High-fluidity anti-crack concrete for photovoltaic support foundation structure and preparation method of high-fluidity anti-crack concrete

Abstract

The invention relates to high-flowability anti-crack concrete for a photovoltaic support foundation structure and a preparation method of the high-flowability anti-crack concrete. A preparation method of high-fluidity anti-crack concrete for a photovoltaic support foundation structure comprises the following steps: (1) adding polyethylene glycol and silicone powder into a NaCl solution, uniformly mixing, adding dodecyl dimethyl amine oxide, vinyl silicone oil and a sodium silicate solution, uniformly mixing, performing ultrasonic treatment, and cooling to obtain modified polymer slurry A; (2) adding sucrose ester and benzoic acid into the modified polymer slurry A, uniformly mixing, carrying out microwave heating, adding a magnetic nanoparticle mother solution, uniformly mixing, and standing at 50-55 DEG C for 10-15 hours to obtain modified polymer slurry B; (3) placing the modified polymer slurry B in a 20-25mT magnetic field environment, stirring for 10-15 minutes at the temperature of 50-60 DEG C and the speed of 50-60r / min, and removing supernatant liquid; (4) adjusting to 50-60mT, continuously stirring, and carrying out vacuum infiltration treatment to obtain a modified polymer; and (5) adding the modified polymer into the concrete, and uniformly mixing. According to the technical scheme, the flowability, crack resistance and other properties of the concrete can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete for photovoltaic support foundation structures, and in particular relates to high-fluidity crack-resistant concrete for photovoltaic support foundation structures and a preparation method thereof. Background Art

[0002] As global demand for clean energy continues to grow, photovoltaic power generation, as a sustainable energy solution, is playing an increasingly important role in the energy sector. In recent years, the photovoltaic industry has developed rapidly, and the scale of photovoltaic power station construction has continued to expand. From land to water, from plains to mountains, photovoltaic power stations are being built in a variety of terrains and environmental conditions.

[0003] As a key component supporting photovoltaic modules, the stability and durability of the photovoltaic support infrastructure are directly related to the power generation efficiency and service life of the entire photovoltaic system. In practical applications, the photovoltaic support infrastructure must withstand a variety of complex loads, such as the weight of the photovoltaic modules themselves, wind loads, snow loads, and earthquakes. Furthermore, because photovoltaic power stations are typically built outdoors, the infrastructure is also affected by natural environmental factors such as temperature and humidity fluctuations, ultraviolet radiation, and chemical corrosion. Therefore, extremely high requirements are placed on the concrete used in the photovoltaic support infrastructure, requiring not only sufficient strength but also good fluidity and crack resistance.

[0004] In summary, improving the performance of foundation concrete products and strengthening the control of concrete construction quality can not only ensure construction quality and reduce quality and safety issues, but also reduce construction costs. Currently, some experts and scholars have conducted research on improving the stability of photovoltaic support foundation concrete structures and have achieved certain results, but the research content has certain limitations.

[0005] Literature such as "Construction Technology of Cast-in-Situ Pile Foundations for PV Mounting in Gobi Photovoltaic Projects" (Sichuan Building Materials), "Research on Reinforcement Schemes for PV Power Station Mounting Foundations" (Solar Energy), and "Selection of Photovoltaic Mounting Pile Foundations for Salt-Solar Complementary Projects" (Shanxi Construction) represent the mainstream of current PV foundation research. These focus on controlling the construction quality of PV foundation civil engineering, strengthening measures to address foundation issues, and selecting pile foundations, but lack a focus on addressing PV foundation issues at the root of concrete. Existing literature, such as "Research on Optimization of Concrete Mix Ratio for PV Mounting Foundations" (Shihezi Science and Technology), proposes research on optimizing the concrete mix ratio for PV mounting foundations. However, this research primarily focuses on aggregate control and combines conventional mix ratio adjustment strategies for optimization, resulting in limited results. Existing literature, such as "Nonlinear Finite Element Analysis of Photovoltaic Micro-Reinforced Concrete Cast-in-Situ Pile Foundations Based on ABAQUS" (Solar Energy), uses ABAQUS software to perform nonlinear analysis of fixed-mount micro-reinforced concrete cast-in-place pile foundations under external loads such as deadweight, vertical pressure, and vertical pullout to determine whether the foundation structure meets the required performance. However, effective methods for improving the structural stability of PV mounting foundations are lacking.

[0006] In terms of patents, the current existing patent technologies mainly focus on the optimization of photovoltaic components themselves, prestressed pipe pile structure design, foundation embedding devices and foundation structure optimization, such as "Photovoltaic concrete precast panels with built-in energy storage tubes and thermal insulation and sound insulation material sandwich layers" (invention patent), "A new type of photovoltaic concrete prestressed pipe piles" (utility model patent), "An integrated embedding device and use method for photovoltaic bracket foundations in desert areas" (invention patent), "A new type of typhoon-resistant photovoltaic bracket foundation" (utility model patent), "A photovoltaic bracket foundation and its application" (invention patent), etc., and no technology for improving the performance of the bracket foundation structure concrete itself has been formed.

[0007] In view of this, the present invention proposes a new high-fluidity crack-resistant concrete for photovoltaic support base structure and a preparation method thereof, which can improve the stability, fluidity, crack resistance and density of concrete used for photovoltaic support base structure. Summary of the Invention

[0008] The purpose of the present invention is to provide a method for preparing high-fluidity crack-resistant concrete for photovoltaic bracket foundation structure. Through polymer modification, the fluidity and crack resistance of concrete, as well as the overall quality stability of the photovoltaic bracket foundation concrete structure can be effectively improved.

[0009] In order to achieve the above objectives, the technical solutions adopted are:

[0010] A method for preparing high-fluidity crack-resistant concrete for a photovoltaic support foundation structure comprises the following steps:

[0011] (1) Adding polyethylene glycol and silicone powder to a NaCl solution, stirring thoroughly, then adding dodecyl dimethylamine oxide, vinyl silicone oil, and sodium silicate solution, mixing well, performing ultrasonic treatment, and cooling to room temperature to obtain a modified polymer slurry A;

[0012] (2) adding sucrose ester and benzoic acid to the modified polymer slurry A, mixing uniformly, and then performing microwave heating. Then, adding the magnetic nanoparticle mother solution, mixing uniformly, and standing at 50-55° C. for 10-15 hours to obtain a modified polymer slurry B;

[0013] (3) placing the modified polymer slurry B in a magnetic field environment with a magnetic field strength of 20-25 mT, stirring at 50-60° C. and 50-60 rpm for 10-15 minutes, and removing the supernatant;

[0014] (4) After adjusting the magnetic field intensity to 50-60 mT, stirring was continued at 50-60° C. and 50-60 rpm for 10-15 min, and then vacuum infiltration treatment was performed for 1-1.5 h to obtain a modified polymer;

[0015] (5) Adding the modified polymer into concrete and mixing evenly to obtain the high-fluidity, crack-resistant concrete for the photovoltaic support base structure.

[0016] Furthermore, in the step (1), the mass volume ratios of NaCl, polyethylene glycol, silicone powder, dodecyldimethylamine oxide, vinyl silicone oil, and sodium silicate solution are 5-15g:145-155mg:50-55g:50-60ml and 10-15ml:20-25ml.

[0017] Furthermore, the vinyl silicone oil is DY-V411 vinyl silicone oil (branched type);

[0018] The mass concentration of the sodium silicate solution is 30%.

[0019] Furthermore, in the step (1), the ultrasonic treatment conditions are: amplitude of 45-50%, time of 20-30 min, and pulse on for 5-10 s and off for 5-10 s.

[0020] Furthermore, the mass-to-volume ratio of the NaCl, sucrose ester, benzoic acid, and magnetic nanoparticles is 5-15 g: 30-35 g: 0.5-0.6 g: 0.6-0.8.

[0021] Furthermore, the mass concentration of the magnetic nanoparticles mother liquor is 0.6-0.8 g / L.

[0022] Further, in the step (2), the preparation method of the magnetic nanoparticle mother liquor is as follows: the tricobalt tetroxide nanoparticles are mixed with water, and then ultrasonic dispersion is carried out to obtain the magnetic nanoparticle mother liquor.

[0023] Further, in the step (2), the microwave heating parameters are as follows: 880-920 W, 2.40-2.50 GHz, and 8-12 min.

[0024] Further, in the step (2), the magnetic nanoparticle mother liquor is added, and stirring is carried out at 1000-1200 r / min for 3-5 min.

[0025] Further, in the step (3), 20-30 vt% of the supernatant is removed.

[0026] Further, in the step (5), the addition amount of the modified polymer is 2-3 wt% of the cementitious material in the concrete.

