CN112745050A - Preparation method of modified limestone powder for mass concrete - Google Patents
Preparation method of modified limestone powder for mass concrete Download PDFInfo
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- CN112745050A CN112745050A CN202110007112.XA CN202110007112A CN112745050A CN 112745050 A CN112745050 A CN 112745050A CN 202110007112 A CN202110007112 A CN 202110007112A CN 112745050 A CN112745050 A CN 112745050A
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- limestone powder
- polyethylene glycol
- mass concrete
- copolymer
- stirring
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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
- C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
- C04B20/10—Coating or impregnating
- C04B20/12—Multiple coating or impregnating
-
- 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
- C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B14/02—Granular materials, e.g. microballoons
- C04B14/26—Carbonates
- C04B14/28—Carbonates of calcium
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Civil Engineering (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Other Resins Obtained By Reactions Not Involving Carbon-To-Carbon Unsaturated Bonds (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The invention discloses a preparation method of modified limestone powder for mass concrete, which comprises the following steps: heating and stirring limestone powder and a silane coupling agent in an ethanol solution for 1-2 h: cooling to 60-70 ℃, adding polyoxyethylene ether and ammonium persulfate, stirring for 1-2h, and cooling; adding high molecular polymer and stirring at high speed for 1-2 h; drying to remove ethanol to obtain modified limestone powder. The limestone powder prepared by the invention is grafted with the phase change material on the surface, can be melted into liquid state within the range of 40-60 ℃, adsorbs the hydration heat of concrete, delays the temperature rise rate, is cooled, solidified and releases heat when the temperature of the concrete is lower than 40 ℃, reduces the temperature difference of the inner surface of a concrete structure, and reduces the surface cracking phenomenon.
Description
Technical Field
The invention belongs to the technical field of concrete materials, and particularly relates to a preparation method of modified limestone powder for mass concrete.
Background
The cement hydration heat in concrete can easily cause cracks of mass concrete, for some large-scale engineering projects needing mass concrete, the concrete cracks can easily cause adverse effects on the safety and stability of a concrete structure, and research on the control of the mass concrete cracks has never been stopped at home and abroad. The phase-change material has heat storage property and is widely applied to wall heat-insulating materials. Introducing phase change materials into concrete to control the temperature of the concrete and avoid the damage of the concrete caused by temperature change is also a new research subject.
In recent years, limestone powder is widely applied to concrete to reduce social environmental protection pressure, but the defects of large loss of concrete workability, low strength and the like caused by the natural structural defects (irregular structure and low activity) of the limestone powder after being mixed into the concrete result in a great deal of research on modified limestone powder by scholars, and the problems are mainly solved.
Disclosure of Invention
The invention provides a preparation method of modified limestone powder for mass concrete, and the obtained modified limestone powder can reduce the temperature rise speed of the mass concrete and improve the negative influence of hydration temperature rise on the mass concrete; meanwhile, the particle morphology is changed, the filling property of the limestone powder is improved, and the mixing amount of the concrete admixture is reduced.
In order to achieve the purpose, the technical scheme is as follows:
a preparation method of modified limestone powder for mass concrete comprises the following steps:
1) heating and stirring limestone powder and a silane coupling agent in an ethanol solution for 1-2 h:
2) cooling to 60-70 ℃, adding polyoxyethylene ether and ammonium persulfate, stirring for 1-2h, and cooling;
3) adding high molecular polymer and stirring at high speed for 1-2 h;
4) drying to remove ethanol to obtain modified limestone powder.
According to the scheme, the mass ratio of the limestone powder to the silane coupling agent is 1: 1; the molar ratio of the silane coupling agent to the polyoxyethylene ether is 1: 0.5; the adding amount of the ammonium persulfate is 0.2-0.5 wt% of the polyoxyethylene ether.
According to the scheme, the addition amount of the high molecular polymer is 1-10 wt% of the mass of the limestone powder.
