Title: Properties of Concrete with Bagasse Ash as Fine Aggregate

Author(s): B. K. Baguant

Publication: Symposium Paper

Volume: 153

Issue:

Appears on pages(s): 315-338

Keywords: abrasion resistance; absorption; bagasse; bleeding (concrete); carbonation; chlorides; creep properties; deformation; drying shrinkage; freeze thaw durability; modulus of elasticity; moisture content; strength; workability; Materials Research

DOI: 10.14359/1077

Date: 6/1/1995

Abstract:
Bagasse is the fibrous residue of sugar cane, which is burned for energy leaving various types of ashes as waste residue, of which grate ash is found to be the most suitable for use in concrete. Grate ash shows poor chemical reactivity with portland cement, making it not very effective as a pozzolan. It can, however, be used as a fine aggregate constituent of concrete. Five grades of concrete were tested, ranging from 20 to 60 MPa, to compare the performance of grate ash concrete with that of normal concrete. The use of the ash alone as fine aggregate gave harsh concrete with low workability and poor cohesion. This was improved by blending about 25 percent normal concrete sand with the ash. Bleeding was comparable with, if not generally less than, that of normal concrete. Grate ash concrete, in particular the lower strength mixes, had 10 to 18 percent higher initial drying rates and would, therefore, require more stringent curing precautions than normal concrete. Rates of strength development were comparable in the two concretes. Compressive strengths of over 80 MPa were achieved after one year with the high-strength ash concrete mixtures. But, for a given strength, the grate ash concrete requires more cement than normal concrete. In comparison with normal concrete, grate ash concrete had similar shrinkages, slightly lower modulus of elasticity, and about 40 percent lower creep deformations. For equivalent strengths, the two concretes showed similar durability properties, in terms of their resistances to mechanical abrasion, water absorption, chloride diffusion, and carbonation. However, due to the porosity of the grate ash particles, the concrete had a much better resistance to freezing and thawing attack than normal concrete, even though all concretes were non-air-entrained.