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Introduction
Performance of asphalt mixtures can be further modified by using various percentages of available crumb rubber and polymer modified bitumen options. Both modification types enhance the mechanical properties of asphalt mixtures, leading to increased resistance in fatigue cracking. ITST (Indirect Tensile Strength Test) in the lab can be utilized to quantify and characterize the performance of modifiers based on resistance to fatigue damage [1]. Furthermore, the use of finite element modelling combined with the indirect tensile strength tests of different specimen can be employed to predict the fatigue damage performance of different asphalt mixtures.
Asphalt mixtures are sensitive to variations in climatic conditions and constant increase in yearly traffic growth. Therefore, asphalt performance modifiers are used in various compositions to enhance the viscoelastic properties of asphalt mixtures by various agencies [2]. Depending on the budget and available materials, an optimum type and amount of modifier for asphalt is selected to help increase the pavement performance during extreme climatic and loading conditions. Moreover, other than the improvement in fatigue resistance, Use of such modifiers can improve high temperature stability, elastic recovery, low temperature stiffness and deformation resistance of asphalt mixtures [3].
Performance of various forms of asphalt mixtures can be measured using the ITST. ITST can be used in various forms based on the required output results. It can be used to measure the fatigue life, stiffness as well as low temperature cracking resistance of the mixtures using indirect tensile fatigue test. Furthermore, one of the most common applications of ITST is the evaluation of moisture susceptibility of asphalt mixtures in terms of tensile strength ratio of conditioned and unconditioned specimens. ITST can also be used for evaluation of low temperature cracking resistance asphalt mixtures [4].
ITST is employed in laboratories to evaluate tensile strength properties of asphalt mixtures. Lab prepare specimens can be used for indirect tensile strength testing as well as field core samples. Furthermore, cracking resistance and fatigue damage evaluation can also be preformed using ITST [5]. ITST can also be used to determine the moisture susceptibility of asphalt mixtures. In ITST, cylindrical shaped specimen is continuously loaded with sino soidal load pulse. The specimen is loaded at a speed of around 50 mm/min and maximum load at fracture is recorded [4]....