The primary research objectives of this experiment are to characterize the microstructure of concrete samples and establish precise correlations between microstructural features and variations in compressive strength. To achieve these objectives, we prepared six types of concrete, each type with unique magnitude of cement, sand, water, aggregate1, and aggregate2. The composition of each type was adjusted to ensure a controlled variation in compressive strength. For each type of concrete, eight samples were prepared. Six samples were used to perform a standard compressive strength tests at ages of 7 and 28 days. Then, synchrotron X-ray microtomography was employed on the other two samples to non-destructively examine the internal microstructure of the samples, providing high-resolution 3D images.