1、Designation: C1040/C1040M 16aStandard Test Methods forIn-Place Density of Unhardened and Hardened Concrete,Including Roller Compacted Concrete, By Nuclear Methods1This standard is issued under the fixed designation C1040/C1040M; the number immediately following the designation indicates theyear of o
2、riginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods cover the determination of thein-place d
3、ensity of unhardened and hardened concrete, includ-ing roller compacted concrete, by gamma radiation. For noteson the nuclear test see Appendix X1.1.2 Two test methods are described, as follows:SectionTest Method ADirect TransmissionTest Method BBackscatter891.3 The values stated in either SI units
4、or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 This standard does not p
5、urport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2
6、C29/C29M Test Method for Bulk Density (“Unit Weight”)and Voids in AggregateC125 Terminology Relating to Concrete and Concrete Ag-gregatesC138/C138M Test Method for Density (Unit Weight), Yield,and Air Content (Gravimetric) of ConcreteC670 Practice for Preparing Precision and Bias Statementsfor Test
7、Methods for Construction Materials3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in these test methods,refer to Terminology C125.4. Significance and Use4.1 These test methods are useful as rapid, nondestructivetechniques for the in-place determination of the density ofunhardened c
8、oncrete. The backscatter test method is alsouseful for the same purpose on hardened concrete. Thefundamental assumptions inherent in the test methods are thatCompton scattering is the dominant interaction and that thematerial under test is homogeneous.4.2 These test methods are suitable for control
9、and forassisting in acceptance testing during construction, for evalu-ation of concrete quality subsequent to construction, and forresearch and development.NOTE 1Care must be taken when using these test methods inmonitoring the degree of consolidation, which is the ratio of the actualdensity achieve
10、d to the maximum density attainable with a particularconcrete. The test methods presented here are used to determine the actualdensity. A density measurement, by any test method, is a function of thecomponents of the concrete and may vary, to some extent, in response tothe normal, acceptable variabi
11、lity of those components.4.3 Test results may be affected by reinforcing steel, by thechemical composition of concrete constituents, and by sampleheterogeneity. The variations resulting from these influencesare minimized by instrument design and by the users compli-ance with appropriate sections of
12、the test procedure. Results oftests by the backscatter test method may also be affected by thedensity of underlying material. The backscatter test methodexhibits spatial bias in that the apparatuss sensitivity to thematerial under it decreases with distance from the surface ofthe concrete.NOTE 2Typi
13、cally, backscatter gauge readings represent the density inthe top 75 to 100 mm 3 to 4 in. of material.5. Apparatus5.1 The exact details of construction of the apparatus mayvary, but the apparatus as a whole shall satisfy the requirementsfor system precision stated in Annex A1. The system shallconsis
14、t of the following:1These test methods are under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregatesand are the direct responsibility of SubcommitteeC09.45 on Roller-Compacted Concrete.Current edition approved Dec. 15, 2016. Published January 2017. Originallyapproved in 1985. L
15、ast previous edition approved in 2016 as C1040/C1040M 16.DOI: 10.1520/C1040_C1040M-16A.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summar
16、y page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principl
17、es on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.15.1.1 Gamma SourceAn encapsulated and sealed radio-isotopic source, such as ce
18、sium-137 (see X1.3).5.1.2 DetectorAny type of gamma detector, such as aGeiger-Mller tube, scintillation crystal, or proportional coun-ter.5.1.3 ProbeFor direct transmission measurements, eitherthe gamma source or the detector shall be housed in a probe forinserting in a preformed hole in the materia
19、l to be tested. Theprobe shall be marked in increments of 50 mm 2 in. for testswith probe depths from 50 to 300 mm 2 to 12 in. The probeshall be so made mechanically, that when moved manually tothe marked depth desired, it will be held securely in position atthat depth.5.1.4 Readout InstrumentA suit
