Pre-StiRex

Q: What material is used in PT duct?

PE or PP materials are used for PT Duct.

Q: What bend radius can the PT Duct sustain?

Upto 85 mm - 1500 mm Above 85 mm - 1800 mm

Pre-StiRex

Corrugated PE Ducts for Pre-Stressing & Post-Tensioning Tendors

Pre-StiRex Corrugated Sheathing ducts are made from high-density polyethylene (HDPE), and serve a distinct purpose in the realm of internal bonded post-tensioning of tendons in pre-stressed concrete. These ducts find application in various projects, including flyovers, bridges, nuclear containments, offshore platforms, via ducts, underpasses, tunnels, and more.

The use of flat ducts becomes particularly popular in construction sectors where the utilization of round section ducts in post-tensioned slabs is impractical due to constraints posed by the slab thickness. These HDPE ducts provide an effective solution, allowing for efficient tendon placement and tensioning within the concrete structures. They contribute to the overall strength and durability of the construction, ensuring optimal performance in challenging environments and critical infrastructure projects.

Features & Benefits

Corrosion protection
Helps electrical monitoring of tendons
Good weathering resistance
Good impact and compression strength
Good bond with concrete
Speedy installation due to fewer joints
Chemically inert
Environment friendly
High stiffness and flexibility
Even when bent, cross section of the duct retains its circularity
Wobble co-efficient observed k = 0.00116/M
Friction co-efficient observed u = 0.10 to 0.14

Fields of Application

Flyovers
Bridges
Nuclear Containment Domes

Standards & Specifications

FIB (International Federation for Structural Concrete) Bulletin 7 & 75
IRC (Indian Roads Congress) 112:2020 & IRC 18:2000
NPCIL (Nuclear Power Corporation of India) Spec. No. PP/M/1721
IRS (Indian Railway Standard) CBC (Concrete Bride Code) & Corrigendum Slip No. 6

Available Sizes

ID – 51, 75, 84, 95, 107 mm
Thickness – 2.0, 2.3, 2.5 & 3.0 mm
Length – 6 m in straight duct and 50, 100, 150 m in coil form

FAQs

What material is used in PT duct?

PE OR PP materials are used for PT Duct.

What is the shape of PT Duct?

The duct used in post-tensioning can have either continuous circular corrugation or intermittent circular corrugation based on whether it is for round or flat profiles. Continuous corrugation is used for round profiles, while intermittent corrugation is suitable for flat profiles. The choice depends on the project requirements and structure shape.

What is the application of PT duct?

The PT Ducts are used for protecting tendons from corrosion.

What Is the Friction Coefficient µ?

µ = 0.10 to 0.14

Is Astral PT Duct UV stabilized?

Yes, a minimum carbon content of ≥ 2% is used for UV stabilization in ducts, providing protection against sunlight and enhancing their durability.

What Is significance of Ducts for bonded Post-Tensioning?

Ducts are integral components of bonded post-tensioning systems, serving the purpose of safeguarding the post-tensioning strands once construction is complete. These ducts provide a protective enclosure for the strands, ensuring their long-term performance and preserving their structural integrity. By housing the post-tensioning strands within the ducts, the potential damage from external elements is minimized, leading to a safer and more reliable post-tensioning system.

What pressure Can the PT Ducts Sustain?

0.5 Bar water pressure.

What is the purpose of bond test?

To confirm the bond between the duct and grout, pull-out tests can be conducted. This involves applying a force to the duct embedded in grout and measuring the resistance or load required for the duct to be pulled out. This test helps determine the strength of the bond and ensures that the grout effectively adheres to the duct surface. For assessing the bond between the duct and concrete, bond strength tests can be performed. These tests evaluate the adhesion between the duct and the surrounding concrete by subjecting them to shear or pull-out forces. They provide information on the bond strength, ensuring that the duct is securely anchored within the concrete structure. By conducting these tests, engineers and construction professionals can verify the bond characteristics and take necessary measures to ensure the integrity and performance of the bonded post-tensioning system.

What bend radius can the PT Duct sustain?

"upto 85 mm - 1500 mm Above 85 mm - 1800 mm"

Which connector to be used for PT Duct jointing?

Mostly heat shrink sleeves are used for PT duct joining.