Performance-based approach for durability of concrete containing flash metakaolin as cement replacement
ABSTRACT: Performance-based specifications have recently been introduced into European standard EN 206-1 through the equivalent performance concept. This concept can be applied by comparing reference mixtures and new concrete mixtures. The present study deals with performance and durability of concrete where flash metakaolin (MKF) was used as Portland cement replacement. The replacement rates ranged between 15 and 25% of metakaolin at a constant water/binder ratio of 0.6, cured at 20°C and 100% of humidity, for a hydration periods up to 90 days. The comparisons were made with concretes using CEM I, CEM II, and CEM III with blast-furnace slag, to determine the influence of MKF in ordinary concretes. Many technical benefits for the concrete user, such as lower permeability, higher strength and decreased chloride ion penetration are affirmed. It seems likely that MKF meets the requirements of the equivalent performance concept.