20、able scaler or direct read-out meter.5.1.5 Gauge HousingThe source, detector, readout instru-ment and appropriate power supplies shall be in housings ofrugged construction that are moisture and dust proof.5.1.6 Reference StandardA block of uniform, unchangingdensity provided for checking equipment o
21、peration, back-ground count, and count-rate reproducibility.5.1.7 Guide Plate and Hole-Forming-DeviceFor directtransmission measurements, a guide plate and a device, such asa pin or drill rod, having a nominal diameter slightly larger thanthe probe, for forming a hole normal to the concrete surface
22、arerequired.5.1.8 Calibration Adjustment ContainerThe containershall be rigid and watertight, with minimum inside dimensionslarge enough to allow the calibration curve adjustment proce-dure (6.2) to be followed with no effect of the finite size of thecontainer on the instruments responses. The volum
23、e of thecontainer shall be established following the procedure outlinedin Test Method C29/C29M.NOTE 3For backscatter measurements, a container 450 by 450 by 150mm 18 by 18 by 6 in. will meet this requirement for most equipmentcurrently available commercially. For 50-mm 2-in. depth direct trans-missi
24、on measurements, a container 600 by 600 by 100 mm 24 by 24 by4 in. will meet this requirement.5.1.9 ScaleThe scale shall be accurate to within 0.2 kg0.5 lb of the test load at any point within the range of use. Therange of use shall be considered to extend from the weight ofthe calibration adjustmen
25、t container empty, to the weight of themeasure plus the contents at 2600 kg/m3160 lb/ft3.5.1.10 Strike-Off Plate or BarThis shall be a flat metal orglass plate or metal bar with a length at least 50 mm 2 in.greater than the length, width, or diameter of the calibrationadjustment container. The strik
26、e-off must be rigid, straight, andsmooth enough to finish the concrete surface flat and flush withthe edges of the calibration adjustment container.6. Calibration6.1 Calibration curves are established by determining thenuclear count rate of each of several materials at different andknown densities,
27、plotting the count rate (or count ratio) versuseach known density, and placing a curve through the resultingpoints. The method used to establish the curve must be thesame as that used to determine the density. The materials usedfor calibration must be of uniform density.NOTE 4Calibration curves are
28、supplied by gauge manufacturers, orcan be established using blocks of known density or prepared containersof uniform, unchanging material compacted to known densities. Materialsconsidered satisfactory for use in blocks include granite, aluminum, chalk,limestone, and magnesium.6.2 Adjusting Calibrati
29、on CurvesPrior to use, adjust theinstruments calibration curve, if necessary, to compensate forchemical composition effects. Such an adjustment is necessarywhenever the chemical composition of the concrete to be testeddiffers significantly from that for which the calibration curvewas established. An
30、 adjustment is also necessary if the testingequipment has been changed. Adjustment is particularly im-portant for backscatter test method measurements. Determinethe necessary adjustments using the same mode of operationand at the same depth (if using direct transmission) as thatintended for testing.
31、Arecommended procedure for making thisadjustment is as follows:6.2.1 Prepare a concrete mix similar in composition to thematerial to be tested subsequently.6.2.2 Fill the calibration adjustment container with concreteand consolidate to produce a uniform, homogeneous materialwith approximately the de
32、nsity that will be achieved in theconstruction.NOTE 5Consolidation may be achieved by the procedure used for unitweight testing (Test Method C138/C138M) or by other methods, such asspading the concrete and then dropping the ends of the containeralternately on a rigid surface.6.2.3 Strike off the con
33、tainer with strike-off plate or bar.Take care to make the concrete surface flat and flush with thecontainer edges.NOTE 6A2 mm 116 in. average difference between the concretesurface and the container edges in a 150 mm 6 in. deep container willproducea1to2%error in the weighed density of the concrete.
