Method for physical treatment of cement mortar / concrete mixtures

Abstract

The application provides a physical treatment method of cement mortar / concrete mixture, which comprises the following steps: performing physical ultrasonic treatment on the cement mortar / concrete mixture, wherein the ultrasonic vibration frequency is 15-50 kHz, the ultrasonic vibration treatment time is t, and the ultrasonic treatment time point is T; wherein the cement mortar / concrete mixture contains an additive, and the additive is used for improving the flow performance of the mixed slurry or prolonging the setting time. The physical treatment can be performed immediately after the completion of the concrete mixing, at a certain time point after the mixing to the pouring, during the pouring process, after the completion of the pouring to the setting, or multiple times at the above different time points. The ultrasonic treatment can weaken the inhibition of the additive on the cement hydration, promote the setting and hardening of the cement mortar or concrete mixture, improve the early strength development of the cement mortar or concrete mixture, shorten the form removal time of the concrete prefabricated component, and save energy.

Description

Technical Field

[0001] This application relates to the field of building technology, specifically to a physical treatment method for cement mortar / concrete mixtures. Background Technology

[0002] Precise control of the setting time and early strength development of cement concrete is a key technical challenge in the field of cement concrete. To ensure high fluidity and long slump retention time, admixtures such as water-reducing agents and retarders are often added to control fluidity and its retention over time. However, these admixtures often significantly inhibit cement hydration, prolong setting time, and reduce the early strength of the concrete.

[0003] Ready-mixed concrete, also known as commercial concrete, is an essential basic engineering material in urban and rural construction in my country. It refers to a concrete mixture produced by mixing cement, water, aggregates, mineral admixtures, and additives in a specific ratio at a ready-mixed concrete plant after metering, and then transported to the site of use within a specified time. Ready-mixed concrete requires multiple processes including mixing, transportation, pouring, placement, and curing, and must be poured before initial setting. To ensure sufficient working time, water-reducing agents and retarders are usually added during mixing to give the concrete suitable workability and sufficient workability retention time. After pouring, it is desirable for the concrete to quickly set and harden to generate strength, ensuring construction progress and saving costs.

[0004] Precast concrete refers to concrete manufactured in a factory rather than poured on-site for the final construction process. It is used to prepare pre-formed concrete components for on-site assembly and installation. During the precast concrete preparation process, water-reducing agents are often added to ensure the concrete's fluidity. A common side effect of water-reducing agents is that they can delay the setting and hardening of the concrete to some extent. Typically, to ensure the production efficiency of precast concrete components, it is crucial that the concrete sets and hardens rapidly after being poured into the formwork to achieve high early strength. To promote the rapid development of the strength of the poured concrete, high-temperature steam curing is often required. However, this high-temperature steam curing process significantly increases the energy consumption and production costs of precast concrete. In the context of energy conservation and emission reduction, reducing steam curing temperature, shortening steam curing time, and even completely eliminating the steam curing process are key challenges in the precast concrete production process.

[0005] Therefore, for cement mortar and concrete mixtures, admixtures such as water-reducing agents and retarders are often added to control fluidity and setting time in order to ensure their workability. However, after ready-mixed concrete is poured, or after precast concrete is placed in the formwork, it needs to set and harden rapidly to develop strength. Therefore, the contradiction between the side effects of admixtures, such as prolonged setting time and slow strength development, and the need for rapid setting and hardening and rapid strength development of concrete after pouring / placement is a problem that must be solved. Summary of the Invention

[0006] This application addresses the aforementioned technical challenges by proposing a physical treatment method for cement mortar / concrete mixtures. This method can accelerate concrete strength development, improve construction efficiency, and reduce production costs. Furthermore, for precast concrete, this technology can significantly shorten curing time or reduce curing temperature, and even eliminate the curing process, achieving energy conservation, emission reduction, and lower concrete production costs. The physical treatment method includes:

[0007] The cement mortar / concrete mixture is subjected to physical ultrasonic treatment. The ultrasonic vibration frequency in the physical ultrasonic treatment step is 15KHz~50KHz, the ultrasonic vibration treatment duration is t, and the ultrasonic treatment time point is T. The cement mortar / concrete mixture contains admixtures, which are used to improve the flowability of the mixture or prolong the setting time.

[0008] Optionally, in the physical ultrasonic treatment step, the ultrasonic vibration duration t satisfies: 1min≤t≤15min.

[0009] Optionally, in the step of physically ultrasonically treating the cement mortar / concrete mixture, the time point T for physically ultrasonically treating the cement mortar / concrete mixture includes the first moment T0 when the cement mortar / concrete is completed and the time from the first moment T0 to the second moment T when the cement mortar / concrete mixture begins to be poured. n Between, the second time T n The third moment T when the pouring is completed m Between, the third moment T m At the fourth moment T of the initial setting of the cement mortar / concrete mixture s Any point in time between or any combination of the above points in time.

