accounting for 1 to 5% of the silicate cement.

[0012] Preferably, the waterproof coating has a thickness of 1 mm to 1.6 mm.

[0013] Preferably, the concrete guardrail body comprises an upper guardrail and a lower base, and the lower base is in contact with the ground;

[0014] The upper guardrail is made of silicate cement, wherein water accounts for 40% of the silicate cement, water reducing agent accounts for 1% of the silicate cement, and fly ash accounts for 10% to 30% of the silicate cement.

[0015] Preferably, the hydrophobic agent accounts for 3% of the silicate cement.

[0016] In summary, the concrete and concrete guardrail proposed in the embodiments of the present application can improve the frost resistance of concrete while ensuring the compressive strength of concrete by adjusting the air entraining agent, water reducing agent and water-cement ratio, thereby increasing the service life of concrete in low temperature environments.

[0017] The above description is only an overview of the technical solution of the embodiment of the present application. In order to more clearly understand the technical means of the embodiment of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. DETAILED DESCRIPTION

[0018] The exemplary embodiments of the present application will be described in more detail below. Although the exemplary embodiments of the present application describe various schemes, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein.

[0019] Temperature has a significant impact on the compressive strength and service life of concrete. Especially under the conditions of freeze-thaw cycles, the strength of concrete shows a downward trend to varying degrees. With the increase in the number of freeze-thaw cycles, the decrease in the minimum temperature during the cycle, the increase in the water-cement ratio, and the increase in the environmental moisture content, the degree of damage becomes more serious. The increase in air content is beneficial to the freeze-thaw resistance of concrete. By adding air-entraining agents to increase the air content of concrete to improve the freeze resistance of concrete in high-cold areas, the freeze resistance of concrete can be improved to a certain extent.

[0020] However, the inventors of the present application have found in their research that, although the addition of air entraining agent can improve the antifreeze performance of concrete, the addition of air entraining agent will have a negative impact on the strength of concrete. The "Specifications for the Design of Ordinary Concrete Mix" (JGJ 55-2011) issued by the state also clearly stipulates that the maximum air content in concrete should be less than 7%. Therefore, when considering the antifreeze performance of concrete, it is also necessary to determine the appropriate amount of air entraining agent to ensure that the compressive strength of concrete is not affected.

[0021] In view of this, an embodiment of the present application proposes a concrete, wherein the concrete includes the following raw materials in parts by weight: 136 to 151 parts of water, 252 to 324 parts of cement, 108 to 36 parts of fly ash, 1% of a water reducer based on the cement and fly ash, 1800 to 2000 parts of a sand and gravel mixture with a sand content of 40 to 50%, and 0.02 to 0.05‰ of an air entraining agent based on the cement and fly ash.

[0022] Among them, the cement can be PO42.5 silicate cement, wherein "PO" represents ordinary silicate cement, and "42.5" means that the compressive strength index of the cement after 28 days of curing under standard conditions is 42.5 MPa. In this embodiment of the present application, the concrete contains 252 to 324 parts of cement.

[0023] The fly ash is a kind of fine ash collected from the flue gas after coal combustion, which mainly comes from the solid waste of coal-fired power plants. It is obtained by grinding coal into coal powder below 100 microns in coal-fired power plants, spraying it into the furnace with preheated air to burn in a suspended state, and generating high-temperature flue gas mixed with a large amount of incombustibles, which is captured by a dust collector. The chemical composition of fly ash is similar to that of clay, and the main components are silicon dioxide, aluminum oxide, iron oxide, calcium oxide and unburned carbon. Fly ash can be used to produce building materials such as fly ash cement, fly ash bricks, fly ash silicate blocks, fly ash aerated concrete, etc. Adding fly ash to concrete can save a lot of cement and fine aggregate, improve the workability of concrete, enhance pumpability, reduce hydration heat and thermal expansion, and improve impermeability. In the embodiment of the present application, the concrete contains 108 to 36 parts of fly ash.

[0024] The water reducer is an admixture that can reduce water consumption, improve strength and durability while maintaining a certain workability of the concrete mixture, or improve the workability and fluidity of fresh concrete under the same water consumption conditions. It is mainly composed of high molecular polymers, organic acid salts and sulfonates. It increases the fluidity of concrete by absorbing and reducing the friction and mutual attraction between particles in concrete. Without changing the strength of concrete, it can reduce cement and water consumption, thereby saving costs. In the embodiment of the present application, preferably, the content of the water reducer accounts for 1% of the cement and fly ash.

