Fibers as Structural Element for the Reinforcement of Concrete.
Te c h n i c a l M a n u a l
INDEX
1 - Introduction 2 - Fibers as structural element for the reinforcement of concrete 2.1 - Historical review of the technology of incorporating fibers in concrete 2.2 - Concept of reinforcement of concrete through fibers 2.3 - Fiber types – Classification of current commercial fibers in function of the raw material. Organic fibers (natural and synthetic polymers) and inorganic fibers (metallic) 2.4 - Steel fibers. Classification upon geometrical, physical, chemical, mechanical charcharacteristics and production process 2.5 - Synthetic and natural fibers. Classification based upon geometric, physical, chemical, mechanical characteristics and product production ion process 2.6 - Current standard situation 2.7 - List of MACCAFERRI’s fibers. Classification of MACCAFERRI’s fibers
3 - Fiber reinforced concrete; Basic elements for the structural project 3.1 - Mechanical characterization of fiber reinforced concrete. Most important resistant features 3.2 - Structural compatibility of fiber reinforced concrete elements 3.3 - Instructions for the design of fiber reinforced concrete frameworks 3.4 - Current standard situation
4 - Design and detailed considerations for concrete mixtures; mixtures; advice for fibers incorporation into the mixture 4. 1 - Concrete Concrete,, technological aspects for its formulation 4.2 - Advice for the incorporation of fibers in concrete 4.3 - Advice for insertion of fibers into concretes for prefabricated elements 4.4 - Recommendations for the use of fibers into wet and dry sprayed concretes 4.5 - Concrete admixtures and their compatibility of use in fiber reinforced concrete 4.6 - Typical applications of the structural and not structural fiber reinforced concrete 4.7 - Current standard situation
5 - Applications of fiber-reinforced concrete: tunnels, design of the pre-lining and of the final lining 5.1 - Conventionally bored tunnels and tunnels excavated through TBM 5.2 - Design criteria for tunnel supports and linings 5.3 - Design of supporting structures made of fiber-reinforced shotcrete 5.4 - Design of lining made of fiber fiber-reinforced -reinforced concrete concrete pumped on-site 5.5 - Use of fibers for fire resistance of concrete. Description of fiber mixes, structural and anti-spalling proposal for final linings
INDEX
1 - Introduction 2 - Fibers as structural element for the reinforcement of concrete 2.1 - Historical review of the technology of incorporating fibers in concrete 2.2 - Concept of reinforcement of concrete through fibers 2.3 - Fiber types – Classification of current commercial fibers in function of the raw material. Organic fibers (natural and synthetic polymers) and inorganic fibers (metallic) 2.4 - Steel fibers. Classification upon geometrical, physical, chemical, mechanical charcharacteristics and production process 2.5 - Synthetic and natural fibers. Classification based upon geometric, physical, chemical, mechanical characteristics and product production ion process 2.6 - Current standard situation 2.7 - List of MACCAFERRI’s fibers. Classification of MACCAFERRI’s fibers
3 - Fiber reinforced concrete; Basic elements for the structural project 3.1 - Mechanical characterization of fiber reinforced concrete. Most important resistant features 3.2 - Structural compatibility of fiber reinforced concrete elements 3.3 - Instructions for the design of fiber reinforced concrete frameworks 3.4 - Current standard situation
4 - Design and detailed considerations for concrete mixtures; mixtures; advice for fibers incorporation into the mixture 4. 1 - Concrete Concrete,, technological aspects for its formulation 4.2 - Advice for the incorporation of fibers in concrete 4.3 - Advice for insertion of fibers into concretes for prefabricated elements 4.4 - Recommendations for the use of fibers into wet and dry sprayed concretes 4.5 - Concrete admixtures and their compatibility of use in fiber reinforced concrete 4.6 - Typical applications of the structural and not structural fiber reinforced concrete 4.7 - Current standard situation
5 - Applications of fiber-reinforced concrete: tunnels, design of the pre-lining and of the final lining 5.1 - Conventionally bored tunnels and tunnels excavated through TBM 5.2 - Design criteria for tunnel supports and linings 5.3 - Design of supporting structures made of fiber-reinforced shotcrete 5.4 - Design of lining made of fiber fiber-reinforced -reinforced concrete concrete pumped on-site 5.5 - Use of fibers for fire resistance of concrete. Description of fiber mixes, structural and anti-spalling proposal for final linings
INDEX
5.5.1 - Objective of passive protection of concrete against fire 5.5.2 - Polypropylene and cellulose fibers as passive protection of concrete against fire 5.6 - Quality control of fiber-reinforced concrete in tunnels 5.7 - Current standard situation
6 - Appliances in Fiber reinforced reinforced concrete. Floors design 6.1 - Industrial, harbour, airport, road, and special uses 6.2 - Methodology of conventional design for floors 6.3 - Design of joints in floors 6.4 - Methods of floors design in fiber reinforced concrete 6.5 - Fiber reinforced concrete and the joints design 6.6 - Control of quality in fiber reinforced concrete for floorings 6.7 - Current standard situation
