Testing methods of pozzolanas
Practical Action
Similar to the test for pozzolanicity index with Portland cement but using lime. Based
on the compressive strength of the cured lime-pozzolana mix.
13. Reactivity with cement alkalies
Tests to determine the expansion of mortar due to the alkali-aggregate reaction.
British Standards
The British Standards Institute has no specific test to determine the reactivity of pozzolanic
material. There is however a test for determining the pozzolanicity of pozzolanic cements (BS
EN 196-5: 1995).
Using the Rio-Fratini method, the pozzolanicity is assessed by comparing the quantity of
calcium hydroxide in the aqueous solution in contact with the hydrated cement, after a fixed
period of time, with the quantity of calcium hydroxide capable of saturating a solution of the
same alkalinity. The test is considered positive if the concentration of calcium hydroxide in
the solution is lower than the saturation concentration.
Figure 1: Example of British standard pozzolanicity test - for heap burned rice husk ash
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