The superior compressive strength of ultra-high performance cement (UHPC) compared to regular concrete makes it ideal for various critical applications, such as bridges, ultra-high-rise buildings, and areas prone to seismic activity. Recent advancements in UHPC development have introduced additives, including nanoparticles, that enhance and maintain concrete strength while also reducing environmental impacts and costs. Nano-alumina demonstrated the most consistent improvement in the mechanical properties of cement over time compared to the other nanoparticles tested. It enhanced compressive strength by 15% at 7 days and by 1-6% at later stages. Nano-alumina also reduced open porosity, resulting in denser and more durable cement pastes.