Sanding of polymer tactile paving

Polymer blind pathways, designed to provide safe navigation for visually impaired individuals, are an integral part of modern urban infrastructure. However, the issue of sanding, where the surface material wears off, can significantly compromise their functionality and durability. This article delves into the causes of sanding in polymer blind pathways and presents comprehensive preventive measures.

Causes of Sanding in Polymer Blind Pathways

The primary reason for sanding in polymer blind pathways lies in the material composition and installation process. Inadequate resin-to-aggregate bonding, improper material ratios, and insufficient surface preparation can all contribute to this issue. Additionally, environmental factors such as temperature fluctuations, humidity, and exposure to ultraviolet radiation can accelerate the wear and tear process.

Comprehensive Preventive Measures

To effectively prevent sanding in polymer blind pathways, a multifaceted approach involving material optimization, installation techniques, and maintenance management is essential.

1. Material Optimization

High-Solid Epoxy Resin: Using high-solid epoxy resin (with a solid content of ≥95%) ensures better bonding and durability.

Aggregate Ratio: Controlling the aggregate ratio (65-70% by mass) allows the resin to fully encapsulate the aggregates.

Additives: Incorporating coupling agents (e.g., KH-550 at a dosage of 0.5-1%) enhances the bonding strength between the resin and aggregates. Adding short-cut basalt fibers or polypropylene acrylonitrile fibers boosts tensile strength and crack resistance.

2. Surface Preparation and Bonding Enhancement

Cleaning the Substrate: Employing shot blasting machines or high-pressure water guns (with a pressure of ≥15 MPa) to remove surface laitance and expose a hard aggregate surface.

Bonding Agent Application: Applying a two-component epoxy bonding agent (with a thickness of 0.2-0.3 mm and a penetration depth of >2 mm) increases bond strength to ≥2.5 MPa.

3. Installation Techniques

Mixing and Application: Using planetary mixers (operating at 30-50 r/min) to ensure uniform aggregate dispersion and adequate mixing time (≥8 minutes). Vacuum degassing (at a vacuum level of -0.08 MPa for 2 minutes) removes bubbles and reduces porosity.

Layering: Applying a pure resin layer (1-2 mm thick) as the first layer, followed by a blind aggregate layer (4-6 mm thick) after the resin layer has cured (surface drying in about 4 hours).

4. Environmental Control and Curing

Environmental Conditions: Maintaining an ambient humidity of 50-70% and a temperature of 15-30°C during installation to avoid adverse effects from wind or direct sunlight.

Curing Management: Using ice water (≤10°C) for mixing in high temperatures to slow down the curing process. Covering the surface with plastic film to maintain humidity (≥90%) and temperature (20-25°C for the first 24 hours, gradually increasing to 30°C over the next 48 hours).

5. Post-Installation Care and Maintenance

Curing Duration: Allowing a 7-day curing period before applying a wear-resistant protective layer of two-component aliphatic polyurethane varnish (80-100 μm thick).

Inspection and Repairs: Regularly inspecting the pathways for signs of wear or damage and conducting timely repairs to prevent further deterioration.

Conclusion

By adopting these systematic preventive measures, the issue of sanding in polymer blind pathways can be effectively mitigated. Proper material selection, rigorous installation procedures, and diligent maintenance practices will ensure the long-term functionality and durability of these vital accessibility features. The ultimate goal is to provide safe, reliable, and visually distinctive pathways for visually impaired individuals, thereby enhancing their overall mobility and independence.