CN103353518A - Design method of ternary component cementing material for inhibiting alkali-aggregate reaction - Google Patents

Abstract

A method for designing a ternary component cementitious material that inhibits the alkali-aggregate reaction, including the following steps: (1) According to the principle of the factor design method, establish the relationship between the composition of the ternary component cementitious material and the expansion rate of the alkali-aggregate reaction Regression equation; (2) Select the ternary cementitious material components for testing; (3) Use the coordinate transformation relationship to draw the contour map in the ternary map using the existing contour mapping software under the Cartesian coordinate system ; Obtain the safe area and non-safe area of the cementitious material that inhibits the alkali-aggregate reaction through the drawn ternary diagram; (4) Solve the regression equation; (5) Predict the alkali composition of any cementitious material within the constraints of the cementitious material - Aggregate reaction expansion rate. The invention has the advantages of simple principle, convenient contour map drawing and high prediction result accuracy, and provides effective preventive measures for preventing alkali-aggregate reaction engineering damage caused by the use of alkali-activated aggregates.

Description

A Design Method of Ternary Component Cementitious Materials for Inhibiting Alkali-Aggregate Reaction

technical field

The invention relates to a design method of a cementitious material, in particular to a design method of a three-component cementitious material which inhibits alkali-aggregate reaction. the

Background technique

The alkali-aggregate reaction of concrete is one of the main factors affecting the durability of concrete structures. Since the alkali-aggregate reaction is relatively slow, it can be found in a few years at a short time and decades in a long time, and once it happens, it cannot be repaired and remedied. , known as the "cancer" of concrete, is also recognized as the second largest concrete disease after steel corrosion, which has attracted great attention from all over the world. the

The distribution of active aggregates in my country is very wide, and the amount of high-alkali cement is also large. Therefore, a large number of examples of alkali-aggregate reaction failure projects have been found all over the country since the early 1990s. For half a century, although the research on the alkali-aggregate reaction has never been interrupted and has not been cured, it is generally believed that the addition of mineral admixtures (such as fly ash, mineral powder, silica fume, etc.) An effective measure of alkali-aggregate reaction expansion. In addition, the addition of mineral admixtures can also improve the durability of concrete, reduce the amount of cement used, thereby saving costs, and reduce the waste of raw materials and damage to the ecological environment caused by cement production. the

More and more studies have also found that when high-activity pozzolanic materials (such as silica fume and metakaolin) are mixed with low-activity pozzolanic materials (such as fly ash and mineral powder) as mineral admixtures, in many cases there will be It shows a synergistic effect, and the effect of double doping is better than single doping. However, when mineral admixtures are double-mixed, the factors affecting the design of the mix ratio increase, and the design of the cementitious material becomes a problem. Moreover, most of the current concrete design methods consider the influence of one mineral admixture, and there are few direct research methods on the simultaneous influence of two mineral admixtures on the performance of concrete. The most commonly used method for traditional cementitious material design is the experimental method, because it is difficult to find a model and use it to establish the relationship between the composition parameters of the cementitious material and the material properties, especially when the composition of the cementitious material is large. For example, the commonly used orthogonal design test method and artificial neural network algorithm cannot reflect the relationship between material properties and its composition well, and the calculation is complicated and the test volume is large. the

Contents of the invention

The technical problem to be solved by the present invention is to provide a ternary component cementing material design method that can well reflect the relationship between material properties and its composition, is simple to calculate, and has a small test amount to inhibit the alkali-aggregate reaction. Using this method, the optimization of the ratio of components in the ternary gelling system can be realized, and the safe area and non-safe area of the cementitious material components that inhibit the alkali-aggregate reaction can be obtained. Provide basis for the design of cementitious materials. the

The technical solution adopted by the present invention to solve the technical problems is: a method for designing a ternary component cementitious material that suppresses the alkali-aggregate reaction, comprising the following steps:

(1) According to the principle of factorial design method, the regression equation of the three-component cementitious material composition and the alkali-aggregate reaction expansion rate is established;

(2) Select the components of ternary cementitious materials for testing;

(3) Using the coordinate transformation relationship, the contour map is drawn in the ternary diagram by using the existing contour drawing software under the Cartesian coordinate system; the gelation that inhibits the alkali-aggregate reaction is obtained through the drawn ternary diagram The safe area and non-safe area of the material;

(4) Solve the regression equation;

(5) Predict the alkali-aggregate reaction expansion rate of any cementitious material composition within the cementitious material constraints.

