CN112694274A - Internal curing material suitable for light high-strength high-ductility cement-based cementing composite material and pretreatment method thereof - Google Patents
Internal curing material suitable for light high-strength high-ductility cement-based cementing composite material and pretreatment method thereof Download PDFInfo
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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
- C04B40/0028—Aspects relating to the mixing step of the mortar preparation
- C04B40/0039—Premixtures of ingredients
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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
- 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
- C04B28/02—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 hydraulic cements other than calcium sulfates
- C04B28/04—Portland cements
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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
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/20—Mortars, concrete or artificial stone characterised by specific physical values for the density
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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
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
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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
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
- C04B2201/52—High compression strength concretes, i.e. with a compression strength higher than about 55 N/mm2, e.g. reactive powder concrete [RPC]
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A30/00—Adapting or protecting infrastructure or their operation
- Y02A30/30—Adapting or protecting infrastructure or their operation in transportation, e.g. on roads, waterways or railways
Abstract
The invention discloses an internal curing material suitable for a light high-strength high-ductility cement-based cementing composite material and a pretreatment method thereof, wherein the internal curing material comprises the following components in percentage by weight: 75-85% of coal cinder, 5-10% of dolomite and 10-20% of perlite, wherein the coal cinder is waste residue discharged by other coal-fired equipment such as a thermal power plant, an industrial boiler, a civil boiler and the like, and comprises the following components: SiO 2240％‑50％、Al2O330％‑35％、Fe2O34% -20% of dolomite, CaCO3The content of (1) is 30-35%, MgCO3The content of the perlite is 20 to 25 percent, the water content of the perlite is 2 to 6 percent, and the density is 2.2 to 2.4g/cm3The perlite comprises the following components of SiO268％‑74％、Al2O312％‑15％、Fe2O31% -3%, the bulk density of the internal curing material is 300-3The grain diameter is 0.08-0.135mm, the specific surface area is 2300m2Kg, fine pores are uniformly distributed in the surface area. The internal curing material obtained by the invention has the advantages of light weight, more pores, small particle size and certain activity, is suitable for being used in light high-strength high-performance concrete, reduces the volume weight of the concrete and ensures higher mechanical property and durability.
Description
Technical Field
The invention belongs to the technical field of concrete materials, and particularly relates to an internal curing material suitable for a light high-strength high-ductility cement-based cementing composite material and a pretreatment method thereof.
Background
With the increasing requirements of engineering application, high-performance concrete is widely used. The high-performance concrete mainly comprises ultrahigh-performance concrete (UHPC) with ultrahigh strength, Engineering Cementitious Composite (ECC) with ultrahigh ductility and the like. Compared with common concrete, the high-performance concrete has the characteristics of excellent mechanical property and durability, can better meet the structural function requirement and the construction process requirement, prolongs the service life of a concrete structure to the maximum extent, and reduces the construction cost. However, high performance concrete has the characteristic of larger cement consumption, which results in low cement-to-cement ratio of the concrete. In the cement hydration process, due to insufficient water, water in pores around cement particles is continuously consumed and becomes unsaturated, so that the water in capillary pores generates a concave liquid surface under the action of surface tension, and the pore walls are inwardly tightenedCausing the concrete to self-shrink. This may result in microcracks on the surface and inside of the high performance concrete, and the mechanical and durability properties of the slurry concrete. According to research, the shrinkage strain of the common concrete is 400-600 multiplied by 10-6While the shrinkage strain of UHPC and ECC can reach as high as 1200--6。
Aiming at the defect of large shrinkage of high-performance concrete, researchers mainly use an expanding agent, a shrinkage reducing agent, rice hull ash and pretreated lightweight aggregate to reduce the shrinkage of the high-performance concrete at present, wherein the shrinkage reducing principle is as follows: (1) the expanding agent is mainly used for participating in hydration to generate an expansion phase to compensate shrinkage; (2) the shrinkage reducing agent can be well dispersed into a matrix, stores moisture in the concrete mixing and hardening process, and slowly releases moisture in the curing process to reduce shrinkage; (3) the pretreated lightweight aggregate is characterized in that the porous characteristic of the lightweight aggregate is utilized to absorb and store water in pores in advance, and then water is slowly released in the maintenance process to reduce shrinkage; (4) the rice hull ash can utilize the overlarge specific surface area of the rice hull ash, and the adsorbed water particles are slowly released in the curing process to limit the shrinkage.