[0027] Another object of the present application is to provide a high-fluidity anti-cracking concrete for photovoltaic support foundation structure, which is prepared by the above preparation method.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] The high-fluidity anti-cracking concrete for photovoltaic support foundation structure and the preparation method thereof mainly improve the concrete for photovoltaic support foundation structure by polymer modification.

[0030] 1. In the technical scheme of the present application, silicone powder is used as the reaction raw material of the base body to achieve the effect of strengthening and toughening.

[0031] 2. In the technical scheme of the present application, dodecyl dimethyl amine oxide, vinyl silicone oil and silicone powder are used for polymerization reaction, which has the following effects: (1) solves the problems of low reaction efficiency and weak stability of the constructed system of silicone powder in the polymerization reaction; (2) the addition of dodecyl dimethyl amine oxide can avoid the problems of precipitation and coagulation of vinyl silicone oil in the stirring process, thereby being beneficial to the fluidity of the concrete; (3) dodecyl dimethyl amine oxide can soften the reaction process and improve the stability of the reaction system; (4) vinyl silicone oil and silicone powder have a synergistic effect, which improves the stability of the reaction system and the flow performance of the concrete.

[0032] 3. In the technical scheme of the present application, sucrose ester, benzoic acid and magnetic nanoparticle mother liquor are introduced into the polymer system, which can improve the overall reaction efficiency and structural stability of the polymer, and improve the compactness and anti-cracking performance of the concrete.

[0033] 4、The technical scheme of the present application adopts the magnetic field technology with variable magnetic field intensity, so that the net structure is reasonably dispersed, the reaction efficiency is improved, and the reaction is ensured to be fully carried out. DETAILED DESCRIPTION

[0034] In order to further illustrate the high-fluidity anti-cracking concrete for photovoltaic support foundation structure and the preparation method thereof according to the present application, and achieve the intended purpose of the present application, the high-fluidity anti-cracking concrete for photovoltaic support foundation structure and the preparation method thereof according to the present application, the specific implementation, structure, features and effects thereof are described in detail as follows. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0035] The high-fluidity anti-cracking concrete for photovoltaic support foundation structure and the preparation method thereof according to the present application will be further described in detail as follows by combining specific embodiments:

[0036] The present invention takes the quality control of the concrete structure of the photovoltaic support foundation as the starting point, and provides a high-fluidity and crack-resistant concrete for the photovoltaic support foundation structure and a preparation method thereof, which is mainly achieved through polymer modification: first, sodium chloride is dissolved in distilled water to adjust the saturation of the reaction environment solution, polyethylene glycol and silicone powder are introduced and stirred to form a polymer-modified matrix, dodecyl dimethyl amine oxide, vinyl silicone oil and sodium silicate solution are added and mixed evenly, and ultrasonic dispersion technology is used to mix and prepare a modified polymer slurry A; then, sucrose ester and benzoic acid are introduced and heated by a microwave generator after stirring evenly, and after the treatment is completed, a magnetic nanoparticle mother liquor configured in advance with nano-cobalt tetroxide is added, stirred at high speed and allowed to stand at a certain temperature to obtain a modified polymer slurry B; finally, the magnetic field strength is adjusted by setting up a magnetic field, and the modified polymer slurry B is placed in different magnetic field strength environments at a specific temperature and stirred for a certain time, and then vacuum infiltration treatment is performed to obtain a modified polymer, which is added to the concrete in a certain proportion to effectively improve its fluidity and crack resistance. The modified polymer prepared in the present invention has the characteristics of low glass transition temperature (Tg) (-40℃~-35℃), high elongation at break (600-800%), high bond strength (≥1.8MPa), etc., which can effectively improve the fluidity and crack resistance of concrete. The concrete introduced with the modified polymer of the present invention has the following characteristics: under the same mix ratio, the slump of concrete increased by 20-30mm, the expansion increased by 30-50mm, the collapse flow time decreased by 2-3s, and the V leakage flow time decreased by 8-12s; in terms of crack resistance, the 28d splitting tensile strength increased by 45-60%, the total crack area per unit area in the early crack resistance test decreased by 20-25%, and no through cracks were generated. The technology of the present invention can effectively improve the overall quality stability of the concrete structure of the photovoltaic support foundation and provide reliable data reference for related research.

[0037] The technical solution of the present invention is:

[0038] A method for preparing high-fluidity crack-resistant concrete for a photovoltaic support foundation structure comprises the following steps:

[0039] (1) Adding polyethylene glycol and silicone powder to a NaCl solution, stirring thoroughly, then adding dodecyl dimethylamine oxide, vinyl silicone oil, and sodium silicate solution, mixing well, performing ultrasonic treatment, and cooling to room temperature to obtain a modified polymer slurry A;

[0040] (2) adding sucrose ester and benzoic acid to the modified polymer slurry A, mixing uniformly, and then performing microwave heating. Then, adding the magnetic nanoparticle mother solution, mixing uniformly, and standing at 50-55° C. for 10-15 hours to obtain a modified polymer slurry B;

[0041] (3) placing the modified polymer slurry B in a magnetic field environment with a magnetic field strength of 20-25 mT, stirring at 50-60° C. and 50-60 rpm for 10-15 minutes, and removing the supernatant;

[0042] (4) After adjusting the magnetic field intensity to 50-60 mT, stirring was continued at 50-60° C. and 50-60 rpm for 10-15 min, and then vacuum infiltration treatment was performed for 1-1.5 h to obtain a modified polymer;

[0043] (5) Adding the modified polymer into concrete and mixing evenly to obtain the high-fluidity, crack-resistant concrete for the photovoltaic support base structure.

[0044] Preferably, in step (1), the mass volume ratio of NaCl, polyethylene glycol, silicone powder, dodecyldimethylamine oxide, vinyl silicone oil, and sodium silicate solution is 5-15g:145-155mg:50-55g:50-60ml, 10-15ml:20-25ml.

[0045] Preferably, the vinyl silicone oil is DY-V411 vinyl silicone oil (branched type).

[0046] The mass concentration of the sodium silicate solution is 30%.

[0047] In the above technical solution, the antistatic and electrical insulation properties of dodecyl dimethylamine oxide and vinyl silicone oil can also be retained in the final product performance during the polymer preparation process, thereby preventing current leakage in the concrete of the photovoltaic support base structure.

[0048] Preferably, in the step (1), the ultrasonic treatment conditions are: amplitude of 45-50%, time of 20-30 min, and pulse on for 5-10 s and off for 5-10 s.

[0049] Preferably, the mass-to-volume ratio of the NaCl, sucrose ester, benzoic acid, and magnetic nanoparticles is 5-15 g: 30-35 g: 0.5-0.6 g: 0.6-0.8.

[0050] In the above technical solution, since the -OH group of sucrose in the sucrose ester is a hydrophilic group and the carbon chain portion of the fatty acid is a lipophilic group, it can play a linking and promoting role in the combination process of the oil phase and the water phase reactants in the pretreatment step, thereby improving the overall reaction efficiency and overall structural stability of the polymer.

[0051] Preferably, the mass concentration of the magnetic nanoparticles mother liquor is 0.6-0.8 g / L.

[0052] Preferably, in the step (2), the preparation method of the magnetic nanoparticle mother liquor is: mixing the cobaltic tetraoxide nanoparticles with water, and then performing ultrasonic dispersion to obtain the magnetic nanoparticle mother liquor.

[0053] Preferably, in the step (2), the microwave heating parameters are: 880-920 W, 2.40-2.50 GHz, and 8-12 min.

[0054] Preferably, in the step (2), the magnetic nanoparticle mother liquor is added, and stirring is performed at 1000-1200 r / min for 3-5 min.

[0055] Preferably, in the step (3), 20-30 vt% of the supernatant is removed.

[0056] In the above technical solution, the reason for removing part of the supernatant is to adjust the concentration ratio of the polymer slurry, so as to promote the directional distribution of the particles after the second stage of adjusting the magnetic field intensity and the further reaction of the material.

[0057] Preferably, in the step (5), the addition amount of the modified polymer is 2-3 wt% of the cementitious material in the concrete.

[0058] In the examples and comparative examples, the raw materials are all conventional specifications in the art, which can be obtained by marketing.

