Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2020/r/bayburt/14311
  Optimising High Lime Fly Ash Content By Means of Silica Fume Incorporation to Control Alkali-Silica Reaction And Drying Shrinkage of Mortars

  Gökçe, H. Suleyman; Hosseinnezhad, Hojjat; Üzüm, Onur; Hatungimana, Daniel; Ramyar, Kambiz

  In this study, the effect of binary and ternary cementitious systems composed of portland cement, high-lime fly ash and silica fume on the compressive strength, alkali-silica reaction (ASTM C 1567) and drying shrinkage of mortar mixtures was researched. For this purpose, binary and ternary binders were prepared with partial replacement of cement with either fly ash (15wt% and 30wt%) or silica fume (5wt%) or both mineral admixtures (15wt+%5wt% and 30wt%+5wt%). An alkali reactive basalt aggregate was used in this study. It was found that partial replacement of cement with high-lime fly ash reduced the strength of mortar mixtures even up to 28-days. Besides, addition of 5% silica fume had not a significant effect on the early strength of fly ash-bearing mixtures. However, silica fume inclusion improved the 28-day strength of mixtures. In terms of alkali-silica reaction (ASR), the fly ash with lower lime content reduced the 14-day expansion more than that of fly ash with higher lime content. The opposite results were the case in 28-day ASR expansions. The ASR expansions of the fly ash-bearing mixtures were significantly reduced by the introduction of the additional 5% silica fume to these mixtures. However, silica fume incorporation remarkably increased the drying shrinkage values of the mixtures. Finally, fly ash with higher lime content was found to be more satisfactory in terms of compressive strength, alkali-silica reaction and drying shrinkage in the ternary binder system.

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  AtıfOpenAlex1

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• MakaleAçık Erişim2019Scopus SJRQ1/r/bayburt/12349
  Effect of fly ash and silica fume on hardened properties of foam concrete

  Gökçe, H. Süleyman; Hatungimana, Daniel; Ramyar, Kambiz

  In this study, the effects of foam content as well as fly ash and silica fume inclusion on some physical and mechanical properties of foam concrete, subjected to various curing regimes, were researched. Totally, forty-five series of foam concrete mixtures were prepared at three replacement levels of fly ash and silica fume (0, 10 and 20%, by weight of cement), at three foam contents (0, 31 and 47%, by volume) and at three curing regimes (7- and 28-day standard water curing and autoclave curing). Density, water absorption, compressive strength and thermal conductivity values of the mixtures were determined on prismatic specimens with dimensions of 40 × 40 × 160 mm. The density (oven dry), water absorption, compressive strength and thermal conductivity results of the foam concrete were found to be between 873–1998 kg/m3, 3.5–35.9%, 1.5–88.1 MPa and, 0.239–0.942 W/m.K, respectively. A balanced benefit with regard to both compressive strength and water absorption of foam concrete was found in the mix with density of 1320 kg/m3. Particularly in the mixtures having high foam content, silica fume introduction resulted in superior compressive strength values and greater compressive strength/thermal conductivity ratios than fly ash introduction.

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  AtıfScopus271·WoS237·OpenAlex276

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