[0010] Optionally, the time point T for physical ultrasonic treatment of the cement mortar / concrete mixture is from the first moment T0 after the cement mortar / concrete is mixed to the second moment T0 after the cement mortar / concrete mixture is poured. n The process takes place between [time range], where T0 is 0 min.

[0011] Optionally, the ultrasonic vibration treatment in the physical ultrasonic treatment step may be performed at one or more time points T, and the ultrasonic vibration frequency used at each time point T may be the same or different.

[0012] Preferably, when the ultrasonic vibration treatment in the physical ultrasonic treatment step is performed at a time point T, T∈[T0+2min, T0+1h], more preferably T∈[T0+2min, T0+30min];

[0013] Preferably, when the ultrasonic vibration treatment in the physical ultrasonic treatment step is performed using multiple time points T, T is selected from the intervals [T0+2min, T0+10min], [T0+30min, T0+1h], [T0+2h ... n ]、[T n +30min, T m ]、[T m +5min, T s Two or more of [-1h].

[0014] Optionally, the unidirectional input energy in the physical ultrasonic treatment step is the ratio of the product of the ultrasonic vibration treatment power P and the ultrasonic vibration treatment time t to the volume V of the cement mortar / concrete mixture to be treated, and the unidirectional input energy satisfies: 5 × 10 4 KJ / m 3 ≤P×t / V≤5×10 5 KJ / m 3 .

[0015] Optionally, in the physical ultrasonic treatment step, the ultrasonic treatment method includes one or more of the following: immersion ultrasonic treatment method, surface contact ultrasonic treatment method, and surface non-contact ultrasonic treatment method.

[0016] Optionally, the admixture includes at least one of a water-reducing agent and a retarder.

[0017] Optionally, the water-reducing agent includes at least one of polycarboxylate water-reducing agents, polysulfonic acid water-reducing agents, lignosulfonate water-reducing agents, and naphthalene-based water-reducing agents; and / or

[0018] Retarder includes at least one of sugar retarders, hydroxycarboxylic acid and its salt retarders, and organophosphate and its salt retarders.

[0019] Optionally, in the physical ultrasonic treatment step of the cement mortar / concrete mixture, the amount of water-reducing agent in the cement mortar / concrete mixture is 0.05% to 3% of the cement mass; and / or the amount of retarder is 0.02% to 1% of the cement mass.

[0020] Compared with the prior art, this application has at least the following beneficial effects:

[0021] The physical treatment method for cement mortar / concrete mixtures provided in this application involves ultrasonic vibration treatment of the cement mortar / concrete mixture at an ultrasonic vibration frequency of 15kHz to 50kHz for a certain period of time. This can weaken the inhibitory effect of admixtures on cement hydration, and the ultrasonic action can promote the early generation of CSH nanoparticles, thereby increasing the adsorption of admixtures by the nanoparticles. This reduces the content of residual admixtures in the liquid phase of the cement mortar / concrete mixture, promotes the setting and hardening of the cement mortar or concrete mixture, improves the early strength development of the cement mortar or concrete mixture, shortens the demolding time of precast concrete components, accelerates the construction progress, and saves energy. Furthermore, the physical treatment method provided in this application is simple to operate and has a wide range of applications. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0023] Figure 1 This is a schematic diagram comparing the hydration heat curves of Examples 1 to 3 of this application with those of Comparative Example 1;

[0024] Figure 2 This is a schematic diagram comparing the hydration heat curves of Examples 4 to 6 of this application with those of Comparative Example 2;

[0025] Figure 3 This is a schematic diagram comparing the hydration heat curves of Examples 7 to 9 of this application with those of Comparative Example 3;

[0026] Figure 4 This is a schematic diagram comparing the hydration heat curves of Examples 10 to 12 of this application with those of Comparative Example 4;

[0027] Figure 5 This is a schematic diagram comparing the hydration heat curves of Examples 13 to 15 of this application with those of Comparative Example 1;

[0028] Figure 6 This is a schematic diagram comparing the hydration heat curves of Examples 16 to 18 of this application with those of Comparative Example 2;

[0029] Figure 7 This is a schematic diagram comparing the hydration heat curves of Example 16 of this application and Comparative Example 1;

[0030] Figure 8 This is a schematic diagram comparing the hydration heat curves of Example 20 of this application and Comparative Example 2;

[0031] Figure 9This is a schematic diagram comparing the hydration heat curves of Examples 7, 21, and 22 of this application with those of Comparative Example 3;

[0032] Figure 10 This is a schematic diagram comparing the hydration heat curves of Examples 10, 23, and 24 of this application with Comparative Example 4. Detailed Implementation

[0033] To make the purpose, technical solution, and beneficial technical effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the embodiments described in this specification are merely for explaining this application and are not intended to limit it.