[0025] The sand and gravel mixture includes machine-made sand, crushed stone, etc. In the embodiment of the present application, the sand and gravel mixture is composed of machine-made sand and crushed stone of different particle sizes. Among them, the machine-made sand refers to rock, mine tailings or industrial waste particles with a particle size between 0-5mm that have been processed by soil removal, mechanical crushing and screening. In the embodiment of the present application, in order to ensure the particle size of the machine-made sand, a three-stage crushing process can be adopted, which is crushed for the first time by a jaw crusher, then crushed for the second time by an impact crusher, and finally crushed for the third time by an impact crusher. The sample should be dry, clean and free of debris before stirring, and the various performance indicators of the machine-made sand should meet the industry standard technical requirements.

[0026] As a kind of aggregate, the crushed stone can form the skeleton structure of concrete, support the overall shape and volume of concrete, and provide the necessary strength and stability for concrete. Without crushed stone, concrete will find it difficult to maintain its structural form. When subjected to external force, the crushed stone can share the load with cement stone, disperse and transfer stress, reduce the stress concentration of cement stone, and improve the bearing capacity of concrete. At the same time, the crushed stone can fill part of the space in the concrete and reduce the amount of cement paste. Since the density of crushed stone is greater than that of cement paste, the use of crushed stone can reduce the overall cost of concrete and improve the economy of concrete. The addition of crushed stone helps to improve the density of concrete, reduce the porosity inside concrete, and thus improve the strength and durability of concrete. In the embodiment of the present application, the crushed stone can include two types of crushed stone with a particle size of 5 to 10 mm and a particle size of 5-25 mm. The crushed stone and machine-made sand together constitute a sand and gravel mixture. In the embodiment of the present application, the content of the sand and gravel mixture is 1800 to 2000 parts, and its sand content is 40 to 50%, wherein the sand content is the proportion of machine-made sand to the sand and gravel mixture.

[0027] The air entraining agent is an admixture that can introduce a large number of uniformly distributed, stable and closed tiny bubbles during the concrete mixing process. These bubbles can be retained in the hardened concrete, which can buffer the stress generated during the freeze-thaw cycle and reduce the stress concentration inside the concrete, thereby improving the freeze-thaw resistance of the concrete. In the embodiment of the present application, the content of the air entraining agent is 0.015-0.025‰ of the cement and fly ash, and its main components include hexadecyl dimethyl ethyl ammonium bromide, polyoxyethylene alkyl ether or alkyl sulfate, etc.

[0028] In order to improve the frost resistance of the concrete while ensuring that the concrete meets the compressive strength requirements, it is necessary to adjust the water-cement ratio of the concrete, the content of the water-reducing agent and the content of the air-entraining agent so that the slump of the concrete is within the range of 180 mm to 220 mm, the compressive strength is greater than or equal to 30 MPa, and the air content is within the range of 2 to 5%, wherein the water-cement ratio is the ratio of water to a mixture of cement and fly ash.

[0029] The slump refers to the workability of concrete, specifically to ensure the normal progress of construction, including the water retention, fluidity and cohesion of concrete. Slump is a quantitative indicator to measure its degree, which is used to judge whether the construction can proceed normally. The relationship between slump and concrete strength is as follows: the larger the slump, the better the fluidity of concrete, but the compressive strength of concrete will decrease. Therefore, the slump should be controlled within a certain range to ensure normal construction and the final concrete forming strength.

[0030] The compressive strength is the maximum ability of concrete to resist compression damage under external forces. For concrete, compressive strength is one of its most important mechanical performance indicators, usually expressed in MPa (megapascals) to indicate the strength of concrete 28 days after molding.

[0031] The air content refers to the volume percentage of gas contained in concrete, which reflects the content of gas in the internal pores of concrete. The right amount of air content can significantly improve the antifreeze performance of concrete. The tiny bubbles introduced by the air-entraining agent can relieve the stress generated during the freeze-thaw cycle and reduce frost heave damage. However, as the air content of concrete increases, its internal porosity increases, which will also reduce the density and strength of concrete, leading to a decrease in the compressive strength of concrete.

[0032] In the embodiments of the present application, in order to determine the appropriate water-cement ratio, water-reducing agent content and air-entraining agent content of the concrete, the inventors of the present application first determined the appropriate water-cement ratio and water-reducing agent content without adding an air-entraining agent.

