Pozzolanic activity tests have been around in cement chemistry for more than 150 years.Ever since the first published account of a simplified lime reactivity test by Louis Vicat in 1856, pozzolanic activity tests aimed at providing a rapid, relevant and reliable test method to measure the reactivity of a material and predict its contribution to the strength development of cementitious binders.A particular problem of compressive strength tests on blended cements is their extended duration;many pozzolanic materials contribute only significantly to the binder strength at later hydration ages (28, 90 days).Therefore a relevant objective of many pozzolanic activity tests is to reduce the time of experimentation.