[0034] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form a range not explicitly stated; and any lower limit can be combined with other lower limits to form a range not explicitly stated, just as any upper limit can be combined with any other upper limit to form a range not explicitly stated. Furthermore, although not explicitly stated, every point or individual value between the endpoints of the range is included within that range. Therefore, each point or individual value can be used as its own lower or upper limit and combined with any other point or individual value or with other lower or upper limits to form a range not explicitly stated.

[0035] In the description of this application, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, and "multiple" in "one or more" means two or more.

[0036] The foregoing description of this application is not intended to describe every disclosed implementation or method. Instead, the following description provides more specific examples of exemplary embodiments. Throughout the application, guidance is provided through a series of embodiments that can be used in various combinations. The examples listed are representative only and should not be construed as exhaustive.

[0037] Ready-mixed concrete refers to concrete mixtures prepared at a concrete batching plant and transported to the site of use within a specified time using transportation equipment. Ready-mixed concrete requires multiple processes including mixing, transportation, pouring, placement in formwork, and curing, and must be poured and compacted before initial setting. To ensure sufficient working time, water-reducing agents and retarders are usually added during concrete mixing to give the concrete mixture suitable workability and sufficient workability retention time. After pouring, it is desirable for the concrete to quickly set and harden to generate strength, ensuring construction progress and saving costs.

[0038] Precast concrete refers to concrete manufactured in a factory rather than poured on-site for the final construction process. It is used to prepare pre-formed concrete components for on-site assembly and installation. During the precast concrete preparation process, water-reducing agents are often added to ensure the concrete's fluidity. A common side effect of water-reducing agents is that they can delay the setting and hardening of the concrete to some extent. Typically, to ensure the production efficiency of precast concrete components, it is crucial that the concrete sets and hardens rapidly after being poured into the formwork to achieve high early strength. To promote the rapid development of the strength of the poured concrete, high-temperature steam curing is often required. However, this high-temperature steam curing process significantly increases the energy consumption and production costs of precast concrete. In the context of energy conservation and emission reduction, reducing steam curing temperature, shortening steam curing time, and even completely eliminating the steam curing process are key challenges in the precast concrete production process.

[0039] Therefore, for cement mortar and concrete mixtures, admixtures such as water-reducing agents and retarders are often added to control fluidity and setting time in order to ensure workability. However, after ready-mixed concrete is poured, or after precast concrete is placed in the formwork, rapid setting and hardening of the concrete and rapid strength development are required. Therefore, the contradiction between the side effects of admixtures, such as prolonged concrete setting time and slow strength development, and the need for rapid setting and hardening and rapid strength development of concrete after pouring / placement is a problem that must be solved.

[0040] Based on this, the inventors have conducted extensive research, and this application aims to provide a physical treatment method for cement mortar / concrete mixtures to promote the setting of cement mortar or concrete and accelerate strength development without affecting the workability of concrete. An embodiment of this application provides a physical treatment method for cement mortar / concrete mixtures, comprising: subjecting the cement mortar / concrete mixture to physical ultrasonic treatment, wherein the ultrasonic vibration frequency in the physical ultrasonic treatment step is 15KHz~50KHz, the ultrasonic vibration treatment time is t, and the time point of ultrasonic vibration in the physical treatment step is T; wherein the cement mortar / concrete mixture contains an admixture, which is used to improve the flowability of the mixture.

[0041] Understandably, in the preparation of ready-mixed concrete, water-reducing agents and retarders are often added to ensure suitable workability and sufficient workability retention time. Similarly, in the preparation of precast concrete, water-reducing agents are often added to ensure fluidity. After ready-mixed concrete is poured, or after precast concrete is placed in the formwork, rapid setting and hardening, and rapid strength development are required. However, a common side effect of these admixtures is that they delay the setting, hardening, and strength development of concrete to some extent. The contradiction between the prolonged setting time and slow strength gain caused by admixtures and the need for rapid setting, hardening, and strength development after pouring / placement is a problem that must be solved.

[0042] This application provides a physical treatment method for cement mortar / concrete mixtures, which can promote the setting of cement mortar or concrete and accelerate strength development without affecting the workability of concrete.

[0043] According to embodiments of this application, ultrasonic vibration treatment of cement mortar / concrete mixtures can, to a certain extent, weaken the inhibitory effect of admixtures such as water-reducing agents and retarders on cement hydration. Ultrasonic treatment can promote the early formation of CSH nanoparticles, thereby increasing the adsorption of admixtures by the nanoparticles, reducing the content of residual admixtures in the liquid phase of the cement mortar / concrete mixture, promoting the setting and hardening of the cement mortar or concrete mixture, improving the early strength development of the cement mortar or concrete mixture, shortening the demolding time of precast concrete components, ensuring construction progress, and saving energy. Furthermore, the physical treatment method provided in this application is simple to operate and has a wide range of applications.

