Alkali−Silica Activity and Inhibition Measures of Concrete Aggregate in Northwest China

The alkali−silica reaction (ASR)-induced expansion of mortar bars containing four types aggregates originating from different regions in northwest China was studied. chemical composition, mineral vitreous and amorphous substances, rates were determined using X-ray fluorescence, diffraction, polarizing microscope images, the accelerated bar test (AMBT). inhibitory effects fly ash silica fume on aggregate activity evaluated. binary mixes produced tested, cement or as partial replacement. microstructure composition ASR products analyzed by scanning electron energy dispersive spectroscopy (SEM–EDS). results show that all exhibited an alkali activity, 14th day higher than standard 0.1%. lowest highest values 0.2% 0.3%, respectively. primary constituent compositions these found to be silica. Polarization microscopy also confirmed they contained alkali-active cryptolites. Fly could both inhibit a superior inhibition effect. When contents 20% 10%, respectively, less 0.03%.