CN109704609B - Method for inhibiting generation of delayed ettringite in concrete - Google Patents
Method for inhibiting generation of delayed ettringite in concrete Download PDFInfo
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- CN109704609B CN109704609B CN201910133848.4A CN201910133848A CN109704609B CN 109704609 B CN109704609 B CN 109704609B CN 201910133848 A CN201910133848 A CN 201910133848A CN 109704609 B CN109704609 B CN 109704609B
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Abstract
The invention discloses a method for inhibiting generation of delayed ettringite in concrete. The method comprises the following steps: high corrosion-resistant portland cement clinker, dihydrate gypsum and functional components are adopted to replace ordinary portland cement to produce concrete; the components are as follows by weight: 60-90 parts of high corrosion resistant portland cement clinker, 10-20 parts of functional components and 2-6 parts of dihydrate gypsum. The high corrosion resistant Portland cement clinker, dihydrate gypsum and functional component composite system designed by the invention jointly inhibits the generation of delayed ettringite in concrete through multi-aspect synergistic action, and fundamentally solves the problem of delayed ettringite in the existing common Portland cement concrete under high temperature. In addition, the components used in the invention are all green and environment-friendly materials, and have no negative influence on the ecological environment.
Description
Technical Field
The invention belongs to the technical field of materials, and particularly relates to a method for inhibiting generation of delayed ettringite in concrete.
Background
Ettringite is an important hydration product in portland cement and has a chemical molecular formula of 3 CaO. Al2O3·3CaSO4·32H2O, also known as calcium sulfoaluminate trihydrate (AFt). Tricalcium aluminate (C) mainly derived from portland cement clinker3A) Formed by reaction with dihydrate gypsum. The reaction formula is as follows: c3A+3CaSO4·2H2O+26H2O→3CaO·Al2O3·3CaSO4·32H2O。
A large number of researches show that ettringite has important influence on the early hydration process of portland cement. However, it is believed that, during curing at high temperature (generally higher than 70 ℃), ettringite is decomposed to generate calcium sulphoaluminate monosulfide (AFm), and then, when the temperature is reduced to normal temperature, calcium sulphoaluminate monosulfide (AFm) is recombined to form ettringite, thereby causing volume expansion and concrete cracking, which is a delayed ettringite generation mechanism. Therefore, how to inhibit the formation of delayed ettringite in portland cement under high temperature conditions becomes a key concern of the engineering community, and the key problem influences the service durability of concrete materials (especially precast concrete and mass concrete).
Aiming at the problem of delaying ettringite existing in common portland cement concrete, the method of controlling curing temperature and adding an ettringite inhibitor is generally adopted to control the formation of the delayed ettringite. If the mode of controlling the temperature is adopted, the production period of the precast concrete is prolonged, the industrial large-scale production is not facilitated, measures such as additionally arranging a condensation pipe and controlling the temperature of raw materials are required for large-volume concrete, and the construction cost is greatly increased. The patent of the invention with the publication number of CN 107162457A and the name of 'a method for limiting the generation of delayed ettringite in concrete' inhibits the generation of delayed ettringite in concrete by adding a slow-release barium salt, thereby obtaining good effect, but the preparation process is complex, the cost is high, and the barium salt has certain toxicity and can cause adverse effect on the environment.
In summary, the existing control methods for delaying the generation of ettringite in concrete are all controlled from the outside, the control cost is high, the process is complex, and once a certain link is not well controlled in the concrete preparation and construction process, delayed ettringite is inevitably generated. Therefore, it is necessary to find a technical means for inhibiting the delay of the generation of ettringite, thereby improving the durability of concrete and prolonging the service life of concrete.
Disclosure of Invention
The invention aims to provide a method for inhibiting delayed ettringite generation in concrete, which inhibits the delayed ettringite generation in the concrete by reducing the tricalcium aluminate content in a clinker mineral phase and adding functional components, thereby greatly reducing the expansion rate of the concrete.
In order to achieve the purpose, the technical scheme is as follows:
a method of inhibiting delayed ettringite occurrence in concrete comprising the steps of:
high corrosion-resistant portland cement clinker, dihydrate gypsum and functional components are adopted to replace ordinary portland cement to produce concrete;
the components are as follows by weight:
60-90 parts of high corrosion resistant portland cement clinker, 10-20 parts of functional components and 2-6 parts of dihydrate gypsum.