[0044] In some embodiments, the ultrasonic vibration time t in the physical ultrasonic treatment step satisfies: 1min≤t≤15min. For example, the ultrasonic vibration time t can be 1min, 2min, 4min, 5min, 8min, 10min, 12min, 15min, or any combination of the above values.

[0045] According to the embodiments of this application, controlling the appropriate unilateral input energy can save costs on the one hand and achieve a better hydration promotion effect on the other hand. By controlling the appropriate unilateral input energy, the setting time of cement mortar / concrete mixture can be regulated.

[0046] In some embodiments, in the step of physically ultrasonically treating the cement mortar / concrete mixture, the time point T of the ultrasonic vibration for physically treating the cement mortar / concrete mixture includes the first moment T0 when the cement mortar / concrete is completed, and the time from the first moment T0 to the second moment T0 when the cement mortar / concrete mixture begins to be poured. n Between, the second time Tn The third moment T when the pouring is completed m Between, the third time T m At the fourth moment T of the initial setting of the cement mortar / concrete mixture s Any point in time between or any combination of the above points in time.

[0047] In some embodiments, the physical ultrasonic treatment of the cement mortar / concrete mixture is performed between the first moment T0 when the cement mortar / concrete mixture is formed and the second moment T when the cement mortar / concrete mixture is poured. n The process takes place between [time range], where T0 is 0 min.

[0048] In some embodiments, the ultrasonic vibration treatment in the physical ultrasonic treatment step is performed in multiple time periods, and the ultrasonic vibration frequency used at each time point may be the same or different, and the treatment time may be the same or different.

[0049] This application does not limit the number of ultrasonic vibration treatments, for example, it can be once or multiple times, and it does not limit the frequency of each ultrasonic vibration treatment, which can be the same or different.

[0050] In some embodiments, when the ultrasonic vibration treatment in the physical ultrasonic treatment step is performed using a single time point T, T ∈ [T0+2min, T0+1h], more preferably T ∈ [T0+2min, T0+30min]; when the ultrasonic vibration treatment in the physical treatment step is performed using multiple time points T, T is selected from the intervals [T0+2min, T0+10min], [T0+30min, T0+1h], [T0+2h ... n ]、[T n +30min, T m ]、[T m +5min, T s Two or more of [-1h].

[0051] In some embodiments, the ultrasonic vibration power P, the ultrasonic vibration time t, and the volume V of the cement mortar / concrete mixture to be treated in the physical ultrasonic treatment step satisfy: 5 × 10⁻⁶ 4 KJ / m 3 ≤P×t / V≤5×10 5 KJ / m 3 .

[0052] According to embodiments of this application, the ultrasonic time t can be adjusted based on the volume V of the cement mortar / concrete mixture to be treated and the ultrasonic vibration treatment power P.

[0053] In some embodiments, the ultrasonic treatment method in the physical ultrasonic treatment step includes one or more of the following: insertion ultrasonic treatment method, surface contact ultrasonic treatment method, and surface non-contact ultrasonic treatment method.

[0054] According to the embodiments of this application, the insertion ultrasonic treatment method refers to inserting an ultrasonic vibrating rod into the cement mortar / concrete mixture for physical treatment; the surface contact ultrasonic treatment method refers to placing an ultrasonic wave generating panel on the surface of the cement mortar / concrete mixture for physical ultrasonic treatment; and the surface non-contact ultrasonic treatment method refers to placing an ultrasonic wave generating panel 0.5 to 5 cm above the surface of the cement mortar / concrete mixture for physical treatment.

[0055] In this embodiment, there are no particular restrictions on the types of water-reducing agents and retarders, which can be selected according to actual needs. For example, the water-reducing agent includes at least one of polycarboxylic acid water-reducing agents, polysulfonic acid water-reducing agents, lignosulfonate water-reducing agents, and naphthalene-based water-reducing agents; the retarder includes at least one of sugar retarders, hydroxycarboxylic acid and its salt retarders, and organic phosphoric acid and its salt retarders.

[0056] In some embodiments, the water-reducing agent in the cement mortar / concrete mixture accounts for 0.05% to 3% of the cement mass; the retarder accounts for 0.02% to 1% of the cement mass.

[0057] According to embodiments of this application, water-reducing agents and retarders are used to ensure suitable workability and sufficient workability retention time in concrete mixtures, and different quantities can be added as needed.

[0058] The physical treatment method for cement mortar / concrete mixtures provided in this application involves ultrasonic vibration treatment of cement mortar / concrete mixtures containing admixtures. This can, to a certain extent, eliminate the inhibitory effect of water-reducing agents and retarders on cement hydration. Ultrasonic action can promote the early generation of CSH nanoparticles, thereby increasing the adsorption effect of nanoparticles on admixtures, reducing the content of residual admixtures in the liquid phase of cement mortar / concrete mixtures, promoting the setting and hardening of cement mortar or concrete mixtures, improving the early strength development of cement mortar or concrete mixtures, shortening the demolding time of precast concrete components, ensuring construction progress, and saving energy.

