Tubular pile containing functional aggregate and preparation method

Abstract

The invention belongs to the technical field of concrete pipe pile processing, and particularly relates to a functional aggregate-containing pipe pile and a preparation method thereof, the functional aggregate-containing pipe pile comprises reinforcing steel bars and concrete, the concrete is poured outside the reinforcing steel bars, and the concrete comprises the following components in parts by weight: 680-870 parts of functional aggregate, 156-244 parts of self-repairing aggregate, 20-78 parts of cement, 15-20 parts of a water reducing agent and 25-60 parts of water. Through the synergistic effect of the functional aggregate and the self-repairing aggregate and the optimized proportion and preparation technology, the concrete pipe pile can adapt to infrastructure in the land environment and can also adapt to infrastructure in the marine environment, and the practicability of the concrete pipe pile is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of processing concrete pipe piles, and in particular relates to a pipe pile containing functional aggregate and a preparation method thereof. Background Art

[0002] Concrete pipe piles are mainly used in land infrastructure such as high-rise buildings, railway bridge projects, etc. Concrete is a brittle material with a non-homogeneous porous structure. The large number of pores and microcracks inside it are often channels for external corrosive media to invade the concrete. At present, the concrete used for pipe piles is prepared by mixing conventional aggregates with cement and other materials. Pipe piles prepared with this conventional concrete are easily corroded by external corrosive media, resulting in a decrease in their mechanical strength, thus affecting the service life of concrete pipe piles.

[0003] There are studies on the short service life of concrete pipe piles in the prior art, such as patent application CN115650652A wetland corrosion-resistant pipe pile, CN112176986A a concrete pipe pile, etc., which improve the corrosion resistance of concrete pipe piles by using kaolin and sisal fiber or improve the strength of concrete pipe piles by using basalt fiber and steel scraps, solving the problem of short service life caused by using conventional concrete to make pipe piles, but the pipe piles made of existing concrete can only be adapted to land infrastructure construction, but for marine infrastructure construction, it is necessary to control the degree of seawater erosion of concrete, so that concrete pipe piles can meet the marine infrastructure construction; the existing technology is currently difficult to balance the contradiction between land and marine environments, and it is difficult to control the degree of seawater erosion of concrete for infrastructure construction in marine environments. To this end, a new technical solution is needed to solve the above technical problems. Summary of the invention

[0004] The purpose of the present invention is to provide a pipe pile containing functional aggregate and a preparation method thereof, so as to solve the problem mentioned in the above background technology that the pipe piles prepared by concrete at the current stage cannot control the degree of seawater erosion of concrete and are easily corroded by corrosive ions such as seawater, making the pipe piles difficult to be used for marine infrastructure construction.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a pipe pile containing functional aggregate, comprising steel bars and concrete, wherein the concrete is poured on the outside of the steel bars, and the concrete comprises the following components in parts by weight: 680-870 parts of functional aggregate, 156-244 parts of self-repairing aggregate, 20-78 parts of cement, 15-20 parts of water reducer and 25-60 parts of water, wherein the functional aggregate comprises the following components in parts by weight: 350-480 parts of coal gangue system aggregate, 280-330 parts of coal gangue-fly ash system aggregate and 50-60 parts of water, wherein the self-repairing aggregate comprises the following components in parts by weight: 60-70 parts of microbial self-repairing agent, 48-58 parts of metakaolin, 65-85 parts of cement and 10-15 parts of simulated seawater, wherein the simulated seawater is selected from one or a mixture of sodium bicarbonate, calcium chloride dihydrate, magnesium chloride hexahydrate, crystalline sodium sulfate, potassium chloride and sodium chloride.

[0006] Furthermore, the gangue system aggregate is calculated according to the mass percentage of the components: 80-95wt% gangue, 2-15wt% dolomite powder and 3-6wt% plasticizer, and the gangue-fly ash system aggregate is calculated according to the weight percentage of the components: 40-72wt% gangue, 8-40wt% fly ash, 11-13wt% dolomite powder and 8-9wt% plasticizer, wherein the gangue is a mixture of kaolinite and quartz, the fly ash is a mixture of mullite and quartz, the dolomite powder is a mixture of cordierite, mullite, anorthite and quartz, and the plasticizer is selected from one of phthalates, phosphates and aliphatic dibasic acid esters.

