Effects of mineral admixtures on the properties of self-compacting concrete

Abstract

In this study, the effect of using different kinds of fine materials at varyingpercentage compositions on the properties of self-compacting concrete wasinvestigated. Mixtures containing various combinations of fly ash, ground granulatedblast furnace slag and metakaolin and a mixture incorporating only portland cementas the binder material were produced at a constant water-to-binder ratio. For eachmixture, to attain a self-compacting concrete, the amount of superplasticizer to beused was determined during the slump flow test. The concretes were also tested forworkability and mechanical properties. A total of 11 concrete mixtures weredesigned having a constant water/binder ratio of 0.32 and total binder content of 550kg/m3. The control mixture included only a portland cement as the binder while theremaining mixtures incorporated binary and ternary cementitious blends of portlandcement. After mixing, the fresh properties of the concretes were tested for slumpflow time, L-box height ratio, V-funnel flow time and unit weight. Moreover, on theseparated mortar phase of the mixtures, initial and final setting times and viscositywere measured. From each mixture, three cubes were also taken to test the ultrasonicpulse velocity and compressive strength respectively. The performances of mineraladmixtures used varied for different tests. When the workability is of concern, the flyash had the most favorable effect. On the other hand, regarding the strength ofconcretes metakaolin had the best performance compared to the other mineraladmixtures used.