[0059] Example

[0060] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0061] Among them, the polycarboxylate superplasticizer (PCE) was synthesized in the laboratory with a solid content of 29.8%; the polysulfonic acid superplasticizer (PAS) was synthesized in the laboratory with a solid content of 26.8%; the cement was purchased from Jiangxi Shengdehan, grade P·W 52.5; the cyclodextrin (CD) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with a purity of 99%; the ultrasonic cell disruptor was purchased from Fangxu Technology (Shanghai) Co., Ltd., model NE-500Z; and the ultrasonic generator was purchased from Shenzhen Taiheda Co., Ltd., model THD-M1.

[0062] Synthesis method of polycarboxylate superplasticizer (PCE): Weigh 82g of water and 50g of allyl polyoxyethylene ether (HPEG), mix well and pour into a three-necked flask. Heat a constant temperature water bath to 65℃, then add 0.37g of H2O2 (30% mass concentration) to the three-necked flask. Prepare dropwise addition A by mixing 9g of acrylic acid (AA) and 24g of water, and prepare dropwise addition B by mixing 0.204g of mercaptopropionic acid (3-MPA), 0.125g of vitamin C (Vc), and 25g of water. Additions A and B are added dropwise to the three-necked flask at a uniform rate using a peristaltic pump. The addition time for addition A is 3 hours, and the addition time for addition B is 3.5 hours. After the addition is complete, maintain the temperature for 1 hour. After the reaction is complete, the actual solid content is tested, and the solid content is found to be 29.8%.

[0063] Synthesis method of polysulfonic acid water-reducing agent (PAS): 35g of water was added to a three-necked flask. After heating the constant temperature water bath to 60℃, 1.68g of H2O2 (30% mass concentration) was added to the three-necked flask. 45.87g of acrylic acid (AA), 22g of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and 100g of water were mixed evenly to prepare dropwise addition A. 1.58g of mercaptopropionic acid (3-MPA), 0.67g of vitamin C, and 60g of water were mixed evenly to prepare dropwise addition B. Dropwise addition A and dropwise addition B were added dropwise to the three-necked flask at a uniform rate using a peristaltic pump. The dropwise addition time for A was 3 hours, and the dropwise addition time for B was 3.5 hours. After the addition was complete, the mixture was kept at the same temperature for 1 hour. After the reaction was completed, the actual solid content was tested, and the solid content was found to be 26.8%.

[0064] Example 1

[0065] Add 8.73g of polycarboxylate superplasticizer to 513.89g of water and stir well. Place the mixture in a mixing pot. Then add 1300g of cement to the mixing pot and mix well with a mixer. After hydration at room temperature (25℃) for 30 minutes, use an ultrasonic cell disruptor to perform immersion ultrasonic treatment on the cement paste for 2 minutes, with a single-unit input energy of 2*10. 5 KJ / m 3 .

[0066] Example 2

[0067] Example 2 is basically the same as Example 1, except that the ultrasonic treatment time is 1 minute after hydration for 30 minutes, and the single-phase input energy is 1*10. 5 KJ / m 3 .

[0068] Example 3

[0069] Example 3 is basically the same as Example 1, except that the ultrasonic treatment time is 4 minutes after hydration for 30 minutes, and the single-phase input energy is 4*10. 5 KJ / m 3 .

[0070] Example 4:

[0071] Add 17.46g of polycarboxylate superplasticizer to 507.78g of water and stir well. Place the mixture in a mixing pot, then add 1300g of cement and mix thoroughly with a mixer. After hydration at room temperature (25℃) for 30 minutes, use an ultrasonic generator to perform surface contact ultrasonic treatment on the cement paste for 2 minutes, with a single-unit input energy of 2*10. 5 KJ / m 3 .

[0072] Example 5

[0073] The difference between Example 5 and Example 4 lies in the ultrasonic treatment time t. After hydration for 30 minutes, the ultrasonic treatment time is 1 minute, and the single-phase input energy is 1*10. 5 KJ / m 3 .

[0074] Example 6

[0075] The difference between Example 6 and Example 4 lies in the ultrasonic treatment time t. After hydration for 30 minutes, the ultrasonic treatment time is 4 minutes, and the single-phase input energy is 4*10. 5 KJ / m 3 .

[0076] Example 7:

[0077] Add 9.647g of polysulfonic acid water-reducing agent to 512.95g of water and stir well. Place the mixture in a mixing pot, then add 1300g of cement and mix thoroughly with a mixer. After hydration at room temperature (25℃) for 30 minutes, use an ultrasonic cell disruptor to perform immersion ultrasonic treatment on the cement paste for 2 minutes, with a single-unit input energy of 2*10. 5 KJ / m 3 .