[0033] Table 1 shows the slump of the benchmark ordinary concrete mix ratio with a design strength of C30 under concrete mix ratios with different contents of water reducing agent.

[0034] Table 1

[0035]

[0036]

[0037] It can be seen from Table 1 that in order to ensure the consistency of the test, the total number of parts of cement and fly ash is 360 parts, and the total number of parts of the sand and gravel mixture is 1900 parts. Of course, in the actual test process, the ratio of cement and fly ash can be adjusted as needed; the number of parts of the sand and gravel mixture can also be appropriately adjusted. Preferably, the number of parts of the sand and gravel mixture is between 1800 and 2000 parts.

[0038] It can be seen from Table 1 that when the water-cement ratio is 0.38 and the water-reducing agent is 2.34 parts, that is, the water-reducing agent accounts for 0.65% of the amount of cement and fly ash, the slump is too low and the concrete is difficult to mix and shape; when the water-cement ratio is 0.38 and the water-reducing agent is 4.86 parts, that is, the water-reducing agent accounts for 1.35% of the amount of cement and fly ash, the slump is 240mm and the slump is too high.

[0039] As shown in Table 1, when the water-cement ratio is 0.44, the water reducer is 3.6 parts, that is, the water reducer accounts for 1% of the amount of cement and fly ash, the concrete is mixed based on the reference mix ratio parameters, and the slump test is carried out after molding. The slump is measured to be 230mm, but at the same time, it is found that water seepage occurs. The reason for this is that the amount of water reducer used is too large on the one hand, and the water-cement ratio is too large on the other hand. When adjusting the amount of water reducer, it is found that the change in the amount of water reducer has a great influence on the slump. When the amount of water reducer is adjusted to 2.34 parts, that is, the amount of water reducer accounts for 0.65% of the amount of cement and fly ash, the water-cement ratio is 0.44, and the slump test is carried out. The slump is measured to be 125mm, and the concrete is difficult to mix and mold.

[0040] According to the test data in Table 1, the inventors of the present application considered improving water seepage from the perspective of reducing the water-binder ratio, and adjusted the water-binder ratio from 0.44 to 0.42. It can be seen from Table 1 that:

[0041] When the water-cement ratio is 0.42 and the water-reducing agent dosage is kept at 1%, the slump of the concrete is 225mm. The fluidity and encapsulation of the samples prepared under this mix ratio are relatively good.

[0042] When the water-cement ratio is 0.42 and the water-reducing agent dosage is maintained at 0.85%, the slump of the concrete is 195mm. The fluidity and encapsulation of the samples prepared under this mix ratio are relatively good.

[0043] When the water-cement ratio is 0.40 and the water-reducing agent dosage is kept at 1%, the slump of the concrete is 220mm. The fluidity and encapsulation of the samples prepared under this mix ratio are relatively good.

[0044] When the water-cement ratio is 0.40 and the water-reducing agent dosage is maintained at 0.85%, the slump of the concrete is 190 mm. The fluidity and encapsulation of the samples prepared under this mix ratio are relatively good.

[0045] When the water-cement ratio is 0.38 and the water-reducing agent dosage is maintained at 1.15%, the slump of the concrete is 215mm. The fluidity and encapsulation of the samples prepared under this mix ratio are relatively good.

[0046] When the water-cement ratio is 0.38 and the water-reducing agent dosage is kept at 1%, the slump of the concrete is 185mm. The fluidity and encapsulation of the samples prepared under this mix ratio are relatively good.

[0047] Therefore, through the test in Table 1, considering that the influence of the water reducing agent dosage on the concrete performance is small, in order to facilitate the adjustment, the water reducing agent dosage is set at 1% and the water-binder ratio is set to 0.38-0.42 in the embodiment of the present application. In this case, the concrete obtained before adding the air entraining agent has the best slump.

[0048] Under the condition of meeting the requirements of concrete collapse, considering the requirements of concrete anti-freezing performance, the anti-freezing performance of concrete is improved by adding air entraining agent to increase the air content of concrete. However, the addition of air entraining agent will have a negative impact on the strength of concrete, so the strength reduction caused by the addition of air entraining agent can be compensated by a relatively low water-binder ratio.

