CN112745068A - Concrete doped with modified pozzolanic fine powder and preparation method thereof - Google Patents
Concrete doped with modified pozzolanic fine powder and preparation method thereof Download PDFInfo
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- CN112745068A CN112745068A CN201911041533.3A CN201911041533A CN112745068A CN 112745068 A CN112745068 A CN 112745068A CN 201911041533 A CN201911041533 A CN 201911041533A CN 112745068 A CN112745068 A CN 112745068A
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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
- C04B2201/50—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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- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The invention discloses a concrete doped with modified pozzolana fine powder, which is prepared from the following raw materials in parts by mass: 550 parts of cement, 50-165 parts of modified pozzolanic fine powder, 850 parts of ore sand, 800-1350 parts of crushed stone, 240 parts of water and 1.5-10 parts of a water reducing agent; the preparation method comprises the steps of firstly putting the ore sand and the broken stones into a stirrer to be stirred for 10-30s, then putting the cement and the modified pozzolanic fine powder into the stirrer to be stirred for 10-30s, and finally adding the water and the water reducing agent to be stirred for 25-35s to obtain the concrete doped with the modified pozzolanic fine powder. By doping the modified pozzolanic powder, the slump retention property, the workability and the durability of the concrete are improved, the hydration heat is reduced, the alkali aggregate reaction is inhibited, the early strength of the concrete is not obviously reduced, the long-term strength of the concrete can be ensured to be increased through self-maintenance, and the using amount of cement can be further reduced.
Description
Technical Field
The invention relates to a concrete material, in particular to concrete doped with modified pozzolana fine powder and a preparation method thereof.
Background
Concrete is one of the most important building materials at present, and is used in almost all modern buildings. In the construction and civil engineering fields, concrete is generally prepared by mixing a gel material, aggregate and water, and an appropriate amount of additives and admixtures are often added for improving the performance. The fly ash serving as an admixture widely applied at present can improve the workability of concrete mixture, reduce the temperature rise of concrete, improve the durability and the wear resistance of the concrete and reduce the cost of the concrete, but the strength development is slow, the early strength is low, and in addition, the fly ash cannot be well utilized in areas with insufficient fly ash resources or unstable performance indexes, so that a fly ash substitute is urgently needed to be found, the problem of market resources can be solved, and the performance indexes and the environmental adaptability of the concrete mixture can be further improved.
In order to improve the quality of palm oil in the production process of palm oil, fine pozzolanic powder is required to be used as an adsorbent to adsorb phospholipid, saponin, harmful pigments, peculiar smell substances and the like in the palm oil. The fine pozzolana powder is an adsorbent which is prepared by using volcanic ash as a raw material, performing inorganic acidification treatment to enable fine pozzolana powder particles to form a porous structure, rinsing with water and drying, and has a density of 2.3-2.5 g/cm3. The palm oil becomes clear and has good mouthfeel after being filtered by the fine volcanic ash powder, but the adsorptivity of the fine volcanic ash powder is reduced along with the increase of the filtering times of the palm oil, so that the adsorption activity is lost finally. The fine powder without the adsorption activity is a waste product for palm oil processing enterprises. The palm oil residue contains about 75% of palm oil, the oil has certain economic value after being refined and separated, the palm oil residue treatment plant recovers the palm oil residue of palm oil processing enterprises, and the oil and the fine volcanic ash powder are separated under high temperature and high pressure after being processed and refined. In the environment of high temperature and high pressure, the fine pozzolana powder is converted into amorphous state, and the pozzolana activity is improved, namely modified fine pozzolana powder (EPP).
The application of the modified fine pozzolanic powder (EPP) to the technical field of concrete preparation has not been reported at home and abroad.
Disclosure of Invention
The technical problem to be solved is as follows: aiming at the defects of the prior art, the invention provides the concrete doped with the modified pozzolanic fine powder and the preparation method thereof, and the modified pozzolanic fine powder (EPP) is doped into the concrete to replace fly ash, so that the slump retention property, the workability and the durability of the concrete are improved, the hydration heat is reduced, the alkali-aggregate reaction is inhibited, the early strength of the concrete is not obviously reduced, the long-term strength of the concrete is ensured to be increased, and the using amount of the cement can be further reduced.
The technical scheme is as follows: the invention provides a concrete doped with modified pozzolana fine powder, which is prepared from the following raw materials in parts by mass: 550 parts of cement, 50-165 parts of modified pozzolanic fine powder, 850 parts of ore, 800-1350 parts of crushed stone, 240 parts of water and 1.5-10 parts of a water reducing agent.
The invention provides a preparation method of concrete doped with modified pozzolanic fine powder, which comprises the following preparation steps:
(1) firstly, putting 850 parts of 550 sand and 800 parts of sand and 1350 parts of gravel into a stirrer to be uniformly stirred for 10-30s to obtain sandstone aggregate;
(2) then, putting 550 parts of cement 240-550 parts and 50-165 parts of modified pozzolanic fine powder into a stirrer, uniformly stirring the cement and the sand aggregate in the step (1), and stirring for 10-30s to obtain a cementing material;
(3) and (3) finally, adding 240 parts of water 120-sand and 1.5-10 parts of water reducing agent into the cementing material obtained in the step (2), uniformly stirring, and stirring for 25-35s to obtain the concrete doped with the modified pozzolanic fine powder.
