GUIDE TO IMPROVING THE EFFECTIVENESS OF CEMENT-BASED STABILIZATION/SOLIDIFICATION

Abstract

Portland cement-based stabilization/solidification (S/S) has been used to successfully treat a wide variety of wastes. Some situations (because of the waste itself, the disposal scenario, and/or the regulatory requirements) require the use of additives or physical/chemical techniques to improve the effectiveness of cement-based S/S. The problems encountered in S/S can be broadly classified into solidification problems, i.e. obtaining the required physical properties in the treated waste, and stabilization problems, i.e. adequately immobilizing the hazardous constituents of the waste. The Guide lists additives and techniques that can be applid to specific solidification problems such as problems in development of set, compressive strength, and free liquids. Also included are lists of additives and techniques that can be applied to immobilization of specific hazardous constituents such as lead, cadmium, and chromium, as well as classes of constituents such as volatile organics, organo-metallics and soluable salts. The Guide lists a variety of generic additives for specific desired stabilization/solidification effects, including those that can be used to control the pH of wastes; to reduce, oxidize, and co-precipitate constitunts; and to accelerate or retard set.