Investigation of Tensile Strength

investigation of ductile StrengthDirect tension is another method to reason fatigue cracking. In this shew procedure, tensile strength is measured in terms of tensile stress and tensile strain. Tensile stress is basically the impedance to fracture damage and tensile strain at maximum load is the ductility potential. In this interrogation procedure uni axial tension is applied on the model. A cylindrical specimen is required having a 4 pass on (100 mm) diameter and 6 inch (150 mm) or 4 inch (100 mm) flush.(Walubita et al., 2011). The load is usually monotonically increase at loading rate is 0.05 in./min (1.3 mm/min) at 77F . (Walubita et al., 2005). For look tension test specimen were compacted in the Superpave Gyratory Compactor having the mold height of 6.9 in (175 mm) in and a diameter of 5.9 in (150 mm) diameter. Sample is then put for curing for 24 hours and after that, it needs to be glued to the testing device carefully before running the test. Load, vertical displacem ent, and time, these are the three data that is obtained from the test. For the DT test the tensile stress can be computed ast= P/(r2)=P/D2/4Where t=Minimum tensile stress p=load r=specimen radius D= specimen diameter (Dissertation Walubita, 2006)And the tensile strain at maximum axial load can be computed as t=106v/h t=average axial tensile strain, V= average axial specimen deformation h= specimen height. This way, HMA stiffness can be obtained as St= t/t, where St=Youngs Modulus (Stiffness) t= Tensile stress (Maximum) t= Tensile strain at maximum axial load.(Walubita et al., 2005), suggested t=65 psi t=(Lytton, 2012) discussed about the procedure of testing field cores for direct tension. After getting the rectangular sample form the cylindrical field core, having length of 4 inch (102mm) and width of 3 inch (76 mm) and thickness of 1.5-3 inch (38-76 mm). As a steel cap is needed to be glued to the each specimen end, the authors used a special gluing jig to keep the specimen centrally aligned with the cap.In total six LVDTs were attached to measure the vertical and horizontal displacement at top, bottom and center layers. The authors run the test in different temperatures (10C 20 C) in electro hydraulic servo machine (MTS) with a feedback frequency of 2Hz (done in an old machine) 20Hz (done in a impudent machine).Figure 2 Test setup with LVDT arrangement ((Lytton, 2012)ReferencesDissertation, A., Walubita, L. F. (2006). Comparison of hold out Analysis Approaches for Predicting Fatigue Lives of Hot-Mix Asphalt Concrete ( Hmac ) Mixtures Comparison of Fatigue Analysis Approaches for Predicting Fatigue Lives of Hot-Mix Asphalt Concrete ( Hmac ) Mixtures. Analysis, (May).Lytton, R. (2012). Analytical-Numerical Methodology To Measure Undamaged , Fracture and Healing Properties of Asphalt Mixtures, (December).Walubita, L. F., Jamison, B. P., Das, G., Scullion, T., Martin, A. E., Rand, D., Mikhail, M. (2011). Search for a Laboratory Test to Evaluate Cra ck shelter of Hot-Mix Asphalt. Transportation Research Record Journal of the Transportation Research Board, 2210(1), 73-80. https//doi.org/10.3141/2210-08Walubita, L. F., Martin, A. E., Jung, S. H., Glover, C. J., Chowdhury, A., Park, E. S., Lytton, R. L. (2005). Project Title Evaluate the Fatigue Resistance of Rut Resistance Mixes . URL http//tti.tamu.edu/documents/0-4468-1.pdf. Security, 7(2).Wen, H., Investigation of Effects of Testing Methods on Characterization of Asphalt Concrete, Journal of Testing and Evaluation, Vol. 31, No. 6, pp. 1-7, 2003.