Cement-based material carbonization curing system and method capable of monitoring heat release in real time

Abstract

The invention discloses a cement-based material carbonization curing system capable of monitoring heat release in real time. The cement-based material carbonization curing system comprises a carbonization reaction assembly, a thermopile, a cement-based test piece, a reference sample, a COgas cylinder, a signal acquisition and analysis system and a computer, the carbonization reaction assembly comprises a carbonization reaction shell; the COgas cylinder is communicated with the inner top of the carbonization reaction cavity through a communicating pipeline; the cement-based test piece and the reference sample are respectively arranged on the two thermopiles; the thermopile is provided with a shielding double-wire, the other end of the shielding double-wire is connected with a signal acquisition and analysis system, and the signal acquisition and analysis system is connected with a computer. The invention further discloses a cement-based material carbonization curing method. The device and the method have the beneficial effects that the heat release in the carbonization reaction process of the cement-based material can be monitored in real time, and a foundation is laid for researching the carbonization maintenance reaction mechanism of the cement-based material; a reference sample is designed, environmental interference is stripped, and the real heat release amount of the carbonization reaction can be accurately obtained.

Description

Technical Field

[0001] The present invention relates to a detection technology for the carbonation reaction mechanism of low-carbon cement-based materials, and particularly to a carbonation curing system and method for cement-based materials capable of real-time monitoring of heat release. Background Art

[0002] As an advanced technology that can improve the comprehensive performance of cement-based materials and achieve CO2 sequestration, the carbonation curing technology has received increasing attention in recent years. Cement-based materials are widely used in construction projects, and their structure and durability are directly related to the project quality. Carbonation curing utilizes the reaction of CO2 with active components in the material (such as calcium hydroxide and some hydration products) to form calcium carbonate and other carbonates. In this process, since the carbonation reaction itself is an exothermic reaction, the change in the heat release can truly reflect the reaction rate and activity, and also provides key data support for in-depth understanding of the reaction mechanism. In addition, the measurement results of the heat release can also establish a certain correlation with the final properties of the material (such as compressive strength, impermeability performance, etc.), which provides an effective means for real-time monitoring and early warning of project quality. Generally speaking, measuring the heat release of cement-based materials during carbonation curing not only helps to reveal the basic laws and internal mechanisms of the reaction, but also provides strong data support for optimizing curing conditions, improving project quality, and achieving the goals of low-carbon environmental protection. Therefore, there is an urgent need to develop a simple and convenient carbonation reaction heat release measurement device, so as to provide more scientific and reliable technical guidance for the application of carbonation-cured cement-based materials in practical projects, and promote the development of the building materials field towards the direction of energy conservation, environmental protection, and intelligent development.

[0003] Currently, there are also some technologies in the prior art for measuring the degree of carbonation reaction of cement-based materials. For example, a cement-based material carbonation test device and test method disclosed in Chinese Patent No. 201910497411.9 include a carbonation chamber and a CO2 generating device connected to the carbonation chamber. The CO2 generating device generates CO2 gas and introduces it into the carbonation chamber. The carbonation chamber is a sealable chamber structure that can be opened, with a baffle in the middle for placing cement-based material specimens. There is liquid at the bottom of the carbonation chamber, and an air inlet and an air outlet are provided at the top of the carbonation chamber. A CO2 concentration detector and a hygrometer are also provided inside the carbonation chamber.

[0004] Patent CN103713023A discloses a method for testing the carbonation depth of cement-based materials. Impedance spectroscopy tests are performed on hardened cement material specimens after pre-carbonation to obtain impedance spectrograms. The impedance spectrograms are fitted using the electrochemical circuit model of the cement material to obtain electrochemical parameters. Then, the actual carbonation depth of the cement material is measured, and a functional relationship is established between the electrochemical parameters and the actual carbonation depth. Finally, the carbonation depth of the later stage of the cement is calculated by calculating the electrochemical parameters. However, in this method, traditional carbonation test chambers are used for carbonation, and there are still problems such as low resource utilization rate and high economic cost.

[0005] Chinese Patent 200910191152.3 discloses a test device and method for the carbonation resistance performance of cement-based materials. The device of this invention mainly includes a separating funnel, a reaction flask, a magnetic stirrer, etc. in the reaction part, a buffer flask, a thermometer, a glass three-way joint, etc. in the buffer part, and a gas measuring tube composed of a measuring tube, a balance tube, and a drain pipe in the gas collection and measurement part, which are connected by rubber tubes. The method of this invention is to use the device of this invention to complete the test of the carbonation resistance performance of cement-based materials through the preparation of neat paste specimens, accelerated carbonation and slicing treatment, determination of carbonate content, data processing, and result analysis.