[0049] The inventors of the present application found in their research that, when the proportioning is based on 20% fly ash (referring to the ratio of fly ash to the total mass of cement and fly ash) and 1% water reducing agent, at a water-cement ratio of 0.38 and 0.4, and 0.1‰ air entraining agent (referring to the ratio of air entraining agent to the total mass of cement and fly ash), the working performance of concrete is greatly lost, and the relative air content measured and calculated by the bulk density method is 17.3%, which is much larger than the requirement of less than 7% for the maximum air content in the "Code for Design of Ordinary Concrete Mix" (JGJ 55-2011).

[0050] Therefore, the inventors of the present application adjusted the amount of air entraining agent added, and at the same time, measured the compressive strength and frost resistance of concrete at different amounts of air entraining agent added. Table 2 shows the measurement results under different conditions.

[0051] Table 2

[0052]

[0053]

[0054] Table 2 shows the compressive strength of concrete after adding different dosages of air entraining agent under the condition of water-binder ratio of 0.4.

[0055] The first set of data:

[0056] Under the test conditions of a water-binder ratio of 0.4 and a water-reducing agent of 3.6 parts, an air-entraining agent content of 0.01‰ and a fly ash content of 10%, the slump was 210, the air content was 1.12%, the compressive strength was 45.1, the mass loss after 60 freeze-thaw cycles was 1.45%, and the mass loss after 120 freeze-thaw cycles was 6.45%; due to the requirement that the air content of 1.12% is less than 2%, the mass loss after freeze-thaw cycles is high, so under this condition, the compressive strength is good, but its frost resistance is poor.

[0057] The second set of data:

[0058] Under the test conditions of water-binder ratio of 0.4 and water reducer of 3.6 parts, when the air entraining agent content is 0.01‰ and the fly ash content is 20%, the slump is 210, the air content is 1.36%, the compressive strength is 43.4, the mass loss after 60 freeze-thaw cycles is 1.62%, and the mass loss after 120 freeze-thaw cycles is 7.28%; due to the requirement that the air content of 1.36% is less than 2%, the mass loss after freeze-thaw cycles is high, so under this condition, its antifreeze performance is not good.

[0059] The third set of data:

[0060] Under the test conditions of water-binder ratio of 0.4 and water reducer of 3.6 parts, when the air entraining agent content is 0.01‰ and the fly ash content is 30%, the slump is 215, the air content is 1.44%, the compressive strength is 39.5, the mass loss after 60 freeze-thaw cycles is 1.89%, and the mass loss after 120 freeze-thaw cycles is 7.43%; due to the requirement that the air content of 1.44% is less than 2%, the mass loss after freeze-thaw cycles is high, so under this condition, its antifreeze performance is not good.

[0061] The fourth set of data:

[0062] Under the test conditions of water-binder ratio of 0.4 and water reducer of 3.6 parts, when the air entraining agent content is 0.015‰ and the fly ash content is 10%, the slump is 200, the air content is 2.02%, the compressive strength is 40.3, the mass loss after 60 freeze-thaw cycles is 0.83%, and the mass loss after 120 freeze-thaw cycles is 4.58%; since the air content of 2.02% is greater than the requirement of 2%, the compressive strength is greater than 30MPa, and the mass loss after freeze-thaw cycles is small, under this condition, its antifreeze performance and compressive strength can meet the relevant requirements.

[0063] The fifth set of data:

[0064] Under the test conditions of a water-binder ratio of 0.4 and a water-reducing agent of 3.6 parts, when the air-entraining agent content is 0.015‰ and the fly ash content is 20%, the slump is 205, the air content is 2.16%, the compressive strength is 38.8, the mass loss after 60 freeze-thaw cycles is 0.90%, and the mass loss after 120 freeze-thaw cycles is 5.13%; since the air content of 2.16% is greater than the requirement of 2%, the compressive strength is greater than 30MPa, and the mass loss after freeze-thaw cycles is small, under this condition, its antifreeze performance and compressive strength can meet the relevant requirements.

[0065] The sixth set of data:

[0066] Under the test conditions of a water-binder ratio of 0.4 and a water-reducing agent of 3.6 parts, when the air-entraining agent content is 0.015‰ and the fly ash content is 30%, the slump is 215, the air content is 2.28%, the compressive strength is 36.2, the mass loss after 60 freeze-thaw cycles is 0.94%, and the mass loss after 120 freeze-thaw cycles is 5.22%; since the air content of 2.28% is greater than the requirement of 2%, the compressive strength is greater than 30MPa, and the mass loss after freeze-thaw cycles is small, under this condition, its antifreeze performance and compressive strength can meet the relevant requirements.

