Flowable Fly Ash: A New Cement Stabilized Backfill

Cement stabilized fly ash placed at a plastic fluid consistency is a new structural backfill material that flows into place, either above or below water, without using sophisticated construction methods and procedures. This cuts cost and time. It is primarily composed of fly ash, a byproduct made available in quantity from coal burning power plants. Usually 4% to 5% of cement is added along with the appropriate amount of water for the particular application. The advantages and disadvantages of this material—which tests have shown to have qualities and economies that equal or surpass those of conventional backfill materials—are described.