On-site rapid detection method for water content of cement stabilized macadam material

Abstract

The invention discloses a method for rapidly detecting the water content of a cement stabilized macadam material on a construction site. According to the method, firstly, a portable high-frequency electromagnetic wave moisture content rapid tester is subjected to test gear adjustment and zero setting, then a cement stabilized macadam paving layer moisture content test area before rolling is selected on site, and the position of the test area can be consistent with the on-site compactness detection position; a cement stabilized macadam layer in a testing area needs to have the compactness of 65-90%, moisture content testing is conducted on different testing points at the position about 1 / 2 depth in the testing area, 16 testing points are evenly distributed in the range of the testing area, and the moisture content value of the water stabilized macadam on site is determined by calculating the average value of the different testing points through data. The detection method provided by the invention can rapidly and accurately test the water content condition of the water-stabilized crushed stone material on site, improves the test efficiency, facilitates timely adjustment of the raw material mix proportion, optimizes the construction process, and improves the compaction quality of the water-stabilized base layer.

Description

Technical Field

[0001] The invention belongs to the field of highway construction, and in particular is an on-site rapid detection method for the moisture content of cement-stabilized crushed stone materials. Background Art

[0002] Cement-stabilized crushed stone is widely used in highway, municipal road and parking lot construction due to its high bearing capacity and durability. As a mixed proportion material, the proportion quality directly determines the quality and strength of the mixture, thus affecting the quality of the project. Since cement-stabilized crushed stone materials are generally mixed in the factory and transported to the site by vehicles for paving construction, some water will evaporate during the process. Therefore, the on-site determination of the moisture content of water-stabilized crushed stone is of great significance to the quality control of cement-stabilized crushed stone layer paving.

[0003] "Technical Specifications for Highway Pavement Base Construction" (JTG / T F20-2015) 4.7.5 stipulates that the determination of mixture production parameters includes indicators such as binder dosage, moisture content and maximum dry density. Based on the results of mix design and taking into account the climatic conditions during the construction process, the moisture content of cement stabilized materials can be increased by 0.5~1.5 percentage points, and for other stabilized materials, it can be increased by 1~2 percentage points. At present, the common practice for testing the moisture content of water-stabilized materials is to use the drying method. This method takes a long time to test, cannot guide on-site work in a timely manner, and is easily affected by human factors during the test process. The moisture content test of cement-stabilized crushed stone requires a method that is suitable for on-site use, has faster testing, and more stable data. Summary of the invention

[0004] The invention aims to provide a method for quickly detecting the moisture content of cement-stabilized crushed stone materials on construction site.

[0005] The method for rapidly determining the moisture content of cement-stabilized crushed stone is as follows: first, the test gear of the portable high-frequency electromagnetic wave moisture content rapid measuring instrument is adjusted and zeroed, and then a moisture content test area of ​​the cement-stabilized crushed stone paving layer (the paving layer thickness is H) before rolling is selected on site, the position of the test area can be consistent with the on-site compaction detection position, the cement-stabilized crushed stone layer in the test area needs to have a compaction degree of 65%-90%, moisture content tests are performed at different measuring points at about 1 / 2 depth in the test area, 16 measuring points are evenly distributed within the measuring area, and the moisture content value of the cement-stabilized crushed stone on site is determined by calculating the average value of different measuring points through data.

[0006] The field test area described in the present invention is mainly a field cement-stabilized gravel layer that has been paved but not rolled and has a certain degree of compaction. The paving thickness is H (not less than 10 cm), and the compaction requirement of the cement-stabilized gravel layer in the test area should be between 65% and 90%. The location of the test area is consistent with the location of the field compaction detection. The size of a single test area should be 30×30 cm, and the distance between the edge of the test area and the paving edge should not be less than 50 cm.

[0007] The specific steps and requirements of the in-measurement area testing method described in the present invention are as follows: a. 16 measuring points are evenly arranged in each measuring area to test the moisture content; b. When measuring the moisture content of water-stable materials, the instrument measuring rod should be inserted at an angle of 20~45° to the test surface, and the vertical insertion depth should be 1 / 2H±2cm. If a larger particle size material is encountered during the test, the direction should be adjusted in time to avoid damage to the instrument; c. Apply pressure slowly during the insertion process, and read the data accurately after the test data stabilizes. The moisture content reading at each measuring point should be accurate to 0.01%; d. The probe measurement point should be located away from the pores or under large-size stones, and the same measurement point should only be measured once; e. After the reading is completed, the test probe should be cleaned promptly.

[0008] The test data processing and analysis described in the present invention, its specific methods and requirements are: a. When calculating the average moisture content in the survey area, the 3 maximum and 3 minimum values ​​should be eliminated from the 16 moisture content values ​​in the survey area, and the average value of the remaining 10 moisture content values ​​should be calculated. The calculation result should be accurate to 0.01%.

