Small-sized concrete prefabricated part and preparation method thereof

Abstract

The invention discloses a small concrete prefabricated part and a preparation method thereof, and belongs to the technical field of traffic engineering. According to the invention, water granulated slag, carbide slag, cement clinker, phosphorus slag, an admixture and water are used as raw materials, and a small-sized concrete prefabricated part is obtained through pouring. The water granulated slag, the carbide slag, the cement clinker and the phosphorus slag are synergistically excited, so that a high-temperature calcination process for cement production is avoided, and the energy consumption cost and CO2 emission are reduced; in addition, in certain special proportions, the tensile strength, compressive strength and shrinkage resistance of the prefabricated part can be synergistically improved; or the tensile strength, the bending strength, the impact toughness and the shrinkage resistance of the prefabricated part are synergistically improved, and meanwhile, the hardness is kept almost unchanged.

Description

Technical Field

[0001] The invention belongs to the technical field of traffic engineering, and in particular relates to a small concrete prefabricated part and a preparation method thereof. Background Art

[0002] Small concrete precast is a widely used concrete structure, which is mainly composed of the following basic materials: 1. Cement: As the cementitious material in concrete, cement hardens after reacting with water (hydration) and bonds other materials together. Common types of cement include Portland cement, ordinary Portland cement, slag Portland cement, etc. 2. Water: It is used to react with cement and form cement paste to provide fluidity for concrete for easy construction. The quality of water directly affects the performance of concrete, and water containing too much acid, alkali, salt or organic matter should be avoided. 3. Fine aggregate (sand): It is filled in the cement paste to reduce pores and increase the density of concrete. The distribution of sand particle size (gradation) has an important influence on the workability and strength of concrete. 4. Coarse aggregate (stone or crushed stone): It constitutes the skeleton of concrete, enhances the mechanical properties of concrete, reduces the amount of cement, and controls the shrinkage and creep of concrete. In addition to these basic materials, in order to improve certain specific properties of concrete, it may also be added: admixtures: such as fly ash, mineral powder, etc., which can improve the workability and durability of concrete or reduce thermal expansion, etc. Admixtures: including water reducers, early strength agents, retarders, etc., which are used to adjust the setting time, fluidity and hardening properties of concrete.

[0003] Small concrete precast parts have many advantages such as good plasticity and durability, but they also have some disadvantages, mainly including: 1. High energy consumption and environmental pollution: Cement production is a high energy consumption process. Each ton of ordinary Portland cement production requires about 100 kg of energy equivalent to standard coal, and a large amount of carbon dioxide will be released during the entire production process, exacerbating the greenhouse effect and affecting the environment. 2. Resource consumption: The production of cement requires a large amount of raw materials, such as limestone, clay, iron ore, etc., which not only consumes natural resources, but also causes ecological damage in the mining area. 3. Low tensile strength: Compared with compressive strength, concrete has a lower tensile strength, which is only about 1 / 10 to 1 / 12 of the compressive strength, so it is easy to crack, especially when subjected to tension or bending stress. 4. Shrinkage deformation: Concrete will shrink in volume during the hardening process, including chemical shrinkage (drying shrinkage) and physical shrinkage (cold shrinkage caused by temperature difference), which may cause cracks. 5. High initial cost: Although concrete structures are more economical in the long run, their initial construction costs are high, especially compared with some other materials. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the present invention provides a small concrete prefabricated part and a preparation method thereof.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for preparing a small concrete prefabricated part comprises the following steps:

[0007] (1) Mixing small precast concrete component raw materials, admixtures and water to form slurry;

[0008] (2) pouring the slurry to obtain a small concrete precast part;

[0009] The raw materials of the small concrete prefabricated parts include the following raw materials in percentage by mass: 13%-20% of water slag, 5%-10% of carbide slag, 3%-5% of cement clinker and 70%-79% of phosphorus slag.

[0010] As a preferred embodiment of the present invention, the admixture is a water reducing agent.

[0011] As a preferred embodiment of the present invention, the mass ratio of the small prefabricated concrete parts raw materials, admixtures and water is (90-95):(0.3-0.5):(5-10).

[0012] As a preferred embodiment of the present invention, the step (1) specifically comprises: grinding water slag, carbide slag and cement clinker to form a binder, and then mixing the binder, phosphorus slag, water and admixtures intermittently to form a slurry.

