Compaction state estimation method

Abstract

To propose a compaction state estimation method of concrete capable of easily estimating a compaction state of concrete.SOLUTION: A compaction state estimating method comprises the steps of: estimating a response acceleration αx received by concrete at a position at a distance x from a vibrator; and calculating compaction energy E by equation 1 using the response acceleration αx. The response acceleration αx is calculated by using a coefficient a considering the boundary damping, and a coefficient b determining the degree of distance damping.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a method for estimating the compaction state of concrete. [Background technology]

[0002] The concrete poured into the formwork is compacted using a vibrator or other vibrating device to remove air trapped in the concrete when it was poured, making it dense and ensuring the desired quality. Concrete compaction must be carried out so that there are no uneven areas between the concrete around the vibrator and the concrete in the area away from the vibrator. On the other hand, confirmation of the area where concrete compaction is complete is generally managed by visual inspection, etc., which may depend on the skill of the worker.

[0003] For this reason, Patent Document 1 discloses a method for evaluating compaction characteristics that calculates the compaction completion energy and then determines the compaction completion range using a formula. The method for evaluating compaction characteristics in Patent Document 1 makes it possible to quantify the compaction characteristics of concrete, thereby improving workability and quality when pouring concrete. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6619999 Summary of the Invention [Problem to be solved by the invention]

[0005] To calculate the extent of compaction completion, it is necessary to take into account the concrete mix and the model and structure of the vibrator. Therefore, it was necessary to conduct experiments in advance using the materials, mixes, and equipment to be used on site, and set conditions appropriate to the construction situation. Preliminary experiments are large-scale and time-consuming, as they must be adjusted to the construction conditions of the actual work. An object of the present invention is to propose a method for estimating the compaction state of concrete that can easily estimate the compaction state of concrete. [Means for solving the problem]

[0006] The present invention provides a method for estimating the compaction range of concrete, which estimates the response acceleration α x and estimating the response acceleration α x and calculating the compaction energy by Equation 1 using the response acceleration α x is calculated using coefficient a, which takes boundary attenuation into account, and coefficient b, which determines the degree of distance attenuation.

[0007]

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[0008] This method for estimating the compaction state makes it possible to easily calculate the compaction energy without requiring extensive experiments in advance. The compaction state of concrete can also be determined by determining whether the compaction energy has reached the concrete compaction completion energy. The compaction completion energy of concrete may be a value based on the mix proportions from known data, or a value measured using a compaction completion energy measuring device for concrete of any mix proportions. In addition, the response acceleration α x is preferably calculated using Equation 2.

[0009]

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[0010] The coefficients a and b may be estimated by applying the equation 2 to data on response acceleration measured for concrete with a known slump value. In this case, it is desirable to calculate the coefficients a and b corresponding to the target slump using a first coefficient calculation formula that defines the relationship between the slump value and the coefficient a and a second coefficient calculation formula that defines the relationship between the slump value and the coefficient b. [Effects of the Invention]

[0011] According to the compaction range estimation method of the present invention, the compaction completion range of concrete can be easily estimated. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a flowchart showing a method for examining a construction plan when pouring concrete. [Figure 2] FIG. 1 is a cross-sectional view showing a compaction completion energy measuring device. [Figure 3] 1 is a graph showing the relationship between the acceleration of a vibrator in concrete and the diameter of the vibrator. [Figure 4] Graphs (a) to (d) show the relationship between acceleration obtained from previous data and the distance from the vibrator. [Figure 5] Graphs (a) to (d) show the relationship between acceleration and distance from the vibrator obtained from other previous data. [Figure 6] 10 is a graph showing the relationship between the coefficient a and the target slump. [Figure 7] 10 is a graph showing the relationship between coefficient b and target slump. [Figure 8] FIG. 10 is an explanatory diagram showing an example of a method for determining a compaction completion range. DETAILED DESCRIPTION OF THE INVENTION

[0013] In this embodiment, a method for estimating the compaction state during concrete pouring and for carrying out construction planning will be described. The steps of the construction planning method are shown in Figure 1. As shown in Figure 1, the construction planning method of this embodiment includes a compaction completion energy estimation step S1, a compaction state estimation step S2, and a construction planning step S3.

