CN110421696B - Magnesium oxychloride cement foam concrete air hole structure model manufacturing and characterization method based on magnesium oxysulfate cement - Google Patents

Magnesium oxychloride cement foam concrete air hole structure model manufacturing and characterization method based on magnesium oxysulfate cement Download PDF

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CN110421696B
CN110421696B CN201811401030.8A CN201811401030A CN110421696B CN 110421696 B CN110421696 B CN 110421696B CN 201811401030 A CN201811401030 A CN 201811401030A CN 110421696 B CN110421696 B CN 110421696B
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magnesium
foam concrete
cement
oxychloride cement
oxysulfate cement
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CN110421696A (en
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丁秀萍
郑卫新
李宝兰
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Qinghai Institute of Salt Lakes Research of CAS
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Qinghai Institute of Salt Lakes Research of CAS
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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
    • B28B1/00—Producing shaped prefabricated articles from the material
    • B28B1/14—Producing shaped prefabricated articles from the material by simple casting, the material being neither forcibly fed nor positively compacted
    • 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
    • B28B1/00—Producing shaped prefabricated articles from the material
    • B28B1/50—Producing shaped prefabricated articles from the material specially adapted for producing articles of expanded material, e.g. cellular concrete
    • 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
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/30—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing magnesium cements or similar cements
    • 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
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/30—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing magnesium cements or similar cements
    • C04B28/32—Magnesium oxychloride cements, e.g. Sorel cement
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • 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
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/40—Porous or lightweight materials

Abstract

The invention discloses a magnesium oxychloride cement foam concrete pore structure model manufacturing method based on magnesium oxysulfate cement, which is characterized in that magnesium oxysulfate cement with excellent water resistance is paved on the cross section of MOC foam concrete by utilizing the hydrolysis characteristic of MOC in water and the water resistance of the magnesium oxysulfate cement to form a magnesium oxysulfate cement-MOC foam concrete integral test piece; and hydrolyzing the magnesium oxysulfate cement-MOC foam concrete integral test piece, wherein the rest part is the magnesium oxychloride cement foam concrete air hole structure model. The obtained visual model of the internal pore structure of the concrete formed by the magnesium oxysulfate cement observes various characteristic parameters of the pores by adopting instruments such as a microscope, an SEM and the like, and the characterization method not only can more visually observe the internal pore structure of the MOC foam concrete, but also can characterize various parameters of the internal pores of the MOC foam concrete. The method for testing different hole parameters by using one method is simple and easy to implement, and is a simplification of scientific research approaches.

Description

Magnesium oxychloride cement foam concrete air hole structure model manufacturing and characterization method based on magnesium oxysulfate cement
Technical Field
The invention belongs to the technical field of building materials, and particularly relates to a magnesium oxychloride cement foam concrete air hole structure model manufacturing and characterization method based on magnesium oxysulfate cement.
Background
The foam concrete is a light concrete material which is prepared by taking mineral admixture, cement-based material and the like as main gelled materials, adding water and additive, optionally adding fine sand or partial light aggregate and the like to prepare slurry, foaming by a foaming agent, pouring and forming in a construction site or a factory, and curing and contains a large amount of independent, tiny and uniformly distributed air bubble holes. Because the interior of the foam concrete is provided with a large number of closed bubble holes, the foam concrete not only has light weight and heat insulation performance, but also has a 'breathing' function, and can improve the comfort of the living environment. The dry bulk density of the foam concrete is 200-700 kg/m3Is equivalent to the coagulation of common cement1/10-1/3 parts of soil; the thermal conductivity is 0.050-0.135W/(m.k), and the thermal resistance is 20-30 times that of ordinary cement concrete. As an inorganic material, the foam concrete has incombustibility, the fireproof performance reaches the fireproof standard A level, and the foam concrete has good fireproof and fireproof performance. Compared with other inorganic heat-insulating materials (such as aluminum silicate fibers, rock mineral wool, glass wool, ceramsite, expanded perlite, vitrified micro bubbles and the like), the material has the advantages of low price, no environmental pollution, convenience in use, low carbon and the like, and gradually becomes the first choice in modern heat-insulating materials.
