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Measuring Deections using a Portable Impulse Plate Load Test Device1 This standard is issued under the xed designation E; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision.
A number in parentheses indicates the year of last reapproval. A superscript epsilon indicates an editorial change since the last revision or reapproval. Scope 1. The method covers the measurement of deection of the load plate rather than the deection of the surface of the pavement or foundation layers see Note 1.
The values given in parentheses are for information only. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Referenced Documents 2. Summary of Test Method 3. The load is a force pulse generated by a falling mass dropped onto a spring assembly that transmits the load pulse to a plate resting on the material under test.
The device is calibrated to a preset drop height by the manufacturer. The preset drop height shall not be changed by the user. Current edition approved June 1, Published June DOI: Multiple drops from the same preset drop height may be performed at the same test location. Signicance and Use 4. The deection is measured at the center of the top of the load plate see Note 1. NOTE 1If the load plate is in perfectly uniform contact with the unbound material under the plate, then deection of the load plate should be equal to the deection of the surface of the unbound material under test.
Accordingly, the test surface shall be as clean and smooth as possible with loose granules and protruding material removed. For gravel surfaces it is recommended that a thin layer of ne sand be placed over the test point. For ne-grained materials, this will help in obtaining a reasonably uniform contact between the load plate and the surface. See 5. Some uses of the data include quality control and quality assurance of compacted layers, and for structural evaluation of load carrying capacity see Note 2 and Guide D NOTE 2The volume of the pavement foundation materials affected by the applied load is a function of the magnitude of the load, plate size and rigidity, loading rate, buffer stiffness, and the stiffness and shear strength of the pavement foundation materials.
Therefore, care must be taken when analyzing the results because the data obtained by the Portable Impulse Plate Load Test may be obtained under substantially different conditions than when a heavy moving wheel load passes over the pavement surface after construction is complete.
Apparatus 5. E 11 tolerant to relatively high humidity, rain and spray, and other adverse conditions such as dust, shock, and vibrations normally encountered. Designed to operate with negligible friction or resistance.
The stress distribution under the load plate depends on both load plate rigidity and material type, and therefore can be parabolic, inverse parabolic, or uniform 1.
The deection sensor or sensors shall be mounted so that the angular rotation is minimized with respect to its measuring plane at the maximum expected deection. The number and spacing of the sensors is optional and will depend upon the purpose of the test and the material characteristics.
Sensors may be of several types such as velocity transducers or accelerometers. The instrument shall be constructed to measure the vertical plate deection at the center of the point of impact. Does not require a vehicle or trailer for transport. Reagents and Materials 6. Sampling 7. Start the calibration procedure no earlier than 1 hour after preconditioning. The rigid base shall not generate any interfering vibrations as a result of the impact load 2.
Additionally, ensure that the difference between the individually measured force values and the mean force does not exceed 6 2 percent see Note 3. Ensure that the difference between individual measured values is less than or equal to 0.
NOTE 3Replace the spring assembly when the measured impact duration deviates 6 2 msec or greater from the specied impact duration. Verication Testing 8. E 11 8. Hazards 9. Maintenance and Handling Do not grease the guide rod since it is generally made of stainless steel.
NOTE 6For some devices, ensure that the rubber bellow enclosing the spring assembly is providing a tight seal to protect the spring assembly from dust and damage. Site Selection and Preparation Ensure consistent plate test depths are maintained throughout the project for any given material type. NOTE 4It may be benecial to perform verication testing on newly purchased or recently calibrated devices to ensure the device is working properly prior to Portable Impulse Plate Load Test device commissioning.
This would also provide a baseline to which later verication testing could be compared. NOTE 7The depth of inuence is roughly 1 to 1. Consequently, deection measurement obtained for a compacted lift with a thickness less than this inuence depth will be a composite. E 11 deection measurement that is also inuenced by the underlying lift.
NOTE 8Complete test on the compaction surface for locations where the disturbance caused by preparation would cause the deection measurements to increase and therefore become unrepresentative of the actual compacted condition. Procedure Use the rst three drops for seatingi and the next three drops for analysis.
Use the following procedure for each drop: NOTE 9Position the test device at a new test location when a faulty drop occurs. Testing cannot be repeated at the same location. NOTE 10Make sure the falling mass falls precisely from the calibration height 2. NOTE 11Ensure the following for equipment constructed using a centering ball: 1 the guide rod is not removed from the centering ball and 2 the load plate is not displaced during testing 2. NOTE 12Additional compaction may be necessary or the material may be too moist when these conditions are present.
Precision and Bias NOTE 13A Light Weight Deectometer device with a load cell and where surface deections are measured through a hole in the center of the load plate is designed such that the test results obtained may be appreciably different from a Portable Impulse Plate Load Test device without a load cell and where load plate deections are measured.
NOTE 14For Light Weight Deectometer devices referred to in Note 13, the approximate surfacei or composite modulus that results from tests conducted on unbound materials has been estimated to lie between 1.
The main reason for this rather large discrepancy is that by measuring the plate deection, a perfect contact between the plate and the unbound surface under test is not possible. There will always be micro-unevenness of any unbound material; therefore larger plate deections will invariably result than the deection of the uneven surface of the unbound material under test unless a material such as plaster-of-paris is placed between the load plate and the surface under test, and allowed to harden.
NOTE 15The peak force values slowly decrease as the peak deections of the test layer increase e. Reference 4[see Appendix B for granular materials; Appendix C for cohesive materials]; see also Reference 5 [in German] for further details. Keywords Vennapusa, P. Kudla, Freiberg 3 European Committee for Standardization. CWA English Version. CEN Workshop Agreement. ICS Brussels, ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard.
Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every ve years and if not revised, either reapproved or withdrawn.
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ASTM E2835 - 11(2015)
Historical Version s - view previous versions of standard. More E The deflection is measured at the center of the top of the load plate see Note 1. Accordingly, the test surface shall be as clean and smooth as possible with loose granules and protruding material removed. For gravel surfaces it is recommended that a thin layer of fine sand be placed over the test point. For fine-grained materials, this will help in obtaining a reasonably uniform contact between the load plate and the surface. See 5.
The method covers the measurement of deflection of the load plate rather than the deflection of the surface of the pavement or foundation layers see Note 1. The values given in parentheses are for information only. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Multi-user access to over 3, medical device standards, regulations, expert commentaries and other documents. Worldwide Standards We can source any standard from anywhere in the world.