Rheology and bonding characteristics of self-leveling concrete as a repairmaterial

This paper presents the first part of a study undertaken to measure the pot ential of self-leveling concrete to perform overhead repairs. The performan ces of self-leveling concrete in terms of its filling ability and bonding c haracteristics was compared to dry-mixture shotcrete and to normal cast-in- place concrete. Self-leveling mixture characteristics included the presence of super-plasticizer, viscosity-modifying admixture (welan gum), air-entra ining admixture (AEA) and silica fume. On self-leveling concrete and ordinary concrete, rheological parameters (yi eld value and plastic viscosity) were measured with a rheometer, and other fresh properties were determined including air content (ASTM C-231), specif ic weight, slump (ASTM C-143), and slump-flow. It was observed that self-leveling concrete has very good filling ability a nd that the absence of segregation and bleeding enhances the characteristic s of the interface with the old concrete, even in an inverted position. Mic rostructure studies have indicated that self-leveling concrete performed as well as dry-mixture shotcrete and is thus a very interesting repair materi al.