At present, researches show that the use of an expanding agent and a shrinkage reducing agent can influence the hydration of cement and reduce the strength of concrete. The use of the rice husk ash can reduce the fluidity of the concrete and influence the workability of the concrete. The pretreated lightweight aggregate also has disadvantages that the strength of concrete is lowered and the effect of suppressing shrinkage is not remarkable due to insufficient water absorption and water release of the lightweight aggregate.
Publication No. CN101898877A discloses a lightweight aggregate pretreatment method for internal curing of cement-based materials, which is characterized in that: the lightweight aggregate to be used for internal curing is completely immersed in the shrinkage-reducing agent solution and is saturated, and then is filtered out from the shrinkage-reducing agent solution to be used as the concrete internal curing material. The method reduces the shrinkage of the concrete and slightly improves the strength of the concrete. However, the experimental results of the invention show that the strength of the concrete prepared by the lightweight aggregate is lower than that of the pre-saturated water lightweight aggregate, the reinforcing effect is not obvious, and the shrinkage reducing agent is used to increase the manufacturing cost of the concrete.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides an internal curing material suitable for a light-weight high-strength high-ductility cement-based cementing composite material, which has the characteristics of light weight, small particle size, more gaps and the like, is suitable for manufacturing light-weight high-strength high-performance concrete after being pre-protected, greatly reduces the shrinkage of the concrete, and can maintain higher mechanical property when the volume weight of the concrete is reduced. In addition, the invention also provides a pretreatment method of the internal curing material suitable for the light high-strength high-ductility cement-based cementitious composite, after the internal curing material is treated by a vacuum water saturation method, the shrinkage of concrete is further reduced, and the mechanical property is further improved.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides an internal curing material suitable for a light high-strength high-ductility cement-based cementitious composite, which comprises the following components in percentage by weight: 75-85% of coal cinder, 5-10% of dolomite and 10-20% of perlite, wherein the coal cinder is waste residue discharged by other coal-fired equipment such as a thermal power plant, an industrial boiler, a civil boiler and the like, and comprises the following components: SiO 2240％-50％、Al2O330％-35％、Fe2O34% -20% of dolomite, CaCO3The content of (1) is 30-35%, MgCO3The content of the perlite is 20 to 25 percent, the water content of the perlite is 2 to 6 percent, and the density is 2.2 to 2.4g/cm3The perlite comprises the following components of SiO268％-74％、Al2O312％-15％、Fe2O31% -3%, the bulk density of the internal curing material is 300-3The grain diameter is 0.08-0.135mm, the specific surface area is 2300m2Kg, inside which micro pores are uniformly distributed.
Further, the paint comprises the following components in percentage by weight: 75% of coal cinder, 5% of dolomite, 15% of perlite and 5% of water.
Further, the paint comprises the following components in percentage by weight: 80% of coal cinder, 7% of dolomite, 10% of perlite and 3% of water.
Further, the paint comprises the following components in percentage by weight: 75% of coal cinder, 10% of dolomite, 10% of perlite and 5% of water.
Further, the preparation method of the internal curing material comprises the following steps:
step one, crushing coal cinder, dolomite and perlite by using a jaw crusher, pouring the crushed materials into a ball mill for grinding for 4-5 hours, and sieving the obtained powder with a 350-mesh sieve;
secondly, adding the obtained powder into a granulator for stirring at the stirring speed of 150r/min, spraying water mist accounting for 3 percent of the mass of the powder in the stirring process, and stopping stirring when the particle size of the particles is between 80 and 120 meshes to obtain semi-finished product particles;
step three, transferring the semi-finished product particles into a drying kiln, keeping the temperature at 105 +/-5 ℃ for drying for 2 hours, and cooling to room temperature to obtain a semi-finished product internal curing material;
step four, transferring the semi-finished product internal curing material into a rotary kiln for calcination, wherein the rotating speed of the rotary kiln is 250r/min, heating to 980 ℃ at the speed of 10 ℃/min, keeping for 1-1.5h, then heating to 1100 ℃, and keeping for 2 h;
and step five, cooling the calcined semi-finished product curing material in a natural cooling mode, and cooling to room temperature to obtain the finished product internal curing material.