Magnesium Oxychloride Cement (Magnesium Oxychloride Cement abbreviated as MOC) is an air-hardening cementing material formed by mixing Magnesium chloride solution with certain concentration with Magnesium oxide powder, and the main hydration product is Magnesium Oxychloride [ Mg3(OH)5Cl·4H2O]And Mg (OH)2. General magnesium oxychloride [ Mg ]3(OH)5Cl·4H2O]It is easily hydrolyzed into magnesium hydroxide in water, and further, it shows characteristics of strength reduction and pulverization. The modifier is added to change magnesium oxychloride (Mg)3(OH)5Cl·4H2O]The crystal structure of (3) makes it denser and therefore less prone to hydrolysis. The magnesium oxychloride cement slurry is mixed with a certain amount of foam (physical foaming or chemical foaming) to prepare the magnesium oxychloride cement foam concrete building block. The heat-insulating brick has the advantages of high strength, excellent heat-insulating property, high fire resistance, strong durability, easy maintenance and the like. Compared with the traditional building material, the novel magnesium building material has the characteristics of strong cohesive force, heat preservation, heat insulation and the like, thereby occupying an important position in the building energy-saving application technology. Particularly, the foam concrete building material taking the MOC as the base material can maximally realize the characteristics of energy conservation, environmental protection, economy and the like, and has great advantages in the field of building materials.
The foam concrete is characterized by a porous structure and is porous concrete. Currently, different pore structure characteristic parameters have different testing methods. The characterization of the MOC foam concrete pore structure mainly refers to a test method of common foam concrete, and the characteristic parameters mainly comprise porosity, pore size distribution, average pore size, pore distribution, shape factor, pore wall thickness and connectivity.
The porosity, the wall thickness and the connectivity are mainly measured by a direct calculation method, a medium soaking method and the like.
(1) At present, the methods for testing porosity, pore wall thickness and connectivity mainly comprise a direct calculation method, a medium soaking method and the like. If the porosity is expressed by the formula theta-1-M/V.rho s① direct calculation method, porosity is 1-M/V rhosAnd (4) calculating. In the formula: m is the quality of the dried foam concrete; rhosThe density of the foam concrete corresponding to the compact solid, V is the volume of the foam concrete, ② method for soaking medium, firstly weighing the mass w of the measured object M1Then immersing the sample in the liquid for a period of time to fully saturate, taking out and wiping off the liquid on the surface of the sample, and weighing the mass w of M in the air again2. Then the object M is placed on a sling and is immersed in the liquid to be weighed, and the total mass of M and the sling is w3And the mass of the hanger suspended in the working liquid is w4. The porosity adopts the formula theta-1-w1ρt/(w2-w3+w4)ρsCalculation, in the formula: rhotIs the density of the liquid; rhosThe density of the test piece corresponds to the density of the dense solid.
Although the method using calculation simulation can embody the specific parameters of the air holes in the concrete, the biggest disadvantage is that the real shape of the air holes in the concrete cannot be observed intuitively, and only one parameter can be calculated. For example, the porosity formula can only express the porosity in the concrete and cannot calculate the size of the air holes.
(2) At present, the method for testing the pore diameter, pore size distribution, average pore diameter, pore distribution, shape factor and the like mainly obtains a material section image by means of an imaging tool such as a microscope and the like, and then performs necessary processing on the section image to analyze and calculate pore structure parameters. The direct image analysis method needs to damage the test piece, can only obtain local information of the test piece, and has high requirement on selection of an observation point. The biggest disadvantage is that only a virtual picture of the foam concrete structure can be obtained, and the depth of the hole structure is not accurately displayed.
Through the analysis, the method can only reflect the parameters of one hole basically regardless of a calculation method or an image method, and the method can not reflect the real situation of the hole in the foam concrete visually.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and the MOS with excellent water resistance is paved on the section of MOC foam concrete by utilizing the hydrolysis characteristic of MOC in water and the characteristic that Magnesium Oxysulfate cement (MOS) has good water resistance relative to the MOC, so that the MOS forms an intuitive model of a concrete internal hole structure. By combining with SEM and other instruments to observe various characteristic parameters of the holes, the characterization method not only can more intuitively see the structure of the inner holes of the MOC concrete, but also can characterize various parameters of the inner holes of the MOC foam concrete. The method for testing different hole parameters by using one method is simple and easy to implement, and is a simplification of scientific research approaches.