[0059] In the examples and comparative examples, the cement used is Qing Song P.O 42.5R cement; the fly ash is Hong'er power plant F·Ⅲ fly ash with fineness of 35%; the mineral powder is Baoxinshengyuan S75 mineral powder with specific surface area of 390 m 2 / kg; the sand is coarse sand provided by Xinjiang and concrete source building material Co., Ltd., with fineness modulus of 3.4, water content of 2.4%, and clay content of 1.1%; the stone is crushed stone with particle size of 5-20 mm provided by Xinjiang and concrete source building material Co., Ltd., with clay content of 0.3%, crushing index of 3%, and apparent density of 2675 kg / m 3 ; the water reducing agent is polycarboxylic acid high-performance water reducing agent provided by Ke Hui Da Chemical Building Material Co., Ltd., with solid content of 12.15% and water reducing rate of 27%;

[0060] NaCl is produced by Shanghai Maikelin Biotechnology Co., Ltd., with a content of 99%; polyethylene glycol is produced by Haian Petroleum Chemical Factory in Jiangsu Province, with a content of 98%, and a molecular weight of 3600-4400; silicone powder is produced by Sichuan Langtian Resource Comprehensive Utilization Co., Ltd., with a purity of 99%; dodecyl dimethyl amine oxide is produced by Hefei Chip Energy New Material Technology Co., Ltd., with a solid content of 50%±2% and a pH value of 7±1; DY-V411 vinyl silicone oil (branched type) is produced by Shandong Dayi Chemical Co., Ltd., with a specification of V411-5800, a viscosity (25°C, cp) of 5800±200, and a vinyl content (mol / 100g) of 0.00743-0.00905; sodium silicate is produced by Baoding Runfeng Industry Co., Ltd., and is of an industrial grade; nano cobalt tetraoxide is produced by Shanghai Maikelin Biotechnology Co., Ltd., with a diameter of 10-40nm; sucrose ester is produced by Henan Anrui Biological Technology Co., Ltd., with a model number of SE-11 and a purity of 99%; benzoic acid is produced by Zhengzhou Maliang Chemical Co., Ltd., with a content of 99%.

[0061] The vacuum degree used in the vacuum infiltration treatment is 5×10 -2 ~ 5×10 -3 Pa, and the treatment time is 1-1.5h. The main purpose is to remove part of the impurities in the modified polymer, eliminate harmful gases in the pores, and at the same time enhance the uniformity and dispersity of the whole modified polymer, which is beneficial to the improvement of the application efficiency in the subsequent concrete.

[0062] The purity of the polyethylene glycol used in the embodiment is 98%.

[0063] The solid content of the dodecyl dimethyl amine oxide used in the embodiment is 50%±2%, and the pH value is 7±1.

[0064] The sucrose ester used in the embodiment is a sucrose fatty acid polyester.

[0065] The mass concentration of the sodium silicate solution is 30%.

[0066] Embodiment 1.

[0067] The specific operation steps are as follows:

[0068] (1) 10g of NaCl is added to 330ml of distilled water, and after dissolution, 150mg of polyethylene glycol and 52g of silicone powder are added. After being fully stirred, 55ml of dodecyl dimethyl amine oxide, 12ml of vinyl silicone oil, and 22ml of sodium silicate solution are added, and the mixture is uniformly mixed.

[0069] The ultrasonic analyzer is used for ultrasonic treatment (ultrasonic treatment for 25min under the condition of 48%, with a pulse of 8s on and 8s off), and the ice bath is cooled to room temperature to obtain the modified polymer slurry A.

[0070] (2) 0.7 g of tricobalt tetroxide (Co3O4) nanoparticles were mixed with 1 L of distilled water, and then dispersed by ultrasonic cell disruptor for 43 min to obtain 1 L of magnetic nanoparticle mother liquor.

[0071] (3) 32 g of sucrose ester and 0.55 g of benzoic acid were added to the modified polymer slurry A, stirred for 35 min, and then heated in a microwave generating device (900 W, 2.45 GHz) for 10 min. Immediately, 1 L of the magnetic nanoparticle mother liquor was added, and stirred at a speed of 1100 r / min for 4 min. After completion, the modified polymer slurry B was obtained by standing at 52°C for 13 h.

[0072] (4) The modified polymer slurry B was placed in a magnetic field environment with a magnetic field strength of 22 mT, and stirred at 55°C and 55 r / min for 13 min. Then, 25% of the supernatant was removed.

[0073] (5) After adjusting the magnetic field strength to 55 mT, the slurry was further stirred at 55°C and 55 r / min for 13 min, and then subjected to vacuum infiltration treatment for 1.2 h. After the treatment, the modified polymer was obtained.

[0074] Tests showed that the modified polymer had a low glass transition temperature (Tg) (-38°C), a high elongation at break (750%), and a high bonding strength (1.9 MPa), which could effectively improve the fluidity and crack resistance of concrete.

[0075] (6) The modified polymer was added to concrete (conventional C40 grade) at an amount of 2.5 wt% of the cementitious material (i.e. cement, fly ash, and mineral powder in the concrete), to obtain high-fluidity and crack-resistant concrete for photovoltaic support foundation structure.

[0076] Application Example 1

[0077] The modified polymer obtained in Example 1 was applied to prepare concrete (C40 grade) for photovoltaic support foundation structure, and the specific steps included:

[0078] First, the coarse and fine aggregates were uniformly stirred in a mixer for 20 s. Then, the cementitious material (total design amount of 395 kg / m 3 ) was dry-stirred in the mixer for 30 s. Then, the modified polymer was added and stirred for 1 min. Finally, water was poured into the mixer and stirred for 5 min. The amount of water reducing agent was adjusted to control the slump of the concrete to be (180±20) mm. The specific mix proportion is shown in Table 1, and the performance test results of the obtained concrete are shown in Table 2.

[0079] Table 1: Concrete mix proportion (kg / m 3 )

[0080]

[0081]

[0082] Table 2 Performance test results of the concrete obtained in Example 1

[0083]

[0084] The above results show that the modified polymer concrete obtained in the present embodiment can simultaneously improve the mechanical properties, fluidity and crack resistance of the concrete compared with the reference group concrete of the same grade, specifically, in terms of mechanical properties, the 28d compressive strength is increased by 11% compared with the reference group; in terms of fluidity, the slump is increased by 30mm, the spread is increased by 40mm, the inverted slump flow time is reduced by 3s, and the V-leakage flow time is reduced by 10s compared with the reference group; in terms of crack resistance, the 28d splitting tensile strength is increased by 53% compared with the reference group, and the total cracking area per unit area in the early crack resistance test is reduced by 23% compared with the reference group.

[0085] Example 2.

[0086] The specific operation steps are as follows:

[0087] (1) 5g of NaCl was added to 300ml of distilled water, after dissolution, 145mg of polyethylene glycol and 50g of silicone powder were added, after stirring, 50ml of dodecyl dimethyl amine oxide, 10ml of vinyl silicone oil, 20ml of sodium silicate solution were added, and mixed uniformly.

[0088] Ultrasonic analysis instrument was used for ultrasonic treatment (ultrasonic treatment for 20min under the condition of 45%, the pulse used the mode of opening for 5s and closing for 5s), ice bath cooling to room temperature, and modified polymer slurry A was obtained.

[0089] (2) 0.6g of cobalt tetroxide (Co3O4) nanoparticles was mixed with 1L of distilled water, and then ultrasonic dispersion was performed for 40min using an ultrasonic cell crusher, and 1L of magnetic nanoparticle mother liquor was obtained.

[0090] (3) 30g of sucrose ester and 0.5g of benzoic acid were added to the modified polymer slurry A, stirred for 30min, and then heated in a microwave generating device (880W, 2.50GHz) for 8min, immediately added 1L of magnetic nanoparticle mother liquor, stirred at a speed of 1000r / min for 5min, after completion, placed at 50℃ for 15h, and modified polymer slurry B was obtained.

[0091] (4) A magnetic field generating device was set up to generate a magnetic field, the modified polymer slurry B was placed in a magnetic field environment with a magnetic field strength of 20mT, stirred at 60℃ and 60r / min for 10min, and then 20vt% of the upper clear liquid was removed.

[0092] (5) After adjusting the magnetic field strength to 50 mT again, continue stirring at 60 °C and 60 r / min for 10 min, then perform vacuum infiltration treatment on the slurry for 1 h. After the treatment, the modified polymer is obtained. The test results show that the modified polymer has a low glass transition temperature (Tg) (-38 °C), a high elongation at break (740%), and a high bonding strength (1.8 MPa), which can effectively improve the fluidity and crack resistance of concrete.

[0093] (6) The modified polymer is added to concrete (conventional C40 grade), and the addition amount of the modified polymer is 2 wt% of the cementitious material, to obtain high-fluidity and crack-resistant concrete for photovoltaic support foundation structures.

[0094] Application Example 2

[0095] The modified polymer obtained in Example 2 is applied to prepare concrete (C40 grade) for photovoltaic support foundation structures. The specific steps include:

[0096] First, the coarse and fine aggregates are uniformly stirred in a mixer for 20 s. Then, the cementitious material (the total designed amount is 395 kg / m 3 ) is dry-stirred in the mixer for 30 s. Then, the modified polymer is added and stirred for 1 min. Finally, water is poured into the mixer and fully stirred for 5 min. The water-reducing agent amount is adjusted to control the concrete slump to (180 ± 20) mm. The specific mix proportion is shown in Table 3, and the performance test results of the obtained concrete are shown in Table 4.

