Concrete containing recycled aggregates for the preparation of precast concrete foundation formwork

Abstract

This invention relates to the field of concrete technology, specifically disclosing a type of concrete containing recycled aggregate for preparing precast concrete foundation formwork. The concrete containing recycled aggregate for preparing precast concrete foundation formwork comprises the following components in parts by weight: 100 parts water; 210-220 parts cement; 28-30 parts fly ash; 1115-1135 parts recycled aggregate; 1.4-1.6 parts water-reducing agent; and 1.8-2 parts modified plant fiber. The modified plant fiber is obtained by precipitating calcium carbonate on the surface of plant fibers through a composite microbial process. This invention has the advantage of improving the strength of concrete, thereby reducing cracking of precast concrete foundation formwork. The use of recycled aggregate reduces material waste, saves energy, reduces the space occupied by waste concrete, and is more environmentally friendly, thus achieving better green environmental protection.

Description

Technical Field

[0001] This invention relates to the field of concrete, and more particularly to a type of concrete containing recycled aggregate for preparing precast concrete foundation formwork. Background Technology

[0002] During the construction of building pile caps, when there are a large number of pile caps, the construction efficiency and quality of the pile caps become an important factor affecting the construction cycle of the basement.

[0003] Traditional foundation formwork mainly uses block masonry construction. After the bricklaying is completed, plastering is required. The process is complicated and the construction period is long. It is also susceptible to water accumulation in the foundation pit and soft soil caused by heavy rain and other severe weather, which can affect the masonry construction of the formwork. Moreover, common quality problems such as cracking and collapse of foundation formwork occur from time to time, which in turn affect the normal construction of the project.

[0004] By using precast concrete foundation formwork, the construction of foundation formwork can be completed quickly. Moreover, since the foundation formwork is a precast component, its quality is well controlled, resulting in more stable foundation formwork quality. It is gradually replacing the traditional block masonry construction method.

[0005] However, during the construction of the foundation formwork, the foundation formwork needs to surround the pile head and be internally supported by steel pipes after the foundation formwork is assembled. When the pile head size is large, the required foundation formwork length is long. In order to facilitate transportation, the thickness of the foundation formwork is generally 60-100mm, while the length usually reaches 1200-2500mm. As a result, the foundation formwork may still crack or break due to insufficient strength when under stress. Therefore, there is still room for improvement. Summary of the Invention

[0006] In order to improve the strength of concrete and thus reduce cracking of precast foundation formwork, this application provides a concrete containing recycled aggregate for preparing assembled precast foundation formwork.

[0007] This application provides a technical solution for preparing precast concrete foundation formwork containing recycled aggregate, using the following method: A type of concrete containing recycled aggregate for preparing precast concrete foundation formwork comprises the following components in parts by weight: 100 parts water; 210-220 parts cement; 28-30 parts fly ash; 1115-1135 parts of recycled aggregate; Water-reducing agent: 1.4-1.6 parts; 1.8-2 parts modified plant fiber; The modified plant fiber is obtained by depositing calcium carbonate on the surface of plant fiber through composite microorganisms.

[0008] By adopting the above technical solution, calcium carbonate is precipitated on the surface of plant fibers using composite microorganisms, resulting in a large number of calcium carbonate particles embedded on the surface of the plant fibers. This increases the surface roughness of the plant fibers. At the same time, since calcium carbonate has higher compatibility with cement stone, the calcium carbonate particles can increase the bonding force between the plant fibers and cement stone. This makes the modified plant fiber reinforced concrete more effective, giving the concrete higher crack resistance and making the resulting foundation formwork less prone to cracking and breakage.

[0009] By embedding calcium carbonate particles on the surface of plant fibers, the plant fibers fill the cracks in the recycled aggregate, and the calcium carbonate can be used to reinforce the recycled aggregate, thereby increasing the compressive strength of the recycled aggregate. This reduces the negative impact of the reduced concrete strength caused by the increased cracks in the recycled aggregate due to external force breakage, which leads to lower strength than natural aggregate. As a result, the compressive strength of the concrete is also significantly improved, and the resulting foundation formwork has higher strength and better quality.

