Characterization of alkali-activated slag paste containing dredged marine sediment

AbstractWe characterized alkali-activated slag paste containing dredged marine sediment according to Na2O concentration by mass of slag in the mixture. The compressive strengths of 3-d cured AAS–sediment paste specimens were similar to those of 28-d cured AAS–sediment paste specimens. The optimum Na2O concentration by mass of slag was 6–8%. Leaching testing of samples cured for 3 d confirmed that heavy metals (Cr, Cu, Cd, and Pb) were below the detection limits for all these metals. X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy analyses revealed that the microstructure, fracture surface, and silicate band of calcium silicate hydrate as the main hydrate of the AAS–sediment paste were similar among the various samples. Despite this, Ca/Si molar ratios and quantitative analysis results differed among samples with different Na2O concentrations by mass of slag.