Determination of the Mechanical Parameters of Dan Granite Crushed Rock for Use in Road Construction in Benin

Abstract

Granitic crushed materials are the most widely used materials in various fields of building and public works. These materials are more available in quantity and quality in Benin. The present study was initiated to determine the mechanical parameters of Dan 0/31.5 granitic crushed stone for use in road construction. To this end, an experimental study based on normative tests was carried out. Identification tests were carried out to determine the particle size at 80 mm and 2 mm sieves, i.e. 6.66% and 24.28%, the dry density, i.e. 2.26 t/cm3 at a water content of 6.49% OPM, the organic matter content, 0.14%, the methylene blue value, 0.16%, the CBR index, i.e. 96.29% with a linear swelling of 0.07%. Micro Deval and Los Angeles values are 7.5% and 23.55% respectively. In addition, the pre-consolidation stress is 29 kPa, the compression index is 0.098% and the swelling index is 0.011%. Finally, the shear test determined the cohesion, i.e. 0.3 kPa, and the angle of internal friction, i.e., 33.6˚. Also, based on a series of results (shear stress and horizontal displacement) from the direct shear test, the maximum shear stress and maximum shear modulus from the Hardin and Drnevich hyperbolic model, i.e. 349.62 kPa and 172.65 kPa, respectively. The odometer test and shear modulus were used to estimate Young’s modulus, i.e. 274.81 MPa, and Poisson’s ratio, i.e. 0.204. Analysis of the various results in accordance with the specifications of the CEBTP 1984 guide, revised in 2019, shows that Dan’s granite crushed stone is an excellent quality road material that can be used in all pavement layers, whatever the type of pavement.