Method for rapidly measuring construction quality index of roller compacted concrete
By using a humidity tester to measure the humidity content and perform correlation analysis, instead of VC value, the problem of long time and many steps when measuring the construction quality index of the rolling concrete in the prior art is solved, and a fast and accurate measurement effect is achieved.
Patent Information
- Application Number
- CN202411477971.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-22
- Publication Date
- 2025-02-28
AI Technical Summary
When measuring the quality indicators of rolling concrete construction, the prior art has problems such as large usage, long time, many steps, difficulty in equipment movement and great influence of human factors, making it difficult to achieve rapid and accurate detection.
By measuring the moisture content of the sieve mixture using a moisture content tester, and confirming the relationship between the moisture content and the VC value through correlation test and regression analysis to replace the VC value, the rapid measurement of the construction quality index of the rolling concrete is achieved.
It realizes rapid and accurate measurement of the quality indicators of rolling concrete construction, reduces the inspection time and labor costs, and improves the convenience and accuracy of measurement.
Smart Images
Figure CN119534563A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of concrete construction quality index measurement, and in particular relates to a method for quickly measuring roller compacted concrete construction quality indexes. Background Art
[0002] At present, the workability test of dry hard concrete mixture usually uses Vebe consistency method, that is, VC value method, which is an important indicator for controlling the construction quality of RCC on site. However, due to the large amount of usage, long time, many steps, difficulty in moving equipment and the large influence of human factors, the Vebe consistency method cannot be quickly and accurately tested on site. Therefore, the Vebe consistency method has certain defects. Before construction, the RCC mix ratio has been determined. During the construction process, the VC value increases as the water consumption per unit volume decreases. Therefore, a reasonable and practical VC value should be equivalent to the optimal water consumption per unit volume. Therefore, under certain mix ratio conditions, there is an inverse relationship between the VC value and the moisture content of concrete, which provides a theoretical basis for replacing the VC value with the moisture content. Therefore, it is necessary to design a method for quickly measuring the construction quality index of RCC to solve the above problems. Summary of the invention
[0003] The technical problem to be solved by the present invention is to provide a method for quickly measuring the construction quality index of roller compacted concrete, which aims to replace the VC value with the moisture content, thereby achieving higher accuracy and faster testing speed.
[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for quickly measuring the construction quality index of roller compacted concrete comprises the following steps: S1, take the workability rolling mixture to be tested, and use a sieve to remove the coarse aggregate; S2, loading the mixture after removing the coarse aggregate into the volume cylinder; S3, gradually use the iron disc to pat and compact the concrete in the volume cylinder until the surface is covered with slurry; S4, using a moisture content tester to measure the moisture content of the sieved mixture; S5. Each time the moisture content of the mixture is measured, the moisture content is tested once along the center, edge and sub-edge of the sample container, and the average value is calculated. The average value is used to characterize the workability of the roller compacted concrete.
[0005] Preferably, the relationship between moisture content and VC value is tested based on the correlation of SPSS software. If the test meets the requirements, it means that the distribution types of the two variables are basically consistent and have a strong correlation. In order to clarify the specific relationship between the two variables, the two variables are then subjected to regression analysis to finally confirm whether the moisture content can replace the VC value.
[0006] Preferably, in step S5, characterizing the workability of the roller compacted concrete by the obtained mean value specifically includes calculating the moisture content of the roller compacted concrete by utilizing the relationship between the moisture content and the dielectric constant.
[0007] Preferably, the dielectric constant is obtained by a roller compacted concrete tester, and the specific method is as follows: The roller compacted concrete tester consists of a probe, an intelligent analysis module and a handheld instrument. The probe of the tester forms an electrode. When the probe is inserted into the concrete, a capacitor is formed. The concrete in between acts as a dielectric. The capacitor and the oscillator form a tuned circuit. The tuned circuit emits electromagnetic waves, which are received by the probe and transmitted to the intelligent module through electrical signals to measure the propagation frequency of the electromagnetic waves. The wave speed is deduced based on the propagation frequency, and finally the dielectric constant of the concrete is deduced. The dielectric constant of water is much larger than that of other materials in concrete. The intelligent module calculates the moisture content of the original concrete through analysis.
