Elucidating the Pozzolanic Characteristics of Pastes Containing CirculatingFluidized Bed Fly Ash

摘要

The aim of this study is to investigate the pozzolanic characteristics of circulating fluidized bed fly ash blendedcement (CFBFABC) paste containing circulating fluidized bed fly ash (CFBFA). The initial and final setting time ofCFBFABC pastes with CFBFA retards with an increasing CFBFA content. CFBFABC pastes containing 10% CFBFAexhibited a compressive strength similar to that of ordinary Portland cement pastes at the ages of 90 days. X-ray diffractionpeaks indicated the presence of portlandite, ettringite, and unreacted C3S (32.6°) and C2S (41.9°). The gel/space ratioof the CFBFABC pastes increased with the curing time and decreased as the CFBFA content increased. The gel/space ratioincreased with the curing time because of the progress of hydration, which led to some of the pores being filled. At theages of 90 days, the gel/space ratio of the CFBFABC pastes containing 10% CFBFA increased to approximately 14%, it ispossibly the consumption of Ca(OH)2 and the formation of C-S-H in the CFBFABC pastes. The CFBFABC pastes containing10% CFBFA did not exhibit any major decrease in the gel/space ratio. It exhibited favorable mechanical characteristicsthat were observed when the mixing ratio of CFBFA was 10%. Furthermore, CFBFA has the potential, as a pozzolanicmaterial, partially to replace ordinary Portland cement.