Asphaltmix, asphalt compression test, and steel tension
Engineersare particularly interested in the mechanical properties when usingthem in various areas of applications. Upon application of forces tothese materials, their dimensions become critical, and failure isundesirable. There are three elementary mechanical properties of thematerial are vital in determining the safe working parameters of amaterial. These are the elastic modulus, the yield point, and theultimate strength. This report contains results of an experiment todetermine the ultimate strength and yielding point.
Materialsdeform in reaction to forces applied to them. The amount of thisdeformation for a fixed force is dependent on the geometry of thematerial. Also, the magnitude of force required to cause a givendeformation is also dependent on the geometry of the material.Therefore, stress is defined by,
Severalmaterials exhibit nonlinear deformation behavior at higher levels ofstress. This occurs when plasticity becomes the dominant deformation.The yield is the point where a transition from elastic to plasticresponse occurs. Deformation tends to be concentrated in a givenregion of materials that exhibit a large plastic response. Proceededdeformation occurs only in this local region and is referred to asnecking. It is at the critical point, the ultimate/breaking stressthat necking begins. It is of great vitality to know the ultimatestress of a material since failure occurs soon after necking (Smith,255).
Thisexperiment uses tensile stress to determine the mechanical propertiesof a cross-sectional bar of steel. Moreover, it uses compressivestress to determine the mechanical properties of a cross-sectionalbar of asphalt mix.
Inthe tension test, the test specimen is held fixed at one end will theother end is pulled in uniaxial tension collinear to the longitudinalaxis of the sample. The force throughout the sample and the testmachine are the same, but a variation exists between stress and thearea of the cross section. In the region of a minimum cross-section,the stress reaches critical values first (Smith, 255).
Inthe compression test, the servo-hydraulic test machine is used toperform a uniaxial compression test on asphalt specimen.
Smith,W.F., Principles of Materials Science and Engineering- 2nd Edition,McGraw Hill, 1990, p 255.