Effects of a clay additive on the properties of no-slump concrete

Abstract

The rheological characteristics of clay cement pastes can be described by help of the DLVO theory. Since the system used, consisting of two type clay minerals, quartz, cement and water is highly complex, further investigation is needed to come to consistant explanations. The potentials resulting from the enhanced rheological properties is shown for an example of no-slump concrete. Despite the low strength of clay particles the compressive strength of concrete is considerably enhanced. The definite enhancement of green strength can be explained by cohesive forces. The knowledge gained up to now should be used additionally for reducing the compaction energy and the sensitivity towards changing water contents and thus give rise to constant product qualities. Some more good results could be obtained in other tests (Budelmann et al. 2006). The clay additive has a CE certification for inert filler material for concrete and mortar in respect of the German standards DIN EN 12620:2003 and DIN EN 13139:2002.