CN109129860B - Maintenance device and maintenance method for gypsum-cement-based composite cementing material - Google Patents
Maintenance device and maintenance method for gypsum-cement-based composite cementing material Download PDFInfo
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- CN109129860B CN109129860B CN201710506698.8A CN201710506698A CN109129860B CN 109129860 B CN109129860 B CN 109129860B CN 201710506698 A CN201710506698 A CN 201710506698A CN 109129860 B CN109129860 B CN 109129860B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B11/00—Apparatus or processes for treating or working the shaped or preshaped articles
- B28B11/24—Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
- B28B11/245—Curing concrete articles
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
- C04B40/02—Selection of the hardening environment
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Abstract
A maintenance device and a maintenance method of a gypsum-cement-based composite cementing material are disclosed, wherein the maintenance device comprises a maintenance room, a temperature control device and a humidity regulating device; the method comprises the following steps: pouring the prepared slurry of the gypsum-cement-based composite cementing material into a mould, vibrating, and scraping redundant slurry; placing the test mould filled with the slurry into the maintenance device; setting the initial temperature and humidity of a curing chamber, and curing in a closed environment; adjusting the temperature and humidity in the curing chamber to a proper state in real time according to the actual situation in the curing process; removing the mould after the gypsum-cement-based composite cementing material is finally set, and continuously maintaining; and finishing maintenance after reaching the specified age, and taking out the test block. By using the maintenance device and the maintenance method, the maintained gypsum-cement-based composite cementing material can obtain better mechanical strength.
Description
Technical Field
The application relates to but is not limited to the field of building materials, in particular to but not limited to a maintenance device and a maintenance method of a gypsum-cement-based composite cementing material.
Background
For gypsum, the mechanical strength (flexural strength and compressive strength) is measured in accordance with GB/T17669.3-1999 determination of mechanical Properties of construction Gypsum. Pouring water with required water amount into a stirring container, pouring weighed building gypsum into the stirring container, standing for 1min, and stirring for 30 circles within 30s by using a stirring rod. Subsequently, the slurry was stirred at a rate of 3r/min to keep the slurry in a suspended state, and then stirred with a spoon until the slurry started to thicken. Then, the slurry was scooped into a test mold while being slowly stirred. The front end of the test mold was lifted by about 10mm and dropped, and this was repeated five times to remove air bubbles. When the overflowed slurry is judged to be initially set, the overflowed slurry is scraped by a leveling knife without repeatedly scraping the surface, and after final setting, the surface of the test piece is marked and the mold is removed. The test piece which needs to be subjected to the strength test after a certain hydration age is immediately stored in a closed position after being demoulded. The temperature of the enclosure air was 20 ℃ 2 ℃ and the relative humidity 90% + -5% throughout the hydration period. After the specified age period is reached, the test piece for measuring dry strength should be dried in an oven at 40 ℃. + -. 4 ℃ to a constant weight, and then the strength measurement is carried out quickly.
For cement gelled materials, the mechanical strength test refers to GB/T17671-1999 Cement mortar Strength test method (ISO method). The test piece is a prism with the size of 40mm multiplied by 160mm, and the underwater curing mode is adopted: and (3) immediately horizontally or vertically placing the marked test piece in water at the temperature of 20 +/-1 ℃ for curing, wherein the scraping plane is upward when the test piece is horizontally placed. The test pieces are placed on the non-rotten grates and are spaced apart from each other to allow water to contact the six surfaces of the test pieces. The interval between the test pieces or the water depth of the upper surface of the test body during the curing process is not less than 5 mm. And each maintenance pool only maintains the same type of cement test pieces. The maintenance tank (or container) is initially filled with tap water and then water is added at any time to maintain a suitable constant level, not allowing for a complete water change during maintenance. Any test bodies up to age, except those aged 24h or demoulded with a delay of 48h, should be removed from the water 15min before the test (breaking). The deposits on the surface of the test bodies were wiped off and covered with a wet cloth until the test. The test body age is calculated from the time of starting the experiment when the cement is stirred with water.