[0097] Table 3: Concrete mix proportion (kg / m 3 )

[0098] Group Cement Fly ash Mineral powder Sand Stone Water Water reducing agent Modified polymer Reference 225 90 80 720 1125 155 8.5 Example 2 225 90 80 720 1125 155 8.5 7.9

[0099] Table 4: Performance test results of the concrete obtained in Application Example 2

[0100]

[0101] The above results show that the modified polymer concrete obtained in the present example can simultaneously improve the mechanical properties, fluidity, and crack resistance of concrete compared with the reference group concrete of the same grade. Specifically, in terms of mechanical properties, the 28d compressive strength is increased by 9% compared with the reference group; in terms of fluidity, the slump is increased by 25 mm, the spread is increased by 35 mm, the slump flow emptying time is reduced by 3 s, and the V leakage emptying time is reduced by 8 s compared with the reference group; and in terms of crack resistance, the 28d splitting tensile strength is increased by 47% compared with the reference group, and the total cracking area per unit area in the early crack resistance test is reduced by 22%.

[0102] Example 3

[0103] The specific operation steps are as follows:

[0104] (1) To 350 ml distilled water, add 15 g NaCl, after dissolving, add 155 mg polyethylene glycol and 55 g silicone powder, after stirring thoroughly, add 60 ml dodecyl dimethyl amine oxide, 15 ml vinyl silicone oil, 25 ml sodium silicate solution, mix evenly.

[0105] Use ultrasonic analyzer for ultrasonic treatment (ultrasonic 30 min under 50% condition, pulse uses the way of opening 10 s, closing 10 s), ice bath cooling to room temperature, get modified polymer slurry A.

[0106] (2) 0.8 g will be mixed with 1L of distilled water after cobalt tetroxide (Co3O4) nanoparticles, using ultrasonic cell disruptor ultrasonic dispersion 45 min, get 1L of magnetic nanoparticles mother liquor.

[0107] (3) To modified polymer slurry A, add 35 g sucrose ester, 0.6 g benzoic acid, stir 40 min, and after heating in microwave generating device (920 W, 2.40 GHz) for 12 min, immediately add 1L of magnetic nanoparticles mother liquor, stir at 1200 r / min for 3 min, after completion, stand at 55℃ for 10 h, get modified polymer slurry B.

[0108] (4) Set up magnetic field generating device to add magnetic field, place modified polymer slurry B in magnetic field environment with magnetic field intensity of 25 mT, stir at 50℃, 50 r / min for 15 min, then remove 30 vt% upper clear liquid.

[0109] (5) After adjusting the magnetic field intensity to 60 mT, continue stirring at 50℃, 50 r / min for 15 min, then vacuum infiltration treatment the slurry for 1.5 h, after treatment, get modified polymer, which has low glass transition temperature (Tg) (-40℃), high elongation at break (760%), high adhesive strength (2.0 MPa), can effectively improve the fluidity and crack resistance of concrete.

[0110] (6) Add modified polymer to concrete (conventional C40), the addition amount of modified polymer is 3 wt% of cementitious materials, get high fluidity and crack resistance concrete for photovoltaic support foundation structure.

[0111] Application example 3.

[0112] Apply the modified polymer obtained in example 3 to prepare concrete (C40 grade) for photovoltaic support foundation structure, the specific steps include:

[0113] First, add coarse and fine aggregates in the mixer and stir evenly for 20 s, then add cementitious materials (the total designed amount is 395 kg / m3 ) Dry stirring in the blender for 30 s, then add the modified polymer, stirring for 1 min, and finally pour the water into the blender and stir well for 5 min. The water-reducing agent is adjusted to control the slump of the concrete to be (180 ± 20) mm. The specific mixing ratio is shown in Table 5, and the performance test results of the obtained concrete are shown in Table 6.

[0114] Table 5 Concrete mixing ratio (kg / m 3 )

[0115] Group Cement Fly ash Mineral powder Sand Stone Water Water reducing agent Modified polymer Reference 225 90 80 720 1125 155 8.5 Example 3 225 90 80 720 1125 155 8.5 11.9

[0116] Table 6 Performance test results of the concrete obtained in Example 3

[0117]

[0118] The above results show that the modified polymer concrete obtained in the present embodiment can simultaneously improve the mechanical properties, flow performance and crack resistance of the concrete compared with the reference group concrete of the same grade. Specifically, in terms of mechanical properties, the 28d compressive strength is increased by 13% compared with the reference group; in terms of flow performance, the slump is increased by 30 mm, the spread is increased by 45 mm, the slump flow emptying time is reduced by 3 s, and the V leakage emptying time is reduced by 11 s compared with the reference group; and in terms of crack resistance, the 28d splitting tensile strength is increased by 57% compared with the reference group, and the total cracking area per unit area in the early crack resistance test is reduced by 25%.

[0119] Comparative Example 1.

[0120] The operation steps are the same as those of Example 1, except that silicone powder is not used. The specific operation steps are as follows:

[0121] A high-flowing crack-resistant concrete for photovoltaic support foundation structure

[0122] (1) 10 g of NaCl was added to 330 ml of distilled water, after dissolution, 150 mg of polyethylene glycol was added, after stirring, 55 ml of dodecyl dimethyl amine oxide, 12 ml of vinyl silicone oil, and 22 ml of sodium silicate solution were added, and mixed uniformly.

[0123] Ultrasonic analysis was used for ultrasonic treatment (ultrasonic treatment for 25 min under the condition of 48%, and the pulse was in the form of 8 s on and 8 s off), and ice bath cooling to room temperature to obtain the modified polymer slurry A.

[0124] (2) 0.7 g of cobalt trioxide (Co3O4) nanoparticles was mixed with 1 L of distilled water, and then ultrasonic dispersion was performed using an ultrasonic cell crusher for 43 min to obtain 1 L of magnetic nanoparticle mother liquor.

[0125] (3) To the modified polymer slurry A, 32 g sucrose ester, 0.55 g benzoic acid were added, stirred for 35 min, and after heating in a microwave generating device (900 W, 2.45 GHz) for 10 min, magnetic nanoparticle mother liquor was immediately added, stirred at a speed of 1100 r / min for 4 min, and after completion, placed at 52°C for 13 h to obtain modified polymer slurry B.

[0126] (4) The modified polymer slurry B was placed in a magnetic field environment with a magnetic field strength of 22 mT, and after stirring at 55°C and 55 r / min for 13 min, 25% of the upper clear liquid was removed.

[0127] (5) After adjusting the magnetic field strength to 55 mT, the slurry was further stirred at 55°C and 55 r / min for 13 min, and then vacuum infiltration treatment was performed for 1.2 h to obtain a modified polymer. The glass transition temperature (Tg) was -25°C, the elongation at break was 300%, and the adhesive strength was 1.2 MPa. The related performance was significantly degraded compared to Example 1.

[0128] (6) The modified polymer was added to concrete (conventional C40 grade), and the addition amount of the modified polymer was 2.5 wt% of the cementitious material to obtain concrete for photovoltaic support foundation structure.

[0129] B application

[0130] The modified polymer obtained in Comparative Example 1 was applied to prepare concrete (C40 grade) for photovoltaic support foundation structure. The specific steps included:

[0131] First, the coarse and fine aggregates were uniformly stirred in a mixer for 20 s, then the cementitious material (total design amount was 395 kg / m 3 ) was dry stirred in the mixer for 30 s, then the modified polymer was added and stirred for 1 min, and finally water was poured into the mixer and fully stirred for 5 min. The water-reducing agent amount was adjusted to control the concrete slump within (180±20) mm. The specific mix proportion is shown in Table 7, and the performance test results of the obtained concrete are shown in Table 8.

[0132] Table 7 Concrete mix proportion (kg / m 3 )

[0133] Group Cement Fly ash Mineral powder Sand Stone Water Water reducing agent Modified polymer Reference 225 90 80 720 1125 155 8.5 Example 4 225 90 80 720 1125 155 8.5 9.9

[0134] Table 8 Performance test results of the concrete obtained in Application Example 4

[0135]

[0136]

[0137] The above results show that the modified polymer concrete obtained in the application example has no obvious improvement effect on the mechanical properties, fluidity and crack resistance of the concrete compared with the benchmark group concrete of the same grade, and even some properties are reduced to a certain extent, as follows: in terms of mechanical properties, the 28d compressive strength is reduced by 4% compared with the benchmark group; in terms of fluidity, the slump is reduced by 10mm compared with the benchmark group, the spread is unchanged, the reverse slump flow time is increased by 2s, and the V leakage flow time is increased by 4s; in terms of crack resistance, the 28d splitting tensile strength is increased by 7% compared with the benchmark group, and the total cracking area per unit area in the early crack resistance test is reduced by 3%. According to the above experimental results, it can be known that the performance of the modified polymer prepared without silicone powder is obviously deteriorated, and there is no obvious improvement effect on the concrete, the mechanical properties and fluidity are slightly decreased compared with the conventional concrete, the crack resistance is slightly improved but not obvious, so the incorporation of silicone powder is necessary for the realization of the beneficial effects of the application.

