Hybrid fly ash cement is a binder with a composition between that of pozzolanic fly ash cement and alkali-activated
fly ash cement. Its production requires less cement clinker than ordinary Portland cement, facilitating a much-needed
reduction in the carbon dioxide footprint related to the production of high-clinker-containing cement. Research on
activation methods is required to overcome the low early age strength and slow strength development in hybrid fly
ash cements. In this study the activation of a South African siliceous fly ash (70%) for use along with Portland cement
(30%) in a hybrid alkaline binder was investigated. Both chemical (the addition of sodium sulfate) and mechanical
(milling) activation of fly ash was studied. The aim of this work was to develop a better understanding of the
characteristics of compressive strength development of hybrid fly ash cement mortars over an extended curing period
of up to a year. The results indicated that the combination of mechanical and chemical activation (sodium sulfate) can
be considered a viable solution to improving early strength and slow strength development, so that hybrid cements
are able to comply with the strength requirements of the BS EN 197 cement specification.
BACKGROUND : Tuberculosis is a world-wide problem affecting humans and animals. There is increasing development of resistance of the pathogens to current antimycobacterial agents. Many authors have investigated activities ...
Becker, John V.W.; Van der Merwe, Marina M.; Van Brummelen, A.C. (Anna Catharina); Pillay, Pamisha; Crampton, Bridget Genevieve; Mmutlane, Edwin M.; Parkinson, Chris; Van Heerden, Fanie R.; Crouch, Neil R.; Smith, Peter J.; Mancama, Dalu; Maharaj, Vinesh J.(BioMed Central, 2011)
BACKGROUND: Anti-malarial drug resistance threatens to undermine efforts to eliminate this deadly disease. The
resulting omnipresent requirement for drugs with novel modes of action prompted a national consortium ...
COUNTRY/LOCALITY/COVERAGE : A smartphone app-based programme that has been activated by more than 415 000 people in South Africa.
TARGET POPULATION : Adult members of Vitality, a health promotion and ...