Using several types of Portland cement and blast furnace slag powder(BFS), relationship between the hydration of BFS blended cement and the microstructural evolution were studied. The rate of consumed calcium hydroxide from BFS hydration do not have the constant value, gradually decreases as hydration progresses. The capillary pore volume of BFS blended cement is larger in lower region of hydration degree, and remarkably decreases as hydration progresses. The amount of drying shrinkage of Portland cement and BFS blended cement mortar can be explained by the volume fraction of C-S-H gel in solid phases, the larger shrinkage of mortar with the lager amount of C-S-H.
Fine waste concrete smaller than 5mm obtained from a recycling plant of waste concrete was used as feed and ground by a wet attrition mill. Recovery of the fine aggregate and cement hydrate powder from the ground fine waste concrete was investigated using a laboratory / pilot scale Mozley multi-gravity separator (MGS). The water absorption of the fine aggregate obtained as the high specific gravity product was less than 3.5 % and the dry density was larger than 2.4 g/cm 3 . The powder obtained as low specific gravity product contained about 29 % of fine aggregate. The reference for normal clinker and the mixture prepared by mixing the reference materials with 38 wt% of the powder were heated at 1,500 °C , with the hydraulic modulus adjusted to 2.18, the silica modulus to 2.8, and the iron modulus to 1.64. The phases of the clinker were identified and quantitatively determined by a microscopic point-count procedure and by the Rietveld analysis using XRD data. There was good agreement in the clinker minerals of the reference and the mixture clinkers. These results show that the fine aggregate and cement hydrate powder recovered from fine waste concrete by MGS can be recycled in cement and concrete production.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.