According to the scheme, the high corrosion resistant Portland cement clinker comprises the main component C3S、C2S、C3A and C4AF; wherein C is3S 30-60wt％、C2S 20-40wt％、C3A 1-5wt％、C4AF 15-30wt％。
According to the scheme, the functional components are a mixture of calcium ferrite, fluorite, steel slag and hydrotalcite; the weight portions are as follows: 5-10 parts of calcium ferrite, 2-8 parts of fluorite, 5-10 parts of steel slag and 1-5 parts of hydrotalcite.
Tricalcium aluminate is easy to react with gypsum under high temperature condition to generate a large amount of single-sulfur hydrated calcium sulphoaluminate (AFm), which is the root cause of delaying the generation of ettringite, while high-corrosion-resistant portland cement clinker contains less tricalcium aluminate, which greatly reduces the generation of single-sulfur hydrated calcium sulphoaluminate (AFm), and in addition, more tetracalcium aluminoferrite inhibits the generation of the single-sulfur hydrated calcium sulphoaluminate (AFm). In addition, calcium ferrite and fluorite in the selected functional components can react with tricalcium aluminate to generate a stable hydration product under a high-temperature condition, so that the conversion to delayed ettringite is avoided; the impurity ions in the steel slag can react with the monosulfuric hydrated calcium sulphoaluminate (AFm) generated at high temperature to form a stable compound; finally, the hydrotalcite is a functional component with ion exchange function, and can exchange sulfate ions in concrete to achieve the function of inhibiting and delaying the generation of ettringite.
Compared with the prior art, the invention has the following beneficial effects:
the cement paste prepared by the cementing material of the invention generates less monosulfide hydrated calcium sulphoaluminate (AFm) under the high-temperature curing condition of 90 ℃, thereby effectively reducing the conversion of delayed ettringite in the subsequent curing stage.
The 100-day expansion rate of the concrete prepared by the method is less than 0.020 percent and is far lower than that of the concrete prepared by using the common silicate cement, the 100-day expansion rate of the concrete is more than 0.120 percent, and the generation of the delayed ettringite is effectively inhibited.
The high corrosion resistant Portland cement clinker, dihydrate gypsum and functional component composite system designed by the invention jointly inhibits the generation of delayed ettringite in concrete through multi-aspect synergistic action, and fundamentally solves the problem of delayed ettringite in the existing common Portland cement concrete under high temperature.
In addition, the components used in the invention are all green and environment-friendly materials, and have no negative influence on the ecological environment.
Drawings
FIG. 1: XRD patterns of the products prepared from example 1 and ordinary portland cement were measured at 90 ℃.
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.
Example 1
A method for inhibiting the generation of delayed ettringite in concrete comprises the following functional components in percentage by weight: 80 parts of high-corrosion-resistance portland cement clinker, 5 parts of calcium ferrite, 4 parts of fluorite, 5 parts of steel slag, 2 parts of hydrotalcite and 4 parts of dihydrate gypsum. The components jointly form a composite cementing material, and the weight ratio is as follows: sand 680kg/m31240kg/m of stone3450kg/m of composite cementing material3130kg/m of water3Forming a concrete test piece with the thickness of 100mm multiplied by 400mm, then performing steam curing at the temperature of 90 ℃ for 6 hours, returning to the normal temperature of 20 ℃ for subsequent curing, and testing the linear expansion rate of the concrete test piece after 28 days, 60 days and 100 days.
The composition and method of example 1 were repeated using ordinary portland cement to form concrete test pieces for comparison.
The XRD patterns of the composite gelled material and the product prepared by the ordinary portland cement obtained in the example 1 at 90 ℃ are shown in the attached figure 1, and the cement paste prepared by the gelled material obtained in the example generates less calcium sulphoaluminate monosulfide (AFm) under the high-temperature curing condition of 90 ℃.
Example 2
A method for inhibiting the generation of delayed ettringite in concrete comprises the following functional components in percentage by weight: 82 parts of high-corrosion-resistance portland cement clinker, 6 parts of calcium ferrite, 2 parts of fluorite, 5 parts of steel slag, 3 parts of hydrotalcite and 2 parts of dihydrate gypsum. Concrete test pieces were then formed as described in example 1 and tested for expansion.
Example 3
A method for inhibiting the generation of delayed ettringite in concrete comprises the following functional components in percentage by weight: 75 parts of high-corrosion-resistance portland cement clinker, 10 parts of calcium ferrite, 3 parts of fluorite, 8 parts of steel slag, 1 part of hydrotalcite and 3 parts of dihydrate gypsum. Concrete test pieces were then formed as described in example 1 and tested for expansion.
