The construction of the Great Pyramid of Giza continues to intrigue scholars into the 21st century. This study explores the hypothesis that the Ancient Egyptians used an in-situ casting method with man-made composite blocks, challenging the traditional theory of transporting and assembling quarried stone blocks. Through a two-phased approach combining material analysis and empirical research, this study sheds new light on the construction techniques employed by the Ancient Egyptians. The findings reveal the remarkable ingenuity, skill, and coordination required for the pyramid's construction, challenging long-held assumptions. Evidence suggests that casting composite blocks on-site was feasible, with the incorporation of sand significantly enhancing the mechanical properties of the blocks. While the study provides compelling insights, it acknowledges limitations in the experimental scope and calls for further interdisciplinary research to fully validate the hypothesis. This research contributes to the ongoing debate on ancient construction methods and offers practical implications for modern construction practices aimed at optimizing material use and structural efficiency.