The gypsum is an air-setting cementing material, the cement is a hydraulic cementing material, and the hydration process of the gypsum-cement-based composite cementing material is a comprehensive process of the hydration of the gypsum in a cement mineral environment, the hydration of the cement in a gypsum saturated solution and the mutual reaction hydration. It is clear that the methods for maintaining the test pieces in the above two strength test standards are no longer applicable to gypsum-cement based composite cementitious materials. At present, the gypsum-cement-based composite cementing material is generally maintained by a maintenance method under natural conditions by default, and a special maintenance device and a special maintenance method for the gypsum-cement-based composite cementing material are lacked. The curing environment under the natural curing condition is extremely unstable (the temperature, humidity and the like are greatly changed), the strength development rule of the gypsum-cement-based composite cementing material cannot be accurately reflected by adopting the curing method under the natural condition, and the curing condition has larger influence on the strength development of the gypsum-cement-based composite cementing material along with the increase of the cement content in the gypsum-cement-based composite cementing material.
Therefore, the method for exploring the curing method suitable for the gypsum-cement-based composite cementing material has great significance.
Disclosure of Invention
The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.
The application provides a maintenance device and a maintenance method suitable for a gypsum-cement-based composite cementing material, which can enable the maintained gypsum-cement-based composite cementing material to obtain better mechanical strength.
Specifically, the application provides a curing means of gypsum-cement based composite cementitious material, the curing means includes:
a curing room;
the temperature control device is used for monitoring the temperature change of the gypsum-cement-based composite cementing material in real time and adjusting the temperature in the curing chamber; and
and the humidity adjusting device is used for monitoring and adjusting the humidity in the curing room in real time.
In an embodiment of the present application, the temperature control device may include one or more thermometers disposed near the gypsum-cement based composite cementitious material in the curing room, and a variable frequency air conditioner, and the humidity control device may include one or more hygrometers and a humidifier.
In an embodiment of the present application, the curing apparatus may further include a microscope for observing nucleation, particle size, structure and shape change, crystal growth and overlapping between crystals of the gypsum-cement based composite cementitious material during curing.
In an embodiment of the present application, the microscope may be a video microscope, the probe of which is disposed near above the gypsum-cement based composite cementitious material in the curing room.
In embodiments of the present application, the microscope may further comprise a video microscope, such as the particle view V19 video microscope from mettler-toledo, the probe of which is inserted into the gypsum-cement based composite cementitious material in the curing room during use.
In an embodiment of the application, the curing device may further comprise a solar panel arranged on the top and/or on the circumferential wall of the curing device.
In an embodiment of the present application, the curing device may further include one or more of a vacuum device, an air exhaust device, and a timing device for recording the age of the test block.
Optionally, the curing room is arranged at the lower part of the curing device, and the temperature control device, the humidity conditioning device, the vacuum device, the air exhaust device and the timing device are arranged at the upper part of the curing device and are separated from the curing room.
The application also provides a maintenance method of the gypsum-cement-based composite cementing material, which comprises the following steps:
pouring the prepared slurry of the gypsum-cement-based composite cementing material into a mould, vibrating, and scraping redundant slurry;
placing the test mold filled with the slurry into the maintenance device;
setting the initial temperature and humidity of a curing room by using a temperature control device and a humidity control device, and curing in a closed environment;
monitoring the crystal growth condition of the gypsum-cement-based composite cementing material and the lap joint between the crystals by using a microscope, simultaneously monitoring the temperature and humidity change of the gypsum-cement-based composite cementing material in the curing process by matching with a temperature control device and a humidity control device, and adjusting the temperature and humidity in a curing room in real time according to the monitoring result;
removing the mould after the gypsum-cement-based composite cementing material is finally set, and continuously maintaining;
and finishing the maintenance after reaching the specified age, and taking out the test block from the maintenance room.
In the embodiment of the present application, the nucleation, the particle size, the structure and the shape change of the gypsum-cement based composite cementitious material, the crystal growth and the lapping between the crystals can be observed by periodic sampling and a microscope.
Optionally, the real-time observation is performed using a video microscope of the maintenance device.
Optionally, the real-time observation is performed by using a video microscope and a video microscope of the curing device, wherein the video microscope is used for observing the gelled material before the gelled material is coagulated, and when the gelled material is coagulated, the probe of the video microscope is taken out of the gelled material and the video microscope is used for observing the gelled material continuously.
In an embodiment of the present application, after the specified age is reached, before the mechanical strength test is performed, the method may further include adjusting the temperature in the curing chamber to 40 ℃ ± 4 ℃, and drying the test block to a constant weight.
In the embodiment of the application, in the process of drying the test block to the constant weight, the pressure in the curing chamber can be adjusted by using the vacuumizing device so as to control the drying rate of the test block.