The invention is realized by the following technical scheme:
a magnesium oxychloride cement foam concrete air hole structure model manufacturing method based on magnesium oxysulfate cement comprises the following steps:
preparing magnesium oxysulfate cement slurry, namely preparing magnesium sulfate and water into a magnesium sulfate solution, wherein the Baume degree of the magnesium sulfate solution is 20-30 DEG Be', and mixing the magnesium sulfate solution and magnesium oxide to form the magnesium oxysulfate cement slurry, wherein the mass ratio of the magnesium oxide to the magnesium sulfate solution is 1: 0.5-1.5;
fixing a circle of mould around the cross section of the magnesium oxychloride cement foam concrete to be detected, and pouring the magnesium oxysulfate cement slurry into the mould to form a magnesium oxysulfate cement-magnesium oxychloride cement foam concrete integral test piece;
and hydrolyzing the magnesium oxysulfate cement-magnesium oxychloride cement foam concrete integral test piece at the hydrolysis temperature of 0-30 ℃, wherein the magnesium oxychloride cement foam concrete to be detected is completely hydrolyzed to be the hydrolysis end point, and the residual magnesium oxysulfate cement part is the model of the pore structure of the magnesium oxychloride cement foam concrete.
In the technical scheme, the magnesium oxide is powder containing active magnesium oxide, such as light-burned magnesium oxide powder, light-burned dolomite powder or magnesia, and the active content of the magnesium oxide is more than 18%.
In the above technical solution, after the magnesium oxysulfate cement slurry is poured into a mold, the method further comprises: and (3) solidifying the magnesium oxysulfate cement slurry into a stable solid, wherein the solidifying process and the maintaining process are included, the solidifying time is 4-36 hours, and the maintaining time is 3-14 days.
In the technical scheme, the time of the hydrolysis process is 3-28 days.
In the technical scheme, because MOC concrete is easy to separate out chloride ions in a water environment, and the chloride ions are easy to corrode iron products, the die is preferably a stainless steel die, a metal die which is not easy to corrode such as copper and the like or a wood die. The fixing mode of the mould is various, such as embedding, linking, buckling, bonding and the like.
A magnesium oxychloride cement foam concrete air hole structure model manufacturing method based on magnesium oxysulfate cement comprises the following steps:
selecting representative magnesium oxychloride cement foam concrete, and cutting a section, wherein the section is kept clean and tidy;
preparing magnesium oxysulfate cement slurry, namely preparing magnesium sulfate and water into a magnesium sulfate solution, wherein the Baume degree of the magnesium sulfate solution is 20-30 DEG Be', and mixing the magnesium sulfate solution and magnesium oxide to form the magnesium oxysulfate cement slurry, wherein the mass ratio of the magnesium oxide to the magnesium sulfate solution is 1: 0.5-1.5; the magnesium oxide is light-burned magnesium oxide powder, light-burned dolomite powder or magnesia with the active content of MgO being more than 18 percent;
fixing a circle of mould around the section, pouring the magnesium oxysulfate cement slurry into the mould, forming a plane on the surface of the poured magnesium oxysulfate cement slurry, enabling the plane to be horizontal to the upper surface of the mould, curing for 7 days after the magnesium oxysulfate cement slurry is solidified for 24 hours to form a stable solid, and forming a magnesium oxysulfate cement-magnesium oxychloride cement foam concrete integral test piece;
and hydrolyzing the magnesium oxysulfate cement-magnesium oxychloride cement foam concrete integral test piece, wherein the hydrolysis temperature is 20-25 ℃, the hydrolysis process time is 7-14 days, and the residual magnesium oxysulfate cement part is the magnesium oxychloride cement foam concrete air hole structure model.
The application of the magnesium oxychloride cement foam concrete pore structure model in the structural characterization of the porosity, pore size distribution, average pore size, pore distribution, shape factor, pore wall thickness or connectivity of the magnesium oxychloride cement foam concrete pores.
