Dense mixtures of conventional fly ashes and water are utilized in many modern mining operations as an underground mine paste backfill, structural fills, fire prevention. The use of MSW fly ashes in such operations are limited as a result of their chemical composition. In this case, the compaction process, accomplished with the use of binder such as Portland cement and/or others, immobilizes the reactive components of this waste and results in the formation of strong granules which remain impervious to leaching. This unables addition of compacted waste to the mixture of fly ash-water. The main purpose of this paper is to evaluate the influence of addition of compacted MSW fly ashes on the properties of fresh and hardened fly ash-water pastes.
