Using a Couette viscometer, we investigated the dependence of the steady-shear viscosity of simulated neutralized current acid waste on pH and different acids. For a fixed weight percent of waste solids, the relative viscosity decreased as pH was lowered. The magnitude of the relative viscosity varied for the different acids. The values of random maximum packing for these different slurries were obtained using a floc-agglomerate structural model proposed by Tsutsumi et ol. (1994). As the weight percent of waste solids is normalized by the value of maximum packing, the relative viscosity data approximately fall onto a single master curve for a specific shear fate. A direct relationship between the macroscopic rheological properties (steady shear viscosity) and the suspension microstructure was established through the packing behavior of a suspension. A comparison of the strongly flocculated and noncolloidal suspensions indicates that besides the normalized weight fraction, the dependence of shear rate must be considered to estimate the relative viscosity for strongly flocculated suspensions.