1、Designation: C1040/C1040M 08 (Reapproved 2013)C1040/C1040M 16Standard 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 de
2、signation indicates theyear of original 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 th
3、e determination of the in-place density of unhardened and hardened concrete, including rollercompacted concrete, by gamma radiation. For notes on the nuclear test see Appendix X1.1.2 Two test methods are described, as follows:SectionTest Method ADirect TransmissionTest Method BBackscatter78Test Meth
4、od ADirect TransmissionTest Method BBackscatter891.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values fro
5、m thetwo systems may result in non-conformance with the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the appl
6、icability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C29/C29M Test Method for Bulk Density (“Unit Weight”) and Voids in AggregateC125 Terminology Relating to Concrete and Concrete AggregatesC138/C138M Test Method for Density (Unit Weight), Yield, and Air Content
7、 (Gravimetric) of ConcreteC670 Practice for Preparing Precision and Bias Statements for Test 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 a
8、s rapid, nondestructive techniques for the in-place determination of the density of unhardenedconcrete. The backscatter test method is also useful for the same purpose on hardened concrete. The fundamental assumptionsinherent in the test methods are that Compton scattering is the dominant interactio
9、n and that the material under test ishomogeneous.4.2 These test methods are suitable for control and for assisting in acceptance testing during construction, for evaluation ofconcrete quality subsequent to construction, and for research and development.NOTE 1Care must be taken when using these test
10、methods in monitoring the degree of consolidation, which is the ratio of the actual density achieved1 These test methods are under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregatesand are the direct responsibility of Subcommittee C09.45on Roller-Compacted Concrete.Current ed
11、ition approved Nov. 15, 2013July 1, 2016. Published December 2013August 2016. Originally approved in 1985. Last previous edition approved in 20082013as C1040 08.C1040/C1040M 08(2013). DOI: 10.1520/C1040_C1040M-08R13.10.1520/C1040_C1040M-16.2 For referencedASTM standards, visit theASTM website, www.a
12、stm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what
13、changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the o
14、fficial document.*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 States1to the maximum density attainable with a particular concrete. The test methods presented here are used t
15、o determine the actual density. A densitymeasurement, by any test method, is a function of the components of the concrete and may vary, to some extent, in response to the normal, acceptablevariability of those components.4.3 Test results may be affected by reinforcing steel, by the chemical composit
16、ion of concrete constituents, and by sampleheterogeneity. The variations resulting from these influences are minimized by instrument design and by the users compliancewith appropriate sections of the test procedure. Results of tests by the backscatter test method may also be affected by the densityo
17、f underlying material. The backscatter test method exhibits spatial bias in that the apparatuss sensitivity to the material underit decreases with distance from the surface of the concrete.NOTE 2Typically, backscatter gauge readings represent the density in the top 75 to 100 mm 3 to 4 in. of materia
18、l.5. Apparatus5.1 The exact details of construction of the apparatus may vary, but the apparatus as a whole shall satisfy the requirements forsystem precision stated in Annex A1. The system shall consist of the following:5.1.1 Gamma SourceAn encapsulated and sealed radioisotopic source, such as cesi
19、um-137 (see X1.2X1.3).5.1.2 DetectorAny type of gamma detector, such as a Geiger-Mller tube, scintillation crystal, or proportional counter.5.1.3 ProbeFor direct transmission measurements, either the gamma source or the detector shall be housed in a probe forinserting in a preformed hole in the mate
20、rial to be tested. The probe shall be marked in increments of 50 mm 2 in. for tests withprobe depths from 50 to 300 mm 2 to 12 in. The probe shall be so made mechanically, that when moved manually to the markeddepth desired, it will be held securely in position at that depth.5.1.4 Readout Instrument
21、A suitable scaler or direct readout meter.5.1.5 Gauge HousingThe source, detector, readout instrument and appropriate power supplies shall be in housings of ruggedconstruction that are moisture and dust proof.5.1.6 Reference StandardA block of uniform, unchanging density provided for checking equipm
22、ent operation, backgroundcount, and count-rate reproducibility.5.1.7 Guide Plate and Hole-Forming-DeviceFor direct transmission measurements, a guide plate and a device, such as a pinor drill rod, having a nominal diameter slightly larger than the probe, for forming a hole normal to the concrete sur
23、face are required.5.1.8 Calibration Adjustment ContainerThe container shall be rigid and watertight, with minimum inside dimensions largeenough to allow the calibration curve adjustment procedure (5.26.2) to be followed with no effect of the finite size of the containeron the instruments responses.
