The effect of waste marble powder and phosphoric acid on the shear angle and cohesion value of expansive soilsS. Syahril, Ambrosio Martins Nuno, M. Rio Eka Shaputra and Eduardo Amaral VongE3S Web of Conf., 479 (2024) 06005DOI: https://doi.org/10.1051/e3sconf/202447906005