Performance Assessment of Cementless Controlled Low-Strength Material (CLSM) Utilizing Coal Ashes

CLSM is a self-compacting flowable fill which is primarily used as backfill material in lieu of conventional compacted soil. This paper reports the results of an investigation conducted on CLSM made without cement. Various CLSM mixtures were developed using coal bottom ash, fly ash and lime. The cementitious property of CLSM was achieved by adding sodium hydroxide into the mixture. The mixtures were inspected for a series of tests in fresh state and hardened state. All the mixtures exhibited acceptable flowability and segregation resistance. The CLSM mixtures showed non-corrosive behavior with good durability characteristics. Compressive strength of all the CLSM specimens ranged from 1.1 to 3.35 MPa. It is concluded that the increment of lime and NaOH leads to an increase in the strength of cementless CLSM.