Structural-grade concrete containing FBC and PCC residues. Part II: Partial-cement concrete

Abstract

Part I of this study focused on the fresh and hardened properties of different non-cement concretes containing pulverised coal combustion (PCC) fly ash and fluidised bed combustion (FBC) spent bed in order to ascertain their capabilities and drawbacks in the production of structural-grade concrete. While these mixtures produced sufficient structural strength, their long setting times and excessive soaked sulfate-induced expansions posed major limitations on their acceptability as viable construction materials. In order to mitigate these concerns, Part II of the study, presented here, evaluates the characteristics of a number of partial-cement concretes in comparison with those of non-cement and a reference (control) Portland cement concrete. The test results revealed that the two abovementioned concerns were eliminated with proper mixture proportioning of partial-cement concretes. It was found that while early-age compressive strengths of partial-cement concretes were lower than those of the reference concrete, late strengths exceeded those of the reference concrete. Their plastic and drying shrinkages were also lower than those of the reference concrete. The studied partial-cement concretes also displayed resistance to abrasion superior to that of the reference concrete under dry conditions, whereas the opposite results were obtained under wet conditions.