PolyJet FT Technology: An Innovative Solution for Geotechnical Challenges

In recent years, engineers have increasingly adopted advanced chemical technologies to address complex ground improvement and structural repair challenges. Among the most effective solutions are injection-based expanding polyurethane systems—particularly the PolyJet FT system.

This technology is widely recognized within the industry as a reliable and innovative solution: it enables fast execution, delivers consistent and durable results, operates within controlled parameters, and meets environmental safety requirements.

This article outlines the core principles of the technology, its physico-chemical properties, implementation process, and key benefits for developers and contractors.

The development of injection polyurethane systems has been driven by advances in high-reactivity foaming catalysts and increasingly stringent safety standards. PolyJet FT is the result of combined research by Russian and international laboratories, as well as practical experience gained from infrastructure, industrial, and civil engineering projects.

PolyJet FT is a two-component polyurethane system specifically designed for geotechnical applications. It performs reliably in challenging climatic and hydrogeological conditions, offering stable material properties and rapid reaction times.

PolyJet FT is based on the controlled mixing of two components—polyol and isocyanate—which initiates a rapid foaming reaction. The resulting cellular structure distributes loads evenly, absorbs vibrations, and stabilizes the surrounding soil.

• Density: 1.1–1.2 g/cm³
• Viscosity: 200–250 mPa·s
• Expansion ratio: up to 32×
• Reaction initiation time: approximately 5 seconds
• Operating temperature range: +3 to +40 °C

The material demonstrates strong adhesion, resistance to biological degradation, and stability when exposed to salts, acids, and alkalis. It does not release hazardous substances into the soil or atmosphere.

Successful application of the technology requires a structured workflow:

1. Site Investigation

• Visual assessment of ground conditions
• Instrumental testing (dynamic and static probing, ground-penetrating radar, and other minimally invasive methods)
• Plate load tests and laboratory analysis
• Identification of zones requiring improvement

2. Injection Design

• Layout of injection points
• Estimation of required material volumes
• Modelling of expected performance using engineering software

3. Equipment Preparation
Specialized equipment is used, including injection pumps, dosing systems, and mixing units. Flow rate and pressure are controlled to ensure uniform distribution of the material.

4. Injection Works

• Drilling of small-diameter holes (typically 10–20 mm)
• Injection of PolyJet FT in accordance with design parameters
• Continuous monitoring of pressure, temperature, and reaction behavior

5. Verification and Quality Control
Within hours of completion, performance is verified using:

• Ground-penetrating radar
• Static and dynamic testing
• Geotechnical monitoring methods

Compared to traditional methods, PolyJet FT offers several key advantages:

• Fast execution: Projects can be completed within hours or days
• Minimal disruption: No need to stop operations or dismantle structures
• Long service life (30–40 years): Material properties remain stable over time
• Environmental compliance: Meets applicable safety and environmental standards
• Precision: Allows localized treatment of specific problem areas
• Accessibility: Suitable for confined or hard-to-reach areas without heavy equipment
• Compatibility: Easily integrated into existing design and construction practices

PolyJet FT has been successfully used in a wide range of projects:

• Industrial floor rehabilitation: Restoring levels without dismantling
• Void filling beneath foundations: Recovering load-bearing capacity
• Sealing of tunnels and utility structures: Eliminating leaks and preventing erosion
• Control of groundwater inflow in excavations: Preventing water ingress and soil washout, ensuring safe working conditions

Additional case studies are available upon request.

PolyJet FT has undergone all required testing and holds relevant certifications, including environmental and health approvals. Injection works are carried out in accordance with applicable standards such as STO NOSTROY 2.3.18-2011 and SP 22.13330.2016.

The available technical documentation supports the use of this technology in projects of any scale—from private developments to major infrastructure works.

PolyJet FT is a proven and effective solution for ground improvement and structural stabilization. It provides a fast, reliable, and cost-efficient approach to addressing weak or unstable soils.

Recommendation:
Consider incorporating PolyJet FT into design solutions for both new construction and rehabilitation projects, particularly where minimal disruption and long-term performance are critical.