[0006] However, the above-mentioned existing technologies mostly focus on the later evaluation of carbonation depth, chemical composition (such as the content of Ca(OH)2), or carbonation resistance performance. Although these detection methods can indirectly reflect the carbonation process, none of them can measure the heat released during the carbonation reaction in real time and continuously. Therefore, it is very necessary to carry out the research and development of the real-time measurement technology for the heat release of cement-based materials during the carbonation curing process. Summary of the Invention

[0007] The purpose of the present invention is to provide a carbonation curing system and method for cement-based materials that can monitor the heat release in real time, aiming at solving the problem that it is difficult to measure the heat release of cement-based materials during the carbonation reaction process in the existing technology.

[0008] The technical solution adopted by the present invention is as follows: A cement-based material carbonization curing system capable of real-time monitoring of heat release includes a carbonization reaction assembly, a thermopile, a cement-based specimen, a reference sample, a CO2 gas cylinder, a signal acquisition and analysis system, and a computer; the carbonization reaction assembly includes a carbonization reaction housing, the top of the carbonization reaction housing is provided with an upper cover plate, the bottom is provided with a lower cover plate, and the upper cover plate, the carbonization reaction housing and the lower cover plate enclose a carbonization reaction cavity; the CO2 gas cylinder is communicated with the inner top of the carbonization reaction cavity through a connecting pipeline, and a gas pressure reducing valve is configured on the connecting pipeline; there are two groups of thermopiles, and the two are respectively fixed inside the carbonization reaction cavity; the cement-based specimen and the reference sample are respectively installed on the two thermopiles; the thermopile is configured with shielded twin wires, one end of the shielded twin wires is connected to the thermopile, and the other end of the shielded twin wires passes through the lower cover plate at the bottom of the carbonization reaction cavity and is connected to the signal acquisition and analysis system, and the signal acquisition and analysis system is connected to the computer.

[0009] According to the above solution, a workbench is provided inside the carbonization reaction cavity, and the workbench is supported by a bracket at the bottom; the thermopile is placed on the workbench; and a partition is used to separate the reference sample and the cement-based specimen.

[0010] According to the above solution, it includes a plurality of carbonization reaction assemblies, the carbonization reaction cavities of each carbonization reaction assembly are respectively communicated with the CO2 gas cylinder, and the thermopiles of each carbonization reaction assembly are respectively configured with shielded twin wires connected to the signal acquisition and analysis system.

[0011] According to the above solution, the cement-based material carbonization curing system includes a multi-pipeline gas exhaust diverter, the inlet of the multi-pipeline gas exhaust diverter is communicated with the outlet end of the gas pressure reducing valve through a first pipeline; the multi-pipeline gas exhaust diverter is provided with a plurality of air outlets, and the air outlets are communicated with the inner top of the carbonization reaction cavity through a second pipeline.

[0012] According to the above solution, the first pipeline and the second pipeline are both pneumatic hoses; both ends of the first pipeline are respectively connected to the outlet of the gas pressure reducing valve and the inlet of the multi-pipeline gas exhaust diverter through quick connectors; both ends of the second pipeline are respectively connected to the air outlet of the multi-pipeline gas exhaust diverter and the inner top of the carbonization reaction cavity through quick connectors.

[0013] According to the above solution, the carbonization reaction housing is a double-layer structure, including an inner cylinder and an outer cylinder, and a phase change material is filled between the inner cylinder and the outer cylinder.

[0014] According to the above solution, the phase change temperature of the phase change material is 20°C to 30°C.

[0015] According to the above solution, the reference sample is an inert mineral that does not react with CO2.

[0016] According to the above solution, the thermopile is composed of a plurality of thermocouples connected in series or parallel, and each pair of thermocouples is made of two different thermoelectric materials.

