Barrier Against Water: Investigating Modified PCC (Portland Cement Concrete) as a Potential Alternative to Commercial WPC (Waterproof Cement Concrete)

Water ingress is a persistent and costly cause of concrete deterioration in rural and coastal regions with heavy rainfall, where annual precipitation often exceeds 2,000-3,000 mm, groundwater tables sit within 1–3 m of the surface, and relative humidity frequently stays above 70%. External waterproofing coatings are expensive and difficult to maintain in these settings, making internal waterproofing built into the concrete itself an attractive alternative. This study evaluates two such approaches at a fixed water–cement ratio of 0.40: Portland Composite Cement (PCC) modified on site with a waterproofing admixture, and factory-produced Waterproof Cement (WPC) concrete, in which hydrophobic compounds are integrated during manufacture. Cylindrical specimens were tested for compressive strength (ASTM C39), splitting tensile strength (ASTM C496) and water absorption (ASTM C642) at 7, 14 and 28 days. WPC consistently outperformed the admixture-modified mix at every age, reaching 50.67 MPa in compression and 3.95 MPa in tension at 28 days, against 36.20 MPa and 3.41 MPa for Modified PCC, alongside markedly lower water absorption (2.76% versus 6.68%). These results are consistent with a denser, more uniformly waterproofed matrix arising from factory-controlled compound distribution rather than field-dosed admixture. WPC is recommended for severe-exposure elements such as foundations and water-retaining structures in rural, coastal or high-rainfall settings, while Modified PCC remains a viable, lower-cost option for moderate-exposure applications with careful dosing and curing control.