The Phu Thu Interchange and Connecting Road Project in Tien Hiep Commune, Phu Ly City, Ha Nam Province is one of the province’s key transport infrastructure projects. Covering an area of more than 34 hectares and funded with nearly VND 1.4 trillion from the provincial budget, the project is managed by the Ha Nam Province Construction Investment Project Management Board. Construction is undertaken by the consortium of Vinaconex and Trung Chinh Trading and Construction Co., Ltd. Vinh Hung participates as a specialist subcontractor, supplying materials and carrying out tunnel waterproofing works for the Phu Thu Underpass since October 2024.

Waterproofing plays an essential role in protecting the structure from groundwater, moisture, leakage, aggressive soil conditions, and chemical attack. The waterproofing system for the underpass and connecting road project consists of three layers:

• Type 1 Waterproofing Layer: Fully bonded pre-applied HDPE membrane installed beneath the tunnel base slab prior to concrete casting.
• Type 2 Waterproofing Layer: Self-adhesive modified bituminous membrane, cold-applied to tunnel walls, pump station walls, and the roof slab of the enclosed tunnel section after completion of the concrete structure.
• Type 3 Waterproofing Layer: Two-component acrylic polymer cementitious waterproofing coating applied to the top surface of the base slab and pile heads.