[0017] The present invention also adopts a carbonation curing method for a cement-based material carbonation curing system capable of real-time monitoring of heat release as described above, including the following steps: Step 1: Obtain a cement-based specimen and a reference sample; Step 2: Place the cement-based specimen and the reference sample on the thermopile inside the carbonation reaction housing, and connect the thermopile, shielded twin wires, signal acquisition and analysis system, and computer; Step 3: Connect the CO2 gas cylinder and the carbonation reaction housing; Step 4: Place the system in an environment of 25°C, turn on the signal acquisition and analysis system and the computer, turn on the CO2 gas cylinder, adjust the gas pressure to the target pressure, record the change law of the temperature of the cement-based specimen with time through the computer, and the computer processes the change law of the temperature with time to draw the temperature change curve and cumulative heat release of the cement-based material during the carbonation curing process in real time.

[0018] The beneficial effects of the present invention are as follows: 1. The cement-based material carbonation curing system and method provided by the present invention can real-time monitor the heat release during the carbonation reaction of the cement-based material, laying a foundation for studying the carbonation curing reaction mechanism of the cement-based material.

[0019] 2. The present invention designs a reference sample, and the reference sample and the cement-based specimen are placed on both sides of the thermopile synchronously. When CO2 is pumped in, the reference sample can real-time monitor the temperature change caused by non-reaction factors such as gas pressurization work and environmental heat exchange. By data processing to peel off environmental interference, the true heat release of the carbonation reaction can be accurately obtained, improving the accuracy of the test results.

[0020] 3. The present invention uses a thermopile to measure the reaction temperature to achieve accurate measurement of the heat release of the cement-based material during the carbonation curing process, and can solve the problem that it is difficult to accurately monitor the heat release during the carbonation reaction of the cement-based material; due to the connection of the signal acquisition and analysis system and the computer, the change law of the specimen temperature and time can be transmitted to the computer in real time and the temperature change curve can be drawn in real time, reducing the error caused by manual reading, and greatly improving the accuracy of the test results.

[0021] 4. By adjusting the low-pressure gauge on the gas pressure reducing valve, the present invention can achieve real-time measurement of the heat release of carbonated cured cement-based materials under different CO2 gas pressures. At the same time, all connections of this system are in the form of threads and quick connectors, featuring simple operation and reusability; the carbonation reaction cavity and the cover plate are connected by threads and silicone rubber seals, and the shielded double wires are locked through the silicone rubber seals in the gland head to achieve a sealed environment during the carbonation reaction process. This device has a simple structure, convenient operation, and is environmentally friendly.

[0022] 5. Through the double-thread and quick-insert sealing structure of the CO2 gas cylinder and the carbonation reaction cavity, as well as the electrical and airtight coupling of the shielded double wires with the signal acquisition module and the reaction cavity, the present invention constructs a stable high-pressure CO2 reaction environment; the precise contact connection between the thermopile and the cement-based specimen, supplemented by the seamless docking of the signal acquisition module and the efficient software interface of the computer, realizes the real-time and accurate monitoring of the heat release characteristics during the entire process of carbonation curing under high-pressure CO2 conditions, and has the excellent performance of modular rapid disassembly and recycling. Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of Embodiment 1.

[0024] Figure 2 It is a schematic structural diagram of the gland head in Embodiment 1.

[0025] Figure 3 It is a graph showing the relationship between the test temperatures of the cement-based specimen and the reference sample over time in Embodiment 2.

[0026] Figure 4 It is a graph showing the relationship between the actual temperature caused by the heat release of the carbonation reaction over time in Embodiment 2.

[0027] Wherein: 1 - CO2 gas cylinder, 2 - nut, 3 - high-pressure gauge, 4 - low-pressure gauge, 5 - gas pressure reducing valve, 6 - flow adjustment knob, 7 - safety valve, 8 - quick connector, 9 - pneumatic hose, 10 - multi-pipeline gas exhaust diverter, 11 - silicone rubber seal A, 12 - upper cover plate, 13 - silicone rubber seal B, 15 - carbonation reaction shell, 16 - phase change material, 17 - cement-based specimen, 18 - reference sample, 19 - thermopile, 20 - bracket, 21 - shielded double wire, 22 - lower cover plate, 23 - gland head, 24 - signal acquisition and analysis system, 25 - computer, 26 - metal nut, 27 - silicone rubber seal, 28 - metal nut, 29 - hollow metal joint body. Detailed Embodiments

[0028] To better understand the present invention, the present invention will be further described below in conjunction with the drawings and specific embodiments.