[0007] Furthermore, the microbial self-repairing agent comprises, according to the mass percentage of the components, 50-72wt% ribosomes, 15-22wt% quartz sand, 13-21wt% silicate cement, and 8-18wt% calcium oxide.

[0008] According to the above setting content, a pipe pile containing functional aggregate is prepared. The specific preparation steps are as follows: first, 680-870 parts of functional aggregate, 20-78 parts of cement, 15-20 parts of water reducer and 25-60 parts of water are poured into a mixer with a rotation speed of 13-15 ft / min for stirring and mixing for 1.5-2 hours, and then 156-244 parts of self-repairing aggregate are added in batches in a decreasing manner for mixing and stirring. After the mixture is evenly mixed, the concrete is formed and then centrifuged and allowed to stand. It is cured by normal pressure steam at a curing temperature of 20-60°C for 7 After 8 to 8 hours, the cured concrete is poured on the outside of the steel bar, and finally the pipe pile containing functional aggregate is naturally cured for 8 to 10 days under natural conditions to obtain the pipe pile, wherein the mixing ratio between the functional aggregate, the self-repairing aggregate and the cement is 1:0.23-0.28:0.03-0.09, the cement is selected from one of silicate cement, slag cement and alumina cement, and the water reducer is selected from one of calcium lignin sulfonate, melamine, polycyclic aromatic sulfonate formaldehyde condensate and aminosulfonate system or a mixture of several thereof.

[0009] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adds functional aggregates to concrete to form a complex and stable microstructure of concrete, effectively improving the compactness and impermeability of concrete, thereby reducing the amount of cement used in concrete pipe piles without affecting their performance indicators, effectively inhibiting the deformation of concrete itself and reducing its deformation rate and thermal expansion coefficient, improving the thermal stability of concrete, and ensuring the strength and stability of concrete pipe piles. Then, through the microbial self-repairing agent in the self-repairing aggregate, a micro-ecological system can be formed inside the concrete, so that microorganisms can sense and produce repair substances to fill cracks when the concrete is corroded, preventing the corrosive medium from further invading the concrete, significantly improving the corrosion resistance of the concrete, and realizing the self-repairing performance of the concrete, so that the concrete pipe column can restore its original mechanical properties and integrity, ensuring the stability and safety of the concrete pipe piles under complex stress conditions, so that the concrete pipe piles can not only adapt to infrastructure construction in land environments, but also adapt to infrastructure construction in marine environments, further improving the practicality of the concrete pipe piles; 2. The present invention uses coal gangue, which is a mixture of kaolinite and quartz, and fly ash, which is a mixture of mullite and quartz, which are industrial wastes, as concrete aggregates, which not only reduces environmental pollution, but also realizes the recycling of resources, conforms to the concept of sustainable development, and can also play a role of filling and skeleton in concrete, effectively improving the density and strength of concrete. The addition of dolomite powder further enhances the stability and durability of concrete aggregates. The introduction of plasticizers such as phthalates, phosphates, and aliphatic dibasic acid esters helps to improve the fluidity of concrete, reduce the energy consumption of concrete during mixing and pouring, and improve the crack resistance and durability of concrete. 3. The present invention uses a microbial self-repairing agent containing ribosomes, quartz sand, silicate cement and calcium oxide, which can form a microbial community in concrete, so that when cracks occur in the concrete, it can be activated and produce mineral precipitation such as calcium carbonate to fill the cracks, thereby achieving self-repair. The addition of metakaolin and cement improves the strength and durability of the concrete, and also provides a good growth environment for the microbial self-repairing agent. The introduction of simulated seawater such as sodium bicarbonate, calcium chloride dihydrate, magnesium chloride hexahydrate, crystalline sodium sulfate, potassium chloride, and sodium chloride provides the microbial self-repairing agent with necessary minerals and nutrients to promote the growth and reproduction of microorganisms, thereby further enhancing the self-repairing ability of the concrete; 4. The present invention adopts a design of adding self-repairing aggregates in batches in a decreasing manner, so that the self-repairing aggregates can be evenly distributed in the concrete, effectively avoiding the problem of uneven mixing caused by adding too much at one time. At the same time, it can also make the microorganisms in the self-repairing aggregates form a more even distribution in the concrete, thereby improving the efficiency of self-repairing, and using centrifugal force to rearrange the particles in the concrete to form a tighter microstructure, thereby improving the mechanical properties and durability of the concrete. The curing method combining steam and nature is used, which helps to further optimize and stabilize the internal structure of the concrete, so that the performance of the concrete reaches the best state. DETAILED DESCRIPTION

