AASHTO T 369-17 pdf free download

AASHTO T 369-17 pdf free download.Evaluation of the Low-Temperature Tensile Property of Hot-Poured Asphalt Crack Sealant by Direct Tension Test.
3. TERMINOLOGY
3.1. DefInitions:
3.1 .1. hot-poured asphalt crack sealant—hot-poured modified asphaltic material used in pavement cracks and joints.
Note 1—Based on the references, hot-poured asphalt crack sealant is typically applied at a temperature of 160°C or above.
3.1.2. effective gauge length—elongation of a standard dog bone—shaped test specimen due to an applied axial load P is equivalent to that of a simple rectangular specimen with the same cross-sectional dimensions of the restricted section. Effective gauge length, Le, is defined as the length of the simple rectangular specimen and has been determined to be 20.3 mm.
3.1.3. tensile stress—tensile load divided by the true area of a cross section of the specimen.
3.1.4. tensile strain—change in the effective gauge length by the application of tensile load divided by the original unloaded effective gauge length.
3.1.5. brittle material—the stress—strain curve is linear up to fracture at about I to 2 percent elongation.
3.1.6. brittle-ductile material—the stress—strain curve is curvilinear and the stress is gradually reduced after the peak point. The failure happens by gradually breaking the molecular bond within the material.
3.1.7. ductile material—the material does not rupture in the direct tension test but elongates due to high strain.
3.1 .8. rubbery behavior—materials that exhibit rubbery behavior can be stretched to extreme elongation without rupture.
3.1.9. percent modulus decav—the percentage modulus deduction after 10 s of loading.
4. SUMMARY OF PRACTICE
4.1. This practice contains the procedure to measure the extendibility and the strain energy density of a hot-poured asphalt crack sealant using a direct tension test (DTT). The material is bonded between two end tabs made of poly(methyl methacrylate) (PMMA) and subjected to a constant strain rate at a specific temperature.
4.2. The test method is developed to select a hot-poured asphalt crack sealant at temperatures where it exhibits rubbery behavior.
4.3. A linear variable differential transformer (LVDT) is used to measure the elongation of the test specimen as it is pulled in tension at a constant strain rate of 6 percent/mm (1.2 mm/mm). A load cell is used to monitor the load during the test. The stress and strain at the point of rupture or peak load are reported.
5.2. The test temperature is determined to be the lowest temperature experienced by the pavement surface in the geographical area for which the sealant is intended.
5.3. The sealant extendibility is a parameter of the capacity of the sealant to sustain large detbrmations due to crack expansion at low temperature without fracture.
5.4. The percent modulus decay is an indication of how fast the sealant can release the imposed loading. A higher percentage decay shows that the sealant can relax the load faster.
5.5. This method is intended for aged sealants, which could become stiffer or softer with age.
6. APPARATUS
6.1. Direct Tension Test (DTT) Device—The DTT system consists of two metal grips to hold the specimen, an environment chamber, a loading device, and a control and data acquisition system. The instrument must meet the requirements stated in T 314.
6.2. Specimen End Tabs and Gripping vstem—End tabs made from PMMA having dimensions as described in Figure 1 that shall be bonded to both ends of the test specimen to transfer the tensile load to the sealant. The manufacturing requirements of the end tabs and the gripping system shall meet the requirement in T 3 1 4.
6.3. Test chamber—A calibrated circulated temperature control system shall have a temperature range from —4 to —40°C. The insulated test chamber shall be capable of maintaining a temperature of
±0.1°C.
6.4. Specimen Molds—The specimen molds should be made from aluminum. Molds shall have dimensions as specified in Figure 1. A silicon-based release agent, as described in Section 7.2, shall be used to prevent the sealant from adhering to the aluminum molds.
6.5. Laboratory Ovens—Two forced-air convection ovens capable of producing, reaching, and maintaining a temperature of 200 ± 0.5°C for heating the sealant and molds.AASHTO T 369-17 pdf download.