According to the scheme, the specific surface area of the limestone powder is 400-500m2Kg, and the activity index is less than or equal to 75 percent.
According to the scheme, the silane coupling agent is KH570 or KH 550.
According to the scheme, the polyoxyethylene ether is one or a mixture of prenol polyoxyethylene ether and hydroxybutyl vinyl ether with the molecular weight of 2400.
According to the scheme, the high molecular polymer in the step 3 is one or a mixture of polyethylene glycol-polycaprolactone copolymer (PEG-PCL) with molecular weight of 20000-25000, polyethylene glycol-polyaspartic acid copolymer (PEG-PBLA) and polyethylene glycol-polytriethylene carbonate copolymer (PEG-PTMC).
According to the scheme, the polyethylene glycol-polycaprolactone copolymer is prepared in the following mode:
adding polyethylene glycol and polycaprolactone into toluene, initiating a heating reaction for 2 hours by stannous octoate, wherein the molar ratio of the polyethylene glycol to the polycaprolactone is 1:1.5, and removing the toluene to obtain the polyethylene glycol-polycaprolactone copolymer.
According to the scheme, the polyethylene glycol-polycaprolactone copolymer is prepared in the following mode:
adding polyethylene glycol and polyaspartic acid into toluene, initiating a heating reaction for 2 hours by stannous octoate, wherein the molar ratio of the polyethylene glycol to polycaprolactone is 1:1.5, and removing the toluene to obtain the polyethylene glycol-polyaspartic acid copolymer.
According to the scheme, the polyethylene glycol-polycaprolactone copolymer is prepared in the following mode:
adding polyethylene glycol and polytriethylene carbonate into toluene, initiating a heating reaction for 2 hours by stannous octoate, wherein the molar ratio of the polyethylene glycol to the polytriethylene carbonate is 1:1.5, and removing the toluene to obtain the polyethylene glycol-polytriethylene carbonate copolymer.
The invention has the beneficial effects that:
1. the limestone powder prepared by the invention is grafted with a phase change material (polyoxyethylene ether) on the surface, can be melted into a liquid state within the temperature range of 40-60 ℃, adsorbs the hydration heat of concrete, delays the temperature rise rate, is cooled, solidified and releases heat when the temperature of the concrete is lower than 40 ℃, reduces the temperature difference of the inner surface of a concrete structure, and reduces the surface cracking phenomenon.
2. The invention utilizes the high molecular polymer to coat the surface of the limestone powder, thereby protecting the phase change material from being damaged by concrete free water and alkaline environment, improving the irregular shape of the limestone powder and improving the filling effect of the limestone powder.
3. The modified limestone powder improves the usability of the limestone powder and improves the economic value of the limestone powder.
Detailed Description
The following examples further illustrate the technical solutions of the present invention, but should not be construed as limiting the scope of the present invention.
In order to better understand the present invention, the following examples are further provided to illustrate the content of the present invention, but the present invention is not limited to the following examples.
Example 1
Dissolving 50g of limestone powder in 200ml of absolute ethyl alcohol, adding 50gKH570 to the solution, and stirring the solution for 1 hour at the temperature of 80 ℃; cooling to 65 ℃, adding 242g of isopentenol polyoxyethylene ether, adding 1g of ammonium persulfate, stirring for 1.5h, and cooling to room temperature; adding 0.5g of PEG-PCL copolymer with molecular weight of 20000, stirring at high speed for 1h, and oven drying to obtain modified limestone powder.
Example 2
Dissolving 50g of limestone powder in 200ml of absolute ethyl alcohol, adding 50gKH550, and stirring for 1.5h at 80 ℃; cooling to 65 ℃, adding 242g of isopentenol polyoxyethylene ether, adding 1g of ammonium persulfate, stirring for 1.5h, and cooling to room temperature; adding 2.5g of PEG-PBLA copolymer with the molecular weight of 20000, stirring at a high speed for 1h, and drying to obtain the modified limestone powder.