[0029] Such as Figure 1A cement-based material carbonation curing system capable of real-time monitoring of heat release, comprising a carbonation reaction assembly, a thermopile 19, a cement-based specimen 17, a reference sample 18, a CO2 gas cylinder 1, a signal acquisition and analysis system 24, and a computer 25; The carbonation reaction assembly includes a carbonation reaction housing 15; The top of the carbonation reaction housing 15 is provided with an upper cover plate 12, and the bottom is provided with a lower cover plate 22. The upper cover plate 12, the carbonation reaction housing 15, and the lower cover plate 22 enclose a carbonation reaction cavity; The CO2 gas cylinder 1 is connected to the inner top of the carbonation reaction cavity through a connecting pipeline, and a gas pressure reducing valve 5 is configured on the connecting pipeline; There are two groups of the thermopiles 19, and the two are respectively fixed inside the carbonation reaction cavity; The cement-based specimen 17 and the reference sample 18 are respectively installed on two thermopiles 19; The thermopile 19 is configured with a shielded twin wire 21. One end of the shielded twin wire 21 is connected to the thermopile 19, and the other end of the shielded twin wire 21 passes out from the lower cover plate 22 at the bottom of the carbonation reaction cavity and is connected to the signal acquisition and analysis system 24, and the signal acquisition and analysis system 24 is connected to the computer 25.

[0030] In the present invention, the reference sample 18 is an inert mineral that does not react with CO2. Specifically, the reference sample 18 can be a quartz block.

[0031] In the present invention, the thermopile 19 is composed of a plurality of thermocouples connected in series or in parallel. Each pair of thermocouples is made of two different thermoelectric materials, and the thermoelectric materials can be Bi-Sb, Bi-Te, or Cu-Constantan.

[0032] In the present invention, a workbench is provided inside the carbonation reaction cavity, and the workbench is supported by a bracket 20 at the bottom; the thermopile 19 is placed on the workbench; and a partition is used to separate the reference sample 18 and the cement-based specimen 17.

[0033] Preferably, the cement-based material carbonation curing system includes a plurality of carbonation reaction assemblies. The carbonation reaction cavities of each carbonation reaction assembly are respectively connected to the CO2 gas cylinder 1, and each thermopile 19 of each carbonation reaction assembly is respectively configured with a shielded twin wire 21 connected to the signal acquisition and analysis system 24.

[0034] In the present invention, by providing a plurality of carbonation reaction assemblies, the heat release during the carbonation process of a plurality of cement-based specimens 17 can be measured in real time using this system respectively.

[0035] Preferably, the carbonation curing system for the cement-based material includes a multi-pipeline gas discharge diverter 10. The inlet of the multi-pipeline gas discharge diverter 10 is connected to the outlet end of the gas pressure reducer 5 through a first pipeline; the multi-pipeline gas discharge diverter 10 is provided with a plurality of air outlets, and the air outlets are connected to the inner top of the carbonation reaction cavity through a second pipeline (specifically connected to the upper cover plate 12).

[0036] In the present invention, the multi-pipeline gas discharge diverter 10 evenly disperses the CO2 gas flowing out of the CO2 gas cylinder 1 into each carbonation reaction cavity.

[0037] In the present invention, both the first pipeline and the second pipeline are pneumatic hoses 9; both ends of the first pipeline are respectively connected to the outlet of the gas pressure reducer 5 and the inlet of the multi-pipeline gas discharge diverter 10 through quick connectors 8; both ends of the second pipeline are respectively connected to the air outlet of the multi-pipeline gas discharge diverter 10 and the inner top of the carbonation reaction cavity through quick connectors 8.

[0038] In the present invention, the gas pressure reducer 5 includes a high-pressure gauge 3, a low-pressure gauge 4, a safety valve 7 and a flow rate adjustment knob 6. The range of the low-pressure gauge 4 is 0-1 MPa, and the accuracy is 0.01 MPa to ensure precise control of the CO2 pressure; the gas pressure reducer 5 is a mature existing device and will not be elaborated here.

[0039] In the present invention, the CO2 gas cylinder 11 is connected to the gas pressure reducer 5 through a nut 2.

[0040] Preferably, the carbonation reaction housing 15 is a double-layer structure, including an inner cylinder and an outer cylinder, and a phase change material 16 is filled between the inner cylinder and the outer cylinder.

[0041] In the present invention, the phase change temperature of the phase change material 16 is 20°C to 30°C, preferably 25°C; the phase change material 16 can be n-hexadecane / n-octadecane eutectic paraffin, or CaCl2·6H2O / Na2SO4·10H2O composite salts, capric acid / lauric acid eutectic. By filling the phase change material 16 between the inner and outer cylinders, the characteristics that the phase change material 16 can absorb the heat released by the cement-based specimen 17 during the curing process and release the latent heat of the phase change material itself when the external environmental temperature fluctuates are utilized to ensure the stable temperature inside the reaction cavity.

