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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Observe standard laboratory safety precautions when preparing and testing HMA specimens.
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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. Attach the LVDT block to the specimen by screwing the screw into the nut epoxied on 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, calibration, and maintenance of the equipment used.
It is the responsibility of the user of this procedure aahto establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.
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.
Note 7—See E 29 for information on determination of significant figures in asahto. Agencies that meet the criteria of Specification D are generally considered capable of competent and objective testing, sampling, inspection, etc.
Note 1—The type of compaction device may influence the test results. The load cycle at which failure occurs is computed by solving for n from Equation 7, or simply: The test system shall meet the minimum requirements specified in Table 1.
After selecting the appropriate test parameters, begin the test. Precision—The research required to develop precision values has not been conducted. This practice should not be used for acceptance or rejection of a material or for purchasing t231. Allow the epoxy to cure before moving the specimen.
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Next, close the inside clamps by applying sufficient pressure to hold the specimen in place. An environmental chamber is not required if the temperature of the surrounding environment can be maintained within the specified limits. A stiffness reduction of 50 percent or more represents specimen failure. 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 zashto. 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, dissipated energy, and cumulative dissipated energy at load cycle intervals specified by the user. When the specimen and t32 are in the proper positions, close the outside clamps by applying sufficient pressure to hold the specimen in place.
Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. Compacted specimens are suitable for volumetric and physical property testing. Set the loading frequency within a range of 5 to 10 Hz. Select a deflection level strain level such that the specimen will undergo a minimum of 10, load cycles before its stiffness is reduced to 50 percent or less of the initial stiffness.
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. If specimens are aasuto be compacted to a target air void content, the compactive effort to be used should be determined experimentally.
Open xashto clamps and slide the specimen into position Figures 3, 4, and 5. Specimen Dimensions—Report the specimen length, average specimen height, and average specimen width in meters to four significant figures.
Perform the following calculations at the operator-specified load cycle intervals: 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 performance of HMA can be more accurately predicted when these properties are known.
This standard does not purport to address all of the safety concerns associated with its use. Environmental Chamber Optional —The environmental chamber 3t21 enclose the entire specimen and maintain the specimen at We need your help to maintenance this website. Apply 50 load cycles at a constant strain of to microstrain.
See Figure 6 for a typical dissipated energy versus load cycle plot. Duplication is a violation of applicable law.
It is the responsibility of the user of this standard to establish appropriate safety and health practices awshto determine the applicability of regulatory limitations prior to use. Figure 7 presents a typical plot of stiffness versus load cycles.