Further, a more specific operation design method includes the following steps:

(1) According to the principle of factorial design method, the regression equation of the three-component cementitious material composition and the alkali-aggregate reaction expansion rate is established:

 ………………………(1)

………………………(1)

In the formula:

Y — alkali-aggregate reaction expansion rate;

—三元胶凝材料组成中水泥所占的质量百分比；

—The mass percentage of cement in the composition of ternary cementitious materials;

- the mass percentage of the pozzolan material A in the composition of the ternary cementitious material;

- the mass percentage of the pozzolan material B in the composition of the ternary cementitious material;

—Regression equation coefficient, dimensionless;

表示水泥和两种火山灰材料三种材料组合对碱-骨料反应膨胀率的影响； Among them, the constraints on the composition of ternary cementitious materials are: , 100%≥ ≥0%, =1, 2, 3; there is no constant term in the formula, only a first-order term and a cross term, and its physical meaning is: a first-order term Indicates the effect of cement and pozzolanic materials alone on the alkali-aggregate reaction expansion rate, the cross term Indicates the effect of pairwise combinations of cement and two pozzolanic materials on the alkali-aggregate reaction expansion rate, the cross term

Indicates the effect of cement and two kinds of pozzolan materials on the expansion rate of alkali-aggregate reaction;

(2) Select the test points of the ternary cementitious material components: select 7 groups of cementitious material components, which are the three vertices of the triangle in the triangle coordinates, the midpoint of the three sides of the triangle and the center point of the triangle, a total of 7 points test point;

Obtain test data: According to the alkali-aggregate reaction expansion test method, test the selected 7 groups of cementitious materials with alkali-activated sand or crushed pebbles, and record the alkali-aggregate reaction expansion rate at the specified age;

(3) Draw the alkali-aggregate reaction contour map: through the coordinate conversion relationship between the triangular coordinate system and the rectangular coordinate system, according to the test data of the selected 7 groups of cementitious materials, use the existing rectangular coordinate system The contour mapping software draws the alkali-aggregate reaction expansion rate contour map in the ternary diagram; through the drawn ternary diagram, the safe area and non-safe area of the cementitious material that inhibits the alkali-aggregate reaction are obtained;

，得回归方程； (4) Solve the regression equation: Substitute the test data of the selected 7 groups of cementitious materials into the regression equation, establish the equation group, and obtain the coefficient of the regression equation

, get the regression equation;

(5) Predict the alkali-aggregate reaction expansion rate of any cementitious material composition within the constraints of the cementitious material: According to the regression equation, the corresponding alkali- Aggregate response expansion rate.

The invention has the advantages of simple principle, convenient contour map drawing and high prediction result accuracy, and provides effective preventive measures for preventing alkali-aggregate reaction damage caused by alkali active aggregate used in engineering. the

Description of drawings

Fig. 1 is the design drawing of cement-slag powder-fly ash ternary gelling component of the embodiment of the present invention;

Fig. 2 is a schematic diagram of the conversion relationship between the rectangular coordinate system and the triangular coordinate system;

Figure 3 is the 14d expansion rate contour map of the Xiangtan section of the Xiangjiang River;

Figure 4 is the 28d expansion rate contour map of the Xiangtan section of the Xiangjiang River;

Figure 5 is the 14d expansion rate contour map of the pebbles in the Xiangtan section of the Xiangjiang River;

Figure 6 is the 28d expansion rate contour map of the pebbles in the Xiangtan section of the Xiangjiang River;

Figure 7 shows the relationship between the predicted and experimental values of the 14d age of sand and pebbles in the Xiangtan section of the Xiangjiang River;

Figure 8 shows the relationship between the predicted and experimental values of the 28-day age of sand and pebbles in the Xiangtan section of the Xiangjiang River;

In Figure 1: SA, SB, SC sand A, B, C three groups of experiments, A group is the design group, B, C group is the prediction group; LA, LB, LC pebbles A, B, C three groups of experiments, A group is the design group, and groups B and C are the prediction group;

In Figure 7: A sand, linear fitting equation and correlation coefficient: y=x-0.0027, R=0.98; B pebble, linear fitting equation and correlation coefficient: y=x-0.0049, R=0.99;

In Figure 8: A sand, linear fitting equation and correlation coefficient: y=x-0.0021, R=0.99; B pebble, linear fitting equation and correlation coefficient: y=x-0.0168, R=0.99.

