Post Tensioning System

PT Duct an effective method for corrosion protection of internal post tensioning tendons; It provides corrosion resistance by complete encapsulation of the tensions. The usage of plastic ducts ad corrosion protection started in the early 1990's initially HDPE ducts were used then it evolved based on projects actual experiences where new designs and material I.E Polypropylene (PP) was used to achieve better performance.

HDPE & PP both are thermoplastic material used in the production of PT ducts; they both have similar basic properties. HDPE in comparison to PP material have better flexibility, better impact strength and easier to handle and weld whereas PP material have better stiffness, can withstand higher temperatures and have better appraising resistance. KAI produce PT-duct using both type of material. End of 2002 Bulletin 7 was establishes to standardize the requirements of PT-ducts, KAI produce PT-Duct that adheres to bulletin 7 requirements for PP & HDPE material.

PP Ducts for Post tensioning application

All ducts are produce according to the following standards

  • AASHTI LRFD Bridge Constructing Specification for internal, external . HDPE and PP ducts.
  • Raw material classifieds by ASTM D41010, ASTM D3350
Corrosion Protection for Post Tensioning Strands for
Flyovers and bridges
Nuclear containments
Offshore platforms
Via dusts
Under passes
Structures exposed to high humidity
Waste water treatment plants
Acid tanks
Better corrosion protection
Improved tendon fatigue performance
Reduced tendon friction
Reduce construction time with the help of post-tensioning slabs(Flat Ducts)

Couplers for PT Ducts


The couplers are manufactured to suit our PT Ducts,

Raw material

The ducts are manufactured from polypropylene resin (PP)

Flyover& Bridges, Offshore platforms structures exposed to high humidity
Under passes, Tunnels

Geometrical Properties

Suitable to KAI PP PT Duct;
Nominal Size
Nominal outside
diameter (mm)
Nominnal thickness
Nominal length
76 101 5.0 150
85 111 5.5 150
100 126 5.0 150
115 142 4.5 200
130 161 5.5 200
144 181 5.5 200

Physical Properties

Description Test method Limits Unit
Density@23C (kg/m3) ASTM D792 900 Kg/m3
Deflection Temperature at 455KPa ASTM D648 80-120 C
lzod impact @23C ASTM D256 300-700 J/m
Flexural mmodules @ 103mm/min ASTM D790 750-1.000 MPa
130 161 5.5 200
Tensile stress at yield @50mm/min ASTM D638 20-30 MPa

Round Polypropylene PT Duct

Diameter Size Inside Diameter of the dust
Outside Diameter of the duct
T-Wall thickness
Length Jointing Packing
Local Overseas
76 74+1.5 90+-1.5 2.5+-0.25 6m+-1% and
  • socket coupler
  • shrink Sleeve
  • butt Welding
11.8ML Loose
85 85±1.5 101±1.5 2.5±0.25 12m x 25nos
100 99+1.5 114+-1.5 3.0+-0.25
115 113+-1.5 133+-1.5 3.0+-0.25 12m x 20nos
144 143+1.5 169+-1.5 3.25+-0.25 12m x 10nos
Raw material   Color  
Polypropylene   white  

Physical properties

Description Test Method Value Unit
Tensile Strength at yield ASTM D638 20-30 MPa
Deflection Temperature at 455Ka ASTM D648 80-120 *c

Round polypropylene PT Duct

Sectional Elevation View "D" "D"

Pt Duct Round
Dn 76

Pt Duct Round
Dn 85

Pt Duct Round
Dn 100

Pt Duct Round
Dn 115

Pt Duct Round
Dn 130

Pt Duct Round
Dn 144


Diameter size Inside Diameter of duct
Outside Diameter of the duct
t- Wall thickness
Length Jointing Packing
73*22 72+-1.0 19+-1.0 88+-1.0/35+-1.0 2.0+- 0.25/2.0+-.025 6m+-1% and
Socket coupler Coil 200m
90/22 86+-1.0 190+-1 102+-1.0/35+-1.0 2.0+-0.25 Shrink sleeve Butt welding
Raw material   Color  
Polypropylene   white  

Physical properties

Description Test method Value Unit
Tensile Strength at yield ASTM D638 20-30 MPa
Deflection Temperature at 445KPa ASTM D648 80-120 *C


Pt Duct Flat
Dn 73x22

Pt Duct Flat
Dn 90x22

Main Projects

Project name Country Supply Duration PT Products
Jahra Road
Kuwait 2014 --PP Internal Duct
Jamal Abdul Nasser Road
Kuwait 2015 --PP Internal Duct
Jaber Al Ahmad Al Sabah Causeway
Kuwait 2015 --PP Internal Duct
Jaber Al Ahmad Road Crossing
Kuwait 2015 --PP Internal Duct
Metro Project K.S.A 2015 --PP Internal Duct
Al-Bedaa Road
Kuwait 2017 --PP Internal Duct
Mutlaa Phase Kuwait 2018 --PP Internal Duct
Development of Nuwaseeb Road
Kuwait 2018 --PP Internal Duct
Jamal Abdul Nasser Road
Kuwait 2018 --PP Internal Duct
Saad Al-Abdullah Road
Kuwait 2018 --PP Internal Duct
Al-Zour Colander
Kuwait 2018 --PP Internal Duct
Development of south Al-Surra Road
Kuwait 2018 --PP Internal Duct
Al-Salmi & Kabad
Kuwait 2019 --PP Internal Duct