[0014] In the compaction completion energy estimation step S1, the compaction completion energy of the concrete is estimated. The compaction completion energy is the energy required for the concrete poured into the formwork to be densely packed. In this embodiment, the compaction completion energy is estimated (calculated) for concrete of any mix proportion from the results of measurement using a compaction completion energy measuring device.

[0015] Figure 2 shows the compaction completion energy measuring device 1. As shown in Figure 2, the compaction completion energy measuring device 1 includes a hollow, bottomed container 2, a plurality of reinforcing bars 3 arranged inside the container 2, a loading plate 4 with through holes formed corresponding to the positions of the reinforcing bars 3, a vibration generator 5, and a displacement meter 6 that measures the amount of settlement of the loading plate 4.

[0016] To estimate the compaction completion energy, first, fresh concrete is poured into a container 2 in which multiple reinforcing bars 3, 3, ... are arranged, and then a loading plate 4 is placed on top of the fresh concrete with the reinforcing bars 3, 3, ... inserted through the through holes. Next, vibrations are applied to the container 2 using a vibration generator 5, and the acceleration of the vibrations is measured, while the displacement (amount of settlement) of the loading plate 4 that has settled due to the vibrations is measured using a displacement meter 6. The compaction completion energy is then calculated from the acceleration and amount of displacement of the vibrations.

[0017] In the compaction state estimation step S2, the compaction completion range is estimated. The compaction completion range is the range in which the energy imparted to the poured concrete from the vibrator is equal to or greater than the compaction completion energy estimated in the compaction completion energy estimation step S1. In the compaction state estimation step S2, the response acceleration is estimated and the compaction energy is calculated using this response acceleration, and the compaction completion range is estimated from this compaction energy.

[0018] The response acceleration is estimated from the acceleration that concrete receives at a distance x from the vibrator when it is compacted by the vibrator. The acceleration that concrete receives from vibration compaction attenuates depending on the distance from the vibrator. Therefore, the response acceleration α x is calculated using a coefficient a that takes boundary damping into account and a coefficient b that determines the degree of distance damping. In this embodiment, the response acceleration α x Calculate.

[0019]

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[0020] In Equation 2, the product (= a'α) of the "coefficient a' that takes load attenuation into account" and the "acceleration α of the vibrator in an unloaded state" is the acceleration of the vibrator in concrete (i.e., the acceleration of the vibrator when the vibrator is inserted into concrete). The acceleration of the vibrator in concrete (the product of the coefficient a' and the acceleration α) may be set based on previous data. In this embodiment, an approximation curve (see FIG. 3) is calculated from the relationship between the vibrator diameter and the acceleration of the vibrator in concrete obtained from previous experimental data, and this approximation curve is used to calculate the "acceleration of the vibrator in concrete." Since the approximation curve in the graph of FIG. 3 is expressed by Equation 3, the acceleration of the vibrator in concrete (= a'α) is estimated using Equation 3. Note that the plot in the graph of FIG. 3 is the acceleration measured by operating a vibrator equipped with an acceleration sensor in concrete (i.e., the acceleration of the vibrator in concrete). a'α=17.7φ-175.62 Equation 3 where φ is the vibrator diameter (mm)

[0021] The coefficients a and b can be estimated from existing data. In this embodiment, Equation 2 is applied to existing data (data on response acceleration actually measured for concrete with known target slump values) to estimate the coefficients a and b for each mix, and the coefficients a and b are then rearranged to obtain a first coefficient calculation formula that defines the relationship between the target slump value and the coefficient a, and a second coefficient calculation formula that defines the relationship between the target slump value and the coefficient b, to calculate the coefficients a and b corresponding to the target slump.

[0022] First, for a mix whose concrete response acceleration due to vibration compaction is known from existing data such as previous literature and laboratory tests, an approximation curve is created using Equation 2, and the coefficients a and b for each mix are estimated. Examples of approximation curves are shown in Figures 4(a) to (d) and Figures 5(a) to (d), and the approximation results are shown in Table 1.