[0010] By using recycled aggregates, we can reduce material waste, save energy, reduce the space occupied by waste concrete, and be more environmentally friendly, thus achieving green environmental protection.

[0011] Preferably, the plant fiber is lignocellulose.

[0012] By adopting the above technical solution and specifically selecting wood fibers, the characteristic of wood fiber surface having a large number of micropores is utilized, so that calcium carbonate microparticles can be more stably embedded on the surface of modified plant fibers. This makes the compatibility of modified plant fibers with cement stone higher, and can better reinforce recycled aggregates, resulting in better modified concrete.

[0013] Preferably, the compound microorganisms are a combination of Staphylococcus, Lactobacillus, Chlorella, and Clostridium.

[0014] By adopting the above technical solution, and by specifically selecting Staphylococcus, Lactobacillus, Chlorella, and Clostridium to form a compound microorganism, calcium carbonate can be quickly precipitated on the surface of plant fibers during modification. Through the combination of various microbial species, the activity of each species is higher and the metabolism is faster, thus increasing the speed of plant fiber modification and giving it higher economic value. Moreover, it has a stronger selectivity for plant fibers and tends to attach to plant fibers for metabolism, thereby better realizing the precipitation of calcium carbonate on plant fibers and achieving better effects in modifying plant fibers.

[0015] Preferably, the mass ratio of Staphylococcus, Lactobacillus, Chlorella, and Clostridium is 2.5-3.5: 3.5-4.5: 0.5-1.5: 1.5-2.5.

[0016] By adopting the above technical solution and by specifically selecting the mass ratio of Staphylococcus, Lactobacillus, Chlorella, and Clostridium, the synergistic effect of each bacterial species is better, and the effect of modifying plant fibers is better.

[0017] Preferably, the mass ratio of Staphylococcus, Lactobacillus, Chlorella, and Clostridium is 3:4:1:2.

[0018] By adopting the above technical solution, Staphylococcus, Lactobacillus, Chlorella, and Clostridium difficile are compounded in a specific mass ratio, which greatly enhances the activity of each strain, resulting in higher efficiency in modifying plant fibers and better quality modified plant fibers.

[0019] Preferably, the modification method of the modified plant fiber is as follows: Step 1): Add Staphylococcus, Lactobacillus, Chlorella, and Clostridium to the culture medium and culture until the OD value of the culture medium is 1.5-2 to obtain a compound bacterial solution. Step 2) Soak the plant fiber in the compound bacterial solution for 15-30 minutes to obtain pretreated plant fiber; Step 3) Transfer the pretreated plant fibers to the treatment solution, soak for 8-9 days, and dry to obtain modified plant fibers; The nutrient solution is composed of water, peptone, yeast extract, glucose, and sodium chloride. The treatment solution is composed of water, calcium lactate, and glucose.

[0020] By adopting the above technical solution, plant fibers are soaked in a compound bacterial solution. Due to the high bacterial concentration in the compound bacterial solution, various bacterial species quickly attach to the surface of the plant fibers. Then, by transferring them to a treatment solution, calcium carbonate is deposited on the surface of the plant fibers through the metabolic action of various bacterial species, thereby achieving the effect of embedding calcium carbonate microparticles on the surface of the plant fibers, thus modifying the plant fibers and producing modified plant fibers of better quality.

[0021] Preferably, the recycled aggregate is a blend of recycled fine aggregate and recycled coarse aggregate, and the mass ratio of the recycled fine aggregate to the recycled coarse aggregate is 1:1.5.

[0022] By adopting the above technical solution and specifically selecting the mass ratio of recycled coarse aggregate to recycled fine aggregate, the quality of the concrete produced is better.

[0023] Preferably, the method for preparing the concrete containing recycled aggregate for preparing precast concrete foundation formwork is as follows: Step 01): Mix water, cement, fly ash, and water-reducing agent evenly to obtain premixed material; Step 02): Add recycled aggregate and modified plant fiber into the premix and mix evenly to obtain concrete containing recycled aggregate for preparing prefabricated pier formwork.

