INVESTIGATION OF LIGNITE-BASED BOTTOM ASH FOR STRUCTURAL CONCRETE

A pilot study was undertaken on the use of lignite-based bottom ash as a fine aggregate in structural grade concrete. Bottom ash is combined with portland cement, crushed limestone coarse aggregate, and water t o produce concretes with a uniform slump of 100 mm (4 +/- 1/4 in.). Fo ur different mixes with cement contents ranging from 297 to 475 kg/m(3 ) (500 to 800 Ib/yd(3)) are utilized, The bottom ash concretes are stu died for fresh properties, hardened characteristics, and long-term dur ability. The engineering characteristics of mixtures made with bottom ash are compared with those of conventional concretes in order to eval uate the effectiveness and suitability of bottom ash as a viable fine aggregate in portland cement-based mixtures. Laboratory test results c onclude that the inclusion of bottom ash increases the demand for mixi ng water in obtaining the required workability. As a consequence, both fresh and hardened properties are impacted, particularly for mixtures of low cement content. When a water-reducing admixture is used, the e ngineering properties of bottom ash concretes are similar, and in most cases superior, to those of control concretes.