Detailed ways

The present invention will be further described below in conjunction with embodiment. the

Example

Use sand and pebbles from the Xiangtan section of the Xiangjiang River, use low-alkali cement, fly ash and slag powder as two pozzolan materials, measure the alkali-aggregate reaction expansion value at 14d and 28d according to the ASTM C1260 method, and design and implement detailed cementitious materials The process is as follows:

(1) According to the principle of factorial design method, the regression equation of the three-component cementitious material composition and the alkali-aggregate reaction expansion rate is established:

 ………………………（1）

………………………(1)

In the formula:

Y—alkali-aggregate reaction expansion rate;

—三元胶凝材料组成中水泥所占的质量百分比；

—The mass percentage of cement in the composition of ternary cementitious materials;

—三元胶凝材料组成中火山灰材料A所占的质量百分比；

- the mass percentage of the pozzolan material A in the composition of the ternary cementitious material;

—三元胶凝材料组成中火山灰材料B所占的质量百分比；

- the mass percentage of the pozzolan material B in the composition of the ternary cementitious material;

—回归方程系数，无量纲；

—Regression equation coefficient, dimensionless;

，100%≥

≥0%，

=1、2、3；式中没有常数项，只有一次项和交叉项，其物理意义为：一次项

表示水泥和火山灰材料单独对碱-骨料反应膨胀率的影响，交叉项

表示水泥和两种火山灰材料两两组合对碱-骨料反应膨胀率的影响，交叉项

表示水泥和两种火山灰材料三种材料组合对碱-骨料反应膨胀率的影响； Among them, the constraints on the composition of ternary cementitious materials are:

, 100%≥

≥0%,

=1, 2, 3; there is no constant term in the formula, only a first-order term and a cross term, and its physical meaning is: a first-order term

Indicates the effect of cement and pozzolanic materials alone on the alkali-aggregate reaction expansion rate, the cross term

Indicates the effect of pairwise combinations of cement and two pozzolanic materials on the alkali-aggregate reaction expansion rate, the cross term

Indicates the effect of cement and two kinds of pozzolan materials on the expansion rate of alkali-aggregate reaction;

(2) Select test points for ternary cementitious material components and obtain test data

a. Selection of test points in ternary cementitious material components

Using two kinds of pozzolanic materials, fly ash and mineral powder, to inhibit the alkali-aggregate reaction, 7 groups of experiments were designed in the cement-fly ash-mineral powder ternary cementitious component system for the design of cementitious materials; considering engineering In the actual situation, the fly ash content is 0%≤Y≤30%, and the mineral powder content is 0%≤Z≤50%, so a small triangle (△①⑤⑦) is designed in the triangular coordinate system, as shown in Figure 1 , and select 7 points as the composition of the cementitious material, which are the three vertices (①, ⑤, ⑦) of the small triangle in the triangular coordinates, the midpoints of the three sides (②, ③, ⑥) and the center point (④ ), a total of 7 test points, see Figure 1 and Table 1.

In order to evaluate the effectiveness of this method, 10 groups of predicted point cementitious material components were designed for the experiment containing Xiangjiang sand and pebbles, as shown in Figure 1 and Table 2. the

the

b. Obtain test data

The test was carried out according to the ASTM C1260 method. The cementitious material components and expansion rates of 14d and 28d of the 7 groups of mortar bar specimens containing sand and pebbles in the Xiangtan section of the Xiangjiang River are listed in Table 3.

(3) Draw the contour map of alkali-aggregate reaction expansion rate

与三角形坐标系的关系，这两种坐标系前者是两个变量，而后者看似是3个变量，由于满足关系

，因而实质上后者也只有两个变量，从而两种坐标系建立一一的对应关系；同时，考虑实施例中矿粉的掺量为0%～50%，粉煤灰掺量为0%～30%，所以三角形坐标的取值范围为：

(水泥)坐标为0.5～1，

(粉煤灰)坐标为0～0.5，

(矿粉)坐标为0～0.5，三角形坐标系中的点(0.5，0，0.5)对应直角坐标系中的原点(0，0)，得到坐标转换公式（2）： See Figure 2 to establish a Cartesian coordinate system

with triangular coordinate system The relationship between the two coordinate systems, the former is two variables, while the latter seems to be three variables, due to satisfying the relationship

, so the latter has only two variables in essence, so that the two coordinate systems establish a one-to-one correspondence; at the same time, considering that the amount of mineral powder in the embodiment is 0% to 50%, and the amount of fly ash is 0% ~30%, so the value range of the triangle coordinates is:

(cement) coordinates are 0.5~1,

(fly ash) coordinates are 0~0.5,

The (mineral powder) coordinates are 0-0.5, and the point (0.5, 0, 0.5) in the triangular coordinate system corresponds to the origin (0, 0) in the rectangular coordinate system, and the coordinate conversion formula (2) is obtained:

At the same time, when using the contour line drawing software to draw the contour line according to the 7 groups of experiments, if you need to choose the interpolation method, it is recommended to choose the Kriging interpolation calculation method, because when the interpolation point coincides with the sampling point in this method, the value of the interpolation point is the value of the sample point value, but other methods cannot guarantee this, so the 14d and 28d alkali-aggregate reaction expansion contours containing Xiangjiang sand and pebbles are obtained, as shown in Figure 3-6, and the alkali-aggregate inhibition is obtained by drawing the ternary diagram The safe area and non-safe area of the reacted gelling material, the gelling material composition area corresponding to the expansion rate less than 0.1% is the safe area, and the gelling material composition area corresponding to the expansion rate greater than 0.1% is the non-safe area.