[0024] By adopting the above technical solution, the concrete prepared into the foundation formwork has high strength, is not prone to cracking or breakage, and has high quality, making it more suitable for foundation formwork construction and effectively improving the construction efficiency and quality of foundation formwork construction.

[0025] In summary, this application has the following beneficial effects: 1. Because this application uses composite microorganisms to precipitate calcium carbonate on the surface of plant fibers, a large number of calcium carbonate particles are embedded on the surface of the plant fibers, which increases the surface roughness of the plant fibers. At the same time, because calcium carbonate has higher compatibility with cement stone, the calcium carbonate particles can increase the bonding force between plant fibers and cement stone, thereby making the modified plant fiber reinforced concrete more effective, giving the concrete higher crack resistance, and making the foundation formwork less prone to cracking and breakage.

[0026] 2. In this application, a composite microorganism is preferably formed by specifically selecting Staphylococcus, Lactobacillus, Chlorella, and Clostridium. When modifying plant fibers, it can quickly precipitate calcium carbonate on the surface of plant fibers. Through the combination of various microbial species, the activity of each species is higher and the metabolism is faster, which improves the speed of plant fiber modification and has higher economic value. Moreover, it has a stronger selectivity for plant fibers and is more inclined to attach to plant fibers for metabolism, thereby better realizing the precipitation of calcium carbonate on plant fibers and achieving better effects of plant fiber modification.

[0027] 3. In this application, it is preferred to soak plant fibers in a compound bacterial solution. Due to the high bacterial concentration in the compound bacterial solution, each bacterial species quickly attaches to the surface of the plant fibers. Then, by transferring them to a treatment solution, calcium carbonate is deposited on the surface of the plant fibers through the metabolic action of each bacterial species, utilizing the nutrients in the treatment solution. This achieves the effect of embedding calcium carbonate particles on the surface of the plant fibers, thereby modifying the plant fibers and producing modified plant fibers of better quality. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the product used in Application Example 1; Figure 2 This is the product installation diagram for Application Example 2. Detailed Implementation

[0029] The present application will be further described in detail below with reference to the embodiments.

[0030] Example 1 A type of concrete containing recycled aggregate for preparing precast concrete foundation formwork is prepared from the following components: Water, cement, fly ash, recycled aggregate, water-reducing agent, modified plant fiber.

[0031] The water in question is tap water.

[0032] The cement used is Runfeng Cement, with the specification being P.O42.5R ordinary Portland cement.

[0033] The fly ash was purchased from Lingshou County Baiyi Mineral Products Processing Plant and is classified as Grade I fly ash.

[0034] Among them, the recycled aggregate is a blend of recycled fine aggregate and recycled coarse aggregate, with a mass ratio of recycled fine aggregate to recycled coarse aggregate of 1:1.5.

[0035] The recycled aggregates were purchased from Tianjin Xinying Technology Co., Ltd. The particle size of the recycled fine aggregates is 5-10mm; the particle size of the recycled coarse aggregates is 25-40mm.

[0036] The water-reducing agent is a polycarboxylate water-reducing agent, which was purchased from Jinan Yanglan New Material Technology Co., Ltd.

[0037] Among them, modified plant fiber is made by precipitating calcium carbonate on the surface of plant fiber through composite microorganisms.

[0038] Plant fiber is wood fiber.

[0039] The wood fibers were purchased from Langfang Changlin Cellulose Co., Ltd., with a fiber length of 0.5-3mm.

[0040] The compound microorganisms are a combination of Staphylococcus, Lactobacillus, Chlorella, and Clostridium.

[0041] Staphylococcus was purchased from the Shanghai Biotechnology Preservation Center, strain number: SHBCC D80806, Staphylococcus xylose.

[0042] Lactobacillus was purchased from the Shanghai Biotechnology Preservation Center, strain number: SHBCC D25103, Lactobacillus plantarum.

[0043] Chlorella was purchased from Beijing Bio-Tech Biotechnology Co., Ltd., strain number: ATCC 30821.

[0044] Clostridium difficile was purchased from Beijing Bio-Tech Biotechnology Co., Ltd., strain number: ATCC 14501.

