Alternative Test Methods for Evaluating Fly Ash for use in Concrete

• Main Author: de Groot, Andre Pieter
• Other Authors: Hooton, Robert Douglas
• Language: en_ca
• Published: 2011
• Subjects: fly Ash; concrete; alkali-silica reaction; ASR; 0543
• Online Access: http://hdl.handle.net/1807/29518

Fly Ash was tested in relation to its ability to mitigate alkali-silica reaction, its contribution to strength, electrical resistance and heat release with the aim of recommending improvements to fly ash specifications. ASTM C 1567 accelerated mortar bar test results were in agreement with an expansion limit of 0.10 % at 14 days. A non-standard alkali leaching test showed that with high alkali fly ashes as replacement level increases the amount of alkalis leached increases while prism expansions decrease. Measures of pozzolanic activity can be improved by measuring against non-pozzolanic fillers, This requires high replacement levels to reduce statistical variability. Isothermal calorimetry tests showed that high calcium fly ashes can lead to delays in hydration, these delays can be reduced by calcium hydroxide additions. Calcium sulphate additions can also improve hydration.