FH is now routinely using the LWD with very good feedback and useful engineering data. The equipment is an easy to use Zorn LWD. This tool should have a similar impact on the construction industry as the laser level. The ability to accurately and reliably measure this aspect of ground condition will improve the quality of the work and remove doubt as to the progress of the project. I bought my ZFG and on the same day less than two hours later, it had paid for itself. Using this instrument, I was able to demonstrate scientifically, repeatably and independently the quality of the work that we had completed for our client.
|Published (Last):||19 September 2011|
|PDF File Size:||7.9 Mb|
|ePub File Size:||3.21 Mb|
|Price:||Free* [*Free Regsitration Required]|
You are on page 1of 5 Search inside document Standard Test Method for 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. 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.
ASTM E2835 - 11(2015)
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.
ASTM E2835-11 international standard