[0042] A carbonation curing method for a carbonation curing system of a cement-based material capable of real-time monitoring of the heat release amount as described above, the method is as follows: Step 1: Obtain a cement-based specimen 17 and a reference sample 18.

[0043] Step 2: Place the cement-based specimen 17 and the reference sample 18 on the thermopile 19 inside the carbonation reaction housing 15, and connect the thermopile 19, the shielded twin wire 21, the signal acquisition and analysis system 24 and the computer 25.

[0044] Step 3: Connect the CO2 gas cylinder 1 and the carbonation reaction housing 15.

[0045] Step 4: Place the system in an environment at 25°C. Turn on the signal acquisition and analysis system 24 and the computer 25, start the data acquisition and analysis program, open the CO2 gas cylinder 1, and adjust the gas pressure to the target pressure (the adjustment range is 0.01 Mpa - 1 Mpa, the adjustment accuracy is 0.01 Mpa, and the preferred pressure is 0.2 Mpa) through the flow adjustment knob 6 on the gas pressure reducing valve 5. Record the change law of the temperature of the cement-based specimen 17 over time through the computer 25, and the computer 25 processes the change law of the temperature over time to real-time plot the temperature change curve and the cumulative heat release of the cement-based material during the carbonation curing process.

[0046] In the present invention, the specific method of Step 1 is as follows: Mix the cement paste according to a specific water-cement ratio (the range of the water-cement ratio is: 0.2 - 0.6, and the preferred water-cement ratio is 0.3), and pour it into a cement mold (the side length of the specimen should not exceed 40 mm, and the preferred size is 20 mm × 20 mm × 20 mm). After standard curing the cement paste for 24 h, remove the cement mold, and dry the hardened cement paste in a dry environment (preferably a vacuum drying oven at a temperature of 40°C) until the remaining water-cement ratio (the preferred remaining water-cement ratio is 0.2) to obtain the cement-based specimen 17; weigh a quartz sample with the same mass as the cement-based specimen 17 as the reference sample 18.

[0047] In the present invention, the specific method of Step 2 is as follows: Install the thermopile 19 with the shielded twin wire 21 on the bracket 20 of the carbonation reaction housing 15. The shielded twin wire 21 sequentially passes through the reserved hole on the lower cover plate 22 and the gland 23 and is connected to the signal acquisition and analysis system 24. The signal acquisition and analysis system 24 is connected to the computer 25 through USB. Tighten the lower cover plate 22 and the gland 23 to realize the sealed connection of the thermopile 19 to the inside of the carbonation reaction housing 15.

[0048] In the present invention, the specific method of Step 3 is as follows: Ensure that the flow adjustment knob 6 of the CO2 gas cylinder 1 and the gas pressure reducing valve 5 is in the closed state, and tighten the nut 2 to ensure the sealed connection between the CO2 gas cylinder 1 and the gas pressure reducing valve 5; install the quick connectors 8 on the gas pressure reducing valve 5, the multi-pipeline gas exhaust diverter 10, and the upper cover plate 12 respectively. Insert both ends of the pneumatic hose 9 as the first pipeline into the quick connectors 8 of the gas pressure reducing valve 5 and the multi-pipeline gas exhaust diverter 10 respectively, insert both ends of the pneumatic hose 9 as the second pipeline into the quick connectors 8 of the multi-pipeline gas exhaust diverter 10 and the upper cover plate 12 respectively, and tighten the thread between the upper cover plate 12 and the carbonation reaction housing 15 to realize their connection.