[0138] Conclusion: Silicone powder is used as the main reaction material of the matrix, which has excellent dispersibility and excellent fluidity, and can also play a role in strengthening and toughening.

[0139] The application also carries out a comparative experiment of using only silicone powder (i.e. without dodecyl dimethyl amine oxide and vinyl silicone oil), and it is found in the operation process that: the use of only silicone powder has the problems of low reaction efficiency and weak system stability in the polymer reaction process, so that the self-advantage performance cannot be effectively fed back during the preparation of the polymer. The addition of dodecyl dimethyl amine oxide and vinyl silicone oil can effectively improve this problem and promote the overall performance of the concrete.

[0140] Comparative Example 2.

[0141] The operation steps are the same as those of Example 1, except that different surfactants are used.

[0142] The specific operation steps are as follows:

[0143] (1) 10g of NaCl was added to 330ml of distilled water, after dissolution, 150mg of polyethylene glycol and 52g of silicone powder were added, after stirring, 55ml of sodium stearate, 12ml of vinyl silicone oil and 22ml of sodium silicate solution were added, and the mixture was uniformly mixed.

[0144] The modified polymer slurry A was obtained by ultrasonic treatment (ultrasonic treatment for 25min under the condition of 48%, and the pulse was in the form of opening for 8s and closing for 8s), and ice bath cooling to room temperature.

[0145] (2) 0.7g of cobalt tetroxide (Co3O4) nanoparticles was mixed with 1L of distilled water, and then ultrasonic dispersion was carried out for 43min using an ultrasonic cell crusher to obtain 1L of magnetic nanoparticle mother liquor.

[0146] (3) To the modified polymer slurry A, 32 g sucrose ester, 0.55 g benzoic acid were added, stirred for 35 min, and after heating in a microwave generating device (900 W, 2.45 GHz) for 10 min, magnetic nanoparticle mother liquor was immediately added, stirred at a speed of 1100 r / min for 4 min, and after completion, placed at 52°C for 13 h to obtain modified polymer slurry B.

[0147] (4) The modified polymer slurry B was placed in a magnetic field environment with a magnetic field strength of 22 mT, and after stirring at 55°C and 55 r / min for 13 min, 25% of the upper clear liquid was removed.

[0148] (5) After adjusting the magnetic field strength to 55 mT, the slurry was further stirred at 55°C and 55 r / min for 13 min, and then vacuum infiltration treatment was performed for 1.2 h to obtain the modified polymer. The glass transition temperature (Tg) was -30°C, the elongation at break was 400%, and the bonding strength was 1.4 MPa. The related performance was significantly deteriorated compared with Example 1.

[0149] (6) The modified polymer was added to concrete (conventional C40 grade), and the addition amount of the modified polymer was 2.5 wt% of the cementitious material to obtain concrete for photovoltaic support foundation structure.

[0150] Application Example 5.

[0151] The modified polymer obtained in Comparative Example 2 was applied to prepare concrete (C40 grade) for photovoltaic support foundation structure. The specific steps included:

[0152] First, the coarse and fine aggregates were uniformly stirred in the mixer for 20 s, then the cementitious material (the total designed amount was 395 kg / m 3 ) was dry stirred in the mixer for 30 s, then the modified polymer was added and stirred for 1 min, and finally water was poured into the mixer and fully stirred for 5 min. The water-reducing agent amount was adjusted to control the concrete slump within (180±20) mm. The specific mix proportion is shown in Table 9, and the performance test results of the obtained concrete are shown in Table 10.

[0153] Table 9 Concrete mix proportion (kg / m 3 )

[0154] Group Cement Fly ash Mineral powder Sand Stone Water Water reducing agent Modified polymer Reference 225 90 80 720 1125 155 8.5 Example 5 225 90 80 720 1125 155 8.5 9.9

[0155] Table 10 Performance test results of the concrete obtained in Application Example 5

[0156]

[0157]

[0158] The above results show that the modified polymer concrete obtained in the application example has no obvious improvement effect on the mechanical properties, fluidity and crack resistance of the concrete compared with the reference group concrete of the same grade, and has a certain degree of decrease, as follows. In terms of mechanical properties, the 28d compressive strength is reduced by 2% compared with the reference group; in terms of fluidity, the slump is reduced by 5mm, the spread is reduced by 10mm, the inverted slump flow time is increased by 1s, and the V-leakage flow time is increased by 2s; in terms of crack resistance, the 28d splitting tensile strength is reduced by 3% compared with the reference group, and the total cracking area per unit area in the early crack resistance test is increased by 1%. From the above experimental results, it can be seen that the modified polymer prepared without using the limited dodecyl dimethyl amine oxide of the application has obvious performance degradation, and has no obvious improvement effect on the concrete, and the mechanical properties, fluidity and crack resistance are all slightly lower than those of the conventional concrete.

[0159] Conclusion: The dodecyl dimethyl amine oxide has a surface activity function, which improves the surface activity of the reaction matrix and contributes to the improvement of the reaction efficiency, and is different from the conventional action of other surfactants; the dodecyl dimethyl amine oxide can also soften the reaction process and improve the stability of the reaction environment in the application. Other active agents cannot effectively play the unique properties of dodecyl dimethyl amine oxide in the reaction process of the application, so the performance of the concrete is lower than that of the conventional group.

[0160] Comparative Example 3.

[0161] The operation steps are the same as those of Example 1, except that the vinyl silicone oil is not used.

[0162] The specific operation steps are as follows:

[0163] (1) 10g of NaCl was added to 330ml of distilled water, and after dissolution, 150mg of polyethylene glycol and 52g of silicone powder were added, and after stirring, 55ml of dodecyl dimethyl amine oxide, 22ml of sodium silicate solution were added, and mixed uniformly.

[0164] The modified polymer slurry A was obtained by ultrasonic treatment (ultrasonic treatment for 25min under the condition of 48%, and the pulse was in the form of opening for 8s and closing for 8s), and ice bath cooling to room temperature.

[0165] (2) 0.7g of cobalt tetroxide (Co3O4) nanoparticles was mixed with 1L of distilled water, and then ultrasonic dispersion was performed for 43min using an ultrasonic cell crusher to obtain 1L of magnetic nanoparticle mother liquor.

[0166] (3) 32 g of sucrose ester and 0.55 g of benzoic acid were added to the modified polymer slurry A, stirred for 35 min, and heated in a microwave generator (900 W, 2.45 GHz) for 10 min. Then, the magnetic nanoparticle mother liquor was immediately added and stirred at a speed of 1100 r / min for 4 min. After completion, the mixture was allowed to stand at 52 °C for 13 h to obtain the modified polymer slurry B.

[0167] (4) A magnetic field generating device was set up to add a magnetic field, and the modified polymer slurry B was placed in a magnetic field environment with a magnetic field strength of 22 mT. After stirring for 13 minutes at 55°C and 55 rpm, 25% of the supernatant was removed.

[0168] (5) After adjusting the magnetic field intensity to 55 mT, the mixture was stirred at 55°C and 55 rpm for 13 min, and then vacuum infiltration treatment was performed on the slurry for 1.2 h. After the treatment, a modified polymer was obtained. After testing, the glass transition temperature (Tg) was -31°C, the elongation at break was 420%, and the bonding strength was 1.4 MPa. The relevant properties were significantly deteriorated compared with those in Example 1.

[0169] (6) The modified polymer is added to concrete (conventional C40 grade), and the added amount of the modified polymer is 2.5 wt % of the cementitious material to obtain concrete for the photovoltaic support foundation structure.

[0170] Application Example 6.

[0171] The modified polymer obtained in Comparative Example 3 was used to prepare concrete (grade C40) for photovoltaic support infrastructure, and the specific steps included:

[0172] First, add coarse and fine aggregates into the mixer and stir evenly for 20 seconds. Then add the cementitious material (total design amount is 395kg / m 3 ) was dry-mixed in a mixer for 30 seconds, and then the modified polymer was added and stirred for 1 minute. Finally, water was poured into the mixer and stirred for 5 minutes. The slump of the concrete was controlled at (180±20) mm by adjusting the amount of water reducer. The specific mix ratio is shown in Table 11, and the performance test results of the obtained concrete are shown in Table 12.