The modified pozzolanic fine powder meets the following parameter conditions: 45 μm sieve reject (%): 10 to 30 percent; 28d Activity index (%): 75-98.1%; water demand ratio (%): 105-115%.
The cement is Portland cement or ordinary Portland cement; the water reducing agent is a high-efficiency water reducing agent taking polycarboxylic acid as a main component. The fineness modulus of the ore sand is 2.0-3.5; the continuous gradation of the crushed stones is 5-40 mm.
The mixer is a forced concrete mixer, the feeding capacity is 750-1500L, and the rotating speed is 20-35 r/min.
Has the advantages that: after the concrete is doped with the modified pozzolanic fine powder, the technical performance indexes are remarkably improved:
(1) the density is low (1.96 g/cm)3The density of the cement is usually 3.05 to 3.15g/cm3) After cement is replaced by the concrete with medium mass, the volume of cement paste is greatly increased, and the workability of the concrete is improved. In the concrete with the same strength grade, the single-component cementing material is added into the concrete with the EPP under the premise of meeting the technical performance of the concrete, and has the similar slurry volume with the concrete only using cementThe dosage is greatly reduced, and the dosage of the cement is reduced by 15 to 30 percent.
The density of the fine pozzolanic powder before modification is 2.3-2.5 g/cm3The density after modification is 1.8 to 2.0g/cm3The density was reduced by about 20.8%. The volcanic ash fine powder has the characteristics of a porous structure, so that the volcanic ash fine powder has a large specific surface area, the surface area contacted with air is large, air and other gases are introduced in the process of breaking and recombining chemical bonds among atoms of fine powder particles in a high-temperature and high-pressure environment, a large number of closed small bubbles are formed in the particles, the apparent volume of the particles is increased, and the density is reduced.
(2) The activity index is high, and the early strength of the concrete can not be obviously reduced after the cement with equal quality is substituted and is doped into the concrete.
Active oxide SiO of EPP2+Al2O3+Fe2O3The content of the high-activity volcanic ash reaches more than 80 percent, so that the high-activity volcanic ash has high volcanic ash reaction activity. The porous structure of the EPP enables the surface of the EPP to have a larger chance of contacting water, thereby not only improving the pozzolanic activity of the EPP, but also enabling the pozzolanic activity of the EPP to be exerted at an earlier age. In addition, with active SiO in EPP2、Al2O3With cement hydration products Ca (OH)2Reacting to form C-S-H gel and C with low calcium-silicon ratio3AS2H2、C3AH6And the hydration products promote the hydration of the cement particles. Therefore, incorporation of EPP in concrete does not significantly reduce early strength.
(3) Due to Ca (OH) in concrete2Low content, secondary hydration product C-S-H, C3AS2H2、C3AH6And the like, so that the micro gaps of the concrete are filled, the compactness of the concrete is improved, and the durability is improved.
(4) The hydration heat of the concrete is reduced, the mold-entering temperature of the concrete can be well controlled, and the heat release peak value of the concrete is reduced and delayed. (5) Can effectively inhibit alkali aggregate reaction
EPP and Cement hydration products Ca (OH)2The secondary hydration reaction of (2) to make Ca (OH) in the concrete2Travel with Chinese character' HeReduced level of free water, presence of Ca (OH)2And free water are necessary conditions for the alkali aggregate reaction to occur. The porous structure of EPP can adsorb Na+And K+Ions, which lower the pH of the concrete pore solution.
(6) The slump retaining property of the concrete doped with the EPP is better. This is also confirmed in tests by the ability of EPP-doped concrete to retain fluidity better than that of non-EPP-doped concrete in the same formulation of water reducing agent, concrete of the same fluidity. The adsorbed water of EPP porous structure will also be EPP and cement hydration product Ca (OH)2The reaction provides water to form self-curing effect, and guarantee is provided for the long-term strength increase of the concrete.
(7) The EPP is added to increase the viscosity of concrete mixture and improve the cohesiveness and water retention property. EPP acts as a viscosity modifier and water retention agent, improving the workability of the concrete mix.
Detailed Description
The present invention is further illustrated by the following examples, but the scope of the invention is not limited thereto but by the description of the invention and the claims.
Examples 1 to 4
The concrete doped with the modified pozzolanic fine powder is prepared according to the components specified in the following table 1 respectively, and comprises the following preparation steps:
(1) firstly, putting ore sand and gravel into a stirrer to be uniformly stirred for 10-30s to obtain gravel aggregate;
(2) then putting cement and the modified pozzolanic fine powder into a stirrer, uniformly stirring the cement and the modified pozzolanic fine powder with the sandstone aggregate obtained in the step (1), and stirring for 10-30s to obtain a cementing material;
(3) and (3) finally, adding water and a water reducing agent into the cementing material obtained in the step (2), uniformly stirring, and stirring for 25-35s to obtain the concrete doped with the modified pozzolanic fine powder.
