An admixture formulation of at least one polycarboxylate dispersant and at least one naphthalene dispersant is provided. When the polycarboxylate dispersant and the naphthalene dispersant of the admixture formulation are combined at various ratios the admixture formulation reduces the tendency for bleed and segregation in cementitious mixtures without increasing water demand, retarding setting, increasing water sensitivity, promoting high viscosity, or reducing flow retention.