Example 3
Dissolving 50g of limestone powder in 200ml of absolute ethyl alcohol, adding 50gKH570 to the solution, and stirring the solution for 2 hours at the temperature of 80 ℃; cooling to 65 ℃, adding 242g of hydroxybutyl vinyl ether, adding 1g of ammonium persulfate, stirring for 1.5h, and cooling to room temperature; adding 2.5g of PEG-PCL copolymer with molecular weight of 20000, stirring at high speed for 1h, and oven drying to obtain modified limestone powder.
Example 4
Dissolving 50g of limestone powder in 200ml of absolute ethyl alcohol, adding 50gKH550, and stirring for 1.5h at 80 ℃; cooling to 65 ℃, adding 242g of isopentenol polyoxyethylene ether, adding 1.5g of ammonium persulfate, stirring for 1h, and cooling to room temperature; adding 5.0g of PEG-PTMC copolymer with the molecular weight of 25000, stirring at a high speed for 1h, and drying to obtain the modified limestone powder.
Example 5
Dissolving 50g of limestone powder in 200ml of absolute ethyl alcohol, adding 50gKH550, and stirring for 1h at 80 ℃; cooling to 65 ℃, adding 242g of isopentenol polyoxyethylene ether, adding 1.2g of ammonium persulfate, stirring for 1h, and cooling to room temperature; adding 1.0g of PEG-PTMC copolymer with the molecular weight of 25000, stirring at a high speed for 1h, and drying to obtain the modified limestone powder.
Example 6
Dissolving 50g of limestone powder in 200ml of absolute ethyl alcohol, adding 50gKH570 to the solution, and stirring the solution for 2 hours at the temperature of 80 ℃; cooling to 65 ℃, adding 242g of hydroxybutyl vinyl ether, adding 1.3g of ammonium persulfate, stirring for 1.5h, and cooling to room temperature; adding 0.8g of PEG-PBLA copolymer with the molecular weight of 20000, stirring at a high speed for 1h, and drying to obtain the modified limestone powder.
The modified limestone powder and common limestone powder obtained in the above examples are used for preparing mass concrete, and the hydrothermal performance of the concrete is detected, and the raw materials of the mass concrete are compatible as shown in table 1.
Table 1 the design mix proportion of the concrete is:
| kind of material | Cement | Fly ash | Mineral powder | Limestone powder | Sand | Stone (stone) | Water (W) | Additive agent |
| Mass/kg | 260 | 100 | 100 | 50 | 752 | 1038 | 160 | 6.0 |
The hydration heat performance test data of mass concrete prepared by the modified limestone powder and the common limestone powder obtained in the above embodiment are shown in table 2.
Table 2 the hydration heat performance test results of the concrete are:
Claims (10)
1. a preparation method of modified limestone powder for mass concrete is characterized by comprising the following steps:
1) heating and stirring limestone powder and a silane coupling agent in an ethanol solution for 1-2 h:
2) cooling to 60-70 ℃, adding polyoxyethylene ether and ammonium persulfate, stirring for 1-2h, and cooling;
3) adding high molecular polymer and stirring at high speed for 1-2 h;
4) drying to remove ethanol to obtain modified limestone powder.
2. The method for preparing modified limestone powder for mass concrete according to claim 1, wherein the mass ratio of the limestone powder to the silane coupling agent is 1: 1; the molar ratio of the silane coupling agent to the polyoxyethylene ether is 1: 0.5; the adding amount of the ammonium persulfate is 0.2-0.5 wt% of the polyoxyethylene ether.
3. The method for preparing modified limestone powder for mass concrete according to claim 1, wherein the addition amount of the high molecular polymer is 1 to 10 wt% of the mass of the limestone powder.
4. The method for preparing modified limestone powder for mass concrete according to claim 1, wherein the specific surface area of the limestone powder is 400-500m2Kg, and the activity index is less than or equal to 75 percent.
