Microstructure and durability properties of high strength self-compacting concrete using micro silica and nano silica

Abstract

One of the unique types of concrete with exceptional strength and durability is self-compacting concrete (SCC). Coarse aggregates in SCC are available in a viscous suspension while allowing flow in presence of high binder concentration and super plasticizer. Typically, a filler substance and cement are employed as the binder. Micro silica (MS) and nano-silica (NS) employed as a filler material. One of the most popular pozzolonic materials is fly ash (FA). MS and NS are pozzolonic substance, very fine, used as an additive in place of cement. The goal of this research is to construct self-compacting concrete by substituting cement with FA, MS and NS. The mechanical qualities, such as compressive strength, flexural strength and split tensile strength, as well as the durability properties, such as water absorption and rapid chloride penetration test (RCPT) have been examined after 28 days in order to fully assess the performance of SSC. The slump flow value is falling within the range of 670–710 mm. It was demonstrated that a 10% increase in MS concentration significantly boosted the specimen’s compressive strength. However, further increases in MS concentration resulted in a decrease in strength. Additionally, the specimen’s strength increased by up to 2% with the addition of NS. The minimum chloride penetration, recorded at 1474 coulombs, was observed for M3 in SCC with MS. Similarly, for SCC with NS, the minimum chloride penetration was 1015 coulombs, observed for M6. The dense microstructure has been observed with the addition of the MS and NS that increased the strength of the SSC.