Results of tests on expansion bars made from conditioned and chemically processed AFB residue showed levels of expansion confirming that ettringite formation may be the main cause of the volume instability observed in road base compositions containing AFB residue. AFB fly ash, when treated with acid washing to remove calcium, has shown an ability to function as an ion exchange material. Further tests have shown that treatment of AFB fly ash by acid washing and the addition of zinc chloride produced a material that behaves like activated carbon in terms of color removal from water. Observations from ten different mix compositions using AFB residue, pulverized coal fly ash, and, in some cases, a gypsum waste sludge, have shown that briquettes having acceptable green strength for normal handling can be made from most formulations using a laboratory scale roll briquetting machine. Loose slurry mixes containing various proportions of AFB residue and pulverized coal fly ash develop sufficient compressive strengths at comparatively low permeabilities to recommend further investigation of their potential use as an expansive grouting material. The addition of portland cement in amounts of 1 to 5 percent for each mix did not significantly affect strength development in any of these mixes.