chopped fiber eng (short)

www.basalt-fibers.com 1

Basalt Chopped Fiber

Basalt Fibers LTD.

New brand TURBOBUILD-24-300 in concrete reinforcement segment

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Types of chopped fibers used in concrete reinforcement

Fibers used in fibrous concrete are divided into the following groups:

• Metal fibers• Chemical fibers (polypropylene, polyacrylonitrile, polyethylene and etc.)• Mineral fibers (AR glass and Basalt fiber)• Carbon fibers• Natural fibers

To represent clearly the differences between above listed fiber’s and their effectiveness for use they should be defined by their physical and chemical parameters (comparison and compatibility). Also defining concrete resistance facilitating factors towards external conditions could improve concrete technical parameters.

www.basalt-fibers.com

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Comparative table of physical and chemical parameters of fibers used for concrete reinforcement

TypeThermal

Conductivity, w/mk

Unit weight m/cm3

Thermalexpansion coefficient,

m/m0kX10-6

Elongationc o e ffi c i e

n t %E-module,

GPaAdhesiveness

in matrixChemicalstability

FiberDiameter,

µ

Heat resistance

Mechanical strength,

MPa

Steel 45 - 230 7-8 10-17 13-21 110-210 bad average 650-800 450-1000

Chemical 0,08-0,5 1,05-1,4 25-130 10-1000 1,2-4,0 bad high 30-50 70-280 25-600

Mineral 0,03-0,04 2,5-2,8 4,5-5,5 3,0-5,3 73-110 best high 6-21 (-270)-(+800) 3300-4800

Carbon22-102 1,7-1,9 5-7 1,5-2,0 200-600 bad high 5-15 300-2300 2200-7200

Natural 0,042 1,5 3-5 7-8 5 average low 10-25 140-160 250-390

Concrete 0,17-2,33 2,2-2,5 10-15 0,2(decrease) 15-40 average (-60)-(+200) 0,8-2,8

Table 1


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In comparison with matrix, the metal fibers sharply high thermal conductivity coefficient and elongation percentage (in terms of large amplitude changes in temperature) create internal destructive forces, which contribute to superficial decay process of reinforced concrete. That is why, it is recommended to place reinforcement deep below the surface of the construction element.

In order to get fibrous concrete characteristics - 15kg metal fibers need to be added to 1m³ concrete due to the high unit weight of metal and large diameter of elementary fiber, which finally causes the price increase of concrete. This obvious disadvantage of metal fiber makes it less preferred in comparison to other reinforcement fibers and eliminates its indicator of high modulus of elasticity.

For having high elongation percentage and low unit weight chemical fibers are prone to concentrate mostly on the concrete surface, which doesn’t further to improvement of elasticity parameters in concrete. Therefore, this type of fibers are used only for surface cracks elimination. www.basalt-fibers.com

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Specific points

Mineral fibers and carbons show the best results when obtaining techno-economic impacts of fibrous concrete, but carbon fibers show up the negative indicator of adhesiveness and high thermal conductivity coefficient (due to which concrete heats-up in depth) in comparison with concrete. Moreover, the carbon filament has a notably high sell price. Therefore, despite having the highest elasticity modulus and the best chemical stability in concrete it has the most expensive price for fibrous concrete production (constriction elements designed on the basis of carbon fiber show the best bending strength parameters).

Having good adhesive properties in concrete, mineral fibers reduce the effect of concrete elastic shrinkage. Usually, special organic additives are used to reduce elastic shrinkage effect of concrete, but this causes worsening of concrete strength parameters by 10-20%!


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Metal fibers effect on concrete parameters

Positive effect:• Thermal expansion coefficient (good);• Chemical stability

(medium);• High rate of elasticity

module.

Negative effect:

• Thermal conductivity;• Unit weight;• Large diameter of fiber;• Adhesiveness.


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Chemical fiber effect on concrete parameters

Positive:• Chemical stability.

Negative:

• High thermal conductivity; Lower unit weight, than of concrete;

• High thermal expansion coefficient;

• High elongation coefficient;• Low elasticity modulus;• No-adherent in concrete;• Large fiber diameter;• Low heat resistance;• Inefficient mechanical strength.


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Carbon fiber effect on concrete parameters

Positive:• Unit weight - close to that

of concrete;• Low elongation %;• Best elasticity modulus;• Best chemical stability;• Small fiber diameter;• Best thermal resistance;• Best mechanical stability.

Negative:• High thermal conductivity;• No-adherent in concrete;• A very high price.


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Mineral fiber effect on concrete parameters

Positive:• Low thermal conductivity;• Unit weight is identical to concrete;• Thermal expansion coefficient

close to that of concrete• Low elongation %;• Best adhesiveness in concrete;• Good chemical stability;• Small fiber diameter;• A wide range of thermal resistance;• Good mechanical strength.

