Split tensile strength of binary blended self compacting concrete containing low volume fly ash and TiO2 nanoparticles

In the present study, split tensile strength along with rheological, thermal, transport and microstructural properties of self compacting concrete (SCC) containing low volume fly ash (FA) and TiO2 nanoparticles have been investigated. With this respect, Portland cement was replaced by low volumes of fly ash and the properties of SCC specimens were measured. It was found that addition of fly ash by 5, 10 and 15 wt% can improve the rheological, mechanical and durability properties of concrete at higher ages. TiO2 nanoparticles with the average particle size of 20 nm were partially added to concrete. TiO2 nanoparticle as a partial replacement of cement up to 4 wt% could accelerate C–S–H gel formation as a result of increased crystalline Ca(OH)2 amount at the early age of hydration and hence increase split tensile strength of concrete specimens. Increasing the TiO2 nanoparticles’ content more than 4 wt% reduced the split tensile strength because of the decreased crystalline Ca(OH)2 content required for C–S–H gel formation. TiO2 nanoparticles could improve the porestructure of concrete and shift the distributed pores to harmless and few harm pores. Microstructures of different concrete mixtures were also investigated through scanning electron microscopy (SEM) and X-ray diffraction (XRD).