Solutions for Plastic Shrinkage Cracking

Since their development and launch in 1970, Alkali Resistant glass fibers have been used in more than 120countries for the reinforcement of cement and concrete products. They are best known for their use infactory-produced GRC elements (Glass fiber Reinforced Concrete), but the range of Anti-Crak® fibres hasbeen developed to target the use of AR glass fibres in concrete and mortar applications for use in flooring andpavements, precast concrete, screeds and renders.

WHY GLASS FIBER?

With its total affinity to cementitious composites, high tensile strength and modulus of elasticity, glass fibersare an ideal reinforcement for concrete, already efficient at very early stages of the cracking process.

Moreover, glass fiber density is similar to concrete, which allows a quick dispersion for very short mixingtimes, with minimum balling risk and exceptionally low influence on workability.

PRODUCT APPLICATION

Anti-Crak® HD fibers have been developed to satisfy different performance requirements, especially theprevention of plastic shrinkage cracking. Anti-Crak® HD product is a monofilament reinforcementrepresenting more than 200 million filaments per kg. The high elastic modulus of Anti-Crak® HD fibers(72 GPa) and their excellent bond into a mineral matrix makes them an ideal reinforcement in plastic andhardened concrete. With a specific gravity similar to that of the aggregate they will neither float or sink in themix, giving excellent dispersed reinforcement.

Testing done by Owens Corning on glass fiber.

Raw Material DensityElastic Modulus

(GPa)Tensile Strength

(MPa)

Concrete 2.4 30 - 40 3 - 4

Cem-FIL® glassPolypropylene

2.70.9

721.5 - 9.5

1700100 - 500

0.3 - 1.0 kg/m3

Usual dosage = 0.6 kg/m3Addition rate

Control of plastic shrinkage crackingPrimary Benefit

High dispersion

>200 million filaments/Kg

Increased flexural strength at early ages

Reduced permeability and bleeding

No matrix modification needed(with water or plasticizer)

Additional Benefits

TRADITION AND QUALITY SINCE 1885

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Anti-Crak® HD fibers have been successfully used to prevent plastic shrinkage cracking inmany applications such as residential, commercial, and industrial floors, as well as outdoorflatworks and self-leveling screeds for housing, either with conventional reinforcement ortaking advantage of the synergies with other fibers of the Anti-Crak® range.

Residential slab-on-ground Car dealership – self-leveling screed Industrial floor

Outdoor walkway Self-leveling screed

Distributed in Italy by:

GAVAZZI TESSUTI TECNICI S.p.A. Socio Unico

Via Gavazzi 3 ● IT-23801 Calolziocorte (LC) Italy

Tel. +39 0341 641051 – Fax +39 0341 633004

e-mail: sales@gavazzispa.it – www.gavazzispa.it

This information and data contained herein is offered solely as a guide in the selection of reinforcement. The information contained in this publication is based on actual laboratory data andfield test experience. We believe this information to be reliable, but do not guarantee its applicability to the user’s process or assume any responsibility or liability arising out of its use orperformance. The user agrees to be responsible for thoroughly testing any application to determine its suitability before committing to production. It is important for the user to determinethe properties of its own commercial compounds when using this or any other reinforcement. Because of numerous factors affecting results, we make no warranty of any kind, express orimplied, including those of merchantability and fitness for a particular purpose. Statements in this publication shall not be construed as representations or warranties or as inducements toinfringe any patent or violate any law safety code or insurance regulation.

Owens Corning reserves the right to modify this document without prior notice. © 2013 Owens Corning. All Rights Reserved.Pub number: 10018581_GA. Anti-Crak HD_GAVAZZI distributor_04_2013_REV0

PLASTIC SHRINKAGE CRACKING

Resistance to plastic shrinkage cracking requires a large number of reinforcingelements with a good bond to the matrix. With more than 200 million monofilamentsof 14 µm diameter per kilogram, HD fibers can drastically reduce/prevent plasticshrinkage cracking in concrete (ASTM C 1579).

Anti-Crak® HD 12mm product @ 0.6 kg/m3

Solution to control plastic shrinkage cracking in combination with standard curingpractices, in flooring applications under severe environmental conditions.

Plain concrete HD120.6 kg/m3

42

200

78%Crack

reduction

ASTM C1579-06

Typical crack patternfor plain concrete

Obtained on concrete class C25(4000 PSI) – workability S2

Coarse aggregate 20mm (3/4 in.)

Cra

ckin

g va

lue (

mm

2)

Testing results from trials done in the US by STRORK Materials Technology, October 2002 – according to Section 4.1.2 of ICBO Acceptance Criteria for Synthetic Fiber-Reinforced Concrete (AC32).

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