In an embodiment of the present application, the method may further comprise using an air exhaust device to assist in reducing the temperature and humidity within the curing chamber during or after curing.
In the embodiment of the present application, the age of the test piece is recorded by a timer device from the time when the gypsum-cement based composite cement powder is mixed with water.
In the embodiment of the present application, the vibration to scrape off the excess slurry means that the front end of the mold containing the slurry is lifted up by about 10mm and dropped down, and this is repeated five times to remove air bubbles and scrape off the overflowed slurry with the leveling blade, but the surface does not need to be scraped repeatedly.
The inventors of the present application found that the temperature and humidity during curing have a large influence on the development of strength of the gypsum-cement based composite cementitious material. While not wishing to be bound by theory, the inventors of the present application conclude that the reason for this may be that temperature and humidity affect the phase equilibrium point and saturated vapor pressure of the various phases (pre-and post-hydration phases) of the gypsum-cement based composite cementitious material; in addition, hydration products of the gypsum-cement-based composite cementing material are calcium sulfate dihydrate, hydrated calcium sulphoaluminate phases with various forms and C-S-H gel substances. The hydration process of the gypsum-cement based composite cementing material is a dissolution crystallization process in which material particles are continuously dissolved and hydration products are continuously separated out. When the temperature is lower, the slurry supersaturation degree of the gypsum-cement-based composite cementing material is higher, more crystal nuclei are formed in a liquid phase, and generated crystal grains are small, so that more crystal contact points are generated, and a crystal structure net is easily formed; at higher temperatures, the supersaturation is lower, fewer crystal nuclei are formed in the liquid phase, the resulting crystal grains are larger, and fewer crystal contact points are formed, so that a larger amount of hydrate is consumed for forming the crystal structure network under the same conditions. After the initial structure is formed, hydrate continues to form, which may further densify the structural network and thus provide reinforcement. However, after a certain limit, the further increase in hydrate causes an internal stress (crystallization stress) to the already formed structural network. The more hydrate crystals continue to form after the structure is compacted, the greater the crystallization stress. When the crystallization stress is greater than the structural strength, it causes structural failure, thereby causing a reduction in the plastic strength of the structure. Thus, at lower temperatures, the maximum plastic strength of the hardened slurry is lower due to the higher supersaturation. The proper curing temperature can control the generation and structural stress of various hydration products, is beneficial to the development of the strength of the composite cementing material and is beneficial to controlling the transformation of the generated ettringite to the monosulfur hydrated calcium sulphoaluminate. In addition, humidity is also a factor influencing the curing of gypsum-cement based composite cementitious materials. Based on this, the inventors of the present application have concluded that gypsum-cement-based composite cementitious materials having different compositions are not suitable for curing at uniform temperature and humidity, and have provided a curing apparatus capable of adjusting temperature and humidity in real time and a method of curing accordingly using the curing apparatus.
The gypsum-cement based composite cementing material undergoes two reaction processes after meeting water: hydration and coagulation hardening, wherein the hydration is a first reaction process, and the coagulation hardening is a second reaction process; hydration is a prerequisite for setting hardening, which is not possible without hydration. The hydration process of the gypsum-cement-based composite cementing material is a comprehensive process of hydration of gypsum in a cement mineral environment, hydration of cement in a gypsum saturated solution and mutual reaction hydration. The inventor of the application finds out through experiments that when the cement content is less than 5%, the hydration and setting hardening process of the gypsum-cement-based composite cementing material basically presents the hydration characteristic of gypsum. The hydration process of the composite cementing material becomes more and more complicated with the increase of the cement content in the composite cementing material. If the hydration process and setting and hardening process of the composite cementitious system can be properly controlled according to different components of the gypsum-cement-based composite cementitious material, better mechanical strength of the cured gypsum-cement-based composite cementitious material can be obtained. However, the curing system (temperature, humidity, pressure, etc.) has a great influence on the hydration process of the gypsum-cement composite cementitious material, and the conditions required in different curing stages are different, so that the curing temperature and humidity are often required to be adjusted in real time in the curing process to ensure that the gypsum-cement composite cementitious material reaches a more ideal curing condition within a specified age. Through a large amount of experimental researches, the inventor of the application initiatively provides a conclusion that the temperature and the humidity have large influence on the strength development of the gypsum-cement-based composite cementing material, and the humidity required to be maintained becomes larger along with the increase of the cement content in the gypsum-cement-based composite cementing material, thereby providing a significant help for the follow-up research on the mechanical strength development of the gypsum-cement-based composite cementing material.