In a second aspect of the present invention, there is provided a method for pretreating an internal curing material suitable for a lightweight, high-strength and high-ductility cement-based cementitious composite, for pretreating the internal curing material, comprising the following steps:
step one, putting an internal curing material into a vacuum container of a vacuum water retention machine, and screwing a vacuum cover above the vacuum container to be in a sealed state;
step two, reducing the air pressure in the vacuum container to 1-5kpa within 5min by using a vacuum pump attached to a vacuum water retention instrument, and maintaining the vacuum degree for 3 hours;
step three, under the condition that the vacuum pump is still operated, running water is injected into the container, and the liquid level height is ensured to submerge the internal curing materials;
and step four, immersing the internal curing material for 1 hour, and continuously immersing for 18 hours to obtain the pretreated internal curing material.
The third aspect of the invention provides a lightweight high-strength high-ductility cement-based cementing material, which comprises 40 parts of the pretreated internal curing material, 400 parts of cement, 250 parts of glass beads, 200 parts of silicon powder, 32 parts of a high-efficiency water reducing agent, 26 parts of synthetic fibers and 240 parts of water.
Further, the cement is ordinary portland cement, the 28d compressive strength is more than or equal to 52.5MPa, and the true density is 3050kg/m3The specific surface area is 455m2Per kg; the specific surface area of the glass beads is 120m2Per kg, bulk density 256kg/m3An apparent density of 400kg/m3The particle size is distributed between 100 and 250 mu m; the activity index of the silica fume is more than 95 percent, and the bulk density is 390kg/m3The specific surface area is 22000m2Per kg, the particle size distribution is between 0.1 and 0.3 mu m; the yellow sand is medium sand, the fineness modulus is 2.5, and the bulk density is 1480kg/m3(ii) a The high-efficiency water reducing agent is a PCA type polycarboxylate water reducing agent, and the water reducing rate is more than 30 percent; the synthetic fiber is high-elastic modulus high-strength polyvinyl alcohol fiber with the length of 12mm, the diameter of 0.04mm and the density of 970kg/m3The tensile strength was 1600MPa, and the elastic modulus was 38 GPa.
Further, the preparation method of the cement-based cementing material comprises the following steps:
step one, mixing and stirring 700 parts of cement, 250 parts of glass beads, 200 parts of silica fume, 250 parts of yellow sand and 40 parts of vacuum pre-saturated internal curing material for 1min to obtain a dry material;
step two, pouring 32 parts of the high-efficiency water reducing agent into 240 parts of water, uniformly stirring, adding the mixture into the dry materials, mixing and stirring for 6min to obtain slurry;
and step three, scattering 26 parts of synthetic fibers into the slurry in a dispersing manner, and stirring for 2min to obtain the light high-strength high-ductility cement-based cementitious composite.
Compared with the prior art, the invention has the beneficial effects that:
(1) the main component of the internal curing material is industrial waste coal slag, so that the pollution of solid waste to the environment is reduced, part of yellow sand can be replaced, and the excessive exploitation of river sand resources is reduced.
(2) The internal curing material obtained by the invention has the advantages of light weight, more pores, small particle size and certain activity, is suitable for being used in light high-strength high-performance concrete, reduces the volume weight of the concrete and ensures higher mechanical property and durability.
(3) The pre-saturation treatment method of the internal curing material is simple and effective, improves the water absorption rate of the internal curing material, greatly reduces the early shrinkage of high-performance concrete, and strengthens the interface transition area of slurry and the internal curing material so as to improve the mechanical property of the concrete. The shrinkage strain of the lightweight high-strength high-ductility cement-based cementing composite material prepared by the method is only 421 multiplied by 10-6The compressive strength reaches 75.1 MPa.