Example 4
A method for inhibiting the generation of delayed ettringite in concrete comprises the following functional components in percentage by weight: 76 parts of high-corrosion-resistance portland cement clinker, 6 parts of calcium ferrite, 5 parts of fluorite, 8 parts of steel slag, 2 parts of hydrotalcite and 3 parts of dihydrate gypsum. Concrete test pieces were then formed as described in example 1 and tested for expansion.
The comparative test results for testing the expansion ratio of the concrete in the above examples are shown in table 1:
TABLE 1
| Age of age | blank-Normal | Example 1 | Example 2 | Example 3 | Example 4 |
| 28 days swell ratio/(part) | 0.057 | 0.011 | 0.005 | 0.010 | 0.013 |
| Swelling ratio/(part) for 60 days | 0.091 | 0.014 | 0.008 | 0.011 | 0.016 |
| 100 days expansion ratio/(part) | 0.122 | 0.018 | 0.013 | 0.013 | 0.017 |
As can be seen from Table 1, the 28-day expansion ratio of the concrete specimen prepared by using the ordinary portland cement reaches 0.057 parts, and the 100-day expansion ratio reaches 0.122 parts, indicating that the more serious delayed ettringite reaction occurs therein, resulting in large-scale expansion of the concrete volume. However, in the concrete prepared by using the composite cement materials prepared in the proportions of examples 1, 2, 3 and 4, the 28-day expansion rate is only about 0.100 part, and the expansion rates are all less than 0.020 part by 100 days. The method for inhibiting the generation of the delayed ettringite in the concrete obviously inhibits the generation of the delayed ettringite in the concrete, thereby greatly reducing the expansion rate of the concrete, ensuring that the concrete prepared by the method has better volume stability, lower cracking risk and more excellent long-term durability after being cured at high temperature, and ensuring that the concrete material prepared by the method can be safely used for a long time.
In conclusion, the method for inhibiting the generation of the delayed ettringite in the concrete greatly inhibits the formation of the delayed ettringite and ensures that the concrete material has excellent volume stability after being cured at high temperature. It should also be noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, while the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims.
Claims (1)
1. A method for inhibiting delayed ettringite generation in concrete, comprising the steps of:
high corrosion-resistant portland cement clinker, dihydrate gypsum and functional components are adopted to replace ordinary portland cement to produce concrete;
the components are as follows by weight:
60-90 parts of high corrosion resistant portland cement clinker, 10-20 parts of functional component and 2-6 parts of dihydrate gypsum;
the main component of the high corrosion resistant Portland cement clinker comprises C3S、C2S、C3A and C4AF; wherein C is3S 30-60wt％、C2S 20-40wt％、C3A 1-5wt％、C4AF 15-30wt％；
The functional component is a mixture of calcium ferrite, fluorite, steel slag and hydrotalcite; the weight portions are as follows: 5-10 parts of calcium ferrite, 2-8 parts of fluorite, 5-10 parts of steel slag and 1-5 parts of hydrotalcite.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1699244A (en) * | 2005-04-30 | 2005-11-23 | 南京师范大学 | Multifunctional chlorine-free alkali-free compound concrete slag admixture and its preparation process |
| CN103043970A (en) * | 2012-12-31 | 2013-04-17 | 中国核工业华兴建设有限公司 | Concrete for nuclear power station |
| CN106082724A (en) * | 2016-06-08 | 2016-11-09 | 武汉理工大学 | The strongest a kind of high, high resistance to corrosion portland cement and preparation method thereof |
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| DE50007784D1 (en) * | 2000-06-21 | 2004-10-21 | Sika Ag, Vorm. Kaspar Winkler & Co | Sulfate and alkali free setting and hardening accelerator |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1699244A (en) * | 2005-04-30 | 2005-11-23 | 南京师范大学 | Multifunctional chlorine-free alkali-free compound concrete slag admixture and its preparation process |
| CN103043970A (en) * | 2012-12-31 | 2013-04-17 | 中国核工业华兴建设有限公司 | Concrete for nuclear power station |
| CN106082724A (en) * | 2016-06-08 | 2016-11-09 | 武汉理工大学 | The strongest a kind of high, high resistance to corrosion portland cement and preparation method thereof |
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| Title |
|---|
| 基于欧洲标准研究内部硫酸盐反应对混凝土体积稳定性的影响;向卫平等;《新型建筑材料》;20170630(第6期);第5-8页 * |
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