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1、1AS 1289.5.8.41998 Australian Standard Methods of testing soils for engineering purposes Method 5.8.4: Soil compaction and density testsNuclear surface moisture-density gaugesCalibration using standard blocks 1SCOPEThis Standard sets out the method for the following: (a)The calibration of the densit
2、y system of a nuclear surface moisture-density gauge using standard blocks. The calibration equation, so derived, defines the relationship betweenthedensitycountratioandfielddensityfordirecttransmission measurement (see Notes 1 and 2). (b)The partial calibration of the moisture system of a nuclear s
3、urface moisture-density gauge using standard blocks. The calibration equation, so derived, defines the slope of the moisture calibration equation. The intercept of the moisture calibration equation for each particular material is determined from actual measurements of field moisture content, as deta
4、iled in AS 1289.5.8.1. 2REFERENCED DOCUMENTSThe following documents are referred to in this Standard: AS 1289Methods of testing soils for engineering purposes 1289.5.8.1Method 5.8.1: Soil compaction and density testsDetermination of field density and field moisture content of a soil using a nuclear
5、surface moisture-density gaugeDirect transmission mode 1289.5.8.5Method 5.8.5: Soilcompactionanddensitytests Nuclearsurface moisture-density gaugesDensity of a Type A or Type C standard density block 1289.5.8.6Method 5.8.6: SoilcompactionanddensitytestsNuclearsurface moisture-density gaugesAssigned
6、density of a Type B standard density block 1289.5.8.7Method 5.8.7: SoilcompactionanddensitytestsNuclearsurface moisture-density gaugesWater content of a standard moisture block using hydrogen content of components 1289.5.8.8Method 5.8.8: SoilcompactionanddensitytestsNuclearsurface moisture-density g
7、augesWater content of a standard moisture block using proportion of water 1289.5.8.9Method 5.8.9: SoilcompactionanddensitytestsNuclearsurface moisture-density gaugesWater content of a standard moisture block using comparison against primary blocks 2891Methods of sampling and testing asphalt 2891.14.
8、1.1Method 14.1.1: Field density testsDetermination of field density of com- pacted asphalt using a nuclear moisture-density gaugeDirect transmission mode COPYRIGHT Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 AS 1289.5.8.419982 3SAFETY PRECAUTIONSThe equipment used in this method utilizes r
9、adioactive materials which may be hazardous to health unless proper precautions are taken. Therefore, it is essential that operators receive instruction on potential hazards and precautions, together with routine safety procedures such as the use of personal radiation monitors, source leak testing a
10、nd use of radiation survey meters. Statutory regulations cover the use and transport of radioactive substances and users shall ensure that these regulations are complied with for the State or Territory in which the gauge is to be used. 4APPARATUSThe following apparatus is required (additional items
11、may be required for some types of gauges): (a)Nuclear surface moisture-density gauge, manufacturers handbook for the gauge and the manufacturers reference block. (b)Standard density blocks, Type A, Type B or Type C, as defined below. The density range spanned by the blocks shall cover the range of d
12、ensities that are expected to be encountered in the field. The density of the blocks shall be evenly spaced throughout the range. Each block shall have the minimum dimensions of 550 mm length 450 mm width and a minimum depth of 50 mm greater than the maximum depth at which the gauge is to be calibra
13、ted. Blocks of not less than 300 mm in width may be used, provided two or more such blocks are strapped together with 50 mm thick aluminium plates on each end. The top surface of each block shall be finished with an out-of-flatness not exceeding 0.5 mm.Whendeterminingthedensityofablockinaccordancewi
14、th AS 1289.5.8.5, using direct measurement of volume, each of the other surfaces of the block shall be finished with an out-of-flatness not exceeding 1.0 mm. A direct transmission access hole of diameter not exceeding 30 mm shall be drilled in the block, normal to the top surface, at least 100 mm fr
15、om the end and on the longitudinal axis of the block. The centre of the access hole shall be at least 150 mm from the sides of the block. The depth of the access hole shall be at least 50 mm greater than the calibration depth. If desired, two access holes, one near each end, may be drilled. When the
16、 gauge probe is placed into the access hole, the gauge base shall rest entirely on the block and shall be clear of any other access holes. The density of a standard density block shall be re-determined at least every 10 years. The set of standard density blocks shall be one of the following: (i)Type
17、 AHomogeneous blocks, of naturally occurring stone and of metal. Five blocks, two of natural stone and three of metal, shall be used. The stone blocks shall be of materials that bracket the mass attenuation coefficients of soils (see Note 3). The density of each block shall be determined in accordan