[0009] b. Ensure that the error between the test results of the two measurement areas is within 0.2%. If the error is large, reselect the measurement area for measurement.

[0010] The detection method of the present invention can quickly and accurately test the moisture content of water-stable crushed stone materials on site, improve the test efficiency, facilitate timely adjustment of the raw material mix ratio, optimize the construction process, and improve the compaction quality of the water-stable base. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of the measurement area and measurement points in Example 1. DETAILED DESCRIPTION

[0012] In order to make the purpose and technical solution of the present invention clearer, the present invention will be further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Example 1

[0013] a. First, adjust the test gear of the portable high-frequency electromagnetic wave moisture content rapid tester and perform zeroing.

[0014] b. Select a test area for moisture content of the cement-stabilized crushed stone paving layer before rolling on site. The size of a single test area should be 30×30cm, and the cement-stabilized crushed stone layer in the test area should have a compaction degree of 65%-90%.

[0015] c. 16 measuring points are evenly arranged within the measuring area (such as Figure 1 As shown in the figure, the moisture content of different measuring points is tested at about 1 / 2 depth in the test area. If a larger particle size material is encountered during the test, the direction should be adjusted in time to avoid damage to the instrument. After each test area is completed, the data of each measuring point is recorded, and the statistical results are shown in Table 1.

[0016] d. When calculating the average moisture content in the survey area, the 3 maximum values ​​and 3 minimum values ​​(each group of data marked in red) should be eliminated from the 16 moisture content values ​​in the survey area, and the average value of the remaining 10 moisture content values ​​should be calculated. The calculation result should be accurate to 0.01%.

[0017] The measurement points are calculated as follows: The statistical results of each measuring point are shown in Table 1.

[0018] e. After the reading is completed, the test probe should be cleaned promptly.

[0019] Table 1. Test data of moisture content in the test area serial number Measurement area 1 (%) Measurement area 2 (%) Measurement area 3 (%) Measurement area 4 (%) …… 1 4.46 3.78 2.27 2.8 2 4.55 3.88 2.52 3.4 3 4.64 4.04 3.62 3.6 4 4.67 4.38 4.23 3.82 5 4.70 4.40 4.33 4.00 6 4.71 4.75 4.62 4.0 7 4.81 4.75 4.62 4.3 8 4.83 4.84 4.65 4.3 9 4.84 4.85 4.67 4.6 10 4.93 4.93 4.68 4.67 11 5.01 4.97 4.79 4.82 12 5.03 5.01 4.81 4.9 13 5.05 5.11 5.16 5.00 14 5.14 5.15 5.19 5.01 15 5.35 5.20 5.47 5.30 16 5.53 5.31 5.53 6.80 Mean 4.86 4.80 4.66 4.44

Claims

1. A method for rapid on-site testing of moisture content of cement-stabilized crushed stone mixture. Features: First, the test gear of the portable rapid moisture content meter is adjusted and zeroed. Then, the cement-stabilized gravel is spread on site. Before rolling, a moisture content test area is selected. The cement-stabilized gravel layer in the test area must have a certain degree of compaction. Moisture content tests are carried out at different measuring points at about 1 / 2 depth in the test area. There are 16 test points. The moisture content of the on-site water-stabilized gravel is determined by calculating the average value of different measuring points through data.

2. The on-site rapid testing method for moisture content of cement-stabilized crushed stone mixture according to claim 1, Features The size of a single measuring area should be 30×30cm, the distance between the edge of the measuring area and the paving edge should not be less than 50cm, and the compaction requirement should be between 65% and 90%.

3. The on-site rapid testing method for moisture content of cement-stabilized crushed stone mixture according to claim 1, Features The steps of the moisture content test operation process are as follows: a. Evenly select 16 measuring points in each measuring area to test the moisture content; b. When measuring the moisture content of water-stabilizing materials, the instrument measuring rod should be inserted at an angle of 20~45° to the test surface, and the vertical insertion depth should be 1 / 2H±2cm, where H is the thickness of the cement-stabilized gravel layer. If a larger particle size material is encountered during the test, the direction should be adjusted in time to avoid damage to the instrument; c. Apply pressure slowly during the insertion process, and read the data accurately after the test data stabilizes. The moisture content reading at each measuring point should be accurate to 0.05%; d. The probe measurement point should be located away from the pores or under large-size stones, and the same measurement point should only be measured once; e. After the reading is completed, the test probe should be cleaned promptly.

4. The on-site rapid testing method for moisture content of cement-stabilized crushed stone mixture according to claim 1, Features :Test data processing and analysis, the specific methods and requirements are: a. When calculating the average moisture content in the measurement area, the 3 maximum and 3 minimum values ​​should be removed from the 16 moisture content values ​​in the measurement area, and the average value of the remaining 10 moisture content values ​​should be calculated, and the calculation result should be accurate to 0.05%; b. Ensure that the error between the test results of the two measurement areas is within 0.2%. If the error is large, reselect the measurement area for measurement.

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