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Description / Abstract:
INTRODUCTION
Historical aspects
Since ancient times, fibers have been used to reinforce brittle
materials. Straw was used to reinforce sun-baked bricks, and
horsehair was used to reinforce masonry mortar and plaster. A
pueblo house built around 1540, believed to be the oldest house in
the U.S., is constructed of sun-baked adobe reinforced with straw.
In more recent times, large scale commercial use of asbestos fibers
in a cement paste matrix began with the invention of the Hatschek
process in 1898. Asbestos cement construction products are widely
used throughout the world today. However, primarily due to health
hazards associated with asbestos fibers, alternate fiber types were
introduced throughout the 1960s and 1970s.
In modern times, a wide range of engineering materials
(including ceramics, plastics, cement, and gypsum products)
incorporate fibers to enhance composite properties. The enhanced
properties include tensile strength, compressive strength, elastic
modulus, crack resistance, crack control, durability, fatigue life,
resistance to impact and abrasion, shrinkage, expansion, thermal
characteristics, and fire resistance.
Experimental trials and patents involving the use of
discontinuous steel reinforcing elements—such as nails, wire
segments, and metal chips—to improve the properties of concrete
date from 1910 [1.2]. During the early 1960s in the United States,
the first major investigation was made to evaluate the potential of
steel fibers as a reinforcement for concrete [1.3]. Since then, a
substantial amount of research, development, experimentation, and
industrial application of steel fiber reinforced concrete has
occurred.
Use of glass fibers in concrete was first attempted in the USSR
in the late 1950s [1.4]. It was quickly established that ordinary
glass fibers, such as borosilicate E-glass fibers, are attacked and
eventually destroyed by the alkali in the cement paste.
Considerable development work was directed towards producing a form
of alkali-resistant glass fibers containing zirconia [1.5]. This
led to a considerable number of commercialized products. The
largest use of glass fiber reinforced concrete in the U.S. is
currently for the production of exterior architectural cladding
panels.
Initial attempts at using synthetic fibers (nylon,
polypropylene) were not as successful as those using glass or steel
fibers [1.6, 1.7]. However, better understanding of the concepts
behind fiber reinforcement, new methods of fabrication, and new
types of organic fibers have led researchers to conclude that both
synthetic and natural fibers can successfully reinforce concrete
[1.8, 1.9].
Considerable research, development, and applications of FRC are
taking place throughout the world. Industry interest and potential
business opportunities are evidenced by continued new developments
in fiber reinforced construction materials. These new developments
are reported in numerous research papers, international symposia,
and state-of-the-art reports issued by professional societies. The
ACI Committee 544 published a state-of-the-art report in 1973
[1.10]. RILEM's committee on fiber reinforced cement composites has
also published a report [1.11]. A Recommended Practice and a
Quality Control Manual for manufacture of glass fiber reinforced
concrete panels and products have been published by the
Precast/Prestressed Concrete Institute [1.12, 1.13]. Three recent
symposium proceedings provide a good summary of the recent
developments of FRC [