Fresh properties and segregation resistance of self-compacting concrete: Fid-Bau Portal

Fresh properties and segregation resistance of self-compacting concrete

Ye, Yanhua / Bonen, David / Shah, Surendra P.

The performance of Self-Compacting Concrete (SCC) is usually considered better than that of ordinary concrete. However, the properties of SCC vary and it is prone to segregation. The latter is attributed more to the inherent lower yield stress and lower aggregate-to-cementitious materials ratio than the corresponding ordinary concrete. Since powder-type SCC differs from VMA(viscosity modified agent)-type SCC by both lower water-to-binder ratio (w/b) and total aggregate-to-binder ratio (Ta/b), it implies that the powder-type SCC has a greater mechanical performance than the corresponding VMA-type SCC. For similar flow characteristics, the resistance to segregation depends on the viscosity of the mixture. The addition of VMA substantially decreases segregation. In turn, the addition of superplasticizer decreases viscosity and increases segregation. An increase of the solid volume of aggregate adversely affects both the segregation and fluidity. To this end, the adverse effect of Ta/b on fluidity is more conspicuous in the VMA-type than the powder-type. The mechanical properties (compressive strength and modulus of elasticity) at 28 days are shown. The compressive strength values vary in a wide range from about 35.5 to 59.8 MPa, whereas the corresponding moduli values vary from about 34.2 to 36.2 GPa. The compressive strength is mainly dependent on the w/b ratio values and in this regard, the powder type SCC outperforms the VMA type. It appears that the strength increases with the increase in the total content of aggregate. This can be attributed to the decrease in total porosity as the total powder content decreases.