Self-consolidating earth concrete (SCEC) is a novel alternative to facilitate the earth-based construction. A new concrete-equivalent mortar (CEM) approach with constant excess-paste (EP) thickness was proposed to evaluate the rheological and thixotropic properties of various SCEC mixtures proportioned with different clay and superplasticizer types. The use of non-esterified polycarboxylate (NE-PC) and sodium polynaphtalene superplasticizer types in combination with a finer clay type led to a thixotropic behavior. Mixtures made with sodium hexametaphosphate resulted in significantly high yield stress and plastic viscosity values. The rheological properties were mainly controlled by the admixture type, followed by the type and content of clay and water-topowder ratio (W/P). Empirical models were proposed to predict the rheology of earth-based paste, CEM, and SCEC mixtures using the governing key mixture parameters, including the fineness of the powder constituents (i. e., clay, silt, and cement), water content, EP thickness, paste volume, and packing of the granular skeleton.