7 - Applications of fiber reinforced concrete: prefabricated elements 7.1 - The use of fiber reinforcement in prefabricated/pre-cast concrete 7.1.1 - Final remarks 7.2 - Design of precast segment in fiber reinforced concrete 7.3 - Examples of applications. Padding panels, prestressed beams, non-structural prefabricated prefabricat ed elements 7.3.1 - Closing panels 7.3.2 - Double T covering prestressed beams 7.3.3 - Structures for flat coverings 7.3.4 - Pre-casted stretched beams 7.3.5 - Different elements 7.4 - SFRC special applications 7.4.1 - Foundation systems 7.4.2 - New potential applications 7.4.2.1 - Structures exposed to earthquakes s 7.4.3 - Flooring covering with metal shaped sheets or precast – metal deck
8. Measuring equipments for Wirand® fibers 8.1 - Equipments for the introduction of fibers into concrete 8.2 - Measuring systems of fibers for shot concrete 8.3 - Measuring systems of fibers for the production of ashlar s 8.4 - Measuring systems of fibers for floorings concrete 8.5 - Measuring systems of organic and polymeric fibers 8.6 - Circular batchers
INDEX
8.6.1 - Description of the machine 8.6.2 - Aim 8.6.3 - Typology 8.6.4 - Principle of working 8.6.5 - Principle of use 8.6.6 - Technical data and main dimensions 8.6.7 - Moving/conveyance 8.6.8 - Necessary electric arrangeme arrangement nt 8.6.9 - Tools and implements necessary to the installation 8.6.10 - Positioning 8.6.11 - Feet fixing 8.6.12 - Eccentric masses adjustment 8.6.13 - Welding operations 8.6.14 - Fibers storage 8.6.15 - Information to gather for the correct configuration of the installation 8.7 - Pneumatic batchers 8.7.1 - Aim 8.7.2 - Typology Typology 8.7.3 - Principle of working 8.7.4 - Principle of use 8.7.5 - DOSOBOX 8.7.6 - SC99/2 8.7.7 - Special machines 8.8 - Personalized machine 9 - Authors 10 - References
1 - Introduction.
The purpose of this manual is to provide general information, criteria and new methodologies for the calculation, project and execution of concrete reinforced works with fibers. They will be presented, therefore, the obtained data of the investigations made by Maccaferri, oriented to the study of the behavior, resistance and efficiency of such structures. The Maccaferri intention is to have new and useful contributions to concrete works reinforced with fibers, helping the consultants and contractors work who act in the segment of structural engineering. For a more detailed analysis on the arguments treated here, we suggest to consult the specific publications that are indicated in the bibliographical references. This manual they will be presented and discussed theoretical foundations, numerical examples of the of the concrete reinforced with fibers applications and details of the use of the Wirand ® metallic fibers and Fibromac ® plastic fibers. Maccaferri is placed to total disposition, to give solution to problems, cradle in its experience, acquired along more than 100 years of existence in all the world.
2 - Fibers as structural element for the reinforcement of concrete.
2.1 - Historical review of the technology of incorporating bers in concrete. The idea of using a fibrous material to provide tensile strength to a material strong in compression but brittle, looses itself in the mists of time; in ancient Egypt straw was added to clay mixtures in order to provide bricks with enhanced flexural resistance, thus providing better handling properties after the bricks had been dried in the sun. Other historical cases of fiber reinforcement exist: plaster reinforced with horsehair, or again with straw in the poorest building conditions, so as to avoid the unsightly occurrence of cracks due to shrinkage, counter-ceilings made of plaster reinforced through reed canes, cement conglomerates fiber-reinforced through asbestos, etc. But the scientific approach to such a problem is definitely more recent. First studies dealing with use of steel fibers and glass fibers in concret e date back to the 1950’s; in the 60’s the first studies concerning fiber reinforced concrete using synthetic fibers appear. Definition of fiber-reinforced concrete (Official Bulletin CNR n.166 part IV): “The purpose of the utilization of fibers within a cement matrix is the formation of a composite material in which the conglomerate, which can already be considered as a composite material that is composed by a litic scaffold dispersed in a matrix of hydrate cement paste, is combined with a reinforcing agent that is made of fibrous material of various nature”.
2.2 - Concept of reinforcement of concrete through fibers. The presence of fibers having adequate tensile strength, and being homogeneously distributed within concrete, builds a micro-scaffolding that, on the one side, demonstrates itself being efficient in counteracting the known phenomenon leading to crack formation due to shrinkage, and, on the other side, leads the concrete’s ductility (1) to become increasingly relevant with increasing strength of the fibers. This provides the concrete with a high toughness (2) as well. As it is known, in the vast majority of currently applied calculation and verification rules, the concrete’s tensile strength is generally neglected in the calculation route, given concrete ’s brittle behaviour. The use of a fiber-reinforced matrix makes it possible to stabilize tensile properties. In this way, the tensile strength can be now be exploited as well between other mechanical properties in the design phase. This highly relevant technical advantage will be reported in details in chapter 3 of the present publication. Given operative difficulties, tensile tests are generally not realized onto the concrete directly. The evaluation of tensile properties, as well as of ductility and toughness, are carried out indi-
Fibers as Structural Element for the Reinforcement of Concrete.
Te c h n i c a l M a n u a l