The maintenance device and the maintenance method can be used for perfecting the hydration process of the gypsum-cement-based composite cementing material, so that the mechanical strength of the gypsum-cement-based composite cementing material can be fully exerted, and the mechanical strength development condition of the gypsum-cement-based composite cementing material can be reflected more accurately.
Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the application. The objectives and other advantages of the application may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
The accompanying drawings are included to provide a further understanding of the claimed subject matter and are incorporated in and constitute a part of this specification, illustrate embodiments of the subject matter and together with the description serve to explain the principles of the subject matter and not to limit the subject matter.
Fig. 1 is a schematic view of a curing device according to example 1 of the present application.
FIG. 2 is a schematic diagram showing the change of mineral composition during hydration and setting hardening of the gypsum-cement composite cementitious material.
Detailed Description
To make the objects, technical solutions and advantages of the present application more apparent, embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.
Example 1
As shown in fig. 1, the curing apparatus of the present embodiment includes four curing rooms 1, a temperature control device 2, a humidity control device 3, a timing device 4, an exhaust fan 5, a vacuum pump 6, a video microscope 7, a video microscope 8 (partileview V19, midle-toledo corporation), and a solar panel 9, which are vertically distributed.
The four curing rooms 1 are arranged at the lower part of the curing device, and doors are arranged on the curing rooms, so that the curing device can be in a closed state when the doors are closed. The temperature control device 2 comprises a plurality of thermometers and a variable frequency air conditioner, wherein the thermometers are arranged around the gypsum-cement-based composite cementing material in the curing room. The humidity control device 3 includes four hygrometers and a humidifier, and the four hygrometers are respectively arranged in the four curing rooms. The variable frequency air conditioner, the humidifier, the timing device 4, the exhaust fan 5 and the vacuum pump 6 are all arranged on the upper portion of the maintenance device and are spaced from the maintenance room 1, so that damage caused by hot and humid air in the maintenance device is avoided. The probe of the video microscope 7 is arranged near the upper part of the gypsum-cement-based composite cementing material in the curing room, and the display of the video microscope 7 is arranged outside the curing device. During use, the probe of the videography microscope 8 is inserted into the gypsum-cement based composite cementitious material in the curing room. The solar panels 9 are arranged on the top and on the peripheral walls of the curing device.
Example 2
The curing apparatus of example 1 was used to cure gypsum-cement based composite cementitious materials of different compositions. The method comprises the following specific steps:
weighing a certain amount of gypsum and cement according to the cement mixing amount shown in the table 1, mixing, placing in a mixing stirrer, and fully mixing;
sampling by adopting a quartering method, adding a proper amount of mixing water (according to the water consumption of standard consistence) into the composite cementing material to prepare gypsum-cement composite cementing material slurry, pouring the slurry into a mold, lifting the front end of the mold filled with the slurry by about 10mm, then dropping the mold, repeating the steps for five times to remove air bubbles, scraping overflowed slurry by using a leveling knife, but not repeatedly scraping the surface;
the test mold filled with the slurry was placed in the curing room 1 of the curing apparatus of example 1;
according to prior experiments and literature investigations[1-8]Combined composite gel material dissolution profile[9]Photo picture[10]And crystallization kinetics analysis, determining initial temperature, humidity and pressure required by the maintenance of the gypsum-cement-based composite cementing material with different compositions, and setting by using a temperature control device 2 and a humidity control device 3 for maintenance;
taking the gypsum-cement-based composite cementing material with 10 wt% of cement as an example, after the composite cementing material is added with water to form slurry, CaO and CaSO in the slurry are added in the whole hydration process4、Al2O3、SiO2、H2The O-equivalent phase concentration is essentially constantly changing. In the initial period of hydration (0-30min), the aqueous solution of the composite cementing material must first form CaSO4·2H2Supersaturated solution of O (FIG. 2), then with CaSO4·2H2CaSO in O precipitation system4The phase is reduced quickly, if the mechanical strength of the composite cementing material is improved, the CaSO which is consumed in a large amount is required to be ensured to be maximum4The composite system of the phase separates out C as much as possible3A·3CaSO4·32H2And O. Through phase diagram analysis, when the composite gelled material is water-solubleWhen the temperature of the solution is 25 ℃, the composition point of the solution is firstly dropped on CaO-Al2O3-CaSO4-H2O System phase diagram (reference [10 ]]FIG. 8) in (C) region I (CaSO)4·2H2Saturation crystallization zone of O), with CaSO4·2H2O is separated out and then quickly enters III2Zone (C)3A·3CaSO4·32H2Saturated crystallization region of O) to form C3A·3CaSO4·32H2Supersaturated solution of O to precipitate C3A·3CaSO4·32H2And O. Therefore, to ensure that the aqueous solution of the gypsum-cement composite cement of this composition (gypsum: cement: 90: 10) is accompanied by CaSO4·2H2C rapidly precipitates after completion of O production and consumption3A·3CaSO4·32H2The O phase, i.e.the one which is very rapidly introduced from zone I into zone III 2, is then initially brought to a reaction temperature of 25 ℃. Meanwhile, in order to ensure the constant saturated vapor pressure of the gas-liquid phase of the composite gelled material in the curing space and the reaction, the pressure at the curing temperature is 77.5mmHg according to an ideal gas state equation.