In the above technical solution, the characterizing includes at least one of observing with a microscope and detecting with a Scanning Electron Microscope (SEM).
The invention has the advantages and beneficial effects that:
the invention has the following advantages: (1) because MOC and MOS belong to magnesium cement class, and the properties of the two materials are very similar, the two materials have stronger affinity during interaction, and MOS slurry can be completely immersed into tiny holes in MOC foam concrete, so that the formed visual model can more finely highlight the structural characteristics of the original holes and truly reflect the structural characteristics of the holes in the MOC foam concrete. (2) The existing analysis method can only analyze a certain specific characteristic parameter in the foam concrete by one means, for example, only the porosity can be analyzed by a soaking medium method, and other characteristics such as the size of pores, the shape of the pores and the like cannot be displayed. The invention can visually observe various parameters of porosity, pore size distribution, average pore size, pore distribution, shape factor and the like of the pores.
Drawings
FIG. 1 is a schematic view of the MOC foam concrete to be tested in example 1;
FIG. 2 is a schematic diagram of MOC foam concrete to be tested after the die is installed in example 1;
FIG. 3 is a schematic view of an integrated magnesium oxysulfate cement-magnesium oxychloride cement foam concrete specimen in example 1;
FIG. 4 is a schematic view showing hydrolysis of an integrated test piece of magnesium oxysulfate cement-magnesium oxychloride cement foam concrete in example 1;
FIG. 5 is a schematic diagram of the pore structure model of the magnesium oxychloride cement foam concrete finally obtained in example 1.
Wherein:
1: air hole, 2: section, 3: MOC foam concrete, 4: mold, 5: fixing bolt, 6: magnesium oxysulfate cement, 7: water bath, 8: water, 9: magnesium oxysulfate cement-magnesium oxychloride cement foam concrete integral test piece, 10: a porous entity.
For a person skilled in the art, other relevant figures can be obtained from the above figures without inventive effort.
Detailed Description
In order to make the technical solution of the present invention better understood, the technical solution of the present invention is further described below with reference to specific examples.
Example one
A magnesium oxychloride cement foam concrete air hole structure model manufacturing method based on magnesium oxysulfate cement comprises the following steps:
selecting representative magnesium oxychloride cement foam concrete, and cutting a section, wherein the section is kept clean and tidy, and the size of a cut sample is 100mm multiplied by 100 mm;
preparing magnesium sulfate cement slurry, namely preparing magnesium sulfate solution from magnesium sulfate and water, wherein the baume degree of the magnesium sulfate solution is 28-degree Be', and uniformly mixing magnesium oxide and the magnesium sulfate solution according to the mass ratio of 1:0.75 and stirring to obtain the magnesium sulfate cement slurry; the magnesium oxide is light-burned magnesium oxide powder with the MgO active content of more than 18 percent; the active content of magnesium oxide is the content of magnesium oxide which reacts with water to form magnesium hydroxide.
The magnesium oxychloride cement foam concrete is placed with the cross section upward, and a circle of wood mold is fixed around the cross section. The wood mold is made of four rectangular wood members (two of the rectangular dimensions are 120mm multiplied by 60mm multiplied by 20mm, and two are 100mm multiplied by 60mm multiplied by 20mm), the four molds are fixed on the upper end of the MOC foam concrete by fixing bolts, and the distance between the section of the MOC foam concrete and the upper surface of the mold is 20 mm. Pouring the magnesium oxysulfate cement slurry into a mold, forming a plane on the surface of the poured magnesium oxysulfate cement slurry, enabling the plane to be horizontal to the upper surface of the mold, standing at room temperature for 24 hours, solidifying the magnesium oxysulfate cement slurry, and maintaining for 3 days to form a stable solid, so as to form a magnesium oxysulfate cement-magnesium oxychloride cement foam concrete integral test piece;
hydrolyzing the magnesium oxysulfate cement-magnesium oxychloride cement foam concrete whole test piece, putting the test piece into a water bath kettle, completely immersing the test piece into water, wherein the hydrolysis temperature is 25 ℃, the hydrolysis time is 7 days, observing that the magnesium oxychloride cement foam concrete completely sinks, and slightly shaking a mould in the water to obtain a magnesium oxysulfate cement part with a clean surface, namely a magnesium oxychloride cement foam concrete pore structure model, wherein the surface distribution point of the formed MOS model is a visual entity of an MOC concrete internal pore structure, namely a pore entity.
