Sammendrag
More sustainable cement production is achieved by increased exploitation of its energy- and raw material consuming by-products. Data published worldwide the last couple of decades were reviewed showing that CKD can be used for example for low level cement substitution and soil stabilization. Modern dry-process plants produce less CKD than older wet process plants and with more reactive phases (CaO, clinker components) and less uncalcined raw feed giving it higher particle density. Loss on ignition (LOI) and SiO2 contents tend to be low and sulfate high in dry plant CKD. CKD has hydraulic or activating properties that in cement-CKD blends give a mean pozzolanic efficiency- or k-factor of 0.6 in mortar and concrete, but varying from 0 to 1.1. CKD can also activate pozzolans like fly ash, slag etc. In OPC – CKD binders the usual cement reactions are found. A main area of use for CKD is probably as partial substitute for cement and lime in clay- and soil stabilization. Mechanisms of cement and lime reaction with clay are therefore reviewed; how clay particles react with lime and cement and convert to CSH and CAH, effective w/b, hydrate spacing, binder dosage etc. A few data exist on CKD hydration with clay indicating similar mechanisms as with lime and cement
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