[0045] The modification methods for modified plant fibers are as follows: Step 1): Add 2.5g of Staphylococcus aureus, 3.5g of Lactobacillus, 0.5g of Chlorella vulgaris, and 1.5g of Clostridium perfringens to 10kg of culture medium and culture until the OD value of the culture medium is 1.5 to obtain a compound bacterial solution.

[0046] Step 2) Soak 2 kg of plant fiber completely in the compound bacterial solution for 15 min to obtain pretreated plant fiber.

[0047] Step 3) Transfer the pretreated plant fiber to 10 kg of treatment solution, soak for 8 days, and dry in an oven at 120 °C to obtain modified plant fiber.

[0048] The nutrient solution is composed of water, peptone, yeast extract, glucose, and sodium chloride, with a mass ratio of 1000:10:30:20:15.

[0049] The treatment solution is composed of water, calcium lactate, and glucose in a mass ratio of 1000:100:25.

[0050] The preparation method of concrete containing recycled aggregate for preparing precast concrete foundation formwork is as follows: Step 01): Add 100kg of water, 210kg of cement, 28kg of fly ash, and 1.4kg of water-reducing agent into a mixing tank, rotate at 120r / min, and stir for 3 minutes until the mixture is uniform to obtain the premixed material.

[0051] Step 02): Add 1115 kg of recycled aggregate and 1.8 kg of modified plant fiber to the premixed material, stir at 60 r / min for 10 min, and mix evenly to obtain concrete containing recycled aggregate for preparing prefabricated pier formwork.

[0052] Example 2 A type of concrete containing recycled aggregate for preparing precast concrete foundation formwork is prepared from the following components: Water, cement, fly ash, recycled aggregate, water-reducing agent, modified plant fiber.

[0053] The water in question is tap water.

[0054] The cement used is Runfeng Cement, with the specification being P.O42.5R ordinary Portland cement.

[0055] The fly ash was purchased from Lingshou County Baiyi Mineral Products Processing Plant and is classified as Grade I fly ash.

[0056] Among them, the recycled aggregate is a blend of recycled fine aggregate and recycled coarse aggregate, with a mass ratio of recycled fine aggregate to recycled coarse aggregate of 1:1.5.

[0057] The recycled aggregates were purchased from Tianjin Xinying Technology Co., Ltd. The particle size of the recycled fine aggregates is 5-10mm; the particle size of the recycled coarse aggregates is 25-40mm.

[0058] The water-reducing agent is a polycarboxylate water-reducing agent, which was purchased from Jinan Yanglan New Material Technology Co., Ltd.

[0059] Among them, modified plant fiber is made by precipitating calcium carbonate on the surface of plant fiber through composite microorganisms.

[0060] Plant fiber is wood fiber.

[0061] The wood fibers were purchased from Langfang Changlin Cellulose Co., Ltd., with a fiber length of 0.5-3mm.

[0062] The compound microorganisms are a combination of Staphylococcus, Lactobacillus, Chlorella, and Clostridium.

[0063] Staphylococcus was purchased from the Shanghai Biotechnology Preservation Center, strain number: SHBCC D80806, Staphylococcus xylose.

[0064] Lactobacillus was purchased from the Shanghai Biotechnology Preservation Center, strain number: SHBCC D25103, Lactobacillus plantarum.

[0065] Chlorella was purchased from Beijing Bio-Tech Biotechnology Co., Ltd., strain number: ATCC 30821.

[0066] Clostridium difficile was purchased from Beijing Bio-Tech Biotechnology Co., Ltd., strain number: ATCC 14501.

[0067] The modification methods for modified plant fibers are as follows: Step 1): Add 3g of Staphylococcus aureus, 4g of Lactobacillus, 1g of Chlorella vulgaris, and 2g of Clostridium perfringens to 10kg of culture medium and culture until the OD value of the culture medium is 1.8 to obtain a compound bacterial solution.

[0068] Step 2) Soak 2 kg of plant fiber completely in the compound bacterial solution for 22.5 min to obtain pretreated plant fiber.

[0069] Step 3) Transfer the pretreated plant fiber to 10 kg of treatment solution, soak for 8.5 days, and dry in an oven at 120℃ to obtain modified plant fiber.

