Qulity and performance:
The use of straw to reinforce bricks dates back to Egyptian time when horse hair was commonly used to reinforce lime/sand plaster until 1950s,and asbestos, until recently
was used for around 100 years as a cement reinforcement for sheets or fiber-proofing products.
Is polypropylene 21st century straw?
Polypropylene is a relatively modern product with a large molcule built up by a repetition of small, simple chemical units until a polymer chain is formed. Polypropylene fibers as a secondary reinforcement, nowadays, are being used extensively throughout the world in all types of constructional concrete. Firstly, they have been proven as an effective method of controlling troublesome shrinkage in concrete.
Then, after curing, the presence of fibers increases concrete long - term durability and toughness. Our monofilament fibers, which are produced from 100%
virgin homopolymer polypropylene, comply with the requirements of ASTM - C1116 and are developed as a
crack - controlling additive for cementitious materials.
It is available as monofilament 12 and 19 mm in length
for concrete reinforcement and 12mm in length for
plaster and mortar.
PP fibers are true monofilaments that totally disperse into the concrete mixing when added at the batch plant or at the job site.
Basic Properties of Polypropylene Fibers |
PP fibers have several unique properties that make them especially suited
for use in concrete. They are chemically inert and stable in the alkaline environment of concrete, with a relatively high melting point and low-cost. They do not absorb water due to a hydrophobic surface which prevents
any chemical adhesion with the concrete matrix, are non-corrosive and compatible with all types of cements and admixtures. They do not affect concrete mix selection, pumpability, placing, setting time or finishing characteristics.
Technical Properties:
| Appearance: |
natural white |
| Specific gravity: |
0.91 gr/cm3 |
Diameter
(din 53816): |
18 microns and higher (based on fiber usage and client request) |
| Tensile strength: |
350 MPA |
| Melting range: |
160 c0 – 165 c0 |
| OPU: |
0.5% (Method, Henkel) |
| Crimp waves/cm: |
0 crimps/cm |
| Thermal conductivity: |
low |
| Electrical conductivity: |
low |
| Salt,acids and alkaline resistance: |
high |
|
Advantages:
 
Improves:
-
Impact and abrasion resistance
-
Shear strength and resistance to tensile splitting
-
Durability and toughness
-
Impact, shatter and abrasion resistance
PLUS:
- Easy to use and cost effective-no labor cost
- Rust proof & corrosion resistant
- Low thermal conductivity
- Retards evaporation (bleed water reduction)
- extends hydration process
Reduces
- Shrinkage and micro- cracking
- Permeability of concrete
- Construction cycle time in precast concrete
- Rebound for use in shotcrete
Application:
It is mainly used as ready mix concrete, precast concrete, shotcrete screeds, rendering mortars, plasters, etc.
The principal uses of fibers include:
Industrial flooring, pavements, asbestos cement pipes and sheets, foundation of cellar walls, silo construction, roads, highways, tunnels, bridges, waterways, kerbs, water retaining structures, etc.
 
Conerete permeability tests (test result):
Samples:
. cement: 6kg
. sand: 20 kg
. course aggregate: 15.2 kg
. medium aggregate: 3.2 kg
. water: 3 kg
. superplasticiser: 30 gr (ASTM C-494 Type F)
fibers: |
a) 0 g pp fibers 19mm |
| b) 18 gr pp fibers 19mm |
Test Result:
ASTM slump: |
a) Time 0': 20 cm, 45': 16cm |
| b) Time 0': 19 cm, 45': 14cm |
Air content: (DIN 1048) |
a) l .8 % |
| b) 1.7 %
|
Compressive strength 15x15x15 cm cubes:
| a) 3 days: 24.8 MPA, 7d: 30.2 MPA, 28d: 36.4 MPA |
| b) 3days: 25.3 MPA, 7d: 29.7 MPA, 28d: 36.8 MPA |
Flexural strength 4x4x12 equiv. Mortar:
| a) 28days: 4 MPA |
| b) 28days: 4.8 MPA
|
|
Instructions:
·The PP fibers should be mixed with the concrete only after the concrete is produced and very important it should immediately be used with only very little movements on the truck; otherwise, the sand will ground the fibers.
·The length of the fibers must be min.1,5 times the diameter of the sand particle- This is mainly true for the fine sands. With coarse sand particle, this comes down to 1-1.2 times.
·Mixing time of fibers always to be as short as possible in order not to damage the fibers.
·If transport from mixing plant to construction site is more than 2.5 hours, then the mixing ratio of the fibers should take place on the construction site.
·The more PP fibers are mixed into the concrete, the better quality of construction- anti micro cracks will be provided.
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