Fresh Properties and Environmental Assessment of Controlled Low Strength Materials Made with Coal Ash

Controlled low strength material (CLSM) is a flowable mixture such that it does not need to be compacted. It is produced by mixing portland cement, fly ash, fine aggregates, water, and chemical admixtures. Sand is the most commonly used fine aggregates in the conventional CLSM, but it is getting more and more difficult to obtain sand in Korea. Fresh properties are those of the most important attributes of CLSM. Flowability, walkability were measured by flow test, setting time test. The environmental assessment in the specific case of CLSM was evaluated. Flow values satisfied standard flow value when the mixture ratio of pond ash and fly ash is 30:70~70:30, cement ratio is 3.0~5.0%, and water content is 31~34%. The results of setting time tests showed that CLSM mixed pond ash with fly ash hardened within one day. The environmental assessment indicated that CLSM with coal ash were found to be environmentally safe