Drawings
Fig. 1 is a graph of shrinkage strain within 28d for the lightweight high strength high ductility cementitious composite of example 4, comparative example 1 and comparative example 4.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.
The materials used in the examples of the present invention are, if not specified, well-known and commercially available chemical materials.
Example 1
The embodiment provides an internal curing material, which consists of the following raw materials in percentage by weight: 75% of cinder, 5% of dolomite, 15% of perlite and 5% of water.
The internal curing material provided in this example is prepared by the following steps:
step one, crushing 75% of coal cinder, 5% of dolomite and 15% of perlite by using a jaw crusher, pouring the crushed materials into a ball mill for ball milling for 4-5h, and sieving the obtained powder with a 350-mesh sieve.
Secondly, adding the obtained powder into a granulator for stirring, wherein the stirring speed is 150r/min, spraying water mist accounting for 5% of the mass of the powder in the stirring process, and stopping stirring when the particle size of the particles is between 80 meshes and 120 meshes to obtain semi-finished product particles;
step three, transferring the semi-finished product particles into a drying kiln, keeping the temperature at 105 +/-5 ℃ for drying for 2 hours, cooling to room temperature, and screening out particles smaller than 80 meshes to obtain a semi-finished product internal curing material;
step four, transferring the semi-finished product internal curing material into a rotary kiln for calcination, wherein the rotating speed of the rotary kiln is 250r/min, heating to 980 ℃ at the speed of 10 ℃/min, keeping for 1-1.5h, then heating to 1100 ℃, and keeping for 2 h;
and step five, cooling the calcined semi-finished product internal curing material in a natural cooling mode, and cooling to room temperature to obtain the finished product internal curing material.
The coal slag in the embodiment is waste slag discharged by other coal-fired equipment such as a thermal power plant, an industrial boiler and a civil boiler, and comprises the following components: SiO 2240％-50％、Al2O330％-35％、Fe2O34% -20% of dolomite, CaCO3The content of (B) is 30-35%, MgCO3The content of the perlite is 20-25%, the water content of the perlite is 2-6%, and the density is 2.2-2.4g/cm3The perlite comprises the following components of SiO268％-74％、Al2O312％-15％、Fe2O31% -3%, the bulk density of the internal curing material is 300-400kg/m3The grain diameter is 0.08-0.135mm, the specific surface area is 2300m2Kg, fine pores are uniformly distributed in the surface area.
Example 2
The embodiment provides an internal curing material, which consists of the following raw materials in percentage by weight: 80% of cinder, 7% of dolomite, 10% of perlite and 3% of water.
The preparation method is the same as that of example 1.
Example 3
The embodiment provides an internal curing material, which consists of the following raw materials in percentage by weight: 75% of cinder, 10% of dolomite, 10% of perlite and 5% of water.
The preparation method is the same as that of example 1.
Example 4
The embodiment provides a lightweight, high-strength and high-ductility cement-based cementitious composite material, which is composed of the following raw materials in percentage by weight: 700 parts of cement, 250 parts of glass beads, 200 parts of silica fume, 250 parts of yellow sand, 40 parts of pretreated internal curing material, 32 parts of high-efficiency water reducing agent, 26 parts of synthetic fiber and 240 parts of water.
The pretreatment method of the internal curing material comprises the following steps:
step one, the internal curing material obtained in the example 1 is put into a vacuum container dried by a vacuum water saturation instrument, and a vacuum cover above the vacuum container is screwed down to be in a sealed state.
And step two, reducing the air pressure in the vacuum container to 1-5kPa within 5min by utilizing a vacuum pump attached to a vacuum water saturation instrument, and keeping the vacuum degree for 3 h.
And step three, under the condition that the vacuum pump is still operated, filling tap water into the container, wherein the liquid level is high enough to submerge the internal curing materials.
And step four, after the internal curing material is immersed for 1h, the normal pressure is recovered, and the internal curing material is continuously immersed for 18h to obtain the vacuum saturated pretreated internal curing material.
