Effects of fly ash and TiO2 nanoparticles on rheological, mechanical, microstructural and thermal properties of high strength self compacting concrete

In the present study, strength enhancement and durability-related characteristics along with rheological, thermal and microstructural properties of high strength self compacting concrete (HSSCC) containing nano TiO2 and industrial waste ash namely as fly ash (FA) have been investigated. With this respect, Portland cement was replaced by up to 15 wt% waste ash and up to 5 wt% TiO2 nanoparticles and the properties of HSSCC specimens were measured.It was found that with the aim of energy saving and recycling of waste materials, addition of FA as a natural pozzolan can improve the rheological, mechanical and durability properties of concrete at higher ages. TiO2 nanoparticles 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 improve the microstructure of concrete leading to improved durability-related properties and strength enhancement of the concrete. Several empirical relationships for predicting flexural and split tensile strength of concrete based on compressive strength for HSSCC containing FA and nano TiO2 at different ages have been obtained. Finally, an energy-based assessment of strength enhancement of nano-containing concrete has been presented.

► Fly ash and nano TiO2 in high strength self compacting concrete (HSSCC).
► Effects of admixtures on workability, flexural and split tensile strength.
► Influence of fly ash and nano TiO2 on durability and microstructure of HSSCC.
► Thermal properties tests via Thermogravimetric analysis and conduction calorimetry.
► SEM and XRD analyses of concrete mixtures at various ages.