[0070] The nutrient solution is composed of water, peptone, yeast extract, glucose, and sodium chloride, with a mass ratio of 1000:10:30:20:15.

[0071] The treatment solution is composed of water, calcium lactate, and glucose in a mass ratio of 1000:100:25.

[0072] The preparation method of concrete containing recycled aggregate for preparing precast concrete foundation formwork is as follows: Step 01): Add 100kg of water, 214kg of cement, 29.4kg of fly ash, and 1.5kg of water-reducing agent to a mixing tank, rotate at 120r / min, and stir for 3 minutes until the mixture is uniform to obtain a premixed material.

[0073] Step 02): Add 1125 kg of recycled aggregate and 1.9 kg of modified plant fiber to the premixed material, stir at 60 r / min for 10 min, and mix evenly to obtain concrete containing recycled aggregate for preparing prefabricated pier formwork.

[0074] Example 3 A type of concrete containing recycled aggregate for preparing precast concrete foundation formwork is prepared from the following components: Water, cement, fly ash, recycled aggregate, water-reducing agent, modified plant fiber.

[0075] The water in question is tap water.

[0076] The cement used is Runfeng Cement, with the specification being P.O42.5R ordinary Portland cement.

[0077] The fly ash was purchased from Lingshou County Baiyi Mineral Products Processing Plant and is classified as Grade I fly ash.

[0078] Among them, the recycled aggregate is a blend of recycled fine aggregate and recycled coarse aggregate, with a mass ratio of recycled fine aggregate to recycled coarse aggregate of 1:1.5.

[0079] The recycled aggregates were purchased from Tianjin Xinying Technology Co., Ltd. The particle size of the recycled fine aggregates is 5-10mm; the particle size of the recycled coarse aggregates is 25-40mm.

[0080] The water-reducing agent is a polycarboxylate water-reducing agent, which was purchased from Jinan Yanglan New Material Technology Co., Ltd.

[0081] Among them, modified plant fiber is made by precipitating calcium carbonate on the surface of plant fiber through composite microorganisms.

[0082] Plant fiber is wood fiber.

[0083] The wood fibers were purchased from Langfang Changlin Cellulose Co., Ltd., with a fiber length of 0.5-3mm.

[0084] The compound microorganisms are a combination of Staphylococcus, Lactobacillus, Chlorella, and Clostridium.

[0085] Staphylococcus was purchased from the Shanghai Biotechnology Preservation Center, strain number: SHBCC D80806, Staphylococcus xylose.

[0086] Lactobacillus was purchased from the Shanghai Biotechnology Preservation Center, strain number: SHBCC D25103, Lactobacillus plantarum.

[0087] Chlorella was purchased from Beijing Bio-Tech Biotechnology Co., Ltd., strain number: ATCC 30821.

[0088] Clostridium difficile was purchased from Beijing Bio-Tech Biotechnology Co., Ltd., strain number: ATCC 14501.

[0089] The modification methods for modified plant fibers are as follows: Step 1): Add 3.5g Staphylococcus, 4.5g Lactobacillus, 1.5g Chlorella, and 2.5g Clostridium to 10kg of culture medium and culture until the OD value of the culture medium is 2 to obtain a compound bacterial solution.

[0090] Step 2) Soak 2 kg of plant fiber completely in the compound bacterial solution for 30 min to obtain pretreated plant fiber.

[0091] Step 3) Transfer the pretreated plant fiber to 10 kg of treatment solution, soak for 9 days, and dry in an oven at 120 °C to obtain modified plant fiber.

[0092] The nutrient solution is composed of water, peptone, yeast extract, glucose, and sodium chloride, with a mass ratio of 1000:10:30:20:15.

[0093] The treatment solution is composed of water, calcium lactate, and glucose in a mass ratio of 1000:100:25.

[0094] The preparation method of concrete containing recycled aggregate for preparing precast concrete foundation formwork is as follows: Step 01): Add 100kg of water, 220kg of cement, 30kg of fly ash, and 1.6kg of water-reducing agent into a mixing tank, rotate at 120r / min, and stir for 3 minutes until the mixture is uniform to obtain a premixed material.