A characterization method of a magnesium oxychloride cement foam concrete air hole structure obtains characteristic parameters of magnesium oxychloride cement foam concrete through characterization of the magnesium oxychloride cement foam concrete air hole structure model, wherein the characteristic parameters comprise porosity, pore size distribution, average pore size, pore distribution, shape factor, pore wall thickness or connectivity.
In the above technical solution, the characterization includes at least one of microscope observation and SEM detection.
Scanning the surface of the model by adopting SEM to measure the number n, the diameter d and the height parameter l of the air hole entity 10. The porosity, pore size distribution, mean pore size, pore distribution, shape factor, pore wall thickness are then calculated.
① porosity, which is the percentage of the volume of pores in the bulk material relative to the total volume of the material in its natural state, the diameter measured above is taken as the average d1According to the mean diameter d1Calculating the volume v of the average pore entity, wherein the volume v multiplied by the number n of the pore entities is the volume of the pore entities at the height of a surface layer, and the height of the surface layer is the average value l of the height parameters1The total volume of pores in the concrete test block can be expressed by the solid volume of pores in the model, V ═ n (4/3) pi (d)1/2)2(L/l1) Then, the MOC foam concrete has a porosity of θ V/L2(L is the side length of the test block).
Pore size distribution and pore distribution: is the percentage by number or volume of the pore sizes of the various stages present in the concrete. The diameter d of the solid pores on the surface of the model measured as above is classified according to the interval according to the sizes of the pores with different diameters, and the number of the pores in each interval is divided by the total number to obtain the pore size distribution.
③ average pore diameter: as described in (i).
④ form factor, the degree to which the geometry of the foam concrete pores deviates from spherical, the pore form factor (S) is expressed by the formula S-P2V (4 π A). In the formula: p is the pore perimeter and A is the pore area can be calculated from the pore diameter d described above. When S is 1, the air holes are spherical; when S is more than 1, the air holes are in a quasi-spherical shape. The larger the value of S, the more the shape of the pores deviates from the spherical shape.
Fifth, the hole wall thickness: scanning the surface of the model by adopting SEM, measuring the distance between two air hole entities, wherein the distance is the wall thickness of the air hole in the concrete, the two air hole entities are communicated with each other, and the communication rate is obtained by dividing the number of the air hole entities by the volume of the air hole.
Example two
A magnesium oxychloride cement foam concrete air hole structure model manufacturing method based on magnesium oxysulfate cement comprises the following steps:
selecting representative magnesium oxychloride cement foam concrete, and cutting a section, wherein the section is kept clean and tidy, and the size of a cut sample is 100mm multiplied by 100 mm;
preparing magnesium sulfate cement slurry, namely preparing magnesium sulfate solution from magnesium sulfate and water, wherein the Baume degree of the magnesium sulfate solution is 29 DEG Be', and uniformly mixing magnesium oxide and the magnesium sulfate solution according to the mass ratio of 1:0.60 and stirring to obtain the magnesium sulfate cement slurry; the magnesium oxide is light-burned magnesium oxide powder with the MgO active content of more than 18 percent; the active content of magnesium oxide is the content of magnesium oxide which reacts with water to form magnesium hydroxide.