[0078] Example 8

[0079] The difference between Example 8 and Example 7 lies in the ultrasonic treatment time t. After hydration for 30 minutes, the ultrasonic treatment time is 1 minute, and the single-phase input energy is 1*10. 5 KJ / m 3 .

[0080] Example 9

[0081] The difference between Example 9 and Example 7 lies in the ultrasonic treatment time t. After hydration for 30 minutes, the ultrasonic treatment time is 4 minutes, and the single-phase input energy is 4*10. 5 KJ / m 3 .

[0082] Example 10:

[0083] Add 0.65g of cyclodextrin to 520g of water and stir well. Place the mixture in a mixing pot, then add 1300g of cement and stir evenly with a mixer. After hydration at room temperature (25℃) for 30 minutes, use an ultrasonic cell disruptor to subject the resulting cement slurry to immersion ultrasonic treatment for 2 minutes, with a single-unit input energy of 2*10. 5 KJ / m 3 .

[0084] Example 11

[0085] The difference between Example 11 and Example 10 lies in the ultrasonic treatment time t. After hydration for 30 minutes, the ultrasonic treatment time is 1 minute, and the single-phase input energy is 1*10. 5 KJ / m 3 .

[0086] Example 12

[0087] The difference between Example 12 and Example 10 lies in the ultrasonic treatment time t. After hydration for 30 minutes, the ultrasonic treatment time is 4 minutes, and the single-phase input energy is 4*10. 5 KJ / m 3 .

[0088] Example 13

[0089] The difference between Example 13 and Example 1 is that the ultrasonic treatment time point T is different; ultrasonic treatment is performed 5 minutes after hydration.

[0090] Example 14

[0091] The difference between Example 14 and Example 1 is that the ultrasonic treatment time point T is different; ultrasonic treatment is performed 1 hour after hydration.

[0092] Example 15

[0093] The difference between Example 15 and Example 1 is that the ultrasonic treatment time point T is different; ultrasonic treatment is performed 2 hours after hydration.

[0094] Example 16

[0095] Add 8.73g of polycarboxylate superplasticizer to 513.89g of water and stir well. Place the mixture in a mixing pot, then add 1300g of cement and mix thoroughly with a mixer. After hydration at room temperature (25℃) for 5 minutes, first use an ultrasonic cell disruptor to perform immersion ultrasonic treatment on the cement paste for 2 minutes, with a single-unit input energy of 2*10. 5 KJ / m 3 Then, the cement slurry was allowed to continue hydration at room temperature for 25 minutes, and after hydration for 30 minutes, it was subjected to ultrasonic treatment again for 2 minutes.

[0096] The difference between Example 16 and Example 1 is the number of ultrasonic treatments. Example 16 is ultrasonically treated after 5 minutes of hydration, and then the cement paste is allowed to continue hydration at room temperature for 30 minutes before being ultrasonically treated again.

[0097] Example 17

[0098] Add 17.46g of polycarboxylate superplasticizer to 507.78g of water and stir well. Place the mixture in a mixing pot, then add 1300g of cement and mix thoroughly with a mixer. After hydration at room temperature (25℃) for 5 minutes, use an ultrasonic cell disruptor to ultrasonically treat the cement paste for 2 minutes, with a single-unit energy input of 2*10. 5 KJ / m 3 .

[0099] The difference between Example 17 and Example 4 is that the ultrasonic treatment time point T is different; ultrasonic treatment is performed 5 minutes after hydration.

[0100] Example 18

[0101] Add 17.46g of polycarboxylate superplasticizer to 507.78g of water and stir well. Place the mixture in a mixing pot, then add 1300g of cement and mix thoroughly with a mixer. After hydration at room temperature (25℃) for 1 hour, use an ultrasonic generator to perform surface contact ultrasonic treatment on the cement paste for 2 minutes, with a single-unit input energy of 2*10. 5 KJ / m 3 .

[0102] The difference between Example 18 and Example 4 is that the ultrasonic treatment time point T is different; ultrasonic treatment is performed 1 hour after hydration.

[0103] Example 19

[0104] Add 17.46g of polycarboxylate superplasticizer to 507.78g of water and stir well. Place the mixture in a mixing pot, then add 1300g of cement and mix thoroughly with a mixer. After hydration at room temperature (25℃) for 2 hours, use an ultrasonic generator to perform surface contact ultrasonic treatment on the cement paste for 2 minutes, with a single-unit input energy of 2*10. 5 KJ / m 3 .

[0105] The difference between Example 19 and Example 4 is that the ultrasonic treatment time point T is different; ultrasonic treatment is performed 2 hours after hydration.

[0106] Example 20

[0107] Add 17.46g of polycarboxylate superplasticizer to 507.78g of water and stir well. Place the mixture in a mixing pot, then add 1300g of cement and mix thoroughly with a mixer. After hydration at room temperature (25℃) for 5 minutes, first use an ultrasonic generator to perform surface contact ultrasonic treatment on the cement paste for 2 minutes, with a single-unit input energy of 2*10. 5 KJ / m 3 The cement paste was then allowed to hydrate at room temperature for 25 minutes. After 30 minutes of hydration, the cement paste was subjected to surface-contact ultrasonic treatment for 2 minutes using an ultrasonic generator, with a single-unit input energy of 2*10. 5 KJ / m 3 .