[0008] Preferably, during the test, since the rolled concrete is filtered through a sieve, the moisture content measured is the moisture content of the concrete after sieving; in order to obtain the moisture content of the original concrete, a simplified calculation method is used to make the following assumptions: During the sieve filtration process, there is no loss of water in the concrete; The amount of test concrete sieved out of equal amounts of concrete mixture under the same mix conditions is equal; The conversion coefficient K between the moisture content of the original concrete and the moisture content of the screened concrete is measured through multiple tests. The moisture content of the original concrete is equal to the measured moisture content multiplied by the coefficient K. The conversion process is completed in the intelligent module.
[0009] The beneficial effects of the method for quickly measuring the construction quality index of roller compacted concrete provided by the present invention are as follows: This application verifies the moisture content-VC value consistency relationship through field tests, and uses a convenient and fast moisture content index control method to establish a new method for quickly and accurately measuring the construction quality index of roller compacted concrete, which provides the possibility for effectively controlling the construction quality index of roller compacted concrete. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 It is a PP diagram of the normal distribution of VC value in the embodiment of the present invention; Figure 2 It is the normal distribution PP diagram of moisture content in the embodiment of the present invention. DETAILED DESCRIPTION
[0011] Embodiment 1: A method for quickly measuring the construction quality index of roller compacted concrete comprises the following steps: S1, take the workability rolling mixture to be tested, and use a sieve to remove the coarse aggregate; S2, loading the mixture after removing the coarse aggregate into the volume cylinder; S3, gradually use the iron disc to pat and compact the concrete in the volume cylinder until the surface is covered with slurry; S4, using a moisture content tester to measure the moisture content of the sieved mixture; S5. Each time the moisture content of the mixture is measured, the moisture content is tested once along the center, edge and sub-edge of the sample container, and the average value is calculated. The average value is used to characterize the workability of the roller compacted concrete.
[0012] Preferably, the relationship between moisture content and VC value is tested based on the correlation of SPSS software. If the test meets the requirements, it means that the distribution types of the two variables are basically consistent and have a strong correlation. In order to clarify the specific relationship between the two variables, the two variables are then subjected to regression analysis to finally confirm whether the moisture content can replace the VC value.
[0013] Preferably, in step S5, characterizing the workability of the roller compacted concrete by the obtained mean value specifically includes calculating the moisture content of the roller compacted concrete by utilizing the relationship between the moisture content and the dielectric constant.
[0014] Preferably, the dielectric constant is obtained by a roller compacted concrete tester, and the specific method is as follows: The roller compacted concrete tester consists of a probe, an intelligent analysis module and a handheld instrument. The probe of the tester forms an electrode. When the probe is inserted into the concrete, a capacitor is formed. The concrete in between acts as a dielectric. The capacitor and the oscillator form a tuned circuit. The tuned circuit emits electromagnetic waves, which are received by the probe and transmitted to the intelligent module through electrical signals to measure the propagation frequency of the electromagnetic waves. The wave speed is deduced based on the propagation frequency, and finally the dielectric constant of the concrete is deduced. The dielectric constant of water is much larger than that of other materials in concrete. The intelligent module calculates the moisture content of the original concrete through analysis.
[0015] Preferably, during the test, since the rolled concrete is filtered through a sieve, the moisture content measured is the moisture content of the concrete after sieving; in order to obtain the moisture content of the original concrete, a simplified calculation method is used to make the following assumptions: During the sieve filtration process, there is no loss of water in the concrete; The amount of test concrete sieved out of equal amounts of concrete mixture under the same mix conditions is equal; The conversion coefficient K between the moisture content of the original concrete and the moisture content of the screened concrete is measured through multiple tests. The moisture content of the original concrete is equal to the measured moisture content multiplied by the coefficient K. The conversion process is completed in the intelligent module.
[0016] Embodiment 2: The following is a detailed description of a method for quickly and accurately measuring the construction quality index of roller compacted concrete provided by the present invention in conjunction with the accompanying drawings: Step 1: Analysis of the equivalence between moisture content and VC value: SPSS software was used to analyze and the relationship between moisture content and VC value was tested by correlation: (1) Variable correlation test: The RCC mix ratio results are shown in Table 1.