The magnesium oxychloride cement foam concrete is placed with the cross section upward, and a circle of wood mold is fixed around the cross section. The wood mold is made of four rectangular wood members (two of the rectangular dimensions are 120mm multiplied by 60mm multiplied by 20mm, and two are 100mm multiplied by 60mm multiplied by 20mm), the four molds are fixed on the upper end of the MOC foam concrete by fixing bolts, and the distance between the section of the MOC foam concrete and the upper surface of the mold is 20 mm. Pouring the magnesium oxysulfate cement slurry into a mold, forming a plane on the surface of the poured magnesium oxysulfate cement slurry, enabling the plane to be horizontal to the upper surface of the mold, standing at room temperature for 24 hours, solidifying the magnesium oxysulfate cement slurry, and maintaining for 3 days to form a stable solid, so as to form a magnesium oxysulfate cement-magnesium oxychloride cement foam concrete integral test piece;
hydrolyzing the magnesium oxysulfate cement-magnesium oxychloride cement foam concrete whole test piece, putting the test piece into a water bath kettle, completely immersing the test piece into water, wherein the hydrolysis temperature is 25 ℃, the hydrolysis time is 7 days, observing that the magnesium oxychloride cement foam concrete completely sinks, and slightly shaking a mould in the water to obtain a magnesium oxysulfate cement part with a clean surface, namely a magnesium oxychloride cement foam concrete pore structure model, wherein the surface distribution point of the formed MOS model is a visual entity of an MOC concrete internal pore structure, namely a pore entity.
A characterization method of a magnesium oxychloride cement foam concrete air hole structure obtains characteristic parameters of magnesium oxychloride cement foam concrete through characterization of the magnesium oxychloride cement foam concrete air hole structure model, wherein the characteristic parameters comprise porosity, pore size distribution, average pore size, pore distribution, shape factor, pore wall thickness or connectivity.
EXAMPLE III
A magnesium oxychloride cement foam concrete air hole structure model manufacturing method based on magnesium oxysulfate cement comprises the following steps:
selecting representative magnesium oxychloride cement foam concrete, and cutting a section, wherein the section is kept clean and tidy, and the size of a cut sample is 100mm multiplied by 100 mm;
preparing magnesium sulfate cement slurry, namely preparing magnesium sulfate solution from magnesium sulfate and water, wherein the Baume degree of the magnesium sulfate solution is 29 DEG Be', and uniformly mixing magnesium oxide and the magnesium sulfate solution according to the mass ratio of 1:0.60 and stirring to obtain the magnesium sulfate cement slurry; the magnesium oxide is light-burned magnesium oxide powder with the active content of MgO being 60 percent; the active content of magnesium oxide is the content of magnesium oxide which reacts with water to form magnesium hydroxide.
The magnesium oxychloride cement foam concrete is placed with the cross section upward, and a circle of wood mold is fixed around the cross section. The wood mold is made of four rectangular wood members (two of the rectangular dimensions are 120mm multiplied by 60mm multiplied by 20mm, and two are 100mm multiplied by 60mm multiplied by 20mm), the four molds are fixed on the upper end of the MOC foam concrete by fixing bolts, and the distance between the section of the MOC foam concrete and the upper surface of the mold is 20 mm. Pouring the magnesium oxysulfate cement slurry into a mold, forming a plane on the surface of the poured magnesium oxysulfate cement slurry, enabling the plane to be horizontal to the upper surface of the mold, standing at room temperature for 24 hours, solidifying the magnesium oxysulfate cement slurry, and maintaining for 3 days to form a stable solid, so as to form a magnesium oxysulfate cement-magnesium oxychloride cement foam concrete integral test piece;
hydrolyzing the magnesium oxysulfate cement-magnesium oxychloride cement foam concrete whole test piece, putting the test piece into a water bath kettle, completely immersing the test piece into water, wherein the hydrolysis temperature is 25 ℃, the hydrolysis time is 7 days, observing that the magnesium oxychloride cement foam concrete completely sinks, and slightly shaking a mould in the water to obtain a magnesium oxysulfate cement part with a clean surface, namely a magnesium oxychloride cement foam concrete pore structure model, wherein the surface distribution point of the formed MOS model is a visual entity of an MOC concrete internal pore structure, namely a pore entity.
A characterization method of a magnesium oxychloride cement foam concrete air hole structure obtains characteristic parameters of magnesium oxychloride cement foam concrete through characterization of the magnesium oxychloride cement foam concrete air hole structure model, wherein the characteristic parameters comprise porosity, pore size distribution, average pore size, pore distribution, shape factor, pore wall thickness or connectivity.
