Alkali activation of a slag at ambient and elevated temperatures

Date

2012-02-01

Author

Altan, Ekin
Erdoğan, Sinan Turhan

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

112
views

0
downloads

Strength development of alkali activated slag (AAS) mortars, activated using alkali hydroxide and sodium silicate, was investigated at room and elevated temperatures. Heat evolution at room temperature was measured using isothermal calorimetry. Important differences were observed between critical activation parameters. Heat cured specimens gain strength rapidly, humid oven conditions being favorable, but given sufficient time room temperature curing yields comparable strengths. Both activators are needed for high strength at room temperature, NaOH solution is more critical and its concentration greatly influences strength. At 80 degrees C however, sodium silicate is essential and even sufficient. KOH is more effective than NaOH at 80 degrees C, but not at room temperature. Lower water-to-slag ratios give higher strength at early ages. AAS hydration evolves less heat than Portland cement hydration. Time to significant strength gain of mixtures can be predicted using their time and heat evolution at setting. Twenty eight-day strength of AAS mortars is roughly related to total evolved heat and increases nearly linearly with the amount of NaOH activator for fixed water glass content.

Subject Keywords

Slag, Alkali activation, High temperature, Ambient, Caustic soda, Water glass

URI

https://hdl.handle.net/11511/46210

Journal

CEMENT & CONCRETE COMPOSITES

DOI

https://doi.org/10.1016/j.cemconcomp.2011.08.003

Collections

Department of Civil Engineering, Article

Suggestions

OpenMETU
Core

Alkali reactivity of mortars containing chert and incorporating moderate-calcium fly ash Bektas, F; Turanli, L; Topal, Tamer; Göncüoğlu, Mehmet Cemal (2004-12-01) This paper reports the results of an experimental program, which aimed to investigate the alkali reactivity of chert and the effect of a moderate-calcium fly ash on the alkali-silica reaction. To determine the expansions, mortar bars were cast and tested in accordance with ASTM C1260. Mortar aggregate was replaced by chert, in controlled amounts, to find out the pessimum limit, if any. To evaluate the degree of cracking, sonic pulse velocity measurements and petrographic analysis were carried out on the cra...
Alkaline solubilization and microwave irradiation as a combined sludge disintegration and minimization method Doğan, Ilgın; Sanin, Faika Dilek (Elsevier BV, 2009-5) Commonly used pretreatment method of alkaline solubilization (using NaOH) and a relatively new technology of microwave (MW) irradiation (160 degrees C) were combined as a pretreatment method of waste activated sludge (WAS) in this study. First alkaline and MW pretreatment methods were examined separately, then their combination for different conditions was investigated in terms of their effect on COD solubilization, turbidity and capillary suction time (CST). For combined pretreatments, soluble COD to total...
Polylactide/organically modified montmorillonite composites; effects of organic modifier on thermal characteristics Ozdemir, Esra; Öztürk, Yurdagül; Hacaloğlu, Jale (2016-12-01) The effects of interspace distance and the possible chemical interactions between PLA and the organic modifier of montmorillonites, Cloisite 15A, 20A and 30B on thermal degradation of PLA in the absence and presence of water vapor were investigated by direct pyrolysis mass spectrometry, (DP-MS) in addition to XRD, TEM, DSC, TGA analyses. The DP-MS results clearly showed that the way in which the polymer was incorporated into the nanocomposite strongly depends on the mixing technique, the interspacing betwee...
Sintering and humidity-sensitive behaviour of the ZnCr2O4-K2CrO4 ceramic system Bayhan, M; Hashemi, T; Brinkman, AW (Springer Science and Business Media LLC, 1997-12-15) Solid state reaction at elevated temperatures and the sintering behaviour of zinc chromite formed by zinc oxide and chromite oxide were investigated. Crystalline structure, surface and fractured morphologies and humidity-sensitivity characteristics of ZnCr2O4-K2CrO4-CuO were studied. The fired ceramic body, which proved to be mainly constructed from ZnCr2O4 spinel grains, was porous. The humidity characteristics of the sensor showed that the resistance decreased as a logarithmic function with an increase in...
Selective oxidation of H2S to elemental sulfur over Ce-V mixed oxide and CeO2 catalysts prepared by the complexation technique Yasyerli, Sena; Dogu, Gulsen; Doğu, Timur (2006-09-30) Selective oxidation of H2S to elemental sulfur was investigated in a fixed bed reactor using Ce-V mixed oxides and cerium oxide (CeO2) catalytic materials prepared by the complexation technique. The Ce-V mixed oxide with a V/Ce atomic ratio of one and with the CeVO4 crystal structure gave very high sulfur selectivity values (close to one) at almost complete conversion of H2S, for O-2/H2S mote ratios close to 0.5. Best operation temperature was found as 250 degrees C with this catalyst. CeO2 gave lower selec...

Citation Formats

E. Altan and S. T. Erdoğan, “Alkali activation of a slag at ambient and elevated temperatures,” CEMENT & CONCRETE COMPOSITES, pp. 131–139, 2012, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/46210.