[0067] The seventh set of data:

[0068] Under the test conditions of a water-binder ratio of 0.4 and a water-reducing agent of 3.6 parts, when the air-entraining agent content is 0.02‰ and the fly ash content is 10%, the slump is 185, the air content is 2.39%, the compressive strength is 42, the mass loss after 60 freeze-thaw cycles is 0.57%, and the mass loss after 120 freeze-thaw cycles is 3.19%; since the air content of 2.39% is greater than the requirement of 2%, the compressive strength is greater than 30MPa, and the mass loss after freeze-thaw cycles is small, under this condition, its frost resistance and compressive strength can meet the relevant requirements.

[0069] The eighth set of data:

[0070] Under the test conditions of a water-binder ratio of 0.4 and a water-reducing agent of 3.6 parts, when the air-entraining agent content is 0.02‰ and the fly ash content is 20%, the slump is 205, the air content is 3.27%, the compressive strength is 36.6, the mass loss after 60 freeze-thaw cycles is 0.63%, and the mass loss after 120 freeze-thaw cycles is 3.81%; since the air content of 3.27% is greater than the requirement of 2%, the compressive strength is greater than 30MPa, and the mass loss after freeze-thaw cycles is small, under this condition, its frost resistance and compressive strength can meet the relevant requirements.

[0071] The ninth set of data:

[0072] Under the test conditions of a water-binder ratio of 0.4 and a water-reducing agent of 3.6 parts, when the air-entraining agent content is 0.02‰ and the fly ash content is 30%, the slump is 210, the air content is 4.24%, the compressive strength is 32.2, the mass loss after 60 freeze-thaw cycles is 0.66%, and the mass loss after 120 freeze-thaw cycles is 3.94%; since the air content of 4.24% is greater than the requirement of 2%, the compressive strength is greater than 30MPa, and the mass loss after freeze-thaw cycles is small, under this condition, its frost resistance and compressive strength can meet the relevant requirements.

[0073] The tenth set of data:

[0074] Under the test conditions of a water-binder ratio of 0.4 and a water-reducing agent of 3.6 parts, when the air-entraining agent content is 0.025‰ and the fly ash content is 10%, the slump is 180, the air content is 2.56%, the compressive strength is 40.7, the mass loss after 60 freeze-thaw cycles is 0.54%, and the mass loss after 120 freeze-thaw cycles is 3.07%; since the air content of 2.56% is greater than the requirement of 2%, the compressive strength is greater than 30MPa, and the mass loss after freeze-thaw cycles is small, under this condition, its antifreeze performance and compressive strength can meet the relevant requirements.

[0075] The eleventh set of data:

[0076] Under the test conditions of a water-binder ratio of 0.4 and a water-reducing agent of 3.6 parts, when the air-entraining agent content is 0.025‰ and the fly ash content is 20%, the slump is 200, the air content is 3.73%, the compressive strength is 34.2, the mass loss after 60 freeze-thaw cycles is 0.60%, and the mass loss after 120 freeze-thaw cycles is 3.64%; since the air content of 3.73% is greater than the requirement of 2%, the compressive strength is greater than 30MPa, and the mass loss after freeze-thaw cycles is small, under this condition, its antifreeze performance and compressive strength can meet the relevant requirements.

[0077] The twelfth set of data:

[0078] Under the test conditions of a water-binder ratio of 0.4 and a water-reducing agent of 3.6 parts, when the air-entraining agent content is 0.025‰ and the fly ash content is 30%, the slump is 205, the air content is 4.86%, the compressive strength is 30.5, the mass loss after 60 freeze-thaw cycles is 0.65%, and the mass loss after 120 freeze-thaw cycles is 3.88%; since the air content of 4.86% is greater than the requirement of 2%, the compressive strength is greater than 30MPa, and the mass loss after freeze-thaw cycles is small, under this condition, its frost resistance and compressive strength can meet the relevant requirements.

[0079] Thirteenth set of data:

[0080] Under the test conditions of a water-binder ratio of 0.4 and a water-reducing agent of 3.6 parts, when the air-entraining agent content is 0.03‰ and the fly ash content is 10%, the slump is 170, the air content is 5.46%, the compressive strength is 26.4, the mass loss after 60 freeze-thaw cycles is 0.53%, and the mass loss after 120 freeze-thaw cycles is 3.92%; although the air content of 5.46% is greater than the requirement of 2%, its compressive strength is less than 30MPa. Therefore, under this condition, its compressive strength cannot meet the relevant requirements.