Inserting a probe of a video microscope 8 into the gypsum-cement-based composite cementing material, monitoring the crystal nucleus generation, particle size, structure and shape change conditions of the gypsum-cement-based composite cementing material, the lapping between crystal growth conditions and crystals by using the video microscope 8, and adjusting the temperature and humidity in the curing device in real time according to an observation result; meanwhile, a thermometer of the temperature control device 2 is used for monitoring the temperature change of the gypsum-cement-based composite cementing material in the curing process in a matching way, the heat change condition of the gypsum-cement-based composite cementing material in the heat release process is calculated according to the temperature change, the hydration speed and the hydration process of the gypsum-cement-based composite cementing material are quantitatively described, and the temperature and the humidity in the curing device are adjusted in real time according to the hydration process;
when the gypsum-cement-based composite cementing material is coagulated, taking out the probe of the video microscope 8 from the cementing material, and continuously monitoring by using the video microscope 7; simultaneously, the temperature in the curing room is monitored and adjusted to a proper state in real time by matching with a thermometer using the temperature control device 2;
after the gypsum-cement based composite cementing material finishes the hydration process, the gypsum-cement based composite cementing material enters the setting and hardening process, namely CaSO4·2H2O promoting C3S and C2S is hydrated to form C-S-H gel, and the C-S-H composition changes with the reaction temperature and time; after several days, a small amount of C in the hardened body3A·3CaSO4·32H2O is decomposed to generate hexagonal platy monosulfur hydrated calcium sulphoaluminate. Effectively controlling the generation rate of C-S-H gel and C at the early stage of the coagulation hardening process3A·3CaSO4·32H2The decomposition rate of O is favorable for the formation and stable development of the strength of the composite cementitious material, and therefore, the curing humidity of the process is regulated. The specific adjusting process is as follows: drawing a heat release curve according to the temperature change detected by the thermometer of the temperature control device 2; and judging whether the strength development of the composite cementing material is consistent with the expected strength development or not according to the combination of the crystal growth speed and the heat release curve in the set curing age, and if not, adjusting the temperature and the humidity in the curing room by using the temperature control device 2 and the humidity adjusting device 3. For example, during the hydration process, the crystal nucleus size and the generation amount of the composite cementing material hydration product are monitored by using a video microscope 8, the hydration temperature is monitored by using a temperature control device 2, and if the hydration temperature is faster than the whole hydration process, the maintenance temperature and humidity are adjusted to be matched with the whole hydration process (the temperature and/or humidity is adjusted to be higher or lower according to actual conditions); in the process of setting and hardening, a video microscope 7 is used for monitoring the crystal growth condition of the gypsum-cement-based composite cementing material and the lap joint between the crystals, a temperature control device 2 is used for monitoring the heat release condition of the gypsum-cement-based composite cementing material, a heat release curve is drawn, and the setting and hardening process is adjusted by adjusting the maintenance temperature and humidity.
Demoulding immediately after the gypsum-cement based composite cementing material is finally set, and continuously maintaining after demoulding;
after the specified age (the maintenance age is 3d) is reached and before a mechanical strength test is carried out, the temperature in the maintenance device is adjusted to 40 +/-4 ℃, the test block is dried to constant weight, a vacuum pump 6 is started in the drying process to adjust the pressure in the maintenance device, and the test block is dried to constant weight;
wherein, the age of the test block is recorded by a timing device from the time when the gypsum-cement composite cementing material is mixed with mixing water.