[0049] Example 1 As Figure 1A cement-based material carbonization curing system capable of real-time monitoring of heat release is shown, which includes a CO2 gas cylinder 1, a gas pressure reducing valve 5, a quick connector 8, pneumatic hoses 9 serving as the first pipeline and the second pipeline, a multi-pipeline gas exhaust shunt 10, an upper cover plate 12, a silica gel seal ring B13, a carbonization reaction housing 15, a phase change material 16, a cement-based specimen 17, a reference sample 18, a thermopile 19, a bracket 20, a shielded twin wire 21, a lower cover plate 22, a gland 23, a signal acquisition and analysis system 24, and a computer 25. Among them, the CO2 gas cylinder 1 is connected to the inlet of the gas pressure reducing valve 5 through a nut 2. The outlet of the gas pressure reducing valve 5 is hermetically connected to the multi-pipeline gas exhaust shunt 10 through the quick connector 8 and the pneumatic hose 9 serving as the first pipeline. The multi-pipeline gas exhaust shunt 10 is connected to the upper cover plate 12 through the quick connector 8 and the pneumatic hose 9 serving as the second pipeline and is sealed with a silica gel seal ring A11. The upper cover plate 12 is threadedly connected to the carbonization reaction housing 15 and is hermetically connected by the silica gel seal ring B13 on the upper part. The carbonization reaction housing 15 is threadedly connected to the lower cover plate 22 and is hermetically connected by the silica gel seal ring B13 on the lower part. One end of the shielded twin wire 21 is connected to the thermopile 19, and the other end passes through the lower cover plate 22 and is connected to the signal acquisition and analysis system 24 through a cold press terminal. The signal acquisition and analysis system 24 is connected to the computer 25 through a USB (Universal Serial Bus) data cable. The position where the shielded twin wire 21 passes through the lower cover plate 22 is sealed by the gland 23 and the silica gel seal C27.

[0050] The gas pressure reducing valve 5 in this embodiment is an existing structure, which consists of a high-pressure gauge 3, a low-pressure gauge 4, a safety valve 7, and a flow regulating knob 6. The range of the low-pressure gauge 4 is 0-1 MPa, and the accuracy is 0.01 MPa to ensure precise control of the CO2 pressure. CO2 enters the cement-based specimen 17 from five surfaces of the cement-based specimen 17 to undergo a carbonization reaction. The upper cover plate 12 and the lower cover plate 22 have the same thickness, which is 20-50 mm. Threads are provided on the inner circles of the two cover plates, and the thread length is 10-30 mm to ensure a sealed connection with the carbonization reaction housing 15. A through hole 14 is provided in the middle of the upper cover plate 12 and the lower cover plate 22, and the hole length is 5-10 mm to ensure that the gas and the shielded twin wire 21 pass through respectively. A threaded hole is provided above the through hole 14, and the hole length is 5-20 mm to ensure the connection of the quick connector 8 and the gland 23 respectively. The carbonization reaction housing 15 is a double-layer structure, including an inner cylinder and an outer cylinder. The phase change material 16 is arranged between the inner cylinder and the outer cylinder to achieve the effect of keeping the temperature inside the carbonization reaction cavity constant. The wall thickness of the inner cylinder and the outer cylinder is 10-20 mm, and the carbonization reaction housing 15 can withstand a pressure of 0-2 MPa. Threads matching the upper cover plate 12 and the lower cover plate 22 are provided on the upper and lower parts of the carbonization reaction housing 15 respectively to ensure a detachable connection with the upper and lower cover plates 22. The upper cover plate 12, the lower cover plate 22, and the carbonization reaction housing 15 are all made of organic glass materials. AsFigure 2 As shown, the gland 23 is of an existing structure, which is composed of a metal nut 26, a silica gel seal 27, a metal screw 28, and a hollow metal joint body 29. There is a 1.5 - 3 mm hole in the middle of the silica gel seal 27 to ensure the smooth passage and sealing of the shielded twin - wire 21; the thermopile 19 is an array formed by connecting multiple thermocouple units in series or parallel, responsible for converting the temperature difference or heat flow between the sample and the reference into a voltage signal. The resolution of the heat power is 10 -7 W, and the resolution of the temperature difference is 10 -5 K; the shielded twin - wire 21 is composed of a conductor material, an insulating layer material, a shielding material, and a sheath material, with a line width of 2 mm; the signal acquisition and analysis system 24 is a USB - interface data acquisition product, which can be connected to various desktop computers 25, laptop computers, and industrial control computers with USB interfaces to form a high - performance data acquisition and measurement system; the computer 25 internally stores a program capable of writing and recording the relationship between the heat release of the test piece and time; the outer diameter and inner diameter of the pneumatic hose 9 (i.e., the first pipeline) connecting the gas pressure reducing valve 5 and the multi - pipeline gas discharge splitter 10 are 10 - 16 mm and 6.5 - 12 mm respectively, with a pressure resistance of 1.2 MPa. The outer diameter and inner diameter of the pneumatic hose 9 (i.e., the second pipeline) connecting the multi - pipeline gas discharge splitter 10 and the upper cover plate 12 are 4 - 8 mm and 2.5 - 5 mm respectively, with a pressure resistance of 1.2 MPa.