[0081] The fourteenth set of data:

[0082] Under the test conditions of water-binder ratio of 0.4 and water reducer of 3.6 parts, when the air entraining agent content is 0.03‰ and the fly ash content is 20%, the slump is 195, the air content is 5.53%, the compressive strength is 26.1, the mass loss after 60 freeze-thaw cycles is 0.58%, and the mass loss after 120 freeze-thaw cycles is 4.02%; although the air content of 5.53% is greater than the requirement of 2%, its compressive strength is less than 30MPa. Therefore, under this condition, its compressive strength cannot meet the relevant requirements.

[0083] The fifteenth set of data:

[0084] Under the test conditions of water-binder ratio of 0.4 and water reducer of 3.6 parts, when the air entraining agent content is 0.03‰ and the fly ash content is 30%, the slump is 190, the air content is 6.18%, the compressive strength is 23.9, the mass loss after 60 freeze-thaw cycles is 0.62%, and the mass loss after 120 freeze-thaw cycles is 4.11%; although the air content of 6.18% is greater than the requirement of 2%, its compressive strength is less than 30MPa. Therefore, under this condition, its compressive strength cannot meet the relevant requirements.

[0085] The sixteenth set of data:

[0086] Under the test conditions of a water-binder ratio of 0.4 and a water-reducing agent of 3.6 parts, when the air-entraining agent content is 0.05‰ and the fly ash content is 10%, the slump is 160, the air content is 6.05%, the compressive strength is 20.5, the mass loss after 60 freeze-thaw cycles is 0.52%, and the mass loss after 120 freeze-thaw cycles is 4.26%; although the air content of 6.05% is greater than the requirement of 2%, its compressive strength is less than 30MPa. Therefore, under this condition, its compressive strength cannot meet the relevant requirements.

[0087] The seventeenth set of data:

[0088] Under the test conditions of water-binder ratio of 0.4 and water reducer of 3.6 parts, when the air entraining agent content is 0.05‰ and the fly ash content is 20%, the slump is 185, the air content is 4.98%, the compressive strength is 28.8, the mass loss after 60 freeze-thaw cycles is 0.55%, and the mass loss after 120 freeze-thaw cycles is 4.19%; although the air content of 4.98% is greater than the requirement of 2%, its compressive strength is less than 30MPa. Therefore, under this condition, its compressive strength cannot meet the relevant requirements.

[0089] The eighteenth set of data:

[0090] Under the test conditions of water-binder ratio of 0.4 and water reducer of 3.6 parts, when the air entraining agent content is 0.05‰ and the fly ash content is 30%, the slump is 190, the air content is 6.56%, the compressive strength is 22.3, the mass loss after 60 freeze-thaw cycles is 0.61%, and the mass loss after 120 freeze-thaw cycles is 4.43%; although the air content of 6.56% is greater than the requirement of 2%, its compressive strength is less than 30MPa. Therefore, under this condition, its compressive strength cannot meet the relevant requirements.

[0091] It can be seen from the experimental data in Table 3 that when the water-binder ratio is 0.4 and the water reducer is 3.6 parts (accounting for 1%), and the air entraining agent content is in the range of 0.015 to 0.025‰, its air content and compressive strength can meet the relevant requirements.

[0092] Similarly, under the conditions of a water-cement ratio of 0.38 and a water-reducing agent of 3.6 parts (accounting for 1%), and an air-entraining agent content of 0.015 to 0.025‰, its air content and compressive strength can meet the relevant requirements, and the relevant test data are no longer listed here one by one.

[0093] Similarly, under the conditions of a water-cement ratio of 0.42 and a water-reducing agent of 3.6 parts (accounting for 1%), when the air-entraining agent content is in the range of 0.015 to 0.025‰, its air content and compressive strength can meet the relevant requirements, and the relevant test data are no longer listed here one by one.

[0094] At the same time, it can be seen from Table 2 that when the sand content of the sand-gravel mixture is 46%, the fly ash content is 20%, the water-binder ratio is 0.4, and the air-entraining agent accounts for 0.02‰ of the cement and fly ash, the air content of the concrete is 3.27%, the compressive strength is 36.6MPa, the mass loss after 60 freeze-thaw cycles is 0.63, and the mass loss after 120 freeze-thaw cycles is 3.81. Its antifreeze performance and compressive strength have achieved the optimal use effect, which can be used as the optimal ratio in the implementation process.

