This paper describes results obtained in a study of the response of alumina-based refractory concretes to coal dry-ash gasifier environments. The investigations were designed to determine the relationship between observed refractory property changes after exposure to dry-ash gasifier environments and variables such as exposure temperature, steam partial pressure, gas velocity, aggregated and cement composition, and the presence of alkalis. Both commercially available and laboratory-formulated refractory concrete compositions, ranging from 45 to 95 pct alumina and containing low, intermediate, and high-purity calcium aluminate cements were studied. The refractories were exposed to environments at pressures ranging from 2.9 to 7.0 Mpa (400 to 1,000 psig) and at temperatures ranging from 760 deg. to 1,000 deg. C. In some exposures, alkalis were introduced into the exposure environment. The steam-induced volatilization and vapor-phase transport of silica from the refractories under a variety of conditions were also studied.