Product Description
STRUX® 90/40 is a unique, high strength, high modulus synthetic macro fibre reinforcement that is added to ready-mix and precast concrete at the batching stage. STRUX® 90/40 controls drying shrinkage cracking, so can be used as an alternative to steel fabric and steel fibre reinforcement. STRUX® 90/40 conforms to EN 14889-2, Fibres for concrete - Part 2: Polymer fibres - Definitions, specifications and conformity.
Advantages
- Controls drying shrinkage cracking by controlling the propagation of micro-cracking - improves toughness and durability of concrete.
- Can be used as an alternative to steel fabric reinforcement and steel fibre reinforcement.
- Uniformly distributed throughout the concrete matrix - no risk of incorrect steel fabric reinforcement placement.
- Improves residual flexural strength, impact and fatigue resistance of concrete - Re,3 values in excess of 30% can be reliably achieved (see Concrete Society Technical Report 34, 3rd Edition).
- Removes a site process so saves time on construction programme.
- No steel fabric storage, movement or crane costs.
- No risk of injuries from moving and installing steel fabric reinforcement.
- Ready-mix concrete truck can back up and freely discharge concrete, could remove/ reduce pumping costs.
Applications
- Ground bearing floor slabs
- External pavements
- Composite steel deck flooring
- Precast concrete
Note: STRUX® 90/40 is not intended as a substitute for steel reinforcement in any application other than those listed. Always consult relevant national and European codes
Addition Rates
STRUX® 90/40 addition rates are dependent on the specific application. Addition rates are also dependant on the desired hardened concrete properties and will vary between 2.3 to 7.0 kg/m3. Please see STRUX® 90/40 engineering bulletin for detailed information.
Comparison of STRUX® 90/40 and Other Types of Reinforcement
Reinforcement Type |
Reduces |
Provides |
Plastic shrinkage cracking |
Drying shrinkage cracking |
Corrosion risk |
Freeze/thaw damage |
Safe easy handling |
Quick, well controlled installation |
Post– crack load carrying capacity |
Polypropylene
“Micro” fibres |
+ |
- |
+ |
+/- |
+ |
+ |
- |
Steel fibres |
- |
+ |
- |
- |
- |
+ |
+ |
Steel fabric |
- |
+ |
- |
- |
- |
- |
+ |
STRUX® 90/40 |
+ |
+ |
+ |
- |
+ |
+ |
+ |
+ = positive effect (1) Only if positioned in top third of floor slab
– = no effect (2) Only if positioned in bottom third of floor slab
Mix Design and Mixing Requirements
STRUX® 90/40 may require the use of a superplasticiser such as ADVA® to achieve the required workability. In addition, slight increases in fine aggregate contents may be needed. At dry batch ready-mix plants, add the STRUX® 90/40 bags to the truck before the concrete constituents. STRUX® 90/40 bags are water degradable and will degrade when wetted. At wet batch ready-mix plants, add the STRUX® 90/40 bags to the truck before the concrete constituents. Add the first batch of concrete constituents to the truck SEMIDRY. This will break up the STRUX® 90/40 bags and evenly disperse the fibres. Remember to make up the water content on subsequent batches. After fibre addition, the concrete must be mixed in a drum at the recommended mixing speed for a minimum of 70 revolutions to ensure adequate dispersion. Please contact GCP for further information.
Compatibility
STRUX® 90/40 is compatible with all GCP admixtures. The action of STRUX® 90/40 in concrete is mechanical and will not affect the hydration process of the cement. Each liquid admixture should be added separately to the concrete mix.
Packaging
STRUX® 90/40 is available in 2.3 kg concrete-ready bags.
Technical Data
STRUX® 90/40 |
Specific Gravity (20°C) |
0.92 |
Absorption |
None |
Modulus of Elasticity |
9.5GPa |
Tensile Strength |
620 MPa. |
Melting Point |
160°C |
Ignition Point |
590°C |
Alkali, Acid & Salt Resistance |
High |
Effect of STRUX® 90/40 Dosage on Residual Strength
Note: These curves are based on averages of several beam tests. The toughness performance will depend on the concrete mix design used
STRUX® 90/40 dosage rate (kg/m3) |
fe,3 (MPa) |
Re,3 (%) |
3.8 |
1.95 |
38% |
4.6 |
2.40 |
46% |
5.4 |
2.75 |
54% |
Note:
These figures (fe,3 and Re,3) are indicative of the performance of concrete mixes containing STRUX® 90/40 but they will vary depending on the hardened properties of the concrete. It is reasonable to expect higher figures when tested in other concrete mixes
Note:
The addition of STRUX® 90/40 fibres, to control plastic shrinkage cracking, does not negate the need for appropriate and efficient curing techniques.