24、The volume of the container shall be established following the procedure outlined in Test MethodC29/C29M.NOTE 3For backscatter measurements, a container 450 by 450 by 150 mm 18 by 18 by 6 in. will meet this requirement for most equipment currentlyavailable commercially. For 50-mm 2-in. depth direct
25、transmission measurements, a container 600 by 600 by 100 mm 24 by 24 by 4 in. will meetthis requirement.5.1.9 ScaleThe scale shall be accurate to within 0.2 kg 0.5 lb of the test load at any point within the range of use. The rangeof use shall be considered to extend from the weight of the calibrati
26、on adjustment container empty, to the weight of the measureplus the contents at 2600 kg/m3 160 lb/ft3 .5.1.10 Strike-Off Plate or BarThis shall be a flat metal or glass plate or metal bar with a length at least 50 mm 2 in. greaterthan the length, width, or diameter of the calibration adjustment cont
27、ainer.The strike-off must be rigid, straight, and smooth enoughto finish the concrete surface flat and flush with the edges of the calibration adjustment container.6. Calibration6.1 Calibration curves are established by determining the nuclear count rate of each of several materials at different and
28、 knowndensities, plotting the count rate (or count ratio) versus each known density, and placing a curve through the resulting points. Themethod used to establish the curve must be the same as that used to determine the density. The materials used for calibration mustbe of uniform density.NOTE 4Cali
29、bration curves are supplied by gauge manufacturers, or can be established using blocks of known density or prepared containers ofuniform, unchanging material compacted to known densities. Materials considered satisfactory for use in blocks include granite, aluminum, chalk,limestone, and magnesium.6.
30、2 Adjusting Calibration CurvesPrior to use, adjust the instruments calibration curve, if necessary, to compensate forchemical composition effects. Such an adjustment is necessary whenever the chemical composition of the concrete to be testeddiffers significantly from that for which the calibration c
31、urve was established. An adjustment is also necessary if the testingequipment has been changed. Adjustment is particularly important for backscatter test method measurements. Determine thenecessary adjustments using the same mode of operation and at the same depth (if using direct transmission) as t
32、hat intended fortesting. A recommended procedure for making this adjustment is as follows:6.2.1 Prepare a concrete mix similar in composition to the material to be tested subsequently.6.2.2 Fill the calibration adjustment container with concrete and consolidate to produce a uniform, homogeneous mate
33、rial withapproximately the density that will be achieved in the construction.NOTE 5Consolidation may be achieved by the procedure used for unit weight testing (Test Method C138/C138M) or by other methods, such asC1040/C1040M 162spading the concrete and then dropping the ends of the container alterna
34、tely on a rigid surface.6.2.3 Strike off the container with strike-off plate or bar. Take care to make the concrete surface flat and flush with the containeredges.NOTE 6A2 mm 116 in. average difference between the concrete surface and the container edges in a 150 mm 6 in. deep container will produce
35、a 1 to 2 % error in the weighed density of the concrete.6.2.4 Weigh the concrete in the container to the nearest 0.2 kg 0.5 lb and determine the weighed density as follows:W5WcV (1)where:W = weighed density of concrete, kg/m3 lbft3,Wc = mass of the concrete, kg lb, andV = volume of the container, m3
36、 ft3.6.2.5 Immediately take three automatically timed direct transmission or backscatter readings with the instrument centered onthe surface of the concrete in the container. Rotate the base of the instrument 90 around the vertical axis, with subsequent rotationsof 180 and 270 from the original posi
