Journal ArticleDOI
Studies on cement and mortar containing low-calcium fly ash, limestone, and dolomitic limestone
Bülent Yılmaz,Asim Olgun +1 more
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In this article, the effects of low-calcium fly ash (FA), limestone (LS), and dolomitic limestone (DLS) on the properties of cement and mortar have been investigated through a number of tests.Abstract:
The effects of low-calcium fly ash (FA), limestone (LS), and dolomitic limestone (DLS) on the properties of cement and mortar has been investigated through a number of tests. Composition of cement hydration products in cement paste and mortar were made with clinker (PC), gypsum (G), FA, LS and DLS. The binders employed were Portland cement (OPC), fly ash–portland cement (FA–OPC), FA–LS–OPC, and FA–DLS–OPC blends with a maximum PC replacement level of 40%, FA level of up to 40%, LS and DLS levels of up to 15%. The hydration rate and products were studied by means of X-ray diffraction (XRD) and Fourier transforms infrared spectroscopy (FTIR). The results showed that the FA, LS and DLS prolong the setting time of the cements. Relative to OPC, in FA–OPC system expansion decreases as the fly ash content of the cement increases. Ternary system, FA–DLS–OPC produces a marked fall in the expansion of the tested specimens.read more
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Hydration mechanisms of ternary Portland cements containing limestone powder and fly ash
TL;DR: In this article, the effect of minor additions of limestone powder on the properties of fly ash blended cements was investigated using isothermal calorimetry, thermogravimetry (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) techniques, and pore solution analysis.
Journal ArticleDOI
Hydration of Portland cement with high replacement by siliceous fly ash
Florian Deschner,Frank Winnefeld,Barbara Lothenbach,Sebastian Seufert,Peter Schwesig,S. Dittrich,Friedlinde Goetz-Neunhoeffer,Jürgen Neubauer +7 more
TL;DR: In this article, the effects of fly ash on the hydration of ordinary Portland cement pastes were investigated over a hydration time of 550 days and the results were compared with a reference blend of OPC containing 50% of inert quartz powder allowing the distinction between "filler effect" and pozzolanic reaction.
Journal ArticleDOI
Compatibility between superplasticizer admixtures and cements with mineral additions
TL;DR: In this article, the effect of limestone, fly ash and silica fume on Portland cement and the interaction of these additions with naphthalene (PNS)-, melamine (PMS)-, lignosulfonate (LS)- and polycarboxylate (PCE)-based admixtures was explored.
Journal ArticleDOI
Changes in mobility of hazardous elements during coal combustion in Santa Catarina power plant (Brazil)
TL;DR: In this paper, changes in mobility of hazardous elements contained in coal during combustion at a power plant in Santa Catarina (Brazil) and the environmental impact potential of ashes were determined by digestion and sequential extraction.
Journal ArticleDOI
Inhibition mechanisms of steel slag on the early-age hydration of cement
Shiyu Zhuang,Qiang Wang +1 more
TL;DR: In this article, the early-age hydration kinetics and the evolution of the solid phases, aqueous species and microstructures in a cement-steel slag composite binder are investigated to explore how steel slag inhibits the early age hydration of cement.
References
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The Role of Calcium Carbonate in Cement Hydration
TL;DR: In this paper, it is shown by experiment and calculation that much, if not all, of this calcite is reactive and affects the distribution of lime, alumina and sulfate and thereby alters the mineralogy of hydrated cement pastes.
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Degree of hydration and gel/space ratio of high-volume fly ash/cement systems
TL;DR: In this article, the degree of hydration of the cement in Portland cement (PC) paste was obtained by determining the non-evaporable water (Wn) content of the fly ash.
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Efficiency of mineral admixtures in mortars: Quantification of the physical and chemical effects of fine admixtures in relation with compressive strength
TL;DR: In this paper, an efficiency concept is proposed in order to take into account the effect of mineral admixture in mortars from both the physical and chemical points of view, using an efficiency function ξ(p) that has notable properties: it is independent of time, independent of fineness and independent of the type of mineral mixture.
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The effect of fly ash composition on the expansion of concrete due to alkali-silica reaction
TL;DR: In this article, the results from expansion tests on concrete prisms and mortar bars containing reactive aggregate and different types and levels of fly ash were tested, and the results show that the bulk chemical composition of the fly ash provides a reasonable indication of its performance in physical expansion tests but cannot be used to accurately predict the degree of expansion or the minimum safe level of fly ashes required to suppress expansion to an acceptable limit.
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Portland-limestone cements. Their properties and hydration compared to those of other composite cements
TL;DR: In this article, a comparison between an ordinary Portland cement and three Portland-composite composite cements containing limestone, natural pozzolana or fly ash was presented, and the mechanical and physical properties of the cements were measured and hydrated products, formed after 1-28 days, were identified by means of XRD.