Cement manufacturing is one of the widest industries in the world and yet largely contributes to the global CO2 emissions. As a result, introducing low carbon sustainable concrete designs without compromising performance has become one of the greatest challenges over the last few decades. This complexity was majorly caused by heterogeneity of concrete due to the existence of cementitious particles, fibers, or fine filler materials. Further, this multi-scale material heterogeneity of concrete influences the performance of concrete at macro levels and makes it more complicated to understand the hydration behaviors. Macroscale trial and error-based mechanical property testing might not always be the feasible way to find the optimum mix designs, because those techniques cannot quantify the root cause relationship to the microstructure. Therefore, microscale quantitative chemical and mechanical characterizations pave the way for cement to upscale strength from microlevel to structural level using strength homogenization, revealing the compositional characteristics which contributed to the strength variation in any novel cement mix. Since microphase identification is crucial to achieve that task, in this study, energy-dispersive x-ray spectroscopy (EDS) together with scanning electron microscopy (SEM) is used to quantify the hydration of an ultra-high-performance cement paste at microlevel. The image analysis is carried out using the mapping data collected from four different locations of the same cement batch, and the accuracy of the hydration quantification is compared with an independent analytical hydration simulation software, Virtual Cement and Concrete Testing Laboratory (VCCTL) by NIST.