Thixotropic behavior of self compacting concrete with different mineral admixtures

• Thixotropic and Bingham parameters of SCC with mineral admixtures silica fume, limestone powder and fly ash investigated.
• Thixotropy index of mineral admixed SCC’s are in general higher compared to the SCC mix without it.
• Silica fume and limestone powder increases the flocculation rate Athix of SCC mixes by a maximum of 50% of the reference mix.
• Replacement of cement by 10% fly ash in SCC increases the structuration rate Athix about 3.5 times that of reference mix.
• Characterization of SCC mixes based on Athix is essential for specifying SCC mixes in various structural components.

Experimental investigations are carried out on Self Compacting Concrete (SCC) in the presence of mineral admixtures silica fume, limestone powder and fly ash for a target slump of 700 ± 20 mm and minimum static segregation. SCC is a thixotropic material whose steady state is governed by Bingham constitutive model and it flocculates with resting time. The characteristic flocculation time is obtained for the different mixes, together with the flocculation rate Athix based on ICAR rheometer measurements. Results indicate that addition of silica fume (2.5% replacement), limestone powder (15% replacement) and fly ash (10% replacement) increases flocculation rate Athix significantly.