34、6.2.4 Weigh the concrete in the container to the nearest 0.2kg 0.5 lb and determine the weighed density as follows:W 5WcV(1)where:W = weighed density of concrete, kg/m3lb ft3,Wc= mass of the concrete, kg lb, andV = volume of the container, m3ft3.6.2.5 Immediately take three automatically timed direc
35、ttransmission or backscatter readings with the instrument cen-tered on the surface of the concrete in the container. Rotate thebase of the instrument 90 around the vertical axis, withsubsequent rotations of 180 and 270 from the originalposition. Obtain three additional automatically timed counts ate
36、ach position. The instrument must be centered over thesurface of the concrete in each rotated position to prevent edgeeffects on the instrument reading.6.2.6 Using the applicable calibration curve, determine thedensity from the average of the 12 counts obtained in 6.2.5.6.2.7 Determine the differenc
37、e between the two densityreadings obtained in 6.2.4 and 6.2.6.6.2.8 Repeat 6.2.2 6.2.7 on two additional concrete mixesof the same proportions. Determine the adjustment factor byaveraging the three values obtained in 6.2.7 and 6.2.8. If one ofC1040/C1040M 16a2the three values differs from the averag
38、e by more than 25kg/m31.5 lb/ft3, discard it as a statistical outlier and recalcu-late the adjustment factor as the average of the remaining twovalues.6.2.9 Use the adjustment factor determined in 6.2.8 to plota corrected count-rate calibration curve which shall be parallelto the original calibratio
39、n curve and offset by the amountindicated in 6.2.8. Alternatively, the value of the adjustmentfactor shall be attached to the instrument and applied to alldensity determinations arrived at from an original (unadjusted)calibration curve.NOTE 7In some circumstances, for example, where chemical compo-s
40、ition changes are minimal, calibration curve adjustments may be estab-lished on permanent, uniform, hardened concrete blocks.7. Standardization7.1 Standardization of the equipment on the reference stan-dard is required at the start of each day and whenever testmeasurements are suspect.NOTE 8In some
41、older instrument models, count rates are stronglyinfluenced by the ambient temperature; frequent standardization may benecessary.7.2 Warm-up time shall be in accordance with the manufac-turers recommendations.7.3 Take at least five readings on the reference standard,more if recommended by the manufa
42、cturer, or take one 4 minor longer count if the instrument is equipped with automaticstandard count storage.7.4 If more than one of the individual readings is outside thelimit set by Eq 2, repeat the standardization. If the secondattempt does not satisfy Eq 2, check the system for a malfunc-tion. If
43、 no malfunction is found, establish a new No(averagecount) by taking the average of a minimum of 10 counts on thereference standard.?Ns2 No?,1.96 =No(2)where:Ns= count currently measured in checking the instrumentoperation, andNo= average count previously established on the referencestandard.In inst
44、ruments where the count has been prescaled, that is,divided by a constant factor k before it is displayed, Eq 2 shallbe replaced by the following:?Ns2 No?,1.96 =No/k (3)7.4.1 If automatic standard count storage is used and thenewly established count is outside the limit set by Eq 2, repeatthe standa
45、rdization.7.4.2 If the second attempt does not satisfy Eq 2, check thesystem for a malfunction.7.4.3 If no malfunction is found, establish a new Noequal tothe average count found in 7.4.2.7.5 If a new Nodiffers by more than 10 % from the standardcount at which the calibration curve (6.1) was establi
46、shed,recalibrate the instrument.TEST METHOD ADIRECT TRANSMISSION (FORUNHARDENED CONCRETE)8. Procedure8.1 Select a test location such that, when the gauge is placedin test position:8.1.1 Any point on the source-detector axis shall be at least230 mm 9 in. from any pavement edge or object.8.1.2 Reinfor
47、cing steel shall not be present in the volumebounded by the extended probe and the detector tubes.8.1.3 The test location shall contain concrete to a depth 25mm 1 in. greater than that to which the probe will be inserted.In thin concrete overlay projects, this may require the removalof the underlyin
48、g (original) concrete 25 to 50 mm 1 to 2 in.down over a small area before placement of the overlay.8.2 Smooth the surface with a wood float. If necessary, usethe guide plate and hole-forming device (5.1.7) to make a holeslightly larger than the probe and perpendicular to the surface.In some concrete
49、s, the probe may be inserted directly into theconcrete without the use of the guide plate and hole-formingdevice.8.3 Insert the probe so that the side of the probe facing thecenter of the gauge is in intimate contact with the side of thehole. Keep all other radioactive sources at such a distance fromthe gauge that the readings will not be affected.NOTE 9The recommended minimum distance from other nucleardensity gauges is 10 m 30 ft.8.4 Use the same warm-up time as in standardization. Takeautomatically timed