[0010] The following examples are used to further illustrate the content of the present invention, but do not limit the application of the present invention. Embodiment 1:

[0011] The components of the functional aggregate are weighed according to the following weight percentages: 390 parts of coal gangue system aggregate, 280 parts of coal gangue-fly ash system aggregate and 52 parts of water, wherein the components of the coal gangue system aggregate are weighed according to weight mass percentage: 80-95wt% of coal gangue, 2-15wt% of dolomite powder and 3-6wt% of phthalate plasticizer, and the components of the coal gangue-fly ash system aggregate are weighed according to weight mass percentage: 40-72wt% of coal gangue, 8-40wt% of fly ash, 11-13wt% of dolomite powder and 8-9wt% of phosphate plasticizer; After uniformly mixing the above 390 parts of coal gangue system aggregate and 280 parts of coal gangue-fly ash system aggregate, 52 parts of water were added and stirred uniformly in a mortar mixer, taken out and sealed with a plastic film, and aged for 5 to 6 hours to obtain a functional aggregate; The components of the self-repairing aggregate are weighed according to the following weight proportions: 62 parts of microbial self-repairing agent, 51 parts of metakaolin, 68 parts of cement and 12 parts of simulated seawater (sodium bicarbonate mixed with calcium chloride dihydrate, magnesium chloride hexahydrate, crystalline sodium sulfate, potassium chloride and sodium chloride), wherein the components of the microbial self-repairing agent are weighed according to weight mass percentage: 50-72wt% ribosomes, 15-22wt% quartz sand, 13-21wt% silicate cement and 8-18wt% calcium oxide; The above 62 parts of microbial self-repairing agent, 51 parts of metakaolin, 68 parts of cement and 12 parts of simulated seawater were mixed evenly in a mortar mixer, and an acetone solution with a concentration of 0.25 g / mL was added. After standing for acetone to evaporate, cement powder or fine sand was added and mixed evenly to obtain a self-repairing aggregate, wherein the cement powder or fine sand is further modified to further modify the self-repairing aggregate, the purpose of which is to make the self-repairing aggregate have better bonding strength with other components of concrete, thereby ensuring that the cracks of the concrete pipe pile can penetrate the self-repairing aggregate when cracking, so as to achieve the purpose of timely repairing the cracks of the concrete pipe pile.

[0012] According to the above concrete components, pipe piles containing functional aggregates are prepared, and the specific preparation steps are as follows: first, 680 parts of functional aggregates, 41 parts of cement (here, cement can be selected from silicate cement), 16 parts of water reducer and 28 parts of water are poured into a mixer with a rotation speed of 13-15 ft / min for stirring and mixing for 1.5-2 hours, and then 170 parts of self-repairing aggregates are added in batches in a decreasing manner for mixing and stirring. After the mixture is evenly mixed, the concrete is formed and then centrifuged and allowed to stand. After the curing temperature is 20-60°C, the normal pressure steam is cured for 7-8 hours, and the cured concrete is poured on the outside of the steel bar. Finally, the concrete pipe piles are naturally cured for 8-10 days under natural conditions to obtain concrete pipe piles with thermal stability and automatic crack repair function, so that the amount of cement used in the concrete pipe piles is reduced without affecting their performance indicators, so that the concrete pipe piles can be used not only in land infrastructure but also in marine infrastructure. Embodiment 2:

[0013] In this embodiment, the concrete formula and preparation method of the concrete pipe pile are consistent with those in Example 1, except that the weight proportions of the various components of the concrete are different, that is, the concrete includes the following components: 870 parts of functional aggregate, 218 parts of self-repairing aggregate, 52 parts of cement, 18 parts of calcium lignin sulfonate and 35 parts of water. Embodiment 3:

[0014] In this embodiment, the concrete formula and preparation method of the concrete pipe pile are consistent with those in Example 1, except that the weight proportions of the various components of the concrete are different, that is, the concrete includes the following components: 736 parts of functional aggregate, 180 parts of self-repairing aggregate, 44 parts of cement, 20 parts of calcium lignin sulfonate and 45 parts of water. Embodiment 4:

[0015] In this embodiment, the concrete formula and preparation method of the concrete pipe pile are consistent with those in Example 1, except that the weight proportions of the various components of the concrete are different, that is, the concrete includes the following components: 824 parts of functional aggregate, 206 parts of self-repairing aggregate, 49 parts of cement, 20 parts of melamine and 56 parts of water.