[0051] Example 2 In this example, the device described in Example 1 is used to measure the heat release during the carbonation curing process of a specific cement - based test piece 17 in real - time. The method for obtaining the cement - based test piece 17 is as follows: Mix the cement paste (a sulfoaluminate cement composed of wollastonite and tetracalcium sulfoaluminate) according to a water - cement ratio of 0.3 (the ratio of water to cement during the mixing of the test piece, 10 g of cement and 3 g of water), pour it into a cement mold with dimensions of 20 mm × 20 mm × 20 mm, cure for 24 h, then remove the cement mold, and dry the hardened cement paste in a vacuum drying oven at 40°C until the remaining water - cement ratio (the ratio of the actual water inside the cement - based test piece 17 to the mass of the cement, preferably the remaining water - cement ratio is 0.2), thus obtaining the cement - based test piece 17. Weigh a quartz sample with the same mass (12 g, calculated according to the water and cement masses in the remaining water - cement ratio) as the cement - based test piece 17 as the reference sample 18.

[0052] The technological process during the use of a carbonation curing system for cement - based materials during carbonation curing is as follows: Step 1: Obtain the cement - based test piece 17 and the reference sample 18; Step 2: Place the cement - based test piece 17 and the reference sample 18 on the thermopile 19 inside the carbonation reaction housing 15, and connect the thermopile 19, the shielded twin - wire 21, the signal acquisition and analysis system 24, and the computer 25.

[0053] Step 3: Connect the CO2 gas cylinder 1 to the carbonation reaction housing 15.

[0054] Step 4: Ensure that the test device is in an environment of 25°C. Turn on the signal acquisition and analysis system 24 and the computer 25, start the data acquisition and analysis program, open the CO2 gas cylinder 1, adjust the gas pressure to the target pressure of 0.2 Mpa through the flow adjustment knob 6 on the gas pressure reducing valve 5, record the change law of the temperature of the cement-based specimen 17 over time through the computer 25, and the computer 25 processes the change law of the temperature over time, and real-time plots the temperature change curve and the cumulative heat release of the cement-based material during the carbonation curing process.

[0055] As Figure 3 shown in the test results after 6 hours of carbonation curing. It can be seen from the figure that when CO2 is input into the carbonation reaction cavity, the initial temperature of the cement-based specimen 17 will rise briefly. On the one hand, this is due to the work done by pumping CO2, which is also illustrated by the temperature rise of the reference sample 18. On the other hand, it is the reaction heat generated by the violent reaction of the hydration products with CO2. When the CO2 pressure reaches and is maintained at 0.2 MPa, both the cement-based specimen 17 and the reference sample 18 undergo temperature changes: the heat exchange between the cement-based specimen 17 and the reference sample 18 and the environment, and the carbonation exothermic reaction of the calcium silicate sample (i.e., the cement-based specimen 7), where the heat exchange with the environment can be reflected by the temperature drop of the reference sample 18. And the finally measured temperature is the superposition effect of these two processes. To better illustrate the carbonation reaction activity of the calcium silicate material, the temperature change caused by the actual carbonation reaction heat release can be calculated by subtracting the temperature change of the reference sample 18, as Figure 4 shown. It can be found from Figure 4 that the carbonation reaction process is mainly divided into two stages: the A-B section, the carbonation reaction acceleration period, where the hydration products in the cement-based material have a high carbonation reaction activity and immediately undergo a rapid reaction when contacting CO2, releasing a large amount of heat and showing the first strong exothermic peak. The reaction time in this stage is extremely short; the B-C section, the carbonation deceleration period, where the reaction rate rapidly decreases with the increase of time, a large amount of reaction products are generated, and the carbonation reaction is gradually controlled by diffusion.

[0056] In the present invention, the design of the reference sample 18 is to detect the heat release of the sample temperature caused by inevitable environmental changes (such as the heat generated by the work of pressurizing CO2 when pumping CO2 into the pressure vessel instantaneously). During the data processing process, the heat release of the cement is subtracted from the heat release of the reference sample 18 to obtain the actual heat release.

