A high temperature resistant building intelligent aggregate and its preparation method and application

Abstract

The present invention discloses a high temperature resistant building intelligent aggregate and its preparation method and application. The intelligent aggregate includes cement-based cementitious material, radio frequency identification material, stress release material, magnetic absorber, water reducer, and water; wherein the stress release material is plant fiber or organic fiber that can be decomposed or melted at 150-300°C. The present invention adds stress release material to the intelligent aggregate, and the stress release material can decompose or melt at high temperature, so that holes and channels are left inside the aggregate, and the water vapor pressure generated inside the intelligent aggregate due to high temperature is released, so as to avoid cracking and failure caused by increased air pressure inside the intelligent aggregate, and ensure that the intelligent aggregate has a wide temperature application range, thereby meeting the application requirements of quality control, information management, product traceability, etc. of concrete products, prefabricated components, and cast-in-place structures in the temperature range from normal temperature to high temperature, and has broad application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of intelligent building materials, and in particular relates to a high-temperature resistant building intelligent aggregate and a preparation method and application thereof. Background Art

[0002] Due to the complexity of concrete in the production and preparation process, when concrete structures have engineering quality problems during service, the root cause of the engineering problems is usually difficult to trace. By using radio frequency tags to store concrete structure information and pre-burying radio frequency tags inside the concrete, and then reading radio frequency tag information through an external reader, the concrete structure can be effectively traced. However, radio frequency tags are generally encapsulated with organic materials, such as epoxy resin. These organic materials have poor compatibility with concrete, resulting in a significant reduction in the mechanical properties of concrete; and when radio frequency tags are pasted on the surface of concrete for use, the service life of radio frequency tags is also short due to the poor weather resistance of organic materials. On the other hand, in addition to serving at room temperature, concrete structures will also be subject to high temperatures. At this time, organic materials will oxidize and decompose at high temperatures, causing radio frequency tags to fail. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a high temperature resistant building intelligent aggregate and its preparation method and application. The intelligent aggregate provided by the present invention has little effect on the mechanical properties of concrete and has a wide temperature application range, meeting the application requirements of concrete products in environments ranging from room temperature to high temperature (400°C), and has broad application prospects.

[0004] To achieve the above object, the present invention is implemented through the following technical solutions:

[0005] A high temperature resistant building intelligent aggregate comprises a cement-based gelling material, a radio frequency identification material, a stress release material, a magnetic wave absorber, a water reducer and water; wherein the stress release material is a plant fiber or an organic fiber that can be decomposed or melted at 150-300°C.

[0006] Preferably, the plant fiber is one or more of sisal fiber, flax fiber, and bamboo fiber; the organic fiber is one or more of polyethylene fiber, polypropylene fiber, and polyvinyl alcohol fiber. The stress release material of the present invention can be decomposed or melted at a temperature of 150 to 300° C. The holes and channels left behind can release the water vapor pressure inside the smart aggregate, thereby preventing the smart aggregate from cracking.

[0007] Preferably, based on a single portion of radio frequency identification material, the weight ratios of cementitious material, stress release material, magnetic absorber, water reducer and water are: (12-68): (0.4-2.1): (1.6-6.3): (0.2-1.4): (3.6-27.5).

[0008] Preferably, the cement-based cementitious material is one or more of ordinary Portland cement, slag Portland cement, pozzolanic Portland cement, fly ash Portland cement, white cement, sulphoaluminate cement, magnesium phosphate cement, magnesium oxychloride cement, and magnesium oxysulfate cement.

[0009] Preferably, the radio frequency identification material includes a radio frequency chip and a radio frequency antenna connected to the radio frequency chip. The radio frequency chip used in the present invention has a unique identification number, which can be written with information to be stored or marked, and the radio frequency antenna can be detected by an external reader and writer, thereby transmitting the information stored in the radio frequency chip. The operating frequency of the external reader and writer includes a low frequency of 30 to 300 kHz, a high frequency of 3 to 30 MHz, and an ultra-high frequency of 433 to 950 MHz.

[0010] Preferably, the magnetic absorber includes one or more of ferrite powder, iron powder, iron alloy powder, aluminum borosilicate. The magnetic absorber can improve the anti-metal interference capability of the smart aggregate signal transmission, so that the external reader can obtain a higher signal strength.

[0011] Preferably, the water reducer is one or more of a polycarboxylic acid-based high-efficiency water reducer, an aliphatic high-efficiency water reducer, a naphthalene-based high-efficiency water reducer, and a lignin sulfonate water reducer.