[0013] As a preferred embodiment of the present invention, the specific surface area of ​​the binder is controlled at 420 m 2 / kg or more.

[0014] As a preferred embodiment of the present invention, the small prefabricated concrete parts are concrete fence columns or tunnel cable trench covers.

[0015] More preferably, when the raw materials of the small concrete prefabricated parts include the following raw materials in percentage by weight: 15% slag, 10% carbide slag, 5% cement clinker and 70% phosphorus slag, the prepared concrete isolation fence columns have the strongest tensile strength, tensile strength, impact toughness and Barcol hardness, and have good moisture and heat resistance and freeze-thaw resistance.

[0016] More preferably, when the raw materials of the small concrete prefabricated parts include the following raw materials in percentage by weight: 13% slag, 5% carbide slag, 4% cement clinker and 78% phosphorus slag, the prepared small concrete tunnel cable trench cover has the strongest flexural strength and compressive strength.

[0017] The present invention also claims protection for the small prefabricated concrete part prepared by the method for preparing the small prefabricated concrete part.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention adopts the synergistic stimulation of multiple solid wastes such as water slag, calcium carbide slag, cement clinker, and phosphorus slag, avoids the high-temperature calcination process of cement production, reduces energy consumption costs and CO2 emissions generated in the corresponding production process, and reduces pollution to the atmosphere; and in certain special proportions, it can synergistically improve the tensile strength, compressive strength and shrinkage resistance of the prepared prefabricated parts; or synergistically improve the tensile strength, bending strength, impact toughness, and shrinkage resistance of the prepared prefabricated parts, while keeping the hardness almost unchanged. In addition, the present invention gives full play to the characteristics of phosphorus slag aggregate, which is light, low cost, and has good tensioning performance in concrete, greatly reduces the material cost of small concrete prefabricated parts, and also avoids the mining of ordinary concrete aggregates, fully reflecting the green and low-carbon social and economic benefits. DETAILED DESCRIPTION

[0019] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0020] Example 1

[0021] A method for preparing a small isolation fence column comprises the following steps:

[0022] (1) Grind slag, carbide slag and cement clinker to form a binder with a specific surface area of ​​420 m 2 / kg or more, and then the binder, phosphorus slag, water and lignin sulfonate are mixed intermittently to form slurry.

[0023] (2) The slurry is poured into a mold to obtain a small isolation fence column.

[0024] The mass percentages of the water slag, carbide slag, cement clinker and phosphorus slag are respectively: 15% water slag, 10% carbide slag, 5% cement clinker and 70% phosphorus slag.

[0025] The mass ratio of the small concrete prefabricated part raw material, lignin sulfonate and water is 90:0.3:10.

[0026] After curing for 28 days, the tensile strength of the column prepared in Example 1 was tested by GB / T 1447-2005 and was 155 MPa, the bending strength was tested by GB / T 1449-2005 and was 279 MPa, and the impact toughness was tested by GB / T 1451-2005 and was 156 kJ / m 2The Barcol hardness was tested by GB / T 3854-2017 and was 43, and its moisture and heat resistance was tested by JT / T848-2013. After 240 hours of testing, the product had no signs of discoloration or erosion. Its freeze-thaw resistance was tested by JT / T848-2013 and the product had no cracking, peeling, delamination or other damage.

[0027] Example 2

[0028] A method for preparing a small concrete tunnel cable trench cover comprises the following steps:

[0029] (1) Grind slag, carbide slag and cement clinker to form a binder with a specific surface area of ​​420 m 2 / kg or more, and then the binder, phosphorus slag, water and naphthalenesulfonate water reducer are mixed intermittently to form slurry.

[0030] (2) The slurry is poured into a mold to obtain a small concrete tunnel cable trench cover.

[0031] The following mass percentage contents of the water slag, carbide slag, cement clinker and phosphorus slag are respectively: 13% water slag, 5% carbide slag, 4% cement clinker and 78% phosphorus slag.

[0032] The mass ratio of the small concrete prefabricated part raw material, naphthalenesulfonate water reducer and water is 95:0.4:8.

[0033] According to tests, the flexural strength of the cable trench cover of a small concrete tunnel after 28 days of maintenance is 18.3MPa, and the compressive strength is 128.6MPa.