[0016] Comparative Example 1: In this comparative example, the preparation method of concrete pipe piles is consistent with that in Example 1, except that the concrete formula of the concrete pipe piles is inconsistent, that is, the concrete adopts a conventional formula, that is, the concrete formula is 400 parts of coarse aggregate, 300 parts of fine aggregate, 220 parts of cement, 135 parts of water, 35 parts of metakaolin, 24 parts of sisal fiber, 3 parts of water reducer, and no functional aggregate and self-repairing aggregate are added. The concrete is prepared by conventional technology, that is, the concrete formula is subjected to tensioning prestressed steel bars, centrifugal forming and steam curing to produce concrete pipe piles.

[0017] Comparative Example 2: In this comparative example, the preparation method of concrete pipe piles is consistent with that of comparative example 1, except that the concrete formula of the concrete pipe piles is inconsistent, that is, the concrete adopts a conventional formula and introduces functional aggregates, but no self-repairing aggregates are added, and is prepared using conventional processes, that is, the concrete formula is subjected to tensioning prestressed steel bars, centrifugal forming and steam curing to produce concrete pipe piles.

[0018] Comparative Example 3: In this comparative example, the preparation method of concrete pipe piles is consistent with that of comparative example 1, except that the concrete formula of the concrete pipe piles is inconsistent, that is, the concrete adopts a conventional formula and introduces functional aggregates and self-repairing aggregates, and is prepared by conventional processes, that is, the concrete formula is subjected to tensioning prestressed steel bars, centrifugal forming and steam curing to produce concrete pipe piles.

[0019] The following is a comparison table of the concrete grade, deformation rate, thermal expansion coefficient, axial compressive strength, axial tensile strength, chloride ion diffusion coefficient and impermeability grade of the concrete pipe piles of Examples 1-4 and Comparative Examples 1-3 measured according to the national standard "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete" (GB / T 50082-2009), the national standard GB / T 50082-2009 "Concrete Structure Design Code" and the industry standard Q / JHJC 57 1001-2021 "High Performance Concrete Pipe Piles": ; As can be seen from the above table, when the concrete pipe piles in Example 1 are subjected to external force, their deformation rate is relatively low, indicating that they have good rigidity and stability, and at the same time have a low thermal expansion coefficient, which means that when the temperature changes, their size changes are small, which is conducive to maintaining the stability of the structure; compared with Example 1, the deformation rate of the concrete pipe piles in Example 2 under the same external force is slightly increased, but still remains within an acceptable range, indicating that it still has good mechanical properties, and also has a low thermal expansion coefficient, showing good thermal stability; when the concrete pipe piles in Example 3 are subjected to external force, their deformation rate is between that of Example 1 and Example 2, indicating that their mechanical properties are moderate, and their thermal expansion coefficient is also low, which meets the requirements of structural stability; compared with Example 3, the deformation rate of the concrete pipe piles in Example 4 under the same external force is slightly reduced, indicating that their rigidity is slightly enhanced, and also shows a low thermal expansion coefficient, which is conducive to maintaining the stability of the structure when the temperature changes; However, when the concrete pipe piles in Comparative Example 1 are subjected to external force, their deformation rate is relatively high, indicating that their rigidity is poor and their thermal expansion coefficient is also high, which may cause the size of the structure to change greatly when the temperature changes, which is not conducive to maintaining the stability of the structure; although functional aggregates are introduced in Comparative Example 2, their deformation rate is still high, indicating that the introduction of functional aggregates alone cannot significantly improve the mechanical properties of concrete, and the thermal expansion coefficient is also high, indicating that the introduction of functional aggregates does not significantly reduce its thermal expansion coefficient; in Comparative Example 3, functional aggregates and self-healing aggregates are introduced at the same time, but their deformation rate is still high, indicating that without optimizing the ratio and preparation process, the simultaneous introduction of these two aggregates cannot significantly improve the mechanical properties of concrete, and the thermal expansion coefficient is also high, indicating that the thermal expansion coefficient cannot be effectively reduced by introducing functional aggregates and self-healing aggregates alone.

