The objective of this research was to assess the impact of a waterproofing admixture on the porosity and capillary absorption of self-compacting concrete with water/cement ratios of 0.40, 0.45, and 0.50. The study began with the characterization of the component materials, followed by the calculation of six different mix designs, including three standard concrete mixtures and three concrete mixtures with the waterproofing admixture. In the fresh state, the temperature and fluidity of each mixture were measured. Thirty cylindrical specimens measuring 15x30cm were then produced and cured for 28 days following ASTM C-31 standards. Porosity and capillary absorption were determined according to ASTM C642. The results for porosity in the standard concrete samples with water/cement ratios of 0.40, 0.45, and 0.50 were 11.57%, 12.16%, and 13.06%, respectively. In contrast, the samples with the wa...