The modified pozzolanic fine powder is sourced from Eco-innovation sdn bhd company of Malaysia; the modified pozzolanic fine powder meets the following parameter conditions: 45 μm sieve reject (%): 10 to 30 percent; 28d Activity index (%): 75-98.1%; water demand ratio (%): 105-115%.
The cement is Portland cement or ordinary Portland cement; the water reducing agent is a high-efficiency water reducing agent taking polycarboxylic acid as a main component. The fineness modulus of the ore sand is 2.0-3.5; the continuous gradation of the crushed stones is 5-40 mm. The mixer is a forced concrete mixer, the feeding capacity is 750-1500L, and the rotating speed is 20-35 r/min.
Table 2 shows the performance index test values of the concrete products prepared in each example.
TABLE 1 component proportions (parts by mass) of the respective examples
TABLE 2 product Performance index values of the examples
In conclusion, after the modified pozzolana fine powder (EPP) is doped into the concrete, the following indexes of the concrete are obviously improved:
(1) on the premise of ensuring the strength and durability of the concrete, the workability, especially the cohesiveness, the water retention and the segregation resistance, of the concrete is improved.
(2) The slump loss resistance of the concrete is improved, and the concrete has good workability when being poured into a mold for pouring.
(3) The adiabatic temperature rise of concrete is reduced, the internal stress of a concrete structure is reduced, and the risk of concrete temperature stress crack is reduced.
(4) The durability of the concrete is improved, the cost of the single concrete is reduced, and the cement consumption is reduced by 15-30%.
(5) After the modified fine pozzolanic powder (EPP) is doped in the concrete, the concrete quality defect caused by insufficient technical indexes is improved, the waste is utilized, and the environment protection is facilitated.
Claims (6)
1. The concrete doped with the modified pozzolanic fine powder is characterized by comprising the following raw materials in parts by mass: 550 parts of cement, 50-165 parts of modified pozzolanic fine powder, 850 parts of ore, 800-1350 parts of crushed stone, 240 parts of water and 1.5-10 parts of a water reducing agent.
2. The method of claim 1, wherein the concrete doped with the modified pozzolanic fines comprises the following steps:
(1) firstly, putting 850 parts of 550 sand and 800 parts of sand and 1350 parts of gravel into a stirrer to be uniformly stirred for 10-30s to obtain sandstone aggregate;
(2) then, putting 550 parts of cement 240-sand and 50-165 parts of modified pozzolanic fine powder into a stirrer, uniformly stirring the cement and the sand aggregate in the step (1), and stirring for 10-30s to obtain a cementing material;
(3) and (3) finally, adding 240 parts of water 120-sand and 1.5-10 parts of water reducing agent into the cementing material obtained in the step (2), uniformly stirring, and stirring for 25-35s to obtain the concrete doped with the modified pozzolanic fine powder.
3. The concrete doped with the modified pozzolanic fines of claim 1, wherein the modified pozzolanic fines satisfy the following parameter conditions: and (4) sieving residue by a 45-micron sieve: 10 to 30 percent; 28d Activity index: 75-98.1%; water demand ratio: 105-115%.
4. The concrete doped with the modified pozzolanic fines of claim 1, wherein the cement is portland cement or ordinary portland cement; the water reducing agent is a high-efficiency water reducing agent taking polycarboxylic acid as a main component.
5. The concrete doped with the modified pozzolanic fines of claim 1, wherein the sand has a fineness modulus of 2.0 to 3.5; the continuous gradation of the crushed stones is 5-40 mm.
6. The concrete doped with the modified pozzolanic fines of claim 1, wherein the mixer is a forced concrete mixer, the feeding capacity is 750-1500L, and the rotation speed is 20-35 r/min.
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| CN201911041533.3A CN112745068B (en) | 2019-10-30 | 2019-10-30 | Concrete doped with modified pozzolanic fine powder and preparation method thereof |
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| CN112745068A true CN112745068A (en) | 2021-05-04 |
| CN112745068B CN112745068B (en) | 2022-07-01 |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101293766A (en) * | 2008-06-11 | 2008-10-29 | 中国水利水电第三工程局 | Only volcanic ash doped roller compacted concrete and preparation method thereof |
| CN109604026A (en) * | 2018-11-16 | 2019-04-12 | 中国路桥工程有限责任公司 | A kind of natural volcanic ash material grinding processing method |
-
2019
- 2019-10-30 CN CN201911041533.3A patent/CN112745068B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101293766A (en) * | 2008-06-11 | 2008-10-29 | 中国水利水电第三工程局 | Only volcanic ash doped roller compacted concrete and preparation method thereof |
| CN109604026A (en) * | 2018-11-16 | 2019-04-12 | 中国路桥工程有限责任公司 | A kind of natural volcanic ash material grinding processing method |
Non-Patent Citations (1)
| Title |
|---|
| 吴必良等: "非洲天然火山灰质材料对混凝土耐久性能的影响研究", 《建筑科学》 * |
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