Influence of Rheological Properties of Pourable Concrete on Formwork Pressure

Abstract

In the course of the wider use of concretes with pourable consistency more and more practice-relevant and economic questions arise. The pressure of concrete on formwork is one of those questions. In the literature very contradictory statements are depicted partially to the pressure of concrete on formwork when using concretes with pourable consistency. Therefore the aim of the research project was to examine the influence of the rheological properties of selfconsolidating concretes (SCC) and vibrated concretes (VC) with consistencies F5/F6 according to DIN EN 206-1:2001-07 on the formwork pressure. The research project was divided into two steps: “Development and investigation of model mixtures for self-compacting concrete (SCC) and vibrated concrete (VC) respectively” and “Measurements of formwork pressure in constructional elements like walls”. In the first step basis mixtures had to be developed. Concretes with F5/F6 consistencies, two powder-type SCC (PT), and two viscosity-agent-type SCC (VAT) were used. The latter mixtures differed considerably in viscosity. Thus all relevant cases regarding the rheological properties were covered by these pourable concrete mixtures. In the second step systematic investigations were conducted to determine the effect of the rheological properties on the fresh concrete pressure on the formwork of constructional elements (walls). By concreting in a precast element plant a reference to practice was given.