In this embodiment, the preparation method of the lightweight, high-strength and high-ductility cement-based cementitious composite material includes the following steps:
step one, mixing and stirring 700 parts of cement, 250 parts of glass beads, 200 parts of silica fume, 250 parts of yellow sand and 40 parts of vacuum saturated water internal curing material for 1min to obtain a dry material;
step two, pouring 32 parts of the high-efficiency water reducing agent into 240 parts of water, uniformly stirring, adding the mixture into the dry materials, mixing and stirring for 6min to obtain slurry;
and step three, scattering 26 parts of synthetic fibers into the slurry in a dispersing manner, and stirring for 2min to obtain the light high-strength high-ductility cement-based cementitious composite.
Example 5
This example shows a lightweight high-strength high-ductility cement-based cementitious composite, which was prepared in the same manner as in example 4, except that the internal curing material obtained in example 2 was used.
Example 6
This example shows a lightweight, high-strength, high-ductility cement-based cementitious composite prepared in a manner similar to that of example 4 for two days, except that the internal curing material obtained in example 3 was used.
Comparative example 1
This example shows a lightweight, high strength, and high ductility cement-based cementitious composite, the internal curing material being the internal curing material of example 1, but not treated with supersaturated water.
The preparation method of the lightweight, high-strength and high-ductility cement-based cementitious composite material described in this embodiment is as follows:
step one, mixing and stirring 700 parts of cement, 250 parts of glass beads, 200 parts of silica fume, 250 parts of yellow sand and 40 parts of internal curing material for 1min to obtain a dry material;
step two, pouring 32 parts of the high-efficiency water reducing agent into 240 parts of water, uniformly stirring, adding the mixture into the dry materials, mixing and stirring for 6min to obtain slurry;
and step three, scattering 26 parts of synthetic fibers into the slurry in a dispersing manner, and stirring for 2min to obtain the light high-strength high-ductility cement-based cementitious composite.
Comparative example 2
This example shows a lightweight, high-strength, high-ductility cement-based cementitious composite prepared in the same manner as in comparative example 1, except that the internal curing material was the internal curing material of example 2 without being treated with saturated water.
Comparative example 3
This example shows a lightweight, high-strength, high-ductility cement-based cementitious composite prepared in the same manner as comparative example 1, except that the internal curing material was not treated with saturated water as comparative example 4 of the internal curing material of example 3
This example provides a lightweight, high-strength, and high-ductility cement-based cementitious composite, where the internal curing material is the internal curing material of example 1, and the internal curing material is treated with saturated water at normal pressure, and the method includes: the internal curing material obtained in example 1 was immersed in tap water at normal pressure and then kept for further 24 hours to obtain a pretreated internal curing material.
The preparation method of the light, high-strength and high-ductility cement-based cementitious composite material of the embodiment is as follows:
step one, mixing and stirring 700 parts of cement, 250 parts of glass beads, 200 parts of silica fume, 250 parts of yellow sand and 40 parts of normal-pressure saturated water internal curing material for 1min to obtain a dry material;
step two, pouring 32 parts of the high-efficiency water reducing agent into 240 parts of water, uniformly stirring, adding the mixture into the dry materials, mixing and stirring for 6min to obtain slurry;
and step three, scattering 26 parts of synthetic fibers into the slurry in a dispersing manner, and stirring for 2min to obtain the light high-strength high-ductility cement-based cementitious composite.
Comparative example 5
This example shows a lightweight high-strength high-ductility cement-based cementitious composite prepared in the same manner as in comparative example 4, except that the internal curing material was the internal curing material obtained in example 2.
Comparative example 6
This example shows a lightweight high-strength high-ductility cement-based cementitious composite prepared in the same manner as in comparative example 4, except that the internal curing material was the internal curing material obtained in example 3.
The weight percentages of the components of the internal curing material in examples 1-3 are summarized in Table 1.
The parts by weight of each component and the pretreatment method in examples 4 to 6 and comparative examples 1 to 6 are summarized in Table 2.
Performance test
1. A method for testing an internal curing material is provided, in which the internal curing materials of examples 1 to 3 and comparative examples 4 to 6 were subjected to a water absorption test in accordance with the Standard "technical Specification for lightweight aggregate concrete" (JGJ 51-2002).