[0023] [Table 1]

[0024] Next, the relationship between the coefficients a and b when creating the approximate curves for each mix shown in Figures 4(a) to (d) and 5(a) to (d) and the target slump value of the mix is ​​organized, and the first coefficient calculation formula (the approximate curve shown by the dashed line in Figure 6) that defines the relationship between the target slump value x and the coefficient a is calculated. 2 -0.4718x + 5.7858) and the second coefficient calculation formula (the approximate curve shown by the dashed line in Figure 7) that defines the relationship between the target slump value x and the coefficient b. 2 +0.0062x+0.0032). Figure 6 shows the relationship between the target slump value x and the coefficient a, and Figure 7 shows the relationship between the target slump value x and the coefficient b.

[0025] When there are multiple mixes with the same target slump value, the average values ​​of the coefficients a and b for each mix are plotted in Figures 6 and 7. For example, in Table 1, since there are two mixes with a target slump value of 3 cm (mixes 1-1 and 1-2), the coefficient a for a target slump value of 3 cm is set to the average value (=4.5) of mixes 1-1 (a=5.0) and 1-2 (a=4.0). Similarly, the coefficient b for a target slump value of 3 cm is set to the average value (=0.018) of mixes 1-1 (b=0.025) and 1-2 (a=0.010).

[0026] In this embodiment, the first coefficient calculation formula and the second coefficient calculation formula are quadratic functions, but this is not intended to limit the type of function, and they may be linear functions, cubic functions, exponential functions, logarithmic functions, or other functions.

[0027] Using the coefficient a obtained from the first coefficient calculation formula, the coefficient b obtained from the second coefficient calculation formula, the coefficient a' obtained from the vibrator diameter, and the product of the acceleration α, the response acceleration α is calculated using Equation 2. x Calculate.

[0028] Next, the calculated response acceleration α x Using this, the compaction energy is calculated using Equation 1. Compaction energy is the cumulative vibration energy received by the concrete during the vibration time.

[0029]

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[0030] The relationship between the distance x from the vibrator calculated using Equation 1 and the compaction energy E can be shown by a curve as shown in Figure 8. The distance x from the vibrator corresponding to the compaction completion energy is the compaction completion range.

[0031] In the construction planning process S3, the compaction completion range is used to set appropriate insertion intervals and vibration times of the vibrator, and a rational construction plan is established.

[0032] According to the method for estimating the compaction state of this embodiment, the compaction energy can be calculated easily. Therefore, there is no need to carry out a large-scale experiment to measure the compaction completion energy, which reduces the time and effort required.

[0033] Furthermore, by determining whether the compaction energy has reached the concrete compaction completion energy, the state of concrete compaction can be determined, which makes it possible to set up a rational construction plan.

[0034] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and each of the above-described components can be modified as appropriate within the scope of the invention. For example, in the above embodiment, the compaction completion energy of concrete is measured using a compaction completion energy measuring device, but known data may be used for the compaction completion energy.

[0035] Response acceleration α x The formula for calculating the above may be, for example, Formula 4, and is not limited to Formula 2. The coefficients a and b in Equation 4 can be obtained from the first and second coefficient calculation formulas, respectively.

[0036]

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[0037] 1. Compaction completion energy measuring device 2 containers 3. Reinforced concrete 4 Loading plate 5. Vibration generator 6. Displacement gauge

Claims

1. The response acceleration α that concrete experiences at a distance x from the vibrator ｘ and estimating The response acceleration α ｘ and calculating the compaction energy according to Equation 1 using the above formula, The response acceleration α ｘ is calculated using a coefficient a that takes into account boundary attenuation and a coefficient b that determines the degree of distance attenuation. [Equation 1]

2. The response acceleration α ｘ The method for estimating the compaction state according to claim 1, wherein is calculated by Equation 2. [Equation 2]

3. 3. The method for estimating a compaction state according to claim 1, further comprising the step of measuring a compaction completion energy of concrete.

4. 3. The method for estimating the compaction state according to claim 2, wherein the coefficients a and b are estimated by applying the formula 2 to data on response acceleration actually measured for concrete with a known slump value.

5. The method for estimating the compaction state described in claim 4, characterized in that the coefficients a and b corresponding to the target slump are calculated using a first coefficient calculation formula that defines the relationship between the slump value and the coefficient a and a second coefficient calculation formula that defines the relationship between the slump value and the coefficient b.

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