Negative:


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Mineral fibers (AR-glass, Basalt fiber) effect comparative analysis in concrete reinforcement

Mineral fibers have absolutely positive influence and good compatibility with concrete compared to all other types of concrete reinforcement fibers.

It’s almost two decades, that in the world construction market is actively used one type of chemically stable glass fiber in especially high alkali concrete solutions (pH13) to which zirconium dioxide (ZrO2) is added.

As for natural mineral fiber – Basalt Fiber- it is being used in construction for several years. It’s only in the last decade that extensive researches and tests have been conducted on this product with a view to its application in building sector.


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The main factor, for chemical stability in mineral fiber reinforced concretes, is the presence of heavy metal oxides in its molecular structure, which prevent mineral fiber structure and the strength determiner SiO2 from alkali leaching (silicon dioxide) in high pH concrete solution.

Number of metal molecules in the fiber molecular structure with respect to thousand molecules of SiO2

Table 2

Oxides AR-glass Basalt fiber

Al2O3 2 78

Fe2O3 0,42 162

ZRO2 161

Sum 163,42 240


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Comparison of physical and mechanical parameters of mineral fibers with respect to the concrete (have equal importance).

Table 3

Parameters AR-glass Basalt fiber Concrete

Thermal expansion coefficient, m/m⁰K*10¯6

2 8 10

Elongation % 4,7 3,15 Elasticmodulus, GPa 70 110

Temperature resistance, ˚C –60 +500 –260 +700

Mechanicalstrength , MPa 3300 4800

Comparison of these two types of fibers show us clearly the expected better effect of basalt fiber in concrete products, when comparing to AR-glass. This makes the basalt chopped fiber more desirable product to modern construction technologies.


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Significant effectIn addition to technical advantages, it is also important to point out, that much more elementary basalt fibers are spread in concrete matrix contributing to the binding process, than in case of other type of fibers.

Fiber properties Metal fiber Polypropylene fiber Basalt fiber

Length 24mm Length 24mm Length 24mm

Diameter Ø0.62mm Diameter Ø0.52mm Diameter Ø14 mcrn.

Amount 30kg/m³ Amount 7kg/m³ Amount 3kg/m³

Amount of fiber in 1 m³ concrete 0.6 mln 1.7 mln 300 mln

That large amount of chopped basalt fiber determine faster formation of cement stone in concrete.

Therefore, the existence of 300 million alkali resistant elementary basalt fibers in 1 m ³ of concrete, unlike other reinforcement fibers, enable by 2 ÷ 3 times intense binding process during continuous concreting, without using expensive accelerators.

Table 4


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Additional comments regarding the certification of basalt chopped fiber

In relation to fiber reinforced concretes and cements basalt chopped fiber refer to alkali resistant mineral fiber class which is defined by C1666/C1666M-08 standard and the following important parameters have to be emphasized :Table 5

Basalt fiber producer “basalt

fibers” LTDStandard norms Standard

1. Tensile strength 1,3 Gpa 1,0÷1,7 GPaASTM P2256

ISO3341JISR3420

2. Maintenance of strength(min. pointer 96 hrs in water 80 °C (176 °F))

380MPa

≥350 MPaFor

complete/integral fibers

ASTM P4963ISO 1887JISR 3420EN14849


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Some research information on advantages of the basalt chopped fiber usage in concrete reinforcement and

its technical parameters improvement

The fact that we are proposing the basalt fiber to customers is based on several years’ researches and tests which were conducted also on our products at one of the leading institutes in Europe. In details:

• Cement grouts are used for oil well completion which are subjected to high pressures and temperatures as high as 200˚C. Therefore much attention is paid to their tensile strength, shock resistance and crack resistance. In such conditions usage of mineral fibers is the best and optimal choice and basalt fiber is one of the most attractive alternatives. (R. Felicetti, C Meyer and S. Shimanovich – Department of Civil Engineering and Engineering Mechanics, Columbia University, New York)


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• Basalt fiber has some particular characteristics like: crack resistance, freeze resistance, shock and impact resistance. Thanks to this properties it extends the operation time of concrete.

– Basalt fiber doesn’t have any side effects while mixing, pouring and curing. It improves adhesiveness and prolongs stability of concrete.

– Basalt fiber increases concrete resistance and reduces its fragility, therefore it can be used in roads and bridges construction, so that to improve the quality of concrete. (“Fibers Unlimited” LTD. - Dutch research)

• Test results of Loads on square slab show that, when using 24 mm basalt fibers in 3,5kg/m³ mixes they get effective bending strength - 0,31 N/mm². This index is slightly less than of metal fiber reinforced concrete one - (0,38 N/mm2). (IBU –Trier, Germany)


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Thank You For your kind Attention!!!


chopped fiber eng (short)

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