2. The cement-based cementitious composite materials obtained in example 1, comparative example 1 and comparative example 4 are tested for non-contact shrinkage value in fresh concrete 28d according to the national standard of test method standard for long-term performance and durability of ordinary concrete (GB/T50082-2009).
3. The cement-based cementitious composite materials obtained in examples 4-6 and comparative examples 1-6 are subjected to compressive strength tests of cement-based cementitious composite materials 7d and 28d according to the national standard 'mechanical property test method for ordinary cement-based cementitious composite materials' (GB/T50081-2002).
4. The cement-based cementitious composite obtained in example 1-2 was subjected to a volume weight test of the cement-based cementitious composite according to the standard test methods for volume weight and air content of fresh-poured cement-based cementitious composite (JIS A1116-1998).
The water absorption test data of the internal curing material are shown in Table 3.
| Serial number | Internal curing material water absorption/%) |
| Example 1 | 17.1 |
| Example 2 | 16.4 |
| Example 3 | 16.1 |
| Comparative example 4 | 14.4 |
| Comparative example 5 | 14.3 |
| Comparative example 6 | 13.9 |
The data of the compressive strength and the volume weight of the light high-strength high-ductility cement-based cementitious composite are shown in table 4.
The implementation effect is as follows:
as can be seen from Table 3, the water absorption of the cured material in the vacuum saturation pretreatment can be increased to a greater extent. As is apparent from fig. 1, the higher the water absorption of the internal curing material, the smaller the shrinkage strain of the cement-based cementitious composite produced therefrom, and it is apparent from the figure that the shrinkage strain of the cement-based cementitious composite produced from the internal curing material after vacuum saturation treatment was the smallest at age 28d, and the value thereof was less than half of that of the unsaturated-treated sample. Moreover, as can be seen from table 4, under the condition that the volume weight is kept basically consistent, the compressive strength of the cement-based cementitious composite material prepared by the internal curing material after vacuum saturation treatment is also greatly improved. Therefore, the internal curing material and the pretreatment method thereof prepared by the invention can greatly improve the shrinkage performance and the mechanical property of the prepared cement-based cementing composite material.
Although the present invention has been described in detail with respect to the above embodiments, it will be understood by those skilled in the art that modifications or improvements based on the disclosure of the present invention may be made without departing from the spirit and scope of the invention, and these modifications and improvements are within the spirit and scope of the invention.
Claims (9)
1. The internal curing material suitable for the light high-strength high-ductility cement-based cementitious composite is characterized by comprising the following components in percentage by weight: 75-85% of coal cinder, 5-10% of dolomite and 10-20% of perlite, wherein the coal cinder is waste residue discharged by coal-fired equipment, and comprises the following components: SiO 2240％-50％、Al2O330％-35％、Fe2O34% -20% of dolomite, CaCO3The content of (1) is 30-35%, MgCO3The content of the perlite is 20 to 25 percent, the water content of the perlite is 2 to 6 percent, and the density is 2.2 to 2.4g/cm3The perlite comprises the following components of SiO268％-74％、Al2O312％-15％、Fe2O31% -3%, the bulk density of the internal curing material is 300-3The grain diameter is 0.08-0.135mm, the specific surface area is 2300m2/kg。
2. The internal curing material suitable for the light-weight, high-strength and high-ductility cement-based cementitious composite material as claimed in claim 1, which is characterized by comprising the following components in percentage by weight: 75% of coal cinder, 5% of dolomite, 15% of perlite and 5% of water.
3. The internal curing material suitable for the light-weight, high-strength and high-ductility cement-based cementitious composite material as claimed in claim 1, which is characterized by comprising the following components in percentage by weight: 80% of coal cinder, 7% of dolomite, 10% of perlite and 3% of water.
4. The internal curing material suitable for the light-weight, high-strength and high-ductility cement-based cementitious composite material as claimed in claim 1, which is characterized by comprising the following components in percentage by weight: 75% of coal cinder, 10% of dolomite, 10% of perlite and 5% of water.