[0034] Comparative Examples 1-4

[0035] In order to verify the synergistic effect between the raw materials of small concrete prefabricated parts, a small isolation fence column is taken as an example to set up a comparative example, and the effects of the set embodiment and the comparative example are verified.

[0036] The only difference between the preparation method of a small isolation fence column in the comparative example and that in the embodiment 1 is that the raw materials of the small concrete prefabricated parts are added according to Table 1.

[0037] Table 1 Mass percentage of each raw material in the raw materials of small concrete prefabricated parts

[0038]

[0039] After curing for 28 days, the performance of the small isolation fence columns of Example 1 and Comparative Examples 1-4 was tested, and the mechanical property test results are shown in Table 2.

[0040]

[0041] According to the comparison between the embodiments and the comparative examples, the present invention realizes the resource utilization of industrial solid wastes such as phosphorus slag and water slag, reduces environmental pollution and occupied land resources, and conforms to the concept of sustainable development. In addition, the present invention uses water slag, carbide slag, cement clinker and phosphorus slag to synergistically improve the performance of concrete: ① Reduce hydration heat: Compared with the small-sized isolation fence columns prepared by ordinary cement concrete and comparative examples 1-4, the small-sized isolation fence columns prepared by embodiment 1 of the present invention can reduce the heat generated during the hydration process, which helps to reduce the concrete cracking caused by temperature difference. ② Improve crack resistance: The present invention can optimize the internal pore structure of concrete, reduce large pores, and increase the proportion of fine pores, thereby improving the overall crack resistance of concrete prefabricated parts. The small-sized isolation fence columns prepared by comparative examples 1-3 show cracking, peeling, and delamination. ③ Enhance late strength: The early strength of the small-sized isolation fence columns prepared by embodiment 1 is equal to that of the small-sized isolation fence columns prepared by ordinary cement concrete, but as time goes by (such as after 28 days), the strength of the small-sized isolation fence columns prepared by embodiment 1 is significantly improved. ④ Retarding effect: The synergistic effect of water slag, calcium carbide slag, cement clinker and phosphorus slag has a retarding effect on concrete, which is beneficial to construction operations, especially when construction is carried out in a high temperature environment, which can extend the working time of concrete.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a small concrete prefabricated part, characterized in that: The steps include: (1) Mixing small precast concrete component raw materials, admixtures and water to form slurry; (2) pouring the slurry to obtain a small concrete precast part; The raw materials of the small concrete prefabricated parts include the following raw materials in percentage by mass: 13%-20% of water slag, 5%-10% of carbide slag, 3%-5% of cement clinker and 70%-79% of phosphorus slag.

2. The method for preparing a small prefabricated concrete part according to claim 1, characterized in that: The external admixture is a water reducing agent.

3. The method for preparing a small concrete prefabricated part according to claim 3, characterized in that: The mass ratio of the small concrete prefabricated part raw material, external admixture and water is (90-95):(0.3-0.5):(5-10).

4. The method for preparing a small prefabricated concrete part according to claim 1, characterized in that: The step (1) specifically comprises: grinding water slag, carbide slag and cement clinker to form a binder, and then mixing the binder, phosphorus slag, water and admixtures intermittently to form a slurry.

5. The method for preparing a small prefabricated concrete part according to claim 4, characterized in that: The specific surface area of ​​the binder is controlled at 420m 2 / kg or more.

6. The method for preparing a small prefabricated concrete part according to claim 1, characterized in that: The small concrete prefabricated parts are concrete isolation fence columns or tunnel cable trench covers.

7. The method for preparing a small prefabricated concrete part according to claim 6, characterized in that: When the small concrete prefabricated parts are concrete isolation fence columns, the raw materials of the small concrete prefabricated parts include the following raw materials in percentage by mass: 15% slag, 10% carbide slag, 5% cement clinker and 70% phosphorus slag.

8. The method for preparing a small prefabricated concrete part according to claim 6, characterized in that: When the small concrete prefabricated component is a small concrete tunnel cable trench cover, the raw materials of the small concrete prefabricated component include the following raw materials in percentage by mass: 13% slag, 5% carbide slag, 4% cement clinker and 78% phosphorus slag.

9. A small precast concrete part prepared by the method for preparing a small precast concrete part according to any one of claims 1 to 8.

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