Technical specifications and construction points of glass fiber self-adhesive tape in building crack repair

The repair of building cracks imposes strict requirements on the durability, bonding strength, and construction convenience of materials. According to the "JGJ/T 235-2011 Technical Specification for Building External Wall Waterproofing Engineering", when the crack width is greater than 0.2mm, a repair scheme combining mechanical fixation and flexible sealing is required, and glass fiber self-adhesive tape is the core material of this scenario. The construction process includes six key steps:

Base treatment: Use an angle grinder to remove floating slurry and oil stains within 200mm on both sides of the crack. The exposed reinforcement area should be polished to a metallic luster with a moisture content of less than 8%.

Crack filling: Using pressure grouting method to inject modified epoxy resin, the grouting pressure is controlled at 0.2-0.4MPa to ensure that the crack filling density is greater than 95%.

Self adhesive tape laying: Cut 50mm wide tape according to the direction of the crack, remove the release paper, and spiral lay it with a 30% overlap rate. Use a rubber hammer to gently tap and remove any bubbles.

Reinforcement layer construction: Apply 2mm thick polymer cement mortar on the surface of the self-adhesive tape, and embed alkali resistant fiberglass mesh cloth (with a unit area mass of 160g/m 2).

Surface treatment: After the initial setting of the mortar, use a trowel to smooth it to be level with the base surface, and after 24 hours, perform sandblasting to form a rough surface.

Acceptance criteria: According to the "GB 50208-2011 Code for Acceptance of Quality of Underground Waterproofing Engineering", the tensile strength of the repaired area should be ≥ 1.5MPa, and there should be no hollowing or cracking.

In terms of technical parameters, high-quality self-adhesive tape needs to meet the following requirements: alkali resistance (strength retention rate>80% after soaking in 5% NaOH solution for 168 hours), UV resistance (QUV accelerated aging test for 3000 hours, color difference Δ E<3), and low-temperature bending (no cracks after 180 ° bending at -10 ℃ environment). In practical application, a commercial complex project used DeYuan glass fiber self-adhesive tape to repair basement settlement cracks. After 5 years of tracking and testing, no secondary cracking occurred in the repair area, and the bonding strength remained above 1.2MPa.