[0017]
[0018] Table 1: RCC mix parameters; In order to determine the correlation analysis method of two variables, it is necessary to test whether the sample data of the variables involved meet the normal distribution. The PP probability diagram reflects the relationship between the cumulative ratio of a variable and the cumulative ratio of a specified distribution, which can be used to test whether the data meets the specified distribution. If the points on the PP diagram are approximately a straight line, it means that the sample data approximately obeys the normal distribution, and the Pearson correlation coefficient method can be used. Draw the VC value and moisture content PP diagram of RCC as shown in Figure 1 and Figure 2 shown.
[0019] Depend on Figure 1 and Figure 2 It can be seen that both VC value and moisture content are approximately normally distributed. Therefore, the Pearson correlation coefficient method can be used to analyze the correlation between VC value and moisture content. The results of the correlation analysis are shown in Table 2.
[0020]
[0021] Table 2: Correlation analysis between VC value and moisture content; The results in Table 2 show that the significant index of the VC value and moisture content under the two-sided test is 0.000, which is less than 0.01. This shows that at the significance level of 0.01, it is preliminarily concluded that there is a strong correlation between the VC value and the moisture content.
[0022] (2) Variable regression model test: Select two different special working conditions and analyze the specific quantitative relationship between VC value and moisture content under the working conditions, that is, randomly extract several pairs of VC value and moisture content corresponding to the same mixture, and each pair of VC value and moisture content should have a one-to-one correspondence; divide these data into two groups, the first group is the second grade distribution, and the second group is the third grade distribution. Considering that the temperature has a great influence on the relative dielectric constant during the test, in order to reduce the error, the temperature factor needs to be considered. The other environmental conditions of each group are roughly the same. The above two groups of data are respectively subjected to regression analysis, and the analysis results are shown in Tables 3 to 5.
[0023]
[0024] Table 3: Model summary table;
[0025] Table 4: ANOVA table;
[0026] Table 5: Coefficient analysis table; It can be seen from Table 3 that the adjusted determination coefficients of Model 1 and Model 2 are R2adj1=0.894 and R2adj2=0.871, respectively, indicating that there is a close linear correlation between the dependent variable VC value and the independent variable moisture content. It can be seen from Table 4 that the significance test statistics of the regression equations of Model 1 and Model 2 are F1=102.583 and F2=71.605, and the test values are both P=0.000<0.05, indicating that the established regression model is statistically significant.
[0027] It can be seen from Table 5 that the significance test P values are 0.052 and 0.074 respectively; at the significance level of α=0.10, the analysis shows that there is a significant linear relationship between VC value and moisture content.
[0028] Step 2: Take the workability rolling mixture to be tested and sieve out the coarse aggregate therein with a sieve; Step 3: Put the mixture after removing the coarse aggregate into the volume cylinder; Step 4: Use an iron disc to pat and compact the concrete in the volume cylinder until the surface is slurry; Step 5. Use a moisture content tester to measure the moisture content of the sieved mixture. Each time the moisture content of the mixture is measured, test it once along the center, edge and secondary edge of the sample container, and calculate the average value. The calculated average value represents the workability of the RCC.
[0029] Step 6: The moisture content is calculated based on the principle that the dielectric constant of water is much greater than the dielectric constants of other materials and the dielectric constant of air. The change in dielectric constant reflects the difference in moisture content of concrete. The relationship between the volume moisture content formula and dielectric constant in concrete is: ; In the formula, Ω is the relative dielectric constant, V1, V2, V3 (V1+V2+V3=1) are the volume concentrations of gas, solid and liquid in RCC, respectively; it can be seen from the formula that the volume moisture content is positively correlated with the relative dielectric constant, and the dielectric constant increases with the increase of unit water consumption.
[0030] Therefore, it is feasible to convert the influencing factor of VC value, water, into volume moisture content through the measured dielectric constant, which means that the moisture content can be used to characterize the VC value of RCC. In actual application, for a certain fixed ratio mixture, the VC value-moisture content relationship model can be derived through the measured data and the above analysis, and then used. Once the relationship model is determined, the measurement method can be used to save a lot of time and manpower on site, and it is more convenient and accurate. Therefore, moisture content test is a feasible new method.