(4) Solve the regression equation

Substituting the seven groups of test results of sand and pebbles in Table 3 into the regression equation, the coefficients of the regression equation are obtained, which are listed in Table 4, and four prediction equations for the 14d and 28d test ages of the sand and pebbles in the Xiangtan section are obtained (3 )-(6).

the

    

   ……（3）

... (3)

  ……（4）

... (4)

  ……（5）

... (5)

    ……（6）

... (6)

(5) Predict the alkali-aggregate reaction expansion rate of any cementitious material composition within the cementitious material constraints

Substitute the cementitious material components at the predicted point of the experimental design into the above equations (3)-(6) to obtain the expansion rate (ie predicted value) of the alkali-aggregate reaction, and at the same time, measure the experimental value according to the ASTM C1260 test method, The alkali-aggregate reaction prediction value and experimental value containing Xiangtan section sand and pebble are listed in Table 5 and Table 6 respectively, the result shows that the predicted value obtained by the present invention is very close to the experimental value result, and meets the accuracy requirement specified by ASTM C1260 . In order to compare the relationship between the two more conveniently, Fig. 7 and Fig. 8 respectively fit the results of sand and pebbles, and the correlation coefficient is as high as 0.98, which further reflects the accuracy, importance and applicability of the present invention. the

 

 

   

 

Claims (2)

1. a ternary component Binder Materials method for designing that suppresses alkali-aggregate reaction is characterized in that, may further comprise the steps:

(1) according to the Factor Design Method principle, sets up the regression equation of ternary component Binder Materials composition and alkali-aggregate reaction expansivity;

(2) choosing the ternary cement components tests;

(3) adopt the coordinate transformation relation, utilize the level line graphics software under the existing rectangular coordinate system that isogram is plotted in the ternary diagram; By be inhibited safety zone and the non-security zone of Binder Materials of alkali-aggregate reaction of the ternary diagram of drawing;

(4) find the solution regression equation;

(5) the alkali-aggregate reaction expansivity that any Binder Materials forms in the prediction Binder Materials constraint condition.

2. the ternary component Binder Materials method for designing of inhibition alkali-aggregate reaction according to claim 1 is characterized in that, may further comprise the steps:

(1) according to the Factor Design Method principle, set up the regression equation of ternary component Binder Materials composition and alkali-aggregate reaction expansivity:

………………………(1)

In the formula:

Y-alkali-aggregate reaction expansivity;

The shared mass percent of cement during-ternary Binder Materials forms;

The shared mass percent of pozzolanic material A during-ternary Binder Materials forms;

The shared mass percent of pozzolanic material B during-ternary Binder Materials forms;

-regression equation coefficient, dimensionless;

Wherein, the constraint condition of ternary Binder Materials composition is: , 100% 〉=

〉=0%, =1,2,3; Do not have constant term in the formula, for once and cross term, its physical significance is: once

Expression cement and pozzolanic material be separately on the impact of alkali-aggregate reaction expansivity, cross term Expression cement and two kinds of pozzolanic material make up the impact on the alkali-aggregate reaction expansivity, cross term in twos

Expression cement and three kinds of combinations of materials of two kinds of pozzolanic material are on the impact of alkali-aggregate reaction expansivity;

(2) choose the testing site of ternary cement components: choose 7 groups of cement components, be respectively 3 summits of triangle coordinate intermediate cam shape, the mid point on Atria bar limit and leg-of-mutton central point, totally 7 testing sites;

Obtain test figure: according to alkali-aggregate reaction expansion method of testing, with 7 groups of Binder Materials choosing respectively with basic active sand or the cobble after pulverizing test the alkali-aggregate reaction expansivity in the length of time of recording prescribed;

(3) draw the alkali-aggregate reaction isogram: by the coordinate transformation relation between trigonometric coordinates system and the rectangular coordinate system, according to the test figure of 7 groups of Binder Materials choosing, utilize the level line graphics software under the existing rectangular coordinate system that alkali-aggregate reaction expansivity isogram is plotted in the ternary diagram; By be inhibited safety zone and the non-security zone of Binder Materials of alkali-aggregate reaction of the ternary diagram of drawing;

(4) find the solution regression equation: in the test figure difference substitution regression equation of 7 groups of Binder Materials will choosing, set up system of equations, try to achieve the regression equation coefficient

, get regression equation;

(5) any alkali-aggregate reaction expansivity that forms of Binder Materials in the prediction Binder Materials constraint condition: according to regression equation, try to achieve any Binder Materials that satisfies constraint condition under the ternary gelling system corresponding alkali-aggregate reaction expansivity when forming.

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