PROPERTIES OF HIGH-CALCIUM DRY BOTTOM ASH CONCRETE

A study of various fresh and hardened properties of bottom ash concret e is reported. Standardized tests were conducted on four series of con crete mixtures having a constant volume of solid constituents and a un iform slump of 4+/-1/4 in. Series A and B were mixes of natural sand ( control mix) and bottom ash concretes, respectively. Series C containe d mixes in which the fine aggregate component of the matrix consisted of equal volumes of natural sand and bottom ash. The mixes of Series D incorporated a high range of water-reducing admixture (12.5 oz/100 lb cement) into the mixtures of Series C. The test results indicated tha t the mixing water requirement increases rapidly when bottom ash is us ed in concrete. The increased water demand, in achieving a constant co nsistency, affected both fresh and hardened characteristics of concret e samples. When 50 percent of the total dry volume of the natural fine aggregate was replaced by bottom ash or a high-range water-reducing a dmixture was used in conjunction with the combined bottom ash and natu ral sand mixtures; the engineering characteristics were similar, and i n most cases superior, to those of reference mixes.