Example four
A magnesium oxychloride cement foam concrete air hole structure model manufacturing method based on magnesium oxysulfate cement comprises the following steps:
selecting representative magnesium oxychloride cement foam concrete, and cutting a section, wherein the section is kept clean and tidy, and the size of a cut sample is 100mm multiplied by 100 mm;
preparing magnesium sulfate cement slurry, namely preparing magnesium sulfate solution from magnesium sulfate and water, wherein the Baume degree of the magnesium sulfate solution is 25 degrees Be', and uniformly mixing magnesium oxide and the magnesium sulfate solution according to the mass ratio of 1:0.80 and stirring to obtain the magnesium sulfate cement slurry; the magnesium oxide is light-burned magnesium oxide powder with the active content of MgO being 55 percent; the active content of magnesium oxide is the content of magnesium oxide which reacts with water to form magnesium hydroxide.
The magnesium oxychloride cement foam concrete is placed with the cross section upward, and a circle of wood mold is fixed around the cross section. The wood mold is made of four rectangular wood members (two of the rectangular dimensions are 120mm multiplied by 60mm multiplied by 20mm, and two are 100mm multiplied by 60mm multiplied by 20mm), the four molds are fixed on the upper end of the MOC foam concrete by fixing bolts, and the distance between the section of the MOC foam concrete and the upper surface of the mold is 20 mm. Pouring the magnesium oxysulfate cement slurry into a mold, forming a plane on the surface of the poured magnesium oxysulfate cement slurry, enabling the plane to be horizontal to the upper surface of the mold, standing at room temperature for 24 hours, solidifying the magnesium oxysulfate cement slurry, and maintaining for 3 days to form a stable solid, so as to form a magnesium oxysulfate cement-magnesium oxychloride cement foam concrete integral test piece;
hydrolyzing the magnesium oxysulfate cement-magnesium oxychloride cement foam concrete whole test piece, putting the test piece into a water bath kettle, completely immersing the test piece into water, wherein the hydrolysis temperature is 25 ℃, the hydrolysis time is 7 days, observing that the magnesium oxychloride cement foam concrete completely sinks, and slightly shaking a mould in the water to obtain a magnesium oxysulfate cement part with a clean surface, namely a magnesium oxychloride cement foam concrete pore structure model, wherein the surface distribution point of the formed MOS model is a visual entity of an MOC concrete internal pore structure, namely a pore entity.
A characterization method of a magnesium oxychloride cement foam concrete air hole structure obtains characteristic parameters of magnesium oxychloride cement foam concrete through characterization of the magnesium oxychloride cement foam concrete air hole structure model, wherein the characteristic parameters comprise porosity, pore size distribution, average pore size, pore distribution, shape factor, pore wall thickness or connectivity.
The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.

Claims (10)

1. A magnesium oxychloride cement foam concrete air hole structure model manufacturing method based on magnesium oxysulfate cement is characterized by comprising the following steps:
preparing magnesium oxysulfate cement slurry, namely preparing magnesium sulfate and water into a magnesium sulfate solution, wherein the Baume degree of the magnesium sulfate solution is 20-30 DEG Be', and mixing the magnesium sulfate solution and magnesium oxide to form the magnesium oxysulfate cement slurry, wherein the mass ratio of the magnesium oxide to the magnesium sulfate solution is 1: 0.5-1.5;
fixing a circle of mould around the cross section of the magnesium oxychloride cement foam concrete to be detected, and pouring the magnesium oxysulfate cement slurry into the mould to form a magnesium oxysulfate cement-magnesium oxychloride cement foam concrete integral test piece;
and hydrolyzing the magnesium oxysulfate cement-magnesium oxychloride cement foam concrete integral test piece at the hydrolysis temperature of 0-30 ℃, and taking the complete hydrolysis of the magnesium oxychloride cement foam concrete to be tested as the hydrolysis end point, wherein the rest part is the magnesium oxychloride cement foam concrete air hole structure model.
2. The method for producing a model of an air pore structure of magnesium oxychloride cement foam concrete according to claim 1, wherein the magnesium oxide is powder containing active magnesium oxide, and the active content of the magnesium oxide is more than 18%.