[0095] Table 3 shows the mass loss after freeze-thaw cycles without adding air entraining agent to the concrete.

[0096] Table 3

[0097]

[0098]

[0099] By comparing the mass loss of concrete after freeze-thaw cycles with the addition of 0.015-0.025‰ air-entraining agent in Table 2 and without adding air-entraining agent in Table 3, it can be seen that when no air-entraining agent is added, the mass loss of concrete after 60 and 120 freeze-thaw cycles is much higher than that of concrete with the addition of air-entraining agent, which fully proves that the frost resistance of concrete is greatly improved after the addition of 0.015-0.025‰ air-entraining agent. At the same time, its compressive strength can also meet the relevant performance requirements.

[0100] Furthermore, the inventor of the present application has also found that in winter in high-altitude and easy-to-freeze areas, in order to quickly de-ice the road surface, salt is often sprinkled on the inside to de-ice, and the use of salt will cause chlorine-containing blood water to enter the interior of the guardrail, and the chloride ions will diffuse in the concrete, which will corrode the steel bars inside the concrete guardrail. In view of this, the embodiment of the present application also proposes a concrete guardrail on the basis of the above embodiment. The main body of the concrete guardrail is made of the concrete proposed in the above embodiment, and a waterproof coating is coated on the surface of the guardrail main body. The waterproof coating mainly includes 70 to 100 parts of silicate cement, 70 to 100 parts of quartz sand, 35 to 55 parts of water and 0.6 to 3% of the hydrophobic agent of the silicate cement. The waterproof coating can effectively prevent chlorine-containing snow water from entering the interior of the guardrail, reduce the diffusion of chloride ions in the concrete guardrail, and thus improve the corrosion resistance of the concrete guardrail steel bars, improve the durability of the concrete guardrail in high-altitude and cold areas, and effectively improve the safety level of road operation.

[0101] The silicate cement can be PO42.5 type cement, the quartz sand is 70-100 mesh, and the hydrophobic agent can be RUCOLAC B-601. The preferred proportion of the waterproof coating is: the ratio of cement to quartz sand is 1:1, the ratio of water to cement is 0.5-0.55, and the proportion of hydrophobic agent to cement is 0.6-3%. After the above materials are stirred evenly, they are brushed twice, and the single thickness is preferably 0.5-0.8 mm, and the final thickness of the coating is controlled to be 1-1.6 mm.

[0102] Table 4 shows the waterproof coating material ratio and related test data.

[0103] Table 4

[0104]

[0105] It can be seen from Table 4 that when the hydrophobic agent dosage is between 0.2% and 0.6%, and the water-binder ratio is within the range of 0.45 to 0.55, its compressive strength is high, and its 28d impermeability pressure and 56d impermeability pressure are low. When the compressive strength is high, cracks are easy to form on the waterproof coating. At the same time, when the impermeability pressure is low, it cannot prevent the infiltration of brine well.

[0106] When the amount of the hydrophobic agent is between 1% and 5%, and the water-cement ratio is in the range of 0.45 to 0.55, its compressive strength is smaller than that of the S1-S9 group data, and it is not easy to crack during use. At the same time, its anti-seepage pressure is significantly improved. Therefore, in the embodiment of the present application, the preferred amount of the hydrophobic agent is 1 to 5% of the silicate cement, which can achieve a better anti-seepage effect.

[0107] At the same time, as shown in the test data of groups S13 to S15, when the hydrophobic agent dosage is 3%, its 3d compressive strength is 2.7 to 3.5 MPa, and the 28d anti-seepage pressure is 14.4 to 18.1 MPa, achieving the optimal balance between compressive strength and anti-seepage pressure, and can be used as the best ratio during construction.

[0108] Furthermore, in order to reduce the construction cost of the concrete guardrail, in the embodiment of the present application, the main body of the concrete guardrail can be divided into an upper guardrail and a lower base, and the lower base is in contact with the ground; the upper guardrail is made of silicate cement, wherein water accounts for 40% of the silicate cement, the water reducer accounts for 1% of the silicate cement, and the fly ash accounts for 10% to 30% of the silicate cement, without being mixed with air entraining agent. Since the lower base is in contact with the ground, an anti-freeze design is required, so the concrete mixed with air entraining agent proposed in the above embodiment can be used. In this way, while saving the cost of the concrete guardrail, the anti-freeze performance of the guardrail can also be effectively improved.