18、ce with AS 1289.5.8.5. The uncertainty of density for each block shall not be greater than 0.3%. (ii)Type BHomogeneous blocks of metal or of naturally occurring stone or a combination of metal and stone blocks. A minimum of three blocks shall be used. For each block, the density shall be assigned an
19、d the uncertainty of density determined in accordance with AS 1289.5.8.6. (iii)Type CHomogeneous blocks of naturally occurring stone. A minimum of four blocks shall be used. The density of each block shall be determined in accordance with AS 1289.5.8.5. The uncertainty of density for each block shal
20、l not be greater than 0.3%. COPYRIGHT Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 3AS 1289.5.8.41998 (c)Standardmoistureblockswithwatercontentsassignedinaccordancewith AS 1289.5.8.7, AS 1289.5.8.8 or AS 1289.5.8.9. The uncertainty of the water content of each block shall not be greater tha
21、n 3.0%. The blocks shall have assigned water contents covering the range of water contents to be encountered in the field. The blocks shall have minimum dimensions of 550 mm length 300 mm width 230 mm depth. The top surface of each block shall be finished with an out-of-flatness not exceeding 0.5 mm
22、. The water content of a standard moisture block shall be re-determined at least every 10 years. The set of standard moisture blocks shall be one of the following: (i)Blocks prepared from quartz sand and polystyrene in various proportions, the hydrogen of the polystyrene substituting for the hydroge
23、n of water. A block of aluminium or magnesium alloy may be used to provide an assigned water content of 0.000 t/m3, by definition. A minimum of three blocks shall be used. The proportions of sand to polystyrene for the blocks shall be such that the assignedwatercontentsareapproximatelyevenlydistribu
24、tedbetween 0.05 t/m3and 0.35 t/m3(see Note 4). The construction and assignment of water content to each block shall be made in accordance with AS 1289.5.8.7. (ii)Blocks made of a regular array of aluminium plates separated by air gaps that can be filled with water. The plates shall be vertical and n
25、ormal to the line between the neutron source and detector or when the gauge is placed on the block. Plates may be added or removed to alter the assigned water content value. Any additional water around the perimeter of the array shall not influence the response as measured by the moisture counts. A
26、block of aluminium or magnesium alloy may be used to provide an assigned water content of 0.000 t/m3, by definition. A minimum of three blocks shall be used. The assignment of water content to each block shall be made in accordance with AS 1289.5.8.8. (iii)Blocks made of polyethylene sheets and alum
27、inium or magnesium alloy sheets, the hydrogen of the polyethylene substituting for the hydrogen of water. A block of aluminium or magnesium alloy may be used to provide an assigned water content of 0.000 t/m3, by definition. A minimum of two blocks shall be used. The assignment of water content to e
28、ach block shall be made in accordance with AS 1289.5.8.9. (d)Radiation monitoring apparatus and personal radiation monitors as required by the regulatory authority. (e)Thermometer, if applicable, covering a range of 050C, with an uncertainty not exceeding 0.5C. 5PROCEDURE 5.1Preparation for calibrat
29、ionThe blocks shall be stored under cover to protect them from the effects of weather. COPYRIGHT Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 AS 1289.5.8.419984 Before a calibration is commenced, ensure that the blocks to be used are sufficiently clear of other nuclear gauges or other sourc
30、es of radiation so that there is no detectable effect on the counts displayed by the gauge. In buildings that are restricted in available area, it may be necessary to provide shielding to achieve this requirement. The location for the standard count determinations and the gauge function checks shall
31、 be at least 1 m from any vertical projection or any known neutron absorber or moderator. There shall be a minimum clearance of 1 m from any vertical projection which is above the level of the top of the blocks. Standard moisture blocks shall be situated at least 1 m from any significant source of h
32、ydrogen or any neutron moderator or absorber. Ensure that the gauge is in good working order. Check that the base of the gauge, the manufacturers reference block and the standard blocks are clean. 5.2GaugefunctioncheckPerformgaugefunctionchecksinaccordancewith procedures specified for the gauge and
33、record the results. If the results of these checks fail to comply with the specified requirements, the function checks shall be repeated. If the results of the second function checks fail to comply with the specified requirements, the gauge shall be withdrawn from service until the reason for the fa