5. The internal curing material for the cement-based cementitious composite material with light weight, high strength and high ductility as claimed in claim 1, wherein the preparation method of the internal curing material comprises the following steps:
step one, crushing coal cinder, dolomite and perlite by using a jaw crusher, pouring the crushed materials into a ball mill for grinding for 4-5 hours, and sieving the obtained powder with a 350-mesh sieve;
secondly, adding the obtained powder into a granulator for stirring at the stirring speed of 150r/min, spraying water mist accounting for 3 percent of the mass of the powder in the stirring process, and stopping stirring when the particle size of the particles is between 80 and 120 meshes to obtain semi-finished product particles;
step three, transferring the semi-finished product particles into a drying kiln, keeping the temperature at 105 +/-5 ℃ for drying for 2 hours, and cooling to room temperature to obtain a semi-finished product internal curing material;
step four, transferring the semi-finished product internal curing material into a rotary kiln for calcination, wherein the rotating speed of the rotary kiln is 250r/min, heating to 980 ℃ at the speed of 10 ℃/min, keeping for 1-1.5h, then heating to 1100 ℃, and keeping for 2 h;
and step five, cooling the calcined semi-finished product curing material in a natural cooling mode, and cooling to room temperature to obtain the finished product internal curing material.
6. A method for pretreating an internal curing material, for pretreating the internal curing material according to any one of claims 1 to 5, comprising the steps of:
step one, putting an internal curing material into a vacuum container of a vacuum water retention machine, and screwing a vacuum cover above the vacuum container to be in a sealed state;
step two, reducing the air pressure in the vacuum container to 1-5kpa within 5min by using a vacuum pump attached to a vacuum water retention instrument, and maintaining the vacuum degree for 3 hours;
step three, under the condition that the vacuum pump is still operated, running water is injected into the container, and the liquid level height is ensured to submerge the internal curing materials;
and step four, immersing the internal curing material for 1 hour, and continuously immersing for 18 hours to obtain the pretreated internal curing material.
7. A light-weight high-strength high-ductility cement-based cementing material is characterized by comprising 40 parts of the pretreated internal curing material of claim 6, 400 parts of cement, 250 parts of glass beads, 200 parts of silicon powder, 32 parts of a high-efficiency water reducing agent, 26 parts of synthetic fibers and 240 parts of water.
8. The lightweight high ductility cement-based cementitious material of claim 7, wherein said cement is ordinary portland cement, having a 28d compressive strength of 52.5MPa or more and a true density of 3050kg/m3The specific surface area is 455m2Per kg; the specific surface area of the glass beads is 120m2Per kg, bulk density 256kg/m3An apparent density of 400kg/m3The particle size is distributed between 100 and 250 mu m; the activity index of the silica fume is more than 95 percent, and the bulk density is 390kg/m3The specific surface area is 22000m2Per kg, the particle size distribution is between 0.1 and 0.3 mu m; the yellow sand is medium sand, the fineness modulus is 2.5, and the bulk density is 1480kg/m3(ii) a The high-efficiency water reducing agent is a PCA type polycarboxylate water reducing agent, and the water reducing rate is more than 30 percent; the synthetic fiber is high-elastic modulus high-strength polyvinyl alcohol fiber with the length of 12mm, the diameter of 0.04mm and the density of 970kg/m3The tensile strength was 1600MPa, and the elastic modulus was 38 GPa.
9. The lightweight high ductility cement-based cementitious material according to claim 7, characterized in that said cement-based cementitious material is prepared by a method comprising the steps of:
step one, mixing and stirring 700 parts of cement, 250 parts of glass beads, 200 parts of silica fume, 250 parts of yellow sand and 40 parts of pretreated internal curing material for 1min to obtain a dry material;
step two, pouring 32 parts of the high-efficiency water reducing agent into 240 parts of water, uniformly stirring, adding the mixture into the dry materials, mixing and stirring for 6min to obtain slurry;
and step three, scattering 26 parts of synthetic fibers into the slurry in a dispersing manner, and stirring for 2min to obtain the light high-strength high-ductility cement-based cementitious composite.
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