[0109] At the same time, the above-mentioned waterproof coating can be further applied on the surface of the upper guardrail and the lower base to prevent the infiltration of brine.

[0110] Table 5 shows the comparison of mass loss after freeze-thaw cycles after applying the waterproof coating.

[0111] Table 5

[0112]

[0113]

[0114] It can be seen from Table 5 that after applying the waterproof coating, the mass loss after 60 and 120 freeze-thaw cycles is greatly reduced. For example, when the water-cement ratio is 0.4, the air entraining agent is 0.2‰, the water reducer is 3.6 parts and the fly ash accounts for 20%, the mass loss after 60 cycles decreases from 0.63% to 0.25%, and the mass loss after 120 cycles decreases from 3.81% to 2.25%. Therefore, it can be seen that the use of the waterproof coating can prevent brine from corroding the concrete guardrail while also greatly reducing the freeze-thaw mass loss.

[0115] In summary, the concrete and concrete guardrail proposed in the embodiments of the present application can improve the frost resistance of concrete while ensuring the compressive strength of concrete by adjusting the air entraining agent, water reducing agent and water-cement ratio, thereby increasing the service life of concrete in low temperature environments.

[0116] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0117] Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various aspects of the invention, in the above description of exemplary embodiments of the present application, the various features of the embodiments of the present application are sometimes grouped together into a single embodiment, or a description thereof.

[0118] Those skilled in the art will appreciate that the modules in the device in the embodiment can be adaptively changed and arranged in one or more devices different from the embodiment. The modules or units or components in the embodiment can be combined into one module or unit or component, and they can be divided into multiple submodules or subunits or subassemblies. Except that at least some of such features and / or processes or units are mutually exclusive, all features disclosed in this specification and all processes or units of any method or device disclosed in this manner can be combined in any combination. Unless otherwise clearly stated, each feature disclosed in this specification can be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0119] It should be noted that the above embodiments illustrate the present application rather than limit the present application, and those skilled in the art may design alternative embodiments without departing from the scope. The steps in the above embodiments, unless otherwise specified, should not be understood as limiting the execution order.

Claims

1. A concrete, characterized in that: The invention comprises the following raw materials in parts by weight: 136-151 parts of water, 252-324 parts of cement, 108-36 parts of fly ash, a water reducing agent accounting for 1% of the cement and fly ash, 1800-2000 parts of a sand-gravel mixture with a sand content of 40-50%, and an air entraining agent accounting for 0.015-0.025‰ of the cement and fly ash.

2. The concrete according to claim 1, characterized in that The sand-gravel mixture is 1900 parts, and the sand content is 46%.

3. The concrete according to claim 2, characterized in that The sand and gravel mixture includes: 874 parts of machine-made sand with a particle size of 0-5 mm, 103 parts of crushed stone with a particle size of 5-10 mm, and 923 parts of crushed stone with a particle size of 5-25 mm.

4. The concrete according to claim 1, characterized in that The fly ash content is 20%.

5. The concrete according to claim 1, characterized in that The air entraining agent accounts for 0.02‰ of the cement and fly ash.

6. The concrete according to claim 5, characterized in that The air entraining agent is hexadecyl dimethyl ethyl ammonium bromide, polyoxyethylene alkyl ether or alkyl sulfate.

7. A concrete guardrail, characterized in that: The concrete guardrail body is made of the concrete as described in any one of claims 1-6, and the surface of the concrete guardrail body is coated with a waterproof coating, which includes 70 to 100 parts of silicate cement, 70 to 100 parts of quartz sand, 35 to 55 parts of water and a hydrophobic agent accounting for 1 to 5% of the silicate cement.

8. The concrete guardrail according to claim 7, characterized in that: The waterproof coating has a thickness of 1 mm to 1.6 mm.

9. The concrete guardrail according to claim 7, characterized in that: The concrete guardrail body comprises an upper guardrail and a lower base, wherein the lower base is in contact with the ground; The upper guardrail is made of silicate cement, wherein water accounts for 40% of the silicate cement, water reducing agent accounts for 1% of the silicate cement, and fly ash accounts for 10% to 30% of the silicate cement.

10. The concrete guardrail according to claim 7, characterized in that: The hydrophobic agent accounts for 3% of the silicate cement.

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