[0095] Step 02): Add 1135 kg of recycled aggregate and 2 kg of modified plant fiber to the premixed material, stir at 60 r / min for 10 min, and mix evenly to obtain concrete containing recycled aggregate for preparing prefabricated pier formwork.

[0096] Comparative Example 1 A type of concrete containing recycled aggregate for preparing prefabricated pier formwork differs from Example 2 only in that: in the modification method of modified plant fibers, an equal amount of St. staphylococcus is used to replace Staphylococcus aureus.

[0097] Among them, the *Sacchariformis* strain was purchased from the Shanghai Biotechnology Preservation Center, strain number: SHBCC D50320.

[0098] Comparative Example 2 A type of concrete containing recycled aggregate for preparing prefabricated pier formwork differs from Example 2 only in that: in the modification method of modified plant fibers, Bacillus spheroidis is used to replace Lactobacillus in an equal amount.

[0099] Among them, Bacillus spheroidae was purchased from Shanghai Biotechnology Preservation Center, strain number: SHBCC D80776.

[0100] Comparative Example 3 A type of concrete containing recycled aggregate for preparing prefabricated foundation formwork differs from Example 2 only in that: in the modification method of modified plant fibers, Bacillus subtilis spores are used to replace Chlorella in an equal amount.

[0101] Among them, Bacillus subtilis was purchased from Shanghai Preservation Biotechnology Center, strain number: SHBCC D50761.

[0102] Comparative Example 4 A type of concrete containing recycled aggregate for preparing prefabricated pier formwork differs from Example 2 only in that: in the modification method of modified plant fibers, Escherichia coli replaces Clostridium in an equal amount.

[0103] Among them, Escherichia coli was purchased from Shanghai Preservation Biotechnology Center, strain number: SHBCC D80665.

[0104] Comparative Example 5 A type of concrete containing recycled aggregate for preparing prefabricated foundation formwork differs from Example 2 only in that: in the modification method of modified plant fibers, Staphylococcus aureus is replaced by an equal amount of St. aureus, Bacillus spheroidis is replaced by an equal amount of Lactobacillus, Bacillus subtilis is replaced by an equal amount of Chlorella, and Escherichia coli is replaced by an equal amount of Clostridium coli.

[0105] Among them, the *Sacchariformis* strain was purchased from the Shanghai Biotechnology Preservation Center, strain number: SHBCC D50320.

[0106] Among them, Bacillus spheroidae was purchased from Shanghai Biotechnology Preservation Center, strain number: SHBCC D80776.

[0107] Among them, Bacillus subtilis was purchased from Shanghai Preservation Biotechnology Center, strain number: SHBCC D50761.

[0108] Among them, Escherichia coli was purchased from Shanghai Preservation Biotechnology Center, strain number: SHBCC D80665.

[0109] Comparative Example 6 A concrete containing recycled aggregate for preparing prefabricated pier formwork, compared with Example 2, differs only in that: in the preparation method of the concrete containing recycled aggregate for preparing prefabricated pier formwork, plant fibers are used to replace modified plant fibers in equal amounts.

[0110] The plant fiber is a wood fiber, sourced from Langfang Changlin Cellulose Co., Ltd., with a fiber length of 0.5-3mm.

[0111] Experiment 1 Physical performance testing: 1. Compressive strength: The 7-day and 28-day compressive strengths of the concrete samples prepared in each example and comparative example were tested according to GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete".

[0112] 2. Flexural strength: The 28-day flexural strength of the concrete samples prepared in each example and comparative example was tested according to GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete".

[0113] The specific test data for Experiment 1 are detailed in Table 1.

[0114] Table 1 According to the data comparison in Table 1, adding modified plant fibers modified by composite microorganisms to concrete can effectively improve the flexural strength of the concrete foundation formwork, making the foundation formwork less prone to cracking and breakage. It also improves the compressive strength of the foundation formwork to a certain extent, resulting in a stable foundation formwork structure and better quality. The construction foundation formwork also has stable and better quality.

