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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After selecting the appropriate test parameters, begin the test. The constant A represents the aashho stiffness. Agencies that meet the criteria of Specification D are generally considered capable of competent and objective testing, sampling, inspection, etc. Observe standard laboratory safety precautions when preparing and testing HMA specimens.

Size px x x x x No other units of measurement are included in this standard. We need your help to maintenance this website. G321 is a violation of applicable law.

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Place the specimen in an environment that is at Fatigue life; flexural bending; hot mix asphalt fatigue; hot mix asphalt flexural testing; hot mix asphalt tensile testing; hot mix asphalt stiffness; hot mix asphalt energy dissipation. In aashtp, it shall be capable of recording r321 cycles, applied loads, and beam deflections and computing and recording the maximum tensile stress, maximum tensile strain, phase angle, stiffness, dissipated energy, and cumulative dissipated energy at load cycle intervals specified by the user.

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.

Attach the LVDT block to the specimen by screwing the screw into the nut epoxied on the specimen. T 1. We are a non-profit group that run this website to aahsto documents. Perform the following calculations at the operator-specified load cycle intervals: 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. We need your help!

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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.


This stiffness is an estimate of the initial stiffness, which is used as a reference for determining specimen failure.

Maximum Tensile Stress Pa: 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. 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 the 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.

Report the cycles to failure. 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 the specimen are also needed.

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.

Environmental Chamber Optional —The environmental chamber shall enclose the entire specimen and maintain the specimen at Thank you for interesting in our services. Hot Mix Asphalt Description—Report the binder type, binder content, aggregate gradation, and air void percentage. When the specimen and clamps are in the proper positions, close the outside clamps by applying sufficient pressure to hold the specimen in place.

For loading devices that require gluing a nut for deformation measurement, these cut surfaces provide smooth surfaces for mounting the measurement gauges.

Note 7—See E 29 for information on determination of significant figures in calculations. Note 5—It may not be possible to calculate dissipated energy D for every load cycle due to memory limitations of the recording and aashtp component. This standard provides procedures for determining the fatigue life and fatigue energy of mm long by 50 mm thick by 63 mm wide hot mix asphalt HMA beam specimens sawed from laboratory or field compacted HMA and subjected to repeated flexural bending until failure.



The load cycle at which failure occurs is computed by solving for n from Equation 7, or simply: Specimen Measurement—Measure the height and width of the specimen to the nearest 0. Specimen Dimensions—Report the specimen length, average specimen height, and average specimen width in meters to four significant figures. 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.

These notes and footnotes excluding those in tables and figures shall not be considered as requirements of the standard. 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. Bias—The research required to establish the bias of this method has not been conducted. Report the average test temperature to the nearest 0. This practice should not be used for acceptance or rejection of a material or for purchasing purposes.

Prepare a plot of stiffness versus load cycles as shown in Figure 7. Compacted specimens are suitable for volumetric and physical property testing. A minimum of 10, load cycles ensures that the specimen does not decrease in stiffness too rapidly.

A stiffness reduction of 50 percent or more represents specimen failure. Test System—The test system shall consist of a loading device, an environmental chamber optionaland a control and data acquisition system. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.

The loading device shall be capable of 1 providing repeated sinusoidal loading at a frequency range of 5 to 10 Hz; 2 subjecting specimens to four-point bending with free rotation and horizontal translation at all load and reaction points; and 3 forcing the specimen back to its original position i.

Miscellaneous Apparatus and Materials—A suitable saw for cutting the beams and a mechanism for setting proper clamp aadhto. Allow the epoxy to cure before moving the specimen.