The mechanical characterisation of bituminous mixtures is carried out using different modes of testing such as compression (dynamic modulus), indirect tension (resilient modulus), flexure (flexural modulus) and shear (absolute shear modulus). The mechanical response obtained under different mode of loading is different; this can be attributed to the different load transfer mechanisms associated with the mode of loading. Out of the different modes of testing, limited studies have been carried out regarding the testing and characterisation of bituminous mixtures in shear. A Superpave shear tester was used to test bituminous mixtures in shear and over the years this test method became obsolete due to several reasons such as, poor repeatability, application of a variable axial load and the need for rigorous computations. These reasons were primarily attributed to the size of the bituminous mixture and hence ASTM D7552 (2022) brought a method to test small-sized bituminous mixtures (sliced from the large bituminous mixture) of size 50×12×10 mm using a dynamic shear rheometer (DSR) in torsion (local shear). There were several challenges associated with the testing and characterisation of these small-sized mixtures in torsion, the main challenge being that these mixtures may or may not be a true representative of the bituminous mixture. This can lead to problems in interpreting the results of the small-sized mixtures. Therefore, there is a need to focus on the mortar part of the bituminous mixture for testing in torsion as this is the region where the load transfer occurs. The mortar of bituminous mixtures is also called fine aggregate matrix (FAM), and it consists of bitumen, fillers and fine aggregates. The proposed research attempts to design a FAM mixture equivalent to bituminous mixtures so that its properties in torsion can be quantified. To achieve this objective, the first step is to develop protocols for sample preparation and testing of FAM. After the sample preparation, tests such as frequency sweep and stress relaxation will be carried out in the linear and nonlinear regime respectively to determine the viscoelastic properties of FAM. In the nonlinear regime further tests such as repeated creep and recovery and time sweep tests will be carried out to quantify the non-recoverable strain and fatigue in laboratory respectively. The understanding obtained from these tests will help in developing models to characterise FAM in torsion.