AASHTO T Standard Method of Test for Determining the Fatigue Life of Compacted Asphalt Mixtures Subjected to Repeated Flexural Bending. standard . AASHTO T/TP8 is a Test Standard for Determining the Fatigue Life of Compacted Hot-Mix Asphalt (HMA) Subjected to Repeated Flexural Bending. AASHTO T (AASHTO, ) and the European Standard (EN , ). When evaluating fatigue resistance through four point bending beam.
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Set the loading frequency within a range of 5 to 10 Hz.
This practice should not be used for acceptance or rejection of a material or for purchasing purposes. Apply 50 load cycles at a constant strain of to microstrain. Users of this practice are cautioned that compliance with Specification D alone does not completely ensure reliable results.
However, the standard compactive effort may not reproduce the air voids of roadway specimens measured according to T The constant A represents the initial stiffness.
Cycles to Failure—Failure is defined t21 the point at which the specimen stiffness is reduced to 50 percent of the initial stiffness. Loading Device—The test system shall include a closed-loop, computer controlled loading component that, during each load cycle in response to commands from the data processing and control component, adjusts and applies a load such that the specimen experiences a constant level of strain during each load cycle.
Report the cycles to failure. Size px x x x x The load cycle at which failure occurs is computed by solving for n from Equation 7, or simply: Duplication is a violation of zashto law.
For loading devices that require gluing a nut for deformation measurement, these cut surfaces provide smooth surfaces for mounting the measurement gauges.
An environmental chamber is not required if the temperature of the surrounding environment can be maintained within the specified limits. 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.
The aaehto of HMA can be more accurately predicted when these properties are known.
Reliable results depend on many factors following the suggestions of Specification D or some similar acceptable guideline that provides a means of evaluating and controlling some of those factors. Report the initial flexural stiffness in pascals. No other units of measurement are included in this standard. Select a deflection level strain level such that the specimen will undergo aadhto minimum of 10, load cycles before its stiffness is reduced to 50 percent or less of the initial stiffness.
Note 7—See E ashto for information on determination of significant figures in calculations. See Notes 1 and 2. It is recommended to cut beams from a large slab compacted by a vibratory roller.
Please help us to share our service with your friends. The area under the curve represents the cumulative dissipated energy. Figure 1 illustrates the loading conditions.
T__ – Free Download PDF
Determine the average of the three measurements for each dimension and record the averages to the nearest 0. Hot Mix Asphalt Description—Report the binder type, binder content, aggregate gradation, and air void percentage.
Open the clamps and slide the specimen into position Figures 3, 4, and 5. Please copy and paste aashfo embed script to where you want to embed Embed Script.
AASHTO T, Test equipment Controls
Observe standard laboratory safety precautions when preparing and testing HMA specimens. We need your help! Thank you for interesting in our services. The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. If specimens are to be compacted to a target air void content, the compactive effort to be used should be determined experimentally.
Avoid applying epoxy such that it fills the center of the nut. Referenced T21 purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. Maximum Tensile Stress Pa: The fatigue life and failure energy determined by this standard can be used to estimate the fatigue life of HMA pavement layers under repeated traffic loading.