[0012] The present invention also provides a method for preparing the above-mentioned high temperature resistant building intelligent aggregate, comprising the following steps:

[0013] uniformly mixing the water reducing agent and water to obtain a liquid mixture;

[0014] uniformly mixing the liquid mixture with the cement-based cementitious material, the stress release material and the magnetic wave absorbing agent to form a mixture;

[0015] The mixed material and the RFID material are filled into a mold, and the aggregate body is obtained after casting and molding;

[0016] The aggregate green body is cured to obtain high temperature resistant building intelligent aggregate.

[0017] Preferably, the aggregate green body is cured at room temperature for 28 days or at 90° C. in steam for 3 days.

[0018] The present invention also provides an application of the above-mentioned high-temperature resistant building intelligent aggregate in concrete products, prefabricated components or cast-in-place structures, ensuring that quality control, information management and product traceability can be performed even in a high-temperature environment.

[0019] The beneficial effects of the present invention are:

[0020] The present invention adds stress release material to the smart aggregate. The stress release material can decompose or melt at high temperature, leaving holes and channels inside the aggregate, releasing the water vapor pressure generated inside the smart aggregate due to high temperature, avoiding cracking and failure caused by increased air pressure inside the smart aggregate, and ensuring that the smart aggregate has a wider temperature application range, thereby meeting the application needs of quality control, information management, product traceability, etc. of concrete products, prefabricated components, and cast-in-place structures in the temperature range from normal temperature to high temperature (400°C), and has broad application prospects.

[0021] Compared with organic materials, the present invention uses a composite of cement-based gelling materials and stress-releasing materials as a packaging shell to prepare building smart aggregates, which have better mechanical strength and better compatibility with the main structure of concrete. Therefore, when the smart aggregates are pre-buried in concrete for use, the mechanical properties of the concrete are less reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings of the embodiment are briefly introduced below.

[0023] Figure 1 This is the internal SEM image of the smart aggregate prepared in Example 1 at room temperature;

[0024] Figure 2 This is the internal SEM image of the smart aggregate prepared in Example 1 after being subjected to a high temperature of 300°C. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The embodiment of the present invention provides a high temperature resistant building smart aggregate, comprising a cement-based cementitious material, a radio frequency identification material, a stress release material, a magnetic wave absorber, a water reducer, and water; wherein the stress release material is a plant fiber or an organic fiber that can be decomposed or melted at 150 to 300°C. The stress release material of the present invention can be decomposed or melted at a temperature of 150 to 300°C, leaving holes and channels inside the smart aggregate to release the water vapor pressure generated inside the smart aggregate, thereby preventing the smart aggregate from cracking.

[0027] In a preferred embodiment, the plant fiber can be one or more of sisal fiber, flax fiber, and bamboo fiber; the organic fiber can be one or more of polyethylene fiber, polypropylene fiber, and polyvinyl alcohol fiber. Based on a single portion of RFID material, the weight ratio of cement-based cementitious material, stress release material, magnetic absorber, water reducer, and water is: (12-68): (0.4-2.1): (1.6-6.3): (0.2-1.4): (3.6-27.5). For example, when using 1 portion of RFID material, the stress release material can be 0.4 portions of flax fiber, 0.8 portions of bamboo fiber, or 1.5 portions of polyethylene fiber, and 2.1 portions of polypropylene fiber.

[0028] In a preferred embodiment, the cement-based cementitious material is one or more of ordinary Portland cement, slag Portland cement, pozzolanic Portland cement, fly ash Portland cement, white cement, sulphoaluminate cement, magnesium phosphate cement, magnesium oxychloride cement, and magnesium oxysulfate cement. The radio frequency identification material includes a radio frequency chip and a radio frequency antenna connected to the radio frequency chip. The radio frequency chip used in the present invention has a unique identification number, which can be written with information to be stored or marked, and the radio frequency antenna can be detected by an external reader, thereby transmitting the information stored in the radio frequency chip. The operating frequency of the external reader includes a low frequency of 30 to 300kHz, a high frequency of 3 to 30MHz, and an ultra-high frequency of 433 to 950MHz. The magnetic absorber is one or more of ferrite powder, iron powder, ferroalloy powder, and aluminum borosilicate. The water reducer is one or more of a polycarboxylic acid-based high-efficiency water reducer, an aliphatic high-efficiency water reducer, a naphthalene-based high-efficiency water reducer, and a lignin sulfonate water reducer.