[0108] The difference between Example 20 and Example 4 is the number of ultrasonic treatments. First, ultrasonic treatment is performed for 2 minutes after hydration for 5 minutes. Then, the cement paste continues to be hydrated at room temperature for 25 minutes. After hydration for 30 minutes, ultrasonic treatment is performed again for 2 minutes.

[0109] Example 21

[0110] Add 9.647g of polysulfonic acid water-reducing agent to 512.95g of water and stir well. Place the mixture in a mixing pot, then add 1300g of cement and mix thoroughly with a mixer. After hydration at room temperature (25℃) for 1 hour, use an ultrasonic cell disruptor to perform immersion ultrasonic treatment on the cement paste for 2 minutes, with a single-unit input energy of 2*10. 5 KJ / m 3 .

[0111] The difference between Example 21 and Example 7 is that the ultrasonic treatment time point T is different; ultrasonic treatment is performed 1 hour after hydration.

[0112] Example 22

[0113] Add 9.647g of polysulfonic acid water-reducing agent to 512.95g of water and stir well. Place the mixture in a mixing pot, then add 1300g of cement to the pot and mix thoroughly with a mixer. After hydration at room temperature (25℃) for 2 hours, use an ultrasonic cell disruptor to perform immersion ultrasonic treatment on the cement paste for 2 minutes, with a single-unit input energy of 2*10. 5 KJ / m 3 .

[0114] The difference between Example 22 and Example 3 is that the ultrasonic treatment time point T is different; ultrasonic treatment is performed 2 hours after hydration.

[0115] Example 23

[0116] Add 0.65g of cyclodextrin to 520g of water and stir well. Place the mixture in a mixing pot, then add 1300g of cement and stir evenly. After hydration at room temperature (25℃) for 1 hour, use an ultrasonic cell disruptor to perform immersion ultrasonic treatment on the cement slurry for 2 minutes, with a single-unit input energy of 2*10. 5 KJ / m 3

[0117] The difference between Example 23 and Example 10 is that the ultrasonic treatment time point T is different; ultrasonic treatment is performed 1 hour after hydration.

[0118] Example 24

[0119] Add 0.65g of cyclodextrin to 520g of water and stir well. Place the mixture in a mixing pot, then add 1300g of cement and mix thoroughly with a mixer. After hydration at room temperature (25℃) for 2 hours, use an ultrasonic cell disruptor to perform immersion ultrasonic treatment on the cement slurry for 2 minutes, with a single-unit input energy of 2*10. 5 KJ / m 3

[0120] The difference between Example 24 and Example 10 is that the ultrasonic treatment time point T is different; ultrasonic treatment is performed 2 hours after hydration.

[0121] Comparative Example 1:

[0122] The difference between Comparative Example 1 and Example 1 is that no ultrasonic treatment was performed after hydration for 30 minutes.

[0123] Comparative Example 2:

[0124] The difference between Comparative Example 2 and Example 4 is that no ultrasonic treatment was performed after hydration for 30 minutes.

[0125] Comparative Example 3:

[0126] The difference between Comparative Example 3 and Example 7 is that no ultrasonic treatment was performed after hydration for 30 minutes.

[0127] Comparative Example 4:

[0128] The difference between Comparative Example 4 and Example 10 is that no ultrasonic treatment was performed after hydration for 30 minutes.

[0129] Test section

[0130] The relevant properties of the concrete slurries prepared in Examples 1-24 and Comparative Examples 1-4 were tested, and the specific test methods are as follows:

[0131] The determination of the compressive strength of cement paste shall be based on GB / T17671—1999 "Test Method for Strength of Cement Mortar (ISO Method)"

[0132] The setting time of cement paste shall be determined in accordance with GB / T1346-2011 "Standard Consistency, Setting Time and Soundness Test Methods for Cement".

[0133] The test results of the concrete slurry in Examples 1-4 and Comparative Examples 1-4 are shown in Table 1.

[0134] Table 1. Setting time and compressive strength of the examples and comparative examples.

[0135]

[0136]

[0137] The cement-admixture system was subjected to ultrasonic treatment, and the single-unit input energy was changed by varying the ultrasonic treatment time. As shown in Table 1, ultrasonic treatment can significantly shorten the initial and final setting times of cement paste, and can also promote the early compressive strength development of cement paste. However, the later compressive strength of cement paste did not change significantly.