[0020] In summary, by comparing the test results of each embodiment and the comparative example, it can be seen that the pipe piles containing functional aggregates and the preparation method thereof provided by the present invention show significant advantages in reducing deformation rate, thermal expansion coefficient, mechanical properties, corrosion resistance and durability. This is mainly due to the synergistic effect of functional aggregates and self-repairing aggregates and the optimized ratio and preparation process. These advantages make the concrete pipe piles provided by the present invention not only suitable for land infrastructure construction, but also can show good performance in marine infrastructure construction.

Claims

1. A pipe pile containing functional aggregate, comprising steel bars and concrete, wherein the concrete is poured outside the steel bars, characterized in that: The concrete comprises the following components in parts by weight: 680-870 parts of functional aggregate, 156-244 parts of self-repairing aggregate, 20-78 parts of cement, 15-20 parts of water reducer and 25-60 parts of water; the functional aggregate comprises the following components in parts by weight: 350-480 parts of coal gangue system aggregate, 280-330 parts of coal gangue-fly ash system aggregate and 50-60 parts of water; the self-repairing aggregate comprises the following components in parts by weight: 60-70 parts of microbial self-repairing agent, 48-58 parts of metakaolin, 65-85 parts of cement and 10-15 parts of simulated seawater.

2. The pipe pile containing functional aggregate according to claim 1, characterized in that: The gangue system aggregate is calculated according to the mass percentage of the components: 80-95wt% gangue, 2-15wt% dolomite powder and 3-6wt% plasticizer; the gangue-fly ash system aggregate is calculated according to the weight percentage of the components: 40-72wt% gangue, 8-40wt% fly ash, 11-13wt% dolomite powder and 8-9wt% plasticizer.

3. The pipe pile containing functional aggregate according to claim 2, characterized in that: The coal gangue is a mixed product of kaolinite and quartz, the fly ash is a mixed product of mullite and quartz, and the dolomite powder is a mixed product of cordierite, mullite, anorthite and quartz.

4. The pipe pile containing functional aggregate according to claim 2, characterized in that: The plasticizer is selected from phthalates, phosphates, and aliphatic dibasic acid esters.

5. The pipe pile containing functional aggregate according to claim 1, characterized in that: The microbial self-repairing agent comprises, according to the mass percentage of the components: 50-72wt% ribosomes, 15-22wt% quartz sand, 13-21wt% silicate cement, and 8-18wt% calcium oxide.

6. The pipe pile containing functional aggregate according to claim 1, characterized in that: The simulated seawater is selected from one of sodium bicarbonate, calcium chloride dihydrate, magnesium chloride hexahydrate, crystalline sodium sulfate, potassium chloride, and sodium chloride, or a mixture of several of them.

7. A method for preparing a pipe pile containing functional aggregate according to any one of claims 1 to 6, characterized in that: The method comprises the following specific steps: firstly, pouring 680-870 parts of functional aggregate, 20-78 parts of cement, 15-20 parts of water reducing agent and 25-60 parts of water into a mixer for stirring and mixing, then gradually adding 156-244 parts of self-repairing aggregate in batches for mixing and stirring, after being evenly mixed, centrifugally forming the concrete, standing it, performing normal pressure steam curing for 7-8 hours under the condition of curing temperature of 20-60°C, pouring the cured concrete on the outside of the steel bar, and finally performing natural curing for 8-10 days under natural conditions to obtain the pipe pile containing the functional aggregate.

8. The method for preparing a pipe pile containing functional aggregate according to claim 7, characterized in that: The rotation speed of the stirrer is 13 to 15 ft / min, and the stirring time is 1.5 to 2 hours.

9. The method for preparing a pipe pile containing functional aggregate according to claim 7, characterized in that: The mixing ratio of the functional aggregate, the self-repairing aggregate and the cement is 1:0.23-0.28:0.03-0.

09.

10. The method for preparing a pipe pile containing functional aggregate according to claim 9, characterized in that: The cement is selected from one of silicate cement, slag cement and alumina cement, and the water reducer is selected from one of calcium lignin sulfonate, melamine, polycyclic aromatic sulfonate formaldehyde condensate and aminosulfonate series or a mixture of several of them.