[0173] Table 11 Concrete mix ratio (kg / m 3 )

[0174]

[0175] Table 12 Performance test results of concrete obtained in Application Example 6

[0176]

[0177]

[0178] The above results show that the modified polymer concrete obtained in the present application example has no obvious improvement effect on the mechanical properties, fluidity and crack resistance of the concrete compared with the reference group concrete of the same grade, and even some properties are reduced to a certain extent, as follows. In terms of mechanical properties, the 28d compressive strength is basically unchanged compared with the reference group. In terms of fluidity, the slump is reduced by 10mm, the spread is reduced by 20mm, the inverted slump flow time is increased by 3s, and the V leakage flow time is increased by 5s compared with the reference group. In terms of crack resistance, the 28d splitting tensile strength is increased by 10% compared with the reference group, and the total cracking area per unit area in the early crack resistance test is reduced by 4%. From the above experimental results, it can be seen that the performance of the modified polymer prepared without using vinyl silicone oil is obviously deteriorated, and there is no obvious improvement effect on the concrete. The mechanical properties and fluidity are slightly lower than those of the conventional concrete, the crack resistance is slightly improved but not obvious. Therefore, the incorporation of vinyl silicone oil is necessary for the realization of the beneficial effects of the present application.

[0179] Conclusion: The vinyl silicone oil used is a methyl vinyl polysiloxane with a vinyl group in the molecular chain, which can react with the silicone powder as an organic silicon polymer, and promote the formation of carbon layer in the polymer system, improving the stability of the reaction system and the flow performance of the polymer product. At the same time, the long chain structure and chain rotation of the methyl vinyl polysiloxane in the vinyl silicone oil can effectively improve the elasticity and plasticity of the polymer product system structure, solving the problem of weak stability of the silicone construction system, which has not been realized in the prior art.

[0180] Comparative Example 4.

[0181] The operation steps are the same as those of Example 1, except that dodecyl dimethyl amine oxide is not used.

[0182] The specific operation steps are as follows:

[0183] (1) 10g NaCl was added to 330ml distilled water, dissolved, then 150mg polyethylene glycol and 52g silicone powder were added, stirred thoroughly, then 12ml vinyl silicone oil and 22ml sodium silicate solution were added, and mixed uniformly.

[0184] The modified polymer slurry A was obtained by ultrasonic treatment (ultrasonic treatment for 25min under the condition of 48%, with the pulse in the form of 8s on and 8s off), and ice bath cooling to room temperature.

[0185] (2) 0.7g of cobalt trioxide nanoparticles (Co3O4) was mixed with 1L distilled water, and then ultrasonic dispersion was performed using an ultrasonic cell crusher for 43min to obtain 1L of magnetic nanoparticle mother liquor.

[0186] (3) To the modified polymer slurry A, 32 g sucrose ester, 0.55 g benzoic acid were added, stirred for 35 min, and after heating in a microwave generating device (900 W, 2.45 GHz) for 10 min, magnetic nanoparticles mother liquor was immediately added, stirred at a speed of 1100 r / min for 4 min, and after completion, placed at 52°C for 13 h to obtain modified polymer slurry B.

[0187] (4) The modified polymer slurry B was placed in a magnetic field environment with a magnetic field strength of 22 mT, and after stirring at 55°C and 55 r / min for 13 min, 25% of the upper clear liquid was removed.

[0188] (5) After adjusting the magnetic field strength to 55 mT, the slurry was further stirred at 55°C and 55 r / min for 13 min, and then vacuum infiltration treatment was performed for 1.2 h to obtain the modified polymer.

[0189] Through observation during the experiment, part of the precipitate was generated during the preparation of the modified polymer slurry A, and the solubility of the reactants decreased significantly. Test results showed that the glass transition temperature (Tg) was -28°C, the elongation at break was 320%, and the adhesive strength was 1.2 MPa. The related performance was significantly deteriorated compared with Example 1.

[0190] (6) The modified polymer was added to the concrete (conventional C40 grade), and the addition amount of the modified polymer was 2.5 wt% of the cementitious material to obtain the concrete for photovoltaic support foundation structure.

[0191] Application Example 7

[0192] The modified polymer obtained in Comparative Example 4 was applied to prepare the concrete (C40 grade) for photovoltaic support foundation structure, and the specific steps included:

[0193] First, the coarse and fine aggregates were uniformly stirred in the mixer for 20 s, then the cementitious material (the total designed amount was 395 kg / m 3 ) was dry stirred in the mixer for 30 s, then the modified polymer was added and stirred for 1 min, and finally the water was poured into the mixer and fully stirred for 5 min. The water-reducing agent amount was adjusted to control the concrete slump within (180±20) mm. The specific mix proportion is shown in Table 13, and the performance test results of the obtained concrete are shown in Table 14.

[0194] Table 13 Concrete mix proportion (kg / m 3 )

[0195] Group Cement Fly ash Mineral powder Sand Stone Water Water reducing agent Modified polymer Reference 225 90 80 720 1125 155 8.5 Example 7 225 90 80 720 1125 155 8.5 9.9

[0196] Table 14 Performance test results of the concrete obtained in Application Example 7

[0197]

[0198]

[0199] The above results show that compared with the same-grade benchmark concrete, the modified polymer concrete obtained in this application example showed no significant improvement in mechanical properties, flow properties, and crack resistance, and all of them decreased to some extent. Specifically, in terms of mechanical properties, the 28-day compressive strength decreased by 4% compared to the benchmark. In terms of flow properties, the slump decreased by 15 mm, the expansion decreased by 30 mm, the collapse flow time increased by 4 seconds, and the V leakage flow time increased by 7 seconds compared to the benchmark. In terms of crack resistance, the 28-day splitting tensile strength decreased by 13% compared to the benchmark, and the total crack area per unit area in the early crack resistance test increased by 4%. These experimental results show that the modified polymer prepared without dodecyldimethylamine oxide significantly deteriorated in performance and had no significant improvement on the concrete. The mechanical properties, flow properties, and crack resistance all decreased slightly compared to conventional concrete.

[0200] Conclusion: From the above, it can be seen that the introduction of dodecyl dimethyl amine oxide is beneficial to the performance of concrete.

[0201] Furthermore, during the experiment, it was found that when no dodecyl dimethylamine oxide was added, that is, in Comparative Example 4, the vinyl silicone oil exhibited adverse phenomena such as precipitation and agglomeration during the stirring process. Therefore, the introduction of dodecyl dimethylamine oxide can also avoid adverse phenomena such as precipitation and agglomeration that may occur during the stirring process due to the presence of vinyl silicone oil.

[0202] At the same time, during the experiment, it was also discovered that small bubbles escaped during the polymerization reaction in Comparative Example 4. However, in Example 1, this phenomenon was significantly reduced, and the small bubbles generated in the reaction system were retained within the reaction system, which improved the fluidity of the concrete. Therefore, small bubbles are generated during the polymerization reaction, and the addition of dodecyldimethylamine oxide can retain these small bubbles in the reactants. When the modified polymer is applied to concrete, the introduced small bubbles can improve the fluidity of the ready-mixed concrete. This is an effect that was not anticipated in the initial design of the present invention and is a significant advantage and innovation of the present invention.

[0203] Comparative Example 5.

[0204] The operation steps are the same as those in Example 1, except that sucrose ester is not used.

[0205] The specific steps are as follows:

[0206] (1) Add 10 g of NaCl to 330 ml of distilled water and dissolve it. Then add 150 mg of polyethylene glycol and 52 g of silicone powder. Stir thoroughly. Then add 55 ml of dodecyl dimethylamine oxide, 12 ml of vinyl silicone oil, and 22 ml of sodium silicate solution and mix well.

[0207] The mixture was ultrasonically treated with an ultrasonic analyzer (ultrasonication at 48% for 25 minutes, with a pulse of on for 8 seconds and off for 8 seconds), and then cooled to room temperature in an ice bath to obtain a modified polymer slurry A.

[0208] (2) After mixing 0.7 g of cobalt trioxide (Co3O4) nanoparticles with 1 L of distilled water, ultrasonic cell disruptor was used to ultrasonically disperse for 43 min to obtain 1 L of magnetic nanoparticle mother solution.

[0209] (3) 0.55 g of benzoic acid was added to the modified polymer slurry A, stirred for 35 min, and heated in a microwave generator (900 W, 2.45 GHz) for 10 min. Then, the magnetic nanoparticle mother liquor was immediately added and stirred at a speed of 1100 r / min for 4 min. After completion, the mixture was allowed to stand at 52 °C for 13 h to obtain the modified polymer slurry B.