Claims
1. A method for quickly measuring the construction quality index of roller compacted concrete, characterized in that: The following steps are involved: S1, take the workability rolling mixture to be tested, and use a sieve to remove the coarse aggregate; S2, loading the mixture after removing the coarse aggregate into the volume cylinder; S3, gradually use the iron disc to pat and compact the concrete in the volume cylinder until the surface is covered with slurry; S4, using a moisture content tester to measure the moisture content of the sieved mixture; S5. Each time the moisture content of the mixture is measured, the moisture content is tested once along the center, edge and sub-edge of the sample container, and the average value is calculated. The average value is used to characterize the workability of the roller compacted concrete.
2. A method for rapidly measuring roller compacted concrete construction quality indicators according to claim 1, characterized in that: The relationship between moisture content and VC value is tested based on the correlation test of SPSS software. If the test meets the requirements, it means that the distribution types of the two variables are basically consistent and have a strong correlation. In order to clarify the specific relationship between the two variables, regression analysis is performed on the two variables to finally confirm whether moisture content can replace VC value.
3. A method for rapidly measuring roller compacted concrete construction quality indicators according to claim 1, characterized in that: In step S5, characterizing the workability of the RCC by the obtained mean value specifically includes calculating the moisture content of the RCC by using the relationship between the moisture content and the dielectric constant.
4. A method for rapidly measuring roller compacted concrete construction quality indicators according to claim 3, characterized in that: The dielectric constant is obtained by the RCC tester. The specific method is as follows: The roller compacted concrete tester consists of a probe, an intelligent analysis module and a handheld instrument. The probe of the tester forms an electrode. When the probe is inserted into the concrete, a capacitor is formed. The concrete in between acts as a dielectric. The capacitor and the oscillator form a tuned circuit. The tuned circuit emits electromagnetic waves, which are received by the probe and transmitted to the intelligent module through electrical signals to measure the propagation frequency of the electromagnetic waves. The wave speed is deduced based on the propagation frequency, and finally the dielectric constant of the concrete is deduced. The dielectric constant of water is much larger than that of other materials in concrete. The intelligent module calculates the moisture content of the original concrete through analysis.
5. A method for rapidly measuring roller compacted concrete construction quality indicators according to claim 4, characterized in that: During the test, since the RCC was filtered through a sieve, the measured moisture content was the moisture content of the concrete after sieving. In order to obtain the moisture content of the original concrete, a simplified calculation method was used to make the following assumptions: During the sieve filtration process, there is no loss of water in the concrete; The amount of test concrete sieved out of equal amounts of concrete mixture under the same mix conditions is equal; The conversion coefficient K between the moisture content of the original concrete and the moisture content of the screened concrete is measured through multiple tests. The moisture content of the original concrete is equal to the measured moisture content multiplied by the coefficient K. The conversion process is completed in the intelligent module.
6. A method for rapidly measuring roller compacted concrete construction quality indicators according to claim 2, characterized in that: In order to determine the correlation analysis method between two variables, the sample data of the variables involved are tested to see whether they meet the normal distribution. The PP probability diagram reflects the relationship between the cumulative ratio of a variable and the cumulative ratio of the specified distribution, and is used to test whether the data meets the specified distribution. If the points on the PP graph are approximately a straight line, it means that the sample data approximately obeys the normal distribution, and the Pearson correlation coefficient method is used for analysis.
7. A method for rapidly measuring roller compacted concrete construction quality indicators according to claim 6, characterized in that: The method for testing the variable regression model is: Two different special working conditions are selected to analyze the specific quantitative relationship between VC value and moisture content under the working conditions, that is, several pairs of VC value and moisture content corresponding to the same mixture are randomly extracted, and each pair of VC value and moisture content should have a one-to-one correspondence; these data are divided into two groups, the first group is the second grade distribution, and the second group is the third grade distribution; considering that the temperature has a greater impact on the relative dielectric constant during the test, a temperature consistency test is required to reduce the error, and regression analysis is performed on the above two groups of data respectively.
8. A method for rapidly measuring roller compacted concrete construction quality indicators according to claim 7, characterized in that: The moisture content is calculated as follows: Based on the relationship between the volume moisture content formula and the dielectric constant in concrete, the moisture content is calculated using the measured dielectric constant: ； In the formula, Ω is the relative dielectric constant, V1, V2, V3 (V1+V2+V3=1) are the volume concentrations of gas, solid and liquid in RCC, respectively; the volume moisture content is positively correlated with the relative dielectric constant, and the dielectric constant increases with the increase of unit water consumption.