[0115] By specifically selecting Staphylococcus, Lactobacillus, Chlorella, and Clostridium to form a compound microorganism to modify plant fibers, the modification effect can be greatly improved. More calcium carbonate can be deposited on the surface of plant fibers, and the calcium carbonate is more firmly embedded on the surface of plant fibers. As a result, the modified plant fibers have a better effect on reinforcing concrete, and the crack resistance of concrete can be significantly improved.

[0116] Application Example 1 The preparation method of precast foundation formwork is as follows: The concrete containing recycled aggregate used in Example 2 for preparing prefabricated foundation formwork was poured into the formwork and cured to obtain the prefabricated foundation formwork.

[0117] For detailed product illustrations of precast foundation formwork, please refer to [link / reference]. Figure 1 .

[0118] Application Example 2 An installation method for precast foundation formwork is as follows: S1. First, process and manufacture precast reinforced concrete slabs with tongue and groove connections according to the dimensions of the foundation mold. S2. Conduct formwork construction measurement and layout, determine and mark the installation position of the precast slab, dig a trench 50mm-100mm deep at the formwork position, place the precast slab, adjust the verticality of the precast slab and temporarily fix it.

[0119] S3. After all the precast mold plates are adjusted to the correct position, insert steel bars into the PVC pre-embedded at the tongue and groove joint and drive them into the ground. For the corner mold, use expansion bolts to insert right-angle stainless steel strips on the outside and tighten the bolts at the reserved holes to fix them.

[0120] S4. Pour cement slurry or mortar into the top of the PVC pipes of each precast slab to achieve reliable rigid fixation at the joints and corners of the precast slabs.

[0121] S5. If necessary, before backfilling the outside of the mold, common steel pipes, top supports, and wooden beams can be used for temporary simple top support to increase the overall stability of the mold. After the backfilling is completed, the temporary support inside the mold is removed.

[0122] For detailed installation diagrams of the assembled foundation formwork, please refer to [link / reference]. Figure 2 .

[0123] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A concrete containing recycled aggregates for the preparation of prefabricated cast-in-place pile caps, characterized in that: The components include the following parts by mass: 100 parts water; 210-220 parts cement; 28-30 parts fly ash; 1115-1135 parts of recycled aggregate; Water-reducing agent: 1.4-1.6 parts; 1.8-2 parts modified plant fiber; The modified plant fiber is obtained by precipitating calcium carbonate on the surface of plant fiber through composite microorganisms; The plant fiber is lignocellulose; The compound microorganisms are a combination of Staphylococcus, Lactobacillus, Chlorella, and Clostridium. The mass ratio of Staphylococcus, Lactobacillus, Chlorella, and Clostridium is 2.5-3.5: 3.5-4.5: 0.5-1.5: 1.5-2.5; The modification method of the modified plant fiber is as follows: Step 1): Staphylococcus, Lactobacillus, Chlorella, and Clostridium difficile are added to the culture medium and cultured until the OD value of the culture medium is 1.5-2 to obtain a compound bacterial solution. Step 2) Soak the plant fiber in the compound bacterial solution for 15-30 minutes to obtain pretreated plant fiber; Step 3) Transfer the pretreated plant fibers to the treatment solution, soak for 8-9 days, and dry to obtain modified plant fibers; The culture medium is composed of water, peptone, yeast extract, glucose, and sodium chloride. The treatment solution is composed of water, calcium lactate, and glucose.

2. The recycled aggregate-containing concrete for preparing the prefabricated pile cap formwork according to claim 1, characterized in that: The recycled aggregate is a blend of recycled fine aggregate and recycled coarse aggregate, with a mass ratio of 1:1.

5.

3. The concrete containing recycled aggregate for preparing precast concrete foundation formwork according to claim 1, characterized in that: The method for preparing the concrete containing recycled aggregate for prefabricated pier formwork is as follows: Step 01): Mix water, cement, fly ash, and water-reducing agent evenly to obtain premixed material; Step 02) Add recycled aggregate and modified plant fiber into the premix and mix evenly to obtain concrete containing recycled aggregate for preparing prefabricated pier formwork.

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