Activation of fly ash cementitious systems in the presence of quicklime. Part II: Nature of hydration products, porosity and microstructure development

Antiohos, S; Papageorgiou, A; Tsimas, S

dc.contributor.author	Antiohos, S	en
dc.contributor.author	Papageorgiou, A	en
dc.contributor.author	Tsimas, S	en
dc.date.accessioned	2014-03-01T01:23:32Z
dc.date.available	2014-03-01T01:23:32Z
dc.date.issued	2006	en
dc.identifier.issn	0008-8846	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/17006
dc.subject	Gel/space ratio	en
dc.subject	Hydration products (B)	en
dc.subject	Mercury porosimetry (B)	en
dc.subject	Microstructure (B)	en
dc.subject	Pore size distribution (B)	en
dc.subject.classification	Construction & Building Technology	en
dc.subject.classification	Materials Science, Multidisciplinary	en
dc.subject.other	Approximation theory	en
dc.subject.other	Crystalline materials	en
dc.subject.other	Fly ash	en
dc.subject.other	Hydration	en
dc.subject.other	Microscopic examination	en
dc.subject.other	Microstructure	en
dc.subject.other	Pore size	en
dc.subject.other	Porosity	en
dc.subject.other	Calcium sulphoaluminates	en
dc.subject.other	Chemical activators	en
dc.subject.other	Gel/space ratio	en
dc.subject.other	Hydration products	en
dc.subject.other	Mercury porosimetry	en
dc.subject.other	Lime	en
dc.title	Activation of fly ash cementitious systems in the presence of quicklime. Part II: Nature of hydration products, porosity and microstructure development	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.cemconres.2006.09.013	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.cemconres.2006.09.013	en
heal.language	English	en
heal.publicationDate	2006	en
heal.abstract	Following the first paper of a two-part series study on the activating effect of industrial quicklime upon different fly ashes, the current paper concludes on its beneficial role by focusing on the nature of hydration products, pore size and microstructure evolution of each system that was investigated. By looking into the development of these properties, the exact effect of the chemical activator could be elucidated, but furthermore a first approximation of the durability efficiency of the examined systems could be obtained. In the frame of this second part, it was demonstrated that, apart from portlandite, calcium sulphoaluminates (ettringite and monosulfoaluminate) along with some gismondine and gehlenite hydrate (C(2)ASH(8)) crystals are formed in activated fly ash-cement pastes from the first week of hydration. Mercury intrusion porosimetry data confirmed the beneficial action of quicklime, towards decreasing the total pore volume (and concurrent increase in the volume occupied by fine pores) in high-lime ash blends. Gel/space ratios were estimated for each blended paste, and fine, almost linear, correlation was established with total porosity values. Microscopical observations revealed that the critical contribution of quicklime in the production of secondary C-S-H nearby the ash particles. The flocculent-like gel collaborates smoothly with needle-like products and finely-dispersed crystals towards the gradual impletion of the pores and strengthening of the paste. (C) 2006 Elsevier Ltd. All rights reserved.	en
heal.publisher	PERGAMON-ELSEVIER SCIENCE LTD	en
heal.journalName	Cement and Concrete Research	en
dc.identifier.doi	10.1016/j.cemconres.2006.09.013	en
dc.identifier.isi	ISI:000243233000003	en
dc.identifier.volume	36	en
dc.identifier.issue	12	en
dc.identifier.spage	2123	en
dc.identifier.epage	2131	en