[0138] Under the condition of constant unilateral energy input, both single and multiple ultrasonic treatments at different time points T can effectively shorten the initial and final setting times of cement paste. Furthermore, ultrasonic treatment improves the early strength of cement while showing no significant change in later strength. Table 1 data demonstrates that ultrasonic treatment can effectively reduce the inhibitory effects of polycarboxylate superplasticizers, polysulfonic acid superplasticizers, and cyclodextrin retarder on the cement hydration process, promote cement setting, and improve the early strength of cement paste, without significantly affecting later strength.

[0139] The hydration heat curves corresponding to Examples 1-12 and Comparative Examples 1-4 were tested using an isothermal calorimeter, as follows: Figure 1-4 As shown in the figure, after ultrasonic treatment with different single-unit input energies, the induction period of cement hydration was significantly shortened and the acceleration period was advanced in cement systems containing different admixtures. This indicates that ultrasonic treatment can effectively reduce the inhibitory effect of admixtures on cement hydration.

[0140] Ultrasonic treatment promotes cement hydration and accelerates cement setting. Furthermore, the promoting effect of ultrasonic treatment on cement hydration becomes more pronounced with increasing single-unit input energy, indicating that the promoting effect of ultrasonic treatment on cement hydration increases with increasing single-unit input energy.

[0141] pass Figure 5-6 and Figure 9-10 It can be seen that in cement systems with different admixtures, ultrasonic treatment at different hydration time points T can significantly reduce the inhibitory effect of admixtures on cement hydration, thereby promoting cement hydration; and it was found that the promoting effect of ultrasonic treatment on hydration is enhanced as the ultrasonic treatment time point T is advanced.

[0142] pass Figure 7-8 It can be seen that multiple ultrasonic treatments at different time points can significantly shorten the induction period of cement, and have a more obvious effect on promoting hydration than a single ultrasonic treatment.

[0143] This application describes ultrasonic vibration treatment of cement mortar / concrete mixtures. This treatment can reduce the inhibitory effect of admixtures on cement hydration, while the ultrasonic action can promote the early formation of CSH nanoparticles, thereby increasing the adsorption of admixtures by the nanoparticles. This reduces the content of residual admixtures in the liquid phase of the cement mortar / concrete mixture, promotes the setting and hardening of the cement mortar or concrete mixture, improves the early strength development of the cement mortar or concrete mixture, shortens the demolding time of precast concrete components, and saves energy. Furthermore, the physical treatment method provided in this application is simple to operate and has a wide range of applications.

[0144] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A physical treatment method for cement mortar / concrete mixtures, characterized in that, include: The cement mortar / concrete mixture is subjected to physical ultrasonic treatment. The vibration frequency of the ultrasound in the physical ultrasonic treatment step is 15KHz~50KHz, the vibration treatment duration is t, the time point of the ultrasound treatment is T, and the vibration duration t satisfies: 1min≤t≤15min. The cement mortar / concrete mixture contains admixtures used to prolong setting time. These admixtures include at least one of a water-reducing agent and a retarder. The water-reducing agent is added at a concentration of 0.05% to 3% of the cement mass; and / or the retarder is added at a concentration of 0.02% to 1% of the cement mass. The time point T for ultrasonic treatment includes the first moment T0 after the cement mortar / concrete is mixed and the second moment T0 after the cement mortar / concrete mixture is poured. n Between, the second time T n The third moment T when the pouring is completed m Between, the third time T m At the fourth moment T of the initial setting of the cement mortar / concrete mixture s Any combination of time points between; In the ultrasonic processing step, the ultrasonic vibration treatment uses multiple time points T for physical ultrasonic treatment, and the ultrasonic vibration frequency used at each time point T may be the same or different; when the ultrasonic vibration treatment uses multiple time points T for physical treatment in the physical ultrasonic processing step, T is selected from the intervals [T0+2min, T0+10min], [T0+30min, T0+1h], [T0+2h ... n ]、[T n +30min, T m ]、[T m +5min, T s Two or more of [-1h]; The unidirectional input energy in the physical ultrasonic treatment step is the ratio of the product of the ultrasonic vibration treatment power P and the ultrasonic vibration treatment time t to the volume V of the cement mortar / concrete mixture to be treated, and the unidirectional input energy satisfies: 5 × 10⁻⁶. 4 KJ / m 3 ≤P×t / V≤5×10 5 KJ / m 3 .

2. The physical processing method according to claim 1, characterized in that, In the physical ultrasonic treatment step, the ultrasonic treatment method includes one or more of the following: insertion ultrasonic treatment method, surface contact ultrasonic treatment method, and surface non-contact ultrasonic treatment method.

3. The physical processing method according to claim 1, characterized in that, The water-reducing agent includes at least one of polycarboxylate water-reducing agents, polysulfonic acid water-reducing agents, lignosulfonate water-reducing agents, and naphthalene-based water-reducing agents; and / or The retarder includes at least one of sugar retarder, hydroxycarboxylic acid and its salt retarder, and organic phosphoric acid and its salt retarder.

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