3. The method for making the model of pore structure of magnesium oxychloride cement foam concrete according to claim 2, wherein the powder containing active magnesium oxide is light-burned magnesia powder, light-burned dolomite powder or magnesite, and the active content of magnesium oxide is more than 18%.
4. The method of claim 1, wherein the step of pouring the magnesium oxychloride cement slurry into the mold further comprises: and (3) solidifying the magnesium oxysulfate cement slurry into a stable solid, wherein the solidifying process and the maintaining process are included, the solidifying time is 4-36 hours, and the maintaining time is 3-14 days.
5. The method for producing the model of the air hole structure of the magnesium oxychloride cement foam concrete according to claim 1, wherein the time of the hydrolysis process is 3 to 28 days.
6. The method for making a model of an air pore structure of magnesium oxychloride cement foam concrete according to claim 1, wherein the mold is a stainless steel mold, a copper metal mold or a wood mold.
7. The method for making a model of an air pore structure of magnesium oxychloride cement foam concrete according to claim 5, wherein the fixing manner of the mold is embedding, linking, buckling or bonding.
8. A magnesium oxychloride cement foam concrete air hole structure model manufacturing method based on magnesium oxysulfate cement comprises the following steps:
selecting representative magnesium oxychloride cement foam concrete, and cutting a section, wherein the section is kept clean and tidy;
preparing magnesium oxysulfate cement slurry, namely preparing magnesium sulfate and water into a magnesium sulfate solution, wherein the Baume degree of the magnesium sulfate solution is 20-30 DEG Be', and mixing the magnesium sulfate solution and magnesium oxide to form the magnesium oxysulfate cement slurry, wherein the mass ratio of the magnesium oxide to the magnesium sulfate solution is 1: 0.5-1.5; the magnesium oxide is light-burned magnesium oxide powder, light-burned dolomite powder or magnesia with the active content of MgO being more than 18 percent;
fixing a circle of mould around the section, pouring the magnesium oxysulfate cement slurry into the mould, forming a plane on the surface of the poured magnesium oxysulfate cement slurry, enabling the plane to be horizontal to the upper surface of the mould, curing for 7 days after the magnesium oxysulfate cement slurry is solidified for 24 hours to form a stable solid, and forming a magnesium oxysulfate cement-magnesium oxychloride cement foam concrete integral test piece;
and hydrolyzing the magnesium oxysulfate cement-magnesium oxychloride cement foam concrete integral test piece, wherein the hydrolysis temperature is 20-25 ℃, the hydrolysis process time is 7-14 days, and the residual magnesium oxysulfate cement part is the magnesium oxychloride cement foam concrete air hole structure model.
9. Use of the magnesium oxychloride cement foam concrete pore structure model according to any one of claims 1 to 8 in structural characterization of porosity, pore size distribution, mean pore size, pore distribution, shape factor, pore wall thickness or connectivity of the pores of magnesium oxychloride cement foam concrete.
10. The use of claim 9, wherein the characterization comprises at least one of microscopic observation and SEM inspection.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101054275A (en) * 2006-04-11 2007-10-17 牛宁民 Polymerization foam concrete cement blowing agent
CN104089863A (en) * 2014-06-24 2014-10-08 中国石油天然气股份有限公司 Characterization method for reservoir micro-pore structure
WO2016023060A1 (en) * 2014-08-15 2016-02-18 Laing O'rourke Australia Pty Limited Method for fabricating a composite construction element
CN105628470A (en) * 2015-12-29 2016-06-01 河海大学 Preparation method of penetrated crack rock mass test specimen based on 3D (three-dimensional) printing technology

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101054275A (en) * 2006-04-11 2007-10-17 牛宁民 Polymerization foam concrete cement blowing agent
CN104089863A (en) * 2014-06-24 2014-10-08 中国石油天然气股份有限公司 Characterization method for reservoir micro-pore structure
WO2016023060A1 (en) * 2014-08-15 2016-02-18 Laing O'rourke Australia Pty Limited Method for fabricating a composite construction element
CN105628470A (en) * 2015-12-29 2016-06-01 河海大学 Preparation method of penetrated crack rock mass test specimen based on 3D (three-dimensional) printing technology

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