[0029] The present invention also provides a method for preparing the above-mentioned high temperature resistant building intelligent aggregate, comprising the following steps:

[0030] The water reducing agent and water are uniformly mixed to obtain a liquid mixture; the liquid mixture is uniformly mixed with a cement-based cementitious material, a stress release material and a magnetic absorber to form a mixture; the mixture and the radio frequency identification material are filled into a mold, and an aggregate body is obtained after casting; the aggregate body is cured at room temperature for 28 days or cured under 90°C steam for 3 days to obtain a high temperature resistant building intelligent aggregate.

[0031] The shape of the aggregate blank of the present invention is not limited, and can be a regular shape such as a cylinder, a square, a disc, etc., or an irregular shape, and it only needs to customize a mold of a corresponding shape.

[0032] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0033] Example 1

[0034] The cement-based cementitious material is P·Ⅰ42.5 ordinary Portland cement, the radio frequency identification material is made of Alien H3 radio frequency chip and aluminum etched radio frequency antenna encapsulated by FR4 glue, the stress release material is sisal fiber, the magnetic absorber is iron powder, and the water reducer is polycarboxylic acid-based high-efficiency water reducer.

[0035] In parts by weight, take 45 parts of ordinary Portland cement, 0.6 parts of sisal fiber, 4.2 parts of iron powder, 0.6 parts of polycarboxylic acid-based high-efficiency water reducer, and 10.5 parts of water. Mix the water reducer and water evenly to obtain a liquid mixture, mix the ordinary Portland cement, sisal fiber, iron powder and liquid mixture evenly to form a mixture for standby use; fill the mixture into a 15mm×15mm×15mm cubic mold, and place 1 part of radio frequency identification material in the center of the mold, and prepare the aggregate blank by casting; place the aggregate blank in a 90℃ steam curing box for 3 days to finally obtain a high temperature resistant intelligent aggregate.

[0036] Example 2

[0037] The only difference from Example 1 is that the stress release material is 1.2 parts of sisal fiber, and the rest is the same as Example 1.

[0038] Example 3

[0039] The only difference from Example 1 is that the stress release material is 1.8 parts of sisal fiber, and the rest is the same as Example 1.

[0040] Comparative Example 1

[0041] Fill epoxy resin into a 15mm×15mm×15mm cubic mold, and place the same radio frequency identification material as in Example 1 at the center of the mold. Prepare an aggregate blank by casting, and place the aggregate blank in a 50°C oven for curing. When the epoxy resin is completely cured, an epoxy resin smart aggregate is obtained.

[0042] Comparative Example 2

[0043] The only difference from Example 1 is that no stress release material sisal fiber is added to the mixture for preparing the smart aggregate, and the rest is the same as Example 1.

[0044] Performance Test:

[0045] (1) Take 3 pieces of smart aggregate prepared in each embodiment and comparative example, test their compressive strength, and calculate the average compressive strength. 3 pieces of smart aggregate prepared in each embodiment and comparative example were embedded in the center of C60 concrete test block, the size of the concrete test block was 100mm×100mm×100mm, and placed in a standard curing box for 28 days. Test the compressive strength of the concrete test block containing smart aggregate, and calculate its average compressive strength, which is recorded in Table 1. The compressive strength was tested in accordance with the national standard "GB / T 50081-2002 Standard for Test Methods of Mechanical Properties of Ordinary Concrete".

[0046] Table 1 Mechanical properties test results of smart aggregates prepared in the examples and comparative examples

[0047]

[0048] As can be seen from Table 1, the smart aggregate prepared by the present invention has higher compressive strength than the comparative example. Compared with the comparative example 1, the smart aggregates of Examples 1 to 3 not only have higher compressive strength, but also when the smart aggregates are pre-buried in concrete, the compressive strength of the concrete is reduced less, indicating that the smart aggregate prepared by the present invention has better compatibility with concrete and has less effect on the mechanical properties of concrete.

[0049] Compared with Comparative Example 2, Example 1 adds stress release materials to improve the mechanical strength of the smart aggregate, while also improving the strength of concrete pre-embedded with the smart aggregate, and has less impact on the mechanical properties of the concrete.

[0050] It can be seen from the compressive strength of Examples 1 to 3 that the compressive strength of the smart aggregate and concrete increases with the increase in the amount of stress release material added, indicating that the stress release material can improve the compatibility of the aggregate and concrete while increasing the compressive strength of the smart aggregate.

