Polymer Modified Asphalt Waterproof Coating For Tunnel Engineering

High‑Polymer Modified Asphalt Waterproof Coating Application Methods

1. Base Surface Treatment The base surface shall be solid, flat, clean, free of sanding, dust and oil stains. Cracks and pits shall be repaired and leveled with polymer mortar. Internal and external corners shall be formed into R50mm circular arcs. Pipe roots and water outlet peripheries shall be compactly repaired without sharp edges and corners. No standing water on the base surface, with moisture content ≤9%. A primer is recommended for loose and sanding base surfaces for reinforcement.
2. Detailed Additional Layer (Key Point) Apply additional layers at internal and external corners, pipe roots, floor drains, expansion joints and water outlets with a width ≥200 mm, adopting the method of two‑coat‑one‑fabric: first apply a thin coat of coating, lay non‑woven fabric / polyester fabric, ensure the reinforcement fabric is fully saturated without wrinkles or edge curling. Apply another coat to cover the fabric after surface‑dry.
3. Large‑Area Coating Construction Stir thoroughly with electric mixer after opening the drum. Do not dilute with water or solvent. Apply by roller, brush or spray. Apply multiple thin coats in cross directions; the subsequent coat shall be applied perpendicular to the previous one. Wait until the previous coat is surface‑dry and non‑tacky before applying the next coat. Interval: 2‑6 h at normal temperature; extend to 8‑24 h under low‑temperature and humid conditions. Generally apply 2‑3 coats. Total dry film thickness ≥1.5 mm (subject to design requirements). Theoretical consumption: approx. 2.5‑3.0 kg/㎡.
4. Curing and Subsequent Procedures After completion of construction, cure naturally for 24‑48 h at normal temperature. Extend curing time under low‑temperature and high‑humidity conditions. No treading, rain exposure or water immersion before full curing. After acceptance of waterproof layer, protective layer (cement mortar, fine aggregate concrete, etc.) must be applied. This product is not suitable for long‑term direct exposure. Water‑storage test: carry out closed‑water test only after full curing of the waterproof layer.

Performance Indexes