37、tion. Obtain three additional automatically timed counts at each position. The instrumentmust be centered over the surface of the concrete in each rotated position to prevent edge effects on the instrument reading.6.2.6 Using the applicable calibration curve, determine the density from the average o
38、f the 12 counts obtained in 5.2.56.2.5.6.2.7 Determine the difference between the two density readings obtained in 5.2.46.2.4 and 5.2.66.2.6.6.2.8 Repeat 5.2.26.2.2 5.2.76.2.7 on two additional concrete mixes of the same proportions. Determine the adjustment factorby averaging the three values obtai
39、ned in 5.2.76.2.7 and 5.2.86.2.8. If one of the three values differs from the average by morethan 25 kg/m3 1.5 lb/ft3, discard it as a statistical outlier and recalculate the adjustment factor as the average of the remainingtwo values.6.2.9 Use the adjustment factor determined in 5.2.86.2.8 to plot
40、a corrected count-rate calibration curve which shall be parallelto the original calibration curve and offset by the amount indicated in 5.2.86.2.8. Alternatively, the value of the adjustment factorshall be attached to the instrument and applied to all density determinations arrived at from an origin
41、al (unadjusted) calibrationcurve.NOTE 7In some circumstances, for example, where chemical composition changes are minimal, calibration curve adjustments may be established onpermanent, uniform, hardened concrete blocks.7. Standardization7.1 Standardization of the equipment on the reference standard
42、is required at the start of each day and whenever testmeasurements are suspect.NOTE 8In some older instrument models, count rates are strongly influenced by the ambient temperature; frequent standardization may be necessary.7.2 Warm-up time shall be in accordance with the manufacturers recommendatio
43、ns.7.3 Take at least five readings on the reference standard, more if recommended by the manufacturer, or take one 4 min or longercount if the instrument is equipped with automatic standard count storage.7.4 If more than one of the individual readings is outside the limit set by Eq 2, repeat the sta
44、ndardization. If the second attemptdoes not satisfy Eq 2, check the system for a malfunction. If no malfunction is found, establish a new No (average count) by takingthe average of a minimum of 10 counts on the reference standard.?Ns 2No?,1.96=No (2)where:Ns = count currently measured in checking th
45、e instrument operation, andNo = average count previously established on the reference standard.In instruments where the count has been prescaled, that is, divided by a constant factor k before it is displayed, Eq 2 shall bereplaced by the following:?Ns 2No?,1.96=No/k (3)7.4.1 If automatic standard c
46、ount storage is used and the newly established count is outside the limit set by Eq 2, repeat thestandardization.7.4.2 If the second attempt does not satisfy Eq 2, check the system for a malfunction.7.4.3 If no malfunction is found, establish a new No equal to the average count found in 6.4.27.4.2.7
47、.5 If a new N o differs by more than 10 % from the standard count at which the calibration curve (5.16.1) was established,recalibrate the instrument.C1040/C1040M 163TEST METHOD ADIRECT TRANSMISSION (FOR UNHARDENED CONCRETE)8. Procedure8.1 Select a test location such that, when the gauge is placed in
48、 test position:8.1.1 Any point on the source-detector axis shall be at least 230 mm 9 in. from any pavement edge or object.8.1.2 Reinforcing steel shall not be present in the volume bounded by the extended probe and the detector tubes.8.1.3 The test location shall contain concrete to a depth 25 mm 1
49、 in. greater than that to which the probe will be inserted. Inthin concrete overlay projects, this may require the removal of the underlying (original) concrete 25 to 50 mm 1 to 2 in. downover a small area before placement of the overlay.8.2 Smooth the surface with a wood float. If necessary, use the guide plate and hole-forming device (4.1.75.1.7) to make a holeslightly larger than the probe and perpendicular to the surface. In some concretes, the probe may be inserted directly into theconcrete without