[0051] (2) The smart aggregate prepared in each embodiment and comparative example was placed in a high temperature furnace for high temperature treatment. The temperature was increased at 10°C / min to 200°C, 300°C, and 400°C, respectively, and maintained for 1 hour. The temperature was naturally cooled to room temperature, and the morphology of the smart aggregate was observed. The results are shown in Table 2. The smart aggregate prepared in Example 1 was scanned by SEM at room temperature and 300°C. The results are shown in Table 2. Figures 1-2 shown.

[0052] Table 2 Test results of high temperature resistance of smart aggregates prepared in various embodiments and comparative examples

[0053]

[0054] As can be seen from Table 2, the smart aggregate prepared by the present invention has good high temperature resistance. Compared with Comparative Example 1, the smart aggregate prepared by the present invention in Examples 1 to 3 still does not show any cracking damage after being subjected to a high temperature of 400°C, while the aggregate prepared using epoxy resin softens and decomposes after 200°C. Compared with Comparative Example 2, the smart aggregate added with stress release material in Example 1 still does not show any cracking damage after being subjected to a high temperature of 400°C, while the aggregate without stress release material shows cracking damage after being subjected to 300°C, indicating that adding stress release material can improve the high temperature resistance of the smart aggregate.

[0055] Figure 1 and Figure 2 The SEM images of the smart aggregate prepared in Example 1 at room temperature and after being heated to 300°C are shown. It can be seen that the sisal fiber added in the present invention, as a stress release material, will decompose and melt when the temperature reaches 300°C, and the holes and channels left behind can release the water vapor pressure inside the smart aggregate, thereby effectively preventing the smart aggregate from cracking in a high temperature environment.

[0056] In summary, the present invention utilizes cement-based cementitious materials, stress release materials, and radio frequency identification materials to prepare building intelligent aggregates, and at the same time gives them high strength, high temperature resistance, and information identification characteristics, thereby meeting the application requirements of quality control, information management, product traceability, etc. for concrete products, prefabricated components, and cast-in-place structures in the temperature range from room temperature to high temperature (400°C), and has broad application prospects.

[0057] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For matters that are not described in detail in some embodiments, reference may be made to the description in other embodiments.

[0058] The above-mentioned embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A high temperature resistant building intelligent aggregate, characterized in that: It includes cement-based cementitious material, radio frequency identification material, stress release material, magnetic wave absorber, water reducer and water; wherein the stress release material is sisal fiber; based on a single radio frequency identification material, the weight ratio of the cement-based cementitious material, stress release material, magnetic wave absorber, water reducer and water is: (12-68): (0.4-2.1): (1.6-6.3): (0.2-1.4): (3.6-27.5).

2. The high temperature resistant building intelligent aggregate according to claim 1, characterized in that: The cement-based cementitious material is one or more of ordinary Portland cement, slag Portland cement, pozzolanic Portland cement, fly ash Portland cement, white cement, sulphoaluminate cement, magnesium phosphate cement, magnesium oxychloride cement and magnesium oxysulfate cement.

3. The high temperature resistant building intelligent aggregate according to claim 1, characterized in that: The radio frequency identification material includes a radio frequency chip and a radio frequency antenna connected to the radio frequency chip.

4. The high temperature resistant building intelligent aggregate according to claim 1, characterized in that: The magnetic wave absorbing agent includes one or more of ferrite powder, iron powder, iron alloy powder, and aluminum borosilicate.

5. The high temperature resistant building intelligent aggregate according to claim 1, characterized in that: The water reducer is one or more of a polycarboxylic acid-based high-efficiency water reducer, an aliphatic high-efficiency water reducer, a naphthalene-based high-efficiency water reducer, and a lignin sulfonate water reducer.

6. The method for preparing high temperature resistant building intelligent aggregate according to any one of claims 1 to 5, characterized in that: The following steps are involved: uniformly mixing the water reducing agent and water to obtain a liquid mixture; The liquid mixture is uniformly mixed with a cement-based gelling material, a stress release material and a magnetic wave absorbing agent to form a mixture; Filling the mixture and the radio frequency identification material into a mold, and casting and molding to obtain an aggregate blank; The aggregate blank is cured to obtain the high temperature resistant building intelligent aggregate.

7. The method for preparing a high temperature resistant building intelligent aggregate according to claim 6, characterized in that: The aggregate green body is cured under the following conditions: curing at room temperature for 28 days or curing under 90° C. steam for 3 days.

8. Use of the high temperature resistant building intelligent aggregate according to any one of claims 1 to 5 in concrete products, prefabricated components or cast-in-place structures.

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