[0210] (4) A magnetic field generating device was set up to add a magnetic field, and the modified polymer slurry B was placed in a magnetic field environment with a magnetic field strength of 22 mT. After stirring for 13 minutes at 55°C and 55 rpm, 25% of the supernatant was removed.

[0211] (5) After adjusting the magnetic field intensity to 55 mT, the mixture was stirred at 55°C and 55 rpm for 13 min, and then vacuum infiltration treatment was performed on the slurry for 1.2 h. After the treatment, a modified polymer was obtained. After testing, the glass transition temperature (Tg) was -30°C, the elongation at break was 415%, and the bonding strength was 1.3 MPa. The relevant properties were significantly deteriorated compared with those in Example 1.

[0212] (6) The modified polymer is added to concrete (conventional C40 grade), and the added amount of the modified polymer is 2.5 wt % of the cementitious material to obtain concrete for the photovoltaic support foundation structure.

[0213] Application Example 8

[0214] The modified polymer obtained in Comparative Example 5 was used to prepare concrete (grade C40) for photovoltaic support infrastructure, and the specific steps included:

[0215] First, add coarse and fine aggregates into the mixer and stir evenly for 20 seconds. Then add the cementitious material (total design amount is 395kg / m 3) was dry-mixed in a mixer for 30 seconds, and then the modified polymer was added and stirred for 1 minute. Finally, water was poured into the mixer and stirred thoroughly for 5 minutes. The slump of the concrete was controlled at (180±20) mm by adjusting the amount of water reducer. The specific mix ratio is shown in Table 15, and the performance test results of the obtained concrete are shown in Table 16.

[0216] Table 15 Concrete mix ratio (kg / m 3 )

[0217]

[0218]

[0219] Table 16 Performance test results of concrete obtained in Application Example 8

[0220]

[0221] The above results show that the modified polymer concrete obtained in this application example showed no significant improvement in mechanical properties, flow properties, and crack resistance compared to the same-grade benchmark concrete, and indeed showed some decline. Specifically, in terms of mechanical properties, the 28-day compressive strength remained essentially unchanged compared to the benchmark. In terms of flow properties, the slump remained essentially unchanged, the expansion decreased by 10 mm, the collapse flow time remained essentially unchanged, and the V leakage flow time increased by 2 seconds. In terms of crack resistance, the 28-day splitting tensile strength decreased by 7% compared to the benchmark, and the total crack area per unit area in the early crack resistance test increased by 1%. These experimental results indicate that the modified polymer prepared without sucrose esters showed no significant improvement in performance, and some properties showed slight declines compared to conventional concrete.

[0222] Conclusion: Since the -OH group of sucrose in sucrose ester is a hydrophilic group and the carbon chain of fatty acid is a lipophilic group, it can play a linking and promoting role in the combination process of oil phase and water phase reactants in step (1), thereby improving the overall reaction efficiency and overall structural stability of the polymer. This is one of the innovative technologies.

[0223] On the one hand, the molecular structure of sucrose ester contains hydrophilic sucrose groups and hydrophobic fatty acid groups. It is a non-ionic surfactant with strong surface activity. It can be combined with dodecyl dimethyl amine oxide to enhance the surface activity of the reactants. The use of microwave generation technology can provide medium energy and effectively improve the efficiency of the polymerization reaction.

[0224] Comparative Example 6.

[0225] The operation steps are the same as those in Example 1, except that microwave heating is not used.

[0226] The specific steps are as follows:

[0227] (1) Add 10 g of NaCl to 330 ml of distilled water and dissolve it. Then add 150 mg of polyethylene glycol and 52 g of silicone powder. Stir thoroughly. Then add 55 ml of dodecyl dimethylamine oxide, 12 ml of vinyl silicone oil, and 22 ml of sodium silicate solution and mix well.

[0228] The mixture was ultrasonically treated with an ultrasonic analyzer (ultrasonication at 48% for 25 minutes, with a pulse of on for 8 seconds and off for 8 seconds), and then cooled to room temperature in an ice bath to obtain a modified polymer slurry A.

[0229] (2) After mixing 0.7 g of cobalt trioxide (Co3O4) nanoparticles with 1 L of distilled water, ultrasonic cell disruptor was used to ultrasonically disperse for 43 min to obtain 1 L of magnetic nanoparticle mother solution.

[0230] (3) Add 32 g of sucrose ester and 0.55 g of benzoic acid to the modified polymer slurry A, stir for 35 min, add the magnetic nanoparticle mother liquor, stir at a speed of 1100 r / min for 4 min, and then let it stand at 52 ° C for 13 h to obtain the modified polymer slurry B.

[0231] (4) A magnetic field generating device was set up to add a magnetic field, and the modified polymer slurry B was placed in a magnetic field environment with a magnetic field strength of 22 mT. After stirring for 13 minutes at 55°C and 55 rpm, 25% of the supernatant was removed.

[0232] (5) After adjusting the magnetic field intensity to 55 mT, the mixture was stirred at 55°C and 55 rpm for 13 min, and then vacuum infiltration treatment was performed on the slurry for 1.2 h. After the treatment, a modified polymer was obtained.

[0233] Through observation during the experimental process, it was found that during the preparation of the modified polymer slurry B, some clumping and flocculent substances were generated and irregularly distributed. After testing, the glass transition temperature (Tg) was -30°C, the elongation at break was 335%, and the bonding strength was 1.3 MPa. The relevant performance was significantly deteriorated compared with Example 1.

[0234] (6) The modified polymer is added to concrete (conventional C40 grade), and the added amount of the modified polymer is 2.5wt% of the cementitious material to obtain high-fluidity crack-resistant concrete for the photovoltaic support base structure.

[0235] Application Example 9

[0236] The modified polymer obtained in Comparative Example 6 was used to prepare concrete (grade C40) for photovoltaic support infrastructure, and the specific steps included:

[0237] First, add coarse and fine aggregates into the mixer and stir evenly for 20 seconds. Then add the cementitious material (total design amount is 395kg / m3 ) was dry-mixed in a mixer for 30 seconds, and then the modified polymer was added and stirred for 1 minute. Finally, water was poured into the mixer and stirred for 5 minutes. The slump of the concrete was controlled at (180±20) mm by adjusting the amount of water reducer. The specific mix ratio is shown in Table 17, and the performance test results of the obtained concrete are shown in Table 18.

[0238] Table 17 Concrete mix ratio (kg / m 3 )

[0239] Group Cement Fly ash Mineral powder Sand Stone Water Water reducing agent Modified polymer Reference 225 90 80 720 1125 155 8.5 Example 9 225 90 80 720 1125 155 8.5 9.9

[0240] Table 18 Performance test results of concrete obtained in Application Example 9

[0241]

[0242] The above results show that compared with the same-grade benchmark concrete, the modified polymer concrete obtained in this application example showed no significant improvement in mechanical properties, flow properties, and crack resistance, and all of them decreased to a certain extent. Specifically, in terms of mechanical properties, the 28-day compressive strength decreased by 2% compared to the benchmark. In terms of flow properties, the slump decreased by 10 mm, the expansion decreased by 20 mm, the collapse flow time increased by 2 seconds, and the V leakage flow time increased by 4 seconds compared to the benchmark. In terms of crack resistance, the 28-day splitting tensile strength decreased by 7%, and the total crack area per unit area in the early crack resistance test increased by 1%. These experimental results show that the modified polymer prepared without microwave treatment significantly deteriorated in performance and had no significant improvement effect on the concrete. The mechanical properties, flow properties, and crack resistance all decreased slightly compared to conventional concrete.

[0243] Conclusion: The existing technology for synthesizing sucrose benzoate by reacting sucrose ester with benzoic acid is to react with polyacrylamide to form a flocculated impermeable mesh film, which prevents water penetration and thus plays an internal curing role. The present invention combines the reaction mechanism, eliminates the polyacrylamide reaction raw material, and adopts the polymerization reaction of dodecyl dimethylamine oxide with sucrose ester and benzoic acid. On the one hand, the molecular structure of sucrose ester contains hydrophilic sucrose groups and hydrophobic fatty acid groups. It is a non-ionic surfactant with strong surface activity, which can be combined with dodecyl dimethylamine oxide to enhance the surface activity of the reactants.

[0244] Meanwhile, flocs were generated during the preparation of modified polymer slurry B in both Comparative Example 6 and Example 1. However, since microwave heating was not used in Comparative Example 6, the amount of flocs generated was smaller, resulting in lower efficiency. Specifically, the use of microwave generation technology can provide dielectric energy, effectively improving polymerization efficiency. Furthermore, more flocs are generated within a reasonable range, thereby forming a watertight interwoven network structure (i.e., the present invention also forms a watertight interwoven network structure without the need for polyacrylamide), thereby providing internal curing. Later, introduction into the concrete system promotes hydration, improving the concrete's density and crack resistance.

