Strength properties and microstructural characterization of green cement composites having nano copper oxide and nano titania

This study investigated the effects of nano titania (NT) and nano copper oxide (CO) on the strength and microstructural properties of fly ash-based green pozzolana Portland cement (PPC) composites. Adding 1 % NT increased the compressive strength by 49.8 %, 25 %, 17.9 %, and 4.1 % at 3, 7, 28, and 56 days, respectively compared to PPC samples without CO or NT. SEM images revealed disordered whisker crystals in the reference mix, while NT and CO mixes showed rod-like and needle-like crystals, with 0.5 % NT promoting C-H and flower-like crystals. EDX detected major elements like Ca, O, Si, and C. NT reduced pores and micro-cracks, boosting strength through C–S–H and ettringite formation. XRD results showed that CO increased C-H and ettringite peaks, while 1 % NT decreased C-H and silicate phases, enhancing hydration.