LABORATORY AND FIELD STUDIES ON PERFORMANCE OF PCC DRY BOTTOM ASH AND FLY ASH CONCRETE IN CAST-IN-PLACE DRILLED SHAFTS

摘要

The primary goal of this research investigation was to ascertain the performance of Pulverized Coal Combustion (PCC) dry bottom ash and fly ash concretes prepared by replacing a portion of Portland cement with fly ash and by partial/full substitution of natural fine aggregate with dry bottom ash when used in cast-in-place drilled shafts. Two PCC dry bottom ash and fly ash matrices and a control concrete were prepared in the laboratory and field at a constant slump of 19 mm. Laboratory-made sample were examined for fresh, hardened, and long-term durability characteristics. Field cores, tested for strength and deformation properties, were used to assess the influence of field curing conditions as compared to the concrete specimens cured under controlled conditions of the laboratory. Tests on the samples prepared and cured in the laboratory revealed that strength, stiffness, and durability characteristics of the dry bottom ash and fly ash concretes were similar to those of the reference mixture. The results obtained from the samples cored from the field drilled shafts showed that the properties of the selected concretes can be easily duplicated in field. For all practical purposes, the hardened characteristics of the field concretes were identical to those of the specimens prepared in the laboratory.