Is UHPC Impermeable? Dense Barriers and Qinglong Group's Waterproof Fortress

The impermeability of UHPC is a direct manifestation of its outstanding durability, essentially stemming from a dual physical and chemical barrier formed by "extremely low porosity, disconnected pore structure, and hydrophobic treatment." High-quality UHPC can reach an impermeability grade of P12 or above (i.e., withstanding 1.2 MPa of water pressure without seepage), with a chloride ion diffusion coefficient as low as the 10⁻¹² m²/s order of magnitude, making it virtually watertight. UHPC produced by Qinglong Group, through a vacuum dewatering process and the addition of silane-based hydrophobic agents, achieves a water absorption rate of ≤6%. On the roof of the Hainan Convention and Exhibition Center, it has withstood ten years of typhoons and torrential rains with zero leakage. Impermeability is the first line of defense for UHPC against environmental attack.

Microstructure Determines Impermeability

Ordinary concrete has a porosity as high as 10-15%, mostly consisting of connected capillary pores through which water easily penetrates. UHPC has a water-binder ratio below 0.2; combined with the filling effect of ultrafine powders such as silica fume, it forms a microstructure dominated by nanoscale gel pores that are tortuous and disconnected, making it difficult for water molecules to migrate. This "innate immunity" structure gives it an impermeability 2-3 orders of magnitude higher than that of ordinary concrete.

Outstanding Performance in Waterproofing Projects

In underground works, hydraulic structures, and roofing systems, the impermeability of UHPC delivers revolutionary advantages. The UHPC segments we supplied for an undersea tunnel in Shenzhen reach an impermeability grade of P16, requiring no additional waterproofing layer. In the planted roof of China Resources MixC One in Wuxiang, Nanning, UHPC structural slabs serve both load-bearing and waterproofing functions, simplifying construction and saving costs.

Technical Measures to Enhance Impermeability

Although UHPC itself offers excellent impermeability, Qinglong Group further enhances its protective capability through surface hydrophobic treatment (such as silane impregnation). This treatment gives the UHPC surface a contact angle greater than 90°, producing a "lotus effect" whereby rainwater beads up and rolls off, carrying away dust and achieving self-cleaning. In the Wuhan Han Show Theatre project, this technology has kept the red curtain wall vibrant over the long term.

Therefore, the impermeability of UHPC is not an added feature but the inevitable result of its material nature. Through meticulous, refined craftsmanship, Qinglong Group brings this advantage to the fullest.