5. The method for preparing modified limestone powder for mass concrete according to claim 1, wherein the silane coupling agent is KH570 or KH 550.
6. The method for preparing modified limestone powder for mass concrete according to claim 1, wherein the polyoxyethylene ether is one or a mixture of prenyl polyoxyethylene ether and hydroxybutyl vinyl ether with a molecular weight of 2400.
7. The method for preparing modified limestone powder for mass concrete according to claim 1, wherein the high molecular weight polymer in step 3 is one or a mixture of polyethylene glycol-polycaprolactone copolymer, polyethylene glycol-polyaspartic acid copolymer and polyethylene glycol-polytriethylene carbonate copolymer with molecular weight of 20000-25000.
8. The method for preparing modified limestone powder for mass concrete according to claim 7, wherein the polyethylene glycol-polycaprolactone copolymer is prepared by the following steps:
adding polyethylene glycol and polycaprolactone into toluene, initiating a heating reaction for 2 hours by stannous octoate, wherein the molar ratio of the polyethylene glycol to the polycaprolactone is 1:1.5, and removing the toluene to obtain the polyethylene glycol-polycaprolactone copolymer.
9. The method for preparing modified limestone powder for mass concrete according to claim 7, wherein the polyethylene glycol-polycaprolactone copolymer is prepared by the following steps:
adding polyethylene glycol and polyaspartic acid into toluene, initiating a heating reaction for 2 hours by stannous octoate, wherein the molar ratio of the polyethylene glycol to polycaprolactone is 1:1.5, and removing the toluene to obtain the polyethylene glycol-polyaspartic acid copolymer.
10. The method for preparing modified limestone powder for mass concrete according to claim 7, wherein the polyethylene glycol-polycaprolactone copolymer is prepared by the following steps:
adding polyethylene glycol and polytriethylene carbonate into toluene, initiating a heating reaction for 2 hours by stannous octoate, wherein the molar ratio of the polyethylene glycol to the polytriethylene carbonate is 1:1.5, and removing the toluene to obtain the polyethylene glycol-polytriethylene carbonate copolymer.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000191350A (en) * | 1998-12-25 | 2000-07-11 | Lion Corp | Solubility improver of powdery cement admixture and composite cement admixture containing the same |
| CN105236805A (en) * | 2015-09-09 | 2016-01-13 | 武汉源锦商品混凝土有限公司 | Polycarboxylic acid surface modified ultrafine stone powder and preparation method thereof |
| DE102015003637A1 (en) * | 2015-03-19 | 2016-09-22 | B.T. Innovation Gmbh | Joint tape for sealing joints |
| CN108996970A (en) * | 2018-09-22 | 2018-12-14 | 西安科技大学 | A kind of ultra-fine earth concrete and preparation method thereof |
| CN111393110A (en) * | 2020-03-28 | 2020-07-10 | 德清高盛交通科技有限公司 | Full-machine-made sand masonry mortar with limestone as aggregate and preparation method thereof |
-
2021
- 2021-01-05 CN CN202110007112.XA patent/CN112745050B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000191350A (en) * | 1998-12-25 | 2000-07-11 | Lion Corp | Solubility improver of powdery cement admixture and composite cement admixture containing the same |
| DE102015003637A1 (en) * | 2015-03-19 | 2016-09-22 | B.T. Innovation Gmbh | Joint tape for sealing joints |
| CN105236805A (en) * | 2015-09-09 | 2016-01-13 | 武汉源锦商品混凝土有限公司 | Polycarboxylic acid surface modified ultrafine stone powder and preparation method thereof |
| CN108996970A (en) * | 2018-09-22 | 2018-12-14 | 西安科技大学 | A kind of ultra-fine earth concrete and preparation method thereof |
| CN111393110A (en) * | 2020-03-28 | 2020-07-10 | 德清高盛交通科技有限公司 | Full-machine-made sand masonry mortar with limestone as aggregate and preparation method thereof |
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| CN112745050B (en) | 2022-03-18 |
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