34、ult is determined and the fault rectified. 5.3Standard count checkPerform the check in accordance with Appendix A. 5.4Determination of density calibration dataInitial and final standard counts together with the completecalibration data for a particular depth shall be determined in one day. If a gaug
35、e has depths calibrated on different days, additional standard counts will need to be determined, at the start and end of each day of calibration. Proceed as follows: (a)Record an initial standard density count for the gauge on the manufacturers reference block in accordance with the procedure speci
36、fied by the manufacturer. Use a counting period of at least 4 minutes. (b)Place the gauge on a standard density block and position the probe above an access hole, orienting the gauge so that its longitudinal axis is parallel to the longitudinal axis of the block. Lower the probe to the required dept
37、h, and pull the gauge towards the centre of the block to ensure that the probe is in contact with the side of the access hole. (c)Without shifting the gauge, obtain and record four one-minute counts or one four- minutecount,inaccordancewiththemanufacturersinstructionsfordirect transmission measureme
38、nt. (d)Repeat Step (c) with the gauge in the same position or where the block contains two access holes, repeat Steps (b) and (c) with the probe located in the other access hole. (e)Repeat Steps (b) to (d) for the remaining standard density blocks. (f)Repeat Steps (b) to (e) for each required depth
39、of the probe. (g)Record a final standard density count of the gauge in accordance with, and at the same location as, Step (a). If this value falls outside the limits determined in accordance with Step (d) of Appendix A, the values determined from Steps (a) to (f) shall be rejected and the calibratio
40、n shall not proceed until the reason for the standard count being outside the limits is determined and the fault rectified. COPYRIGHT Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 5AS 1289.5.8.41998 5.5Determination of moisture calibration dataInitial and final standard counts together with
41、the complete calibration data shall be determined in one day. Proceed as follows: (a)If applicable, fill the standard moisture blocks with water, ensuring that entrapped air is removed. The vertical plates shall be just submerged. Leave the blocks for 30 min to allow temperatures to become stable. R
42、ecord the water temperature of each block and determine the corresponding water density from Table 1. (b)Record an initial standard moisture count for the gauge on the manufacturers reference block in accordance with the procedure specified by the manufacturer. Use a counting period of at least 4 mi
43、n. (c)Place the gauge on a standard moisture block so that it is clear of any access holes. (d)Without shifting the gauge, obtain and record four one-minute counts or one four- minute count, in accordance with the manufacturers instructions for moisture measurement. (e)Repeat Step (d) with the gauge
44、 in the same position, or if desired rotate the gauge 180 about its vertical axis and repeat Steps (c) to (d). (f)Repeat Steps (c) to (e) for the remaining standard moisture block(s). (g)Record a final standard moisture count of the gauge in accordance with, and at the same location as, Step (b). If
45、 this value falls outside the limits determined in accordance with Step (d) of Appendix A, the values determined from Steps (b) to (f) shall be rejected and the calibration shall not proceed until the reason for the standard count being outside the limits is determined and the fault rectified. TABLE
46、1 DENSITY OF WATER AT VARIOUS TEMPERATURES Ct/m3Ct/m3 150.9991230.9975 160.9989240.9973 170.9988250.9970 180.9986260.9968 190.9984270.9965 200.9982260.9962 210.9980290.9959 220.9978300.9956 6CALCULATIONS 6.1Density dataCalculate the following: (a)The mean of the initial and final standard density co
47、unts obtained at Steps 5.4(a) and (g), respectively. (b)The mean of the density counts for each probe depth on each standard density block obtained at Steps 5.4(c) and (d). (c)The density count ratio (DCR) for each probe depth on each standard density block by dividing each mean density count obtain
48、ed at Step (b) by the mean standard density count obtained at Step (a). COPYRIGHT Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 AS 1289.5.8.419986 6.2Density calibration constants 6.2.1Type A blocksThe calibration equation is of the following form: DCR = AeB C. . . 6(1) where DCR= density co
49、unt ratio = density, in tonnes per cubic metre e= natural logarithm base A, B, C = calibration constants for the particular gauge Proceed as follows, for each probe depth: (a)Solve the above equation for A and C using the density count ratio (DCR) and the known density ( ) of each metal block. (b)Calculate the value of B for one of the stone blocks using the A and C constants so derived and the data obtained for that block. (c)Repeat Step (b) for the remaining stone block. (d)Calculate the average value of B derived from the stone blocks. (e)The A an