Study of the effect of silica fume on the mechanical response of a self compacting concrete using non destructive testing methods (NDT)

Abstract

The self-compacting concretes are distinguished by an extreme fluidity, allowing their placement without vibration. mineral additions and admixture are two essential components for the formulation of self-placing concretes (SCC). They are introduced into the concrete to improve their rheological behavior in the fresh state, but also to participate in enhancing the mechanical properties and durability of concretes, especially in the case of active additives.

In this study, a test program was performed on self-placing concretes composed of cement and silica fume and lime filler as mineral addition. The rheological parameters (viscosity and yield strees) were measured using the rheometer at the fresh state. Mechanical characterization was performed by means of the direct (compressive) and non-destructive testing methods (NDT), ultrasonic velocity and rebound hammer for the assessment of the mechanical responses in the hardened state.

The results obtained showed an advantageous effect of these combined additions with an optimal dosage of 10% (5 % Silica fume + 5 % Limestone), with regard to the improvement of the rheological and physico-mechanical properties of the self-compacting concrete mixtures studied.