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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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In addition, it shall be capable of recording load cycles, applied loads, and beam deflections and computing and recording the maximum tensile stress, maximum tensile strain, phase angle, stiffness, aashtto energy, and cumulative dissipated energy at load cycle intervals specified by the user. Report the initial flexural stiffness in pascals. Thank you for interesting in our services.

The fatigue life and failure energy determined by this standard can be used to estimate the fatigue axshto of HMA pavement layers under repeated traffic loading. Apply 50 load cycles at a constant strain of to microstrain. Specimen Measurement—Measure the height and width of the specimen to the nearest 0. Apply epoxy in a circle around this center point and place the nut on the epoxy such that the center of the nut is over the center point.

This standard does not r321 to address all of the safety concerns associated with its use.


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. Place the specimen in an environment that is g321 Control and Data Acquisition System—During each load cycle, the control and data acquisition system shall be capable of measuring the deflection of the beam specimen, computing aasnto strain in the specimen, and adjusting the load applied by the loading device such that the specimen experiences a constant level of strain on each load cycle.

After selecting the appropriate test parameters, begin the test. Avoid applying epoxy such that it fills the center of the nut. The load cycle at which failure occurs is computed by solving for n from Equation 7, or simply: See Notes 1 and 2. The total dissipated energy to failure is summarized as part of the output. See Figure 6 for a typical dissipated energy versus load cycle plot. Report the test results listed in Table 2 for each load cycle interval selected by the operator to three significant figures.


T 1. Figure 1 illustrates the loading conditions.

Laboratory-Mixed and Compacted Specimens—Sample asphalt binder in accordance with T 40 and sample aggregate in accordance with T 2. Note 1—The type of compaction device may influence the test results. Compacted specimens are suitable for volumetric and physical property testing. Observe standard laboratory safety precautions when preparing and testing HMA specimens. Note 3—Selection of load cycle intervals at which test results are computed and recorded may be limited by the amount of memory available for storing data.

For loading devices that require gluing a nut for deformation measurement, these cut surfaces provide smooth surfaces for mounting the measurement gauges. 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 constant A represents the initial stiffness. For loading devices that require a glued nut for deformation measurement, a screw, nut suggested size M 8 by 1 and block assembly for referencing the linear variable differential transducer LVDT to the neutral axis of the specimen, and epoxy for attaching the nut to aasnto specimen are also needed.

Precision—The research required to develop precision values has not been conducted. Hot Mix Asphalt Description—Report the binder type, binder content, aggregate gradation, and air aasht percentage.

Environmental Chamber Optional —The environmental chamber sashto enclose the entire specimen and maintain the specimen at We need your help! Activate the recording and control components so that the test results at the selected load cycle intervals are monitored and recorded, ensuring that the test system is operating properly.


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Figure 2 illustrates a nut epoxied to the neutral axis of the specimen. This standard may involve hazardous materials, operations, and equipment. The performance of HMA can be more accurately predicted when these properties are known. Link to Active This link will always route to the current Active version of the standard. Report the cycles to failure.

Note 7—See E 29 for information on determination of significant figures in calculations. When the specimen and clamps are in the proper positions, close the outside clamps by applying sufficient pressure to hold the specimen in place. Prepare a plot of stiffness versus load cycles as shown in Figure 7. This stiffness is an estimate of the initial stiffness, which is used as a reference for determining specimen failure.

When the specimen has experienced greater than 50 percent reduction in stiffness, terminate the test.

Size px x x x aashtp Saw at least 6 mm from both sides of each test specimen to provide parallel saw-cut surfaces to eliminate high air void sections on the specimen surface.

Open the clamps and slide the specimen into position Figures 3, 4, and 5. The test system shall meet the minimum requirements specified in Table 1. Maximum Tensile Stress Pa: Figure 7 presents f321 typical plot of stiffness versus load cycles. Set the loading frequency within a range of 5 to 10 Hz.

We need your help to maintenance this website. Allow the epoxy to cure before moving the specimen. The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, aaashto, and maintenance of the equipment used. Users of this practice are cautioned that compliance with Specification D alone does not completely ensure reliable results.