Title: Using High-Volume Fly Ash in lightweight Concrete with Bottom Ash as Aggregate

Author(s): M. Nisnevich, G. Sirotin, L. Dvoskin, and Y. Eshel

Publication: Symposium Paper

Volume: 199

Issue:

Appears on pages(s): 99-114

Keywords: air void; bottom ash; concrete; density; fly ash; light-weight aggregate; strength; workability

DOI: 10.14359/10486

Date: 6/1/2001

Abstract:
Effective lightweight concrete with highly porous bottom ash (by-product of thermal power stations) as aggregate and high volume of fly ash was developed at the Research Institute of the College of Judea and Samaria, Ariel (Israel). This lightweight concrete has sufficient strength and thermal insulation properties, based on a rational combination of the highly porous aggregate and the relatively dense hardened cement-fly ash paste. In addition, the dense structure of the hardened cement-fly ash paste in the concrete, with low and middle cement contents, improves the durability of the concrete. In the current paper, the results of further studies of this lightweight concrete are presented. These studies were concentrated on lowering the volume of air voids in the cement-fly ash paste of the fresh concrete, and thereby increasing the strength and density of the hardened concrete. This evaluation is based on studying concrete mixture proportions prepared with broad range of the cement and the fly ash content (maximum relation of fly ash FA to cement C in the experiments was FA/(C + FA) = 0.8). In addition, a method for optimization of the lightweight concrete mixture proportions is suggested. This method ensures that the manufacturing the concrete is in compliance simultaneously with two given parameters: density and compressive strength.