Properties of concrete incorporating bed ash from circulating fluidized bed combustion and ground granulates blast-furnace slag

Abstract

The properties of concrete incorporating circulating fluidized bed combustion (CFBC) bed ash and ground granulates blast-furnace slag (GGBS) were studied. Compressive strength, drying shrinkage, mercury intrusion porosimetry (MIP), scanning electronic microscopy (SEM), and X-ray diffraction (XRD) of concrete samples containing CFBC bed ash and GGBS were used. This work used initial surface absorption test (ISAT) and rapid chloride penetration test (RCPT) on concrete to measure the absorption and the ability of concrete to resist chloride ion characteristics for different concrete samples containing CFBC bed ash and GGBS. Open circuit potential (OCP), direct current polarization resistance were obtained to evaluate rebar corrosion. The CFBC bed ash was X-ray amorphous and consist of SiO2, Al2O3 and CaO compounds. As the replacement of CFBC for sand increases, the rate of initial surface absorption (ISA) increases but compressive strength decreases. When the content of CFBC bed ash replacement for sand maintains constant, the replacement of GGBS for cement increases, compressive strength increases but the rate of ISA decreases. Chloride and corrosion resistance of rebar significantly improve by utilizing a proper amount of CFBC bed ash and GGBS in concrete.