[0245] Comparative Example 7.

[0246] The specific operation steps are the same as those in Example 1, except that the magnetic field conditions are changed and one magnetic field treatment technique is reduced.

[0247] The specific steps are as follows:

[0248] (1) Add 10 g of NaCl to 330 ml of distilled water and dissolve it. Then add 150 mg of polyethylene glycol and 52 g of silicone powder. Stir thoroughly. Then add 55 ml of dodecyl dimethylamine oxide, 12 ml of vinyl silicone oil, and 22 ml of sodium silicate solution and mix well.

[0249] The mixture was ultrasonically treated with an ultrasonic analyzer (ultrasonication at 48% for 25 minutes, with a pulse of on for 8 seconds and off for 8 seconds), and then cooled to room temperature in an ice bath to obtain a modified polymer slurry A.

[0250] (2) After mixing 0.7 g of cobalt trioxide (Co3O4) nanoparticles with 1 L of distilled water, ultrasonic cell disruptor was used to ultrasonically disperse for 43 min to obtain 1 L of magnetic nanoparticle mother solution.

[0251] (3) 32 g of sucrose ester and 0.55 g of benzoic acid were added to the modified polymer slurry A, stirred for 35 min, and heated in a microwave generator (900 W, 2.45 GHz) for 10 min. Then, the magnetic nanoparticle mother liquor was immediately added and stirred at a speed of 1100 r / min for 4 min. After completion, the mixture was allowed to stand at 52 °C for 13 h to obtain the modified polymer slurry B.

[0252] (4) A magnetic field generating device was set up to add a magnetic field, and the modified polymer slurry B was placed in a magnetic field environment with a magnetic field strength of 55 mT. After stirring for 13 minutes at 55°C and 55 r / min, the slurry was subjected to vacuum infiltration treatment for 1.2 hours. After the treatment was completed, the modified polymer was obtained.

[0253] Through observation during the experimental process, it was found that during the treatment with the additional magnetic field technology, the flocculent substances in the product underwent partial directional displacement, but some flocculent substances were unevenly distributed and flowed disorderly in the slurry. After testing, the glass transition temperature (Tg) was -33°C, the elongation at break was 420%, and the bonding strength was 1.4 MPa. The relevant performance was deteriorated to a certain extent compared with Example 1.

[0254] (6) The modified polymer is added to concrete (conventional C40 grade), and the added amount of the modified polymer is 2.5 wt % of the cementitious material to obtain concrete for the photovoltaic support foundation structure.

[0255] Application Example 10.

[0256] The modified polymer obtained in Comparative Example 7 was used to prepare concrete (grade C40) for photovoltaic support infrastructure, and the specific steps included:

[0257] First, add coarse and fine aggregates into the mixer and stir evenly for 20 seconds. Then add the cementitious material (total design amount is 395kg / m 3 ) was dry-mixed in a mixer for 30 seconds, and then the modified polymer was added and stirred for 1 minute. Finally, water was poured into the mixer and stirred thoroughly for 5 minutes. The slump of the concrete was controlled at (180±20) mm by adjusting the amount of water reducer. The specific mix ratio is shown in Table 19, and the performance test results of the obtained concrete are shown in Table 20.

[0258] Table 19 Concrete mix ratio (kg / m 3 )

[0259] Group Cement Fly ash Mineral powder Sand Stone Water Water reducing agent Modified polymer Reference 225 90 80 720 1125 155 8.5 Example 10 225 90 80 720 1125 155 8.5 9.9

[0260] Table 20 Performance test results of concrete obtained in Application Example 10

[0261]

[0262] The above results show that compared with the same-grade benchmark concrete, the modified polymer concrete obtained in this application example has no significant improvement in mechanical properties, flow properties, and crack resistance, and some properties have decreased to a certain extent. Specifically, in terms of mechanical properties, the 28-day compressive strength is basically unchanged compared to the benchmark group; in terms of flow properties, the slump is reduced by 5mm, the expansion is reduced by 15mm, the collapse flow time is increased by 1s, and the V leakage flow time is increased by 2s compared to the benchmark group; in terms of crack resistance, the 28-day splitting tensile strength is reduced by 13% compared to the benchmark group, and the total crack area per unit area in the early crack resistance test is increased by 4%. In summary, the experimental results show that the modified polymer prepared without the two-stage additional magnetic field technology specified in this patent has a certain degree of deterioration in performance and has no significant improvement effect on concrete. The flow properties and crack resistance are slightly reduced compared to conventional concrete.

[0263] Conclusion: The introduced magnetic nanoparticle mother liquor, due to its large specific surface area and small particle size, can adhere to the surface of the water-impermeable reticular structure after being introduced into the system, and has a catalytic effect on the polymerization reaction of the silicone powder in the previous step, promoting the full progress of the reaction.

[0264] The application adopts an additional magnetic field technology to stir the polymer under different intensity magnetic fields, and the main function is to use the magnetic nanoparticles attached to the inside of the polymer product structure in the early stage to perform directional migration and reasonable distribution, improve the functional group combination efficiency in the polymer, and thus improve the reaction efficiency. At the same time, under the first stage magnetic field intensity, the main purpose is to strengthen the combination and adhesion strength of the magnetic nanoparticles and the inside of the polymer product structure under the action of the magnetic field, and under the second stage magnetic field intensity, the main purpose is to make the magnetic nanoparticles drive the polymer product structure to perform directional and reasonable distribution under the action of the magnetic force, and the part of the material not completely reacted in the early stage is further reacted, which is the innovative technology of the process of the patent.

[0265] The above is only the preferred embodiment of the present application, and does not limit the embodiments of the present application in any form. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the embodiments of the present application still belong to the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing high-fluidity crack-resistant concrete for photovoltaic support infrastructure, characterized in that: The following steps are involved: (1) Adding polyethylene glycol and silicone powder to a NaCl solution, stirring thoroughly, then adding dodecyl dimethylamine oxide, vinyl silicone oil, and sodium silicate solution, mixing well, performing ultrasonic treatment, and cooling to room temperature to obtain a modified polymer slurry A; (2) adding sucrose ester and benzoic acid to the modified polymer slurry A, mixing uniformly, and then performing microwave heating. Then, adding the magnetic nanoparticle mother solution, mixing uniformly, and standing at 50-55° C. for 10-15 hours to obtain a modified polymer slurry B; (3) placing the modified polymer slurry B in a magnetic field environment with a magnetic field strength of 20-25 mT, stirring at 50-60° C. and 50-60 rpm for 10-15 minutes, and removing the supernatant; (4) After adjusting the magnetic field intensity to 50-60 mT, stirring was continued at 50-60° C. and 50-60 rpm for 10-15 min, and then vacuum infiltration treatment was performed for 1-1.5 h to obtain a modified polymer; (5) Adding the modified polymer into concrete and mixing evenly to obtain the high-fluidity, crack-resistant concrete for the photovoltaic support base structure.

2. The preparation method according to claim 1, characterized in that In the step (1), the mass volume ratios of NaCl, polyethylene glycol, silicone powder, dodecyl dimethylamine oxide, vinyl silicone oil, and sodium silicate solution are 5-15g:145-155mg:50-55g:50-60ml and 10-15ml:20-25ml.

3. The preparation method according to claim 1, characterized in that In the step (1), the vinyl silicone oil is DY-V411 vinyl silicone oil; The ultrasonic treatment conditions are: amplitude of 45-50%, time of 20-30 min, and pulse on for 5-10 s and off for 5-10 s.

4. The preparation method according to claim 1, characterized in that The mass volume ratio of the NaCl, sucrose ester, benzoic acid, and magnetic nanoparticles is 5-15g:30-35g:0.5-0.6g:0.6-0.8g; The mass concentration of the magnetic nanoparticle mother liquor is 0.6-0.8 g / L.

5. The preparation method according to claim 1, characterized in that In the step (2), the preparation method of the magnetic nanoparticle mother liquor is as follows: after mixing cobalt trioxide nanoparticles with water, ultrasonic dispersion is performed to obtain the magnetic nanoparticle mother liquor.

6. The preparation method according to claim 1, characterized in that In the step (2), the parameters of microwave heating are: 880-920W, 2.40-2.50GHz, 8-12min.

7. The preparation method according to claim 1, characterized in that In the step (2), the magnetic nanoparticle mother solution is added and stirred at 1000-1200 r / min for 3-5 minutes.

8. The preparation method according to claim 1, characterized in that In the step (3), 20-30% by volume of the upper clear liquid is removed.

9. The preparation method according to claim 1, characterized in that In the step (5), the amount of the modified polymer added is 2-3 wt% of the cementitious material in the concrete.

10. A high-fluidity, crack-resistant concrete for a photovoltaic support foundation structure, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 9.

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