[0057] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0058] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. However, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A cement-based material carbonization curing system capable of real-time monitoring of heat release, characterized in that, It includes a carbonation reaction component, a thermopile, a cement-based specimen, a reference sample, a CO2 gas cylinder, a signal acquisition and analysis system, and a computer; the carbonation reaction component includes a carbonation reaction housing, the top of the carbonation reaction housing is provided with an upper cover plate, the bottom is provided with a lower cover plate, and the upper cover plate, the carbonation reaction housing and the lower cover plate enclose a carbonation reaction cavity; the CO2 gas cylinder is communicated with the inner top of the carbonation reaction cavity through a connecting pipeline, and a gas pressure reducing valve is configured on the connecting pipeline; there are two groups of thermopiles, which are respectively fixed inside the carbonation reaction cavity; the cement-based specimen and the reference sample are respectively installed on the two thermopiles; the thermopile is configured with shielded twin wires, one end of the shielded twin wires is connected to the thermopile, and the other end of the shielded twin wires passes out of the lower cover plate at the bottom of the carbonation reaction cavity and is connected to the signal acquisition and analysis system, and the signal acquisition and analysis system is connected to the computer.

2. The carbonation curing system for cement-based materials capable of real-time monitoring of heat release according to claim 1, wherein A workbench is arranged inside the carbonation reaction cavity, and the workbench is supported by a bracket at the bottom; the thermopile is placed on the workbench; and the reference sample and the cement-based specimen are separated by a partition board.

3. The carbonation curing system for cement-based materials capable of real-time monitoring of heat release according to claim 1, characterized in that, It includes a plurality of carbonation reaction components, the carbonation reaction cavities of each carbonation reaction component are respectively communicated with the CO2 gas cylinder, and the thermopile of each carbonation reaction component is respectively configured with shielded twin wires connected to the signal acquisition and analysis system.

4. The carbonation curing system for cement-based materials capable of real-time monitoring of heat release according to claim 1, characterized in that, The cement-based material carbonation curing system includes a multi-pipeline gas exhaust diverter, the inlet of the multi-pipeline gas exhaust diverter is communicated with the outlet end of the gas pressure reducing valve through a first pipeline; the multi-pipeline gas exhaust diverter is provided with a plurality of air outlets, and the air outlets are communicated with the inner top of the carbonation reaction cavity through a second pipeline.

5. The cement-based material carbonization curing system capable of real-time monitoring of heat release according to claim 4, characterized in that, Both the first pipeline and the second pipeline are pneumatic hoses; both ends of the first pipeline are respectively connected to the outlet of the gas pressure reducing valve and the inlet of the multi-pipeline gas exhaust diverter through quick connectors; both ends of the second pipeline are respectively connected to the air outlet of the multi-pipeline gas exhaust diverter and the inner top of the carbonation reaction cavity through quick connectors.

6. The carbonation curing system for cement-based materials capable of real-time monitoring of heat release according to claim 1, characterized in that, The carbonation reaction housing is of a double-layer structure, including an inner cylinder and an outer cylinder, and a phase change material is filled between the inner cylinder and the outer cylinder.

7. The carbonation curing system for cement-based materials capable of real-time monitoring of heat release according to claim 6, characterized in that, The phase change temperature of the phase change material is 20°C to 30°C.

8. The carbonation curing system for cement-based materials capable of real-time monitoring of heat release according to claim 1, characterized in that, The reference sample is an inert mineral that does not react with CO2.

9. The cement-based material carbonization curing system capable of real-time monitoring of heat release according to claim 1, characterized in that, The thermopile is composed of a plurality of thermocouples connected in series or parallel, and each pair of thermocouples is made of two different thermoelectric materials.

10. A carbonation curing method for a cement-based material carbonation curing system capable of real-time monitoring of heat release according to any one of claims 1 to 9, characterized in that, It includes the following steps: Step 1: Obtain the cement-based specimen and the reference sample; Step 2: Place the cement-based specimen and the reference sample on the thermopiles inside the carbonation reaction housing, and connect the thermopiles, the shielded twin wires, the signal acquisition and analysis system, and the computer; Step 3: Connect the CO2 gas cylinder and the carbonation reaction housing; Step 4: Place the system in an environment of 25°C, turn on the signal acquisition and analysis system and the computer, open the CO2 gas cylinder, adjust the gas pressure to the target pressure, record the change law of the temperature of the cement-based specimen with time through the computer, and the computer processes the change law of the temperature with time, and real-time draws the temperature change curve and the cumulative heat release amount of the cement-based material during the carbonation curing process.

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