In the curing process, if the temperature or the humidity in the curing device needs to be reduced according to the crystal growth condition of the gypsum-cement-based composite cementing material and the mutual overlapping, the exhaust fan 5 is started so as to rapidly reduce the temperature or the humidity; similarly, after the curing is finished and the test block is taken out from the curing device, the exhaust fan 5 may be turned on.
The initial curing schedule for the hydration and setting hardening of the gypsum-cement based composite cementitious material is shown in tables 1 and 2.
TABLE 1 environmental control of composite cementitious materials hydration Process
TABLE 2 environmental control of the setting and hardening process of composite cementitious materials
Comparative example 1
Curing the gypsum-cement-based composite cementing material with different compositions by using a gypsum curing mode (curing method specified in GB/T17669.3-1999) (curing age is 3 d).
Comparative example 2
The gypsum-cement based composite cementing material with different compositions is cured under natural environment conditions (13-25 ℃, humidity RH50-85 percent) (the curing age is 3 d).
Test example
The mechanical strength of the gypsum-cement based composite cementitious material after curing in example 2 and comparative example 1 was tested according to the national standard GB/T17669.3-1999 test for mechanical Properties of building Gypsum. The results are reported in Table 3.
TABLE 3
As can be seen from table 3, compared with the gypsum curing mode and the curing mode under natural conditions, after curing by using the curing device and the curing method of the present application, the flexural strength and the compressive strength of the gypsum-cement-based composite cementitious material are significantly higher, which indicates that the curing method of the present application can more accurately reflect the mechanical strength development status of the gypsum-cement-based composite cementitious material.
Although the embodiments disclosed in the present application are described above, the descriptions are only for the convenience of understanding the present application, and are not intended to limit the present application. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims.
Reference documents:
[1] modified name research on gypsum-based composite cementing materials by composite portland cement [ J ], commercial concrete, 2014(1)40-42.
[2] Effect of cement in gypsum composite cementitious material system [ J ], 2013, 36 (1): 46-49.
[3] Tanping, Wanhaiyun, Liu Jiaxiang, composite effect [ J ], 2010, 33(2) of power plant desulfurization gypsum powder in cement-based cementing materials: 39-43.
[4] Hokkimen, portland cement-aluminate cement-gypsum ternary composite cementitious material test research [ D ], sienna: west ampere building science and technology university, 2007.
[5] Mugwei phase change study during hydration of hemihydrate gypsum [ J ], silicate science, 2002, 30 (4): 532-536.
[6] Tradition of maintenance system of gypsum-based composite cementitious material [ J ]. novel building material, 2007: 70-72.
[7] Study of periflying, monarch of poplars, royal aromas, desulfurization building gypsum modification and maintenance system [ J ] concrete and cement products, 2012, (7): 49-53.
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[10]CaO-Al of Liu Geng2O3-H2O and CaO-Al2O3-CaSO4-H2O system phase diagram and its application in cement]A institute of building materials, 1980.
Claims (14)
1. A curing apparatus for a gypsum-cement based composite cementitious material, the curing apparatus comprising:
a curing room;
the microscope is used for observing the crystal nucleus generation, the particle size, the structure and the shape change of the gypsum-cement-based composite cementing material in the maintenance process, the crystal growth condition and the lapping condition among crystals;
the temperature control device is used for monitoring the temperature change of the gypsum-cement-based composite cementing material in real time and adjusting the temperature in the curing room so that the temperature in the curing room is matched with the hydration process and the setting and hardening process of the gypsum-cement-based composite cementing material; and
and the humidity adjusting device is used for monitoring and adjusting the humidity in the curing room in real time, so that the humidity in the curing room is matched with the hydration process and the setting and hardening process of the gypsum-cement-based composite cementing material.
2. The curing device of claim 1, wherein the temperature control device comprises one or more thermometers and a variable frequency air conditioner, the humidity control device comprises one or more hygrometers and a humidifier, and the one or more thermometers are disposed in the curing room in the vicinity of the gypsum-cement based composite cementitious material.
3. The curing device of claim 1, wherein the microscope is a video microscope, the probe of which is positioned near above the gypsum-cement based composite cementitious material in the curing chamber.
