Effect of Supplementary Cementitious Materials on Rheology of Different Grades of Self-Compacting Concrete Made with Recycled Aggregates

Abstract

Rheology of two grades of Self-Compacting concrete containing selected volumetric replacement levels of coarse Recycled Concrete Aggregates (SCRCA) is investigated. Fly ash, metakaolin and silica fume were used in different combinations of cementitious materials to achieve the normal- and the medium-strength SCRCAs. Irrespective of the RCA replacement level, a shear thickening response was noted in both the normal- and the medium-strength SCRCAs and their flow behaviour could be described using the Modified Bingham (MB) as well as the Herschel-Bulkley (HB) model. The decrease in the degree of shear thickening with an increase in concrete grade is attributed to the use of either silica fume or metakaolin as part of the ternary cement in the higher strength concretes with silica fume being relatively more effective. Within a given grade, shear thickening increased with increase in the recycled aggregate replacement level. The MB as well as the HB model were equally effective in representing observed flow behaviour.