Alkali activation of a slag at ambient and elevated temperatures

By Ekin Altan, S. Erdoğan. 2012

202 citations recorded by the source corpus.

Abstract 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 °C however, sodium silicate is essential and even sufficient. KOH is more effective than NaOH at 80 °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.

Subfields: Building and Construction, Civil and Structural Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/eefd465872f79ad15ff0c03ddd3668f05e1c95bd

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Citations in the corpus

Reaction kinetics in sodium silicate powder and liquid activated slag binders evaluated using isothermal calorimetry (2012, background): “glass has recently been provided in [30].”
Very early-age reaction kinetics and microstructural development in alkali-activated slag (2015, background): “Temperature is another factor in hydration which may act as an accelerator during the hydration process [9,10,21,28,29].”
Effects of dosage of alkali-activated solution and curing conditions on the properties and durability of alkali-activated slag concrete (2012, result): “Elevated temperature curing has a beneficial effect on compressive strength development which is consistent with results of other studies [27,29].”