4. The curing device of claim 3, wherein the microscope further comprises a video microscope, and during use, a probe of the video microscope is inserted into the gypsum-cement based composite cementitious material in the curing chamber.
5. A maintenance device according to claim 1, further comprising a solar panel arranged on the top and/or on the circumferential wall of the maintenance device.
6. The curing device of claim 5, wherein the curing device further comprises one or more of a vacuum, a venting device, a timing device to record the age of the test block.
7. The curing device of claim 5, wherein the curing room is provided at a lower portion of the curing device, and the temperature control device, the humidity control device, the vacuum pumping device, the air exhaust device, and the timing device are provided at an upper portion of the curing device and spaced apart from the curing room.
8. A method for curing a gypsum-cement based composite cementitious material, comprising:
pouring the prepared slurry of the gypsum-cement-based composite cementing material into a mould, vibrating, and scraping redundant slurry;
placing the test mold filled with the slurry into the curing device according to any one of claims 1 to 7;
according to the previous test and literature research, combined with the composite gelled material dissolution curve, phase diagram and crystallization dynamics analysis, determining the initial temperature, humidity and pressure required by the maintenance of the gypsum-cement-based composite gelled material, setting the initial temperature and humidity of a maintenance room by using a temperature control device and a humidity control device, and performing maintenance in a closed environment;
by sampling periodically, observing the crystal nucleus generation, particle size, structure and shape change conditions, crystal growth conditions and lapping conditions among crystals of the gypsum-cement-based composite cementing material by using a microscope, simultaneously monitoring the temperature and humidity change of the gypsum-cement-based composite cementing material in the curing process by matching with a temperature control device and a humidity control device, calculating the heat change condition in the heat release process according to the temperature change, quantitatively describing the hydration speed and the hydration process of the gypsum-cement-based composite cementing material, and adjusting the temperature and the humidity in a curing room in real time according to the hydration process so that the temperature and the humidity in the curing room are matched with the hydration process of the gypsum-cement-based composite cementing material in the hydration process;
after the gypsum-cement-based composite cementing material finishes a hydration process, entering a setting and hardening process, and drawing a heat release curve according to the temperature change detected by a temperature control device; judging whether the strength development of the gypsum-cement-based composite cementing material is consistent with the expected strength development or not according to the combination of the crystal growth speed and the heat release curve in the set curing age, and if not, adjusting the temperature and the humidity in a curing room by using a temperature control device and a humidity control device so that the temperature and the humidity in the curing room are matched with the setting and hardening process of the gypsum-cement-based composite cementing material in the setting and hardening process;
removing the mould after the gypsum-cement-based composite cementing material is finally set, and continuously maintaining;
and finishing the maintenance after reaching the specified age, and taking out the test block from the maintenance room.
9. The curing method of claim 8, wherein the crystal nucleus generation, particle size, structure and shape change of the gypsum-cement-based composite cementing material are observed by using a microscope, and the crystal growth condition and the lapping condition among the crystals comprise: when the microscope comprises a video microscope, the video microscope of the maintenance device is used for carrying out real-time observation; or when the microscope comprises a video microscope and a video microscope, the video microscope and the video microscope of the maintenance device are used for real-time observation, wherein the video microscope is used for observation before the cementing material is coagulated, and when the cementing material is coagulated, the probe of the video microscope is taken out of the cementing material and is continuously observed by the video microscope.
10. A maintenance method according to claim 8, further comprising adjusting the temperature in the maintenance chamber to 40 ℃ ± 4 ℃ and drying the test block to a constant weight, before performing the mechanical strength test after reaching a prescribed age.
11. The curing device of claim 10, wherein during the drying of the test block to a constant weight, the vacuum is used to adjust the pressure in the curing chamber to control the drying rate of the test block.
12. A curing method according to claim 8, further comprising using an air exhaust device to assist in reducing the temperature and humidity within the curing chamber during or after curing.
13. The curing apparatus of claim 12, wherein the age of the test block is recorded by a timing device from when the gypsum-cement based composite cementitious material powder is mixed with water.
14. A maintenance method according to claim 8, wherein the vibrating and scraping off excess slurry means that the front end of the mold containing the slurry is lifted by 10mm and dropped, and this is repeated five times to remove air bubbles and scrape off the slurry overflow with a leveling blade without repeatedly scraping the surface.
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