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Abstract. Bituminous mortar contains aggregates passing 1.18 mm sieve, fillers (material passing 0.075 mm) and bitumen. In general, the bituminous mortar is characterized in torsion using prismoidal (rectangular cross-section) and cylindrical (circular cross-section) specimen geometries. The properties of the material vary with the cross-section of the specimen geom-etry used for testing. Non-axisymmetric cross-sections, such as rectangular cross-sections, warp (out-of-plane displacement) when subjected to tor-sion, but this displacement is not allowed in a dynamic shear rheometer (DSR). This leads to the development of additional stresses in the material, known as warping stresses. The warping stresses need to be accounted for to obtain the material's true properties. This study investigates the linear vis-coelastic properties of prismoidal bituminous mortar specimens subjected to torsion using a DSR. A frequency sweep experiment is carried out at three temperatures (10, 20 and 30 ⁰C) for frequencies ranging from 0.01 Hz to 20 Hz. Correction factors such as the Vlasov and Szabó are applied to quantify the amount of warping stress in prismoidal specimens. A percent-age difference is computed between the absolute shear modulus obtained from the DSR and the corrected modulus using the Vlasov and Szabó cor-rection factors. It is observed that the percentage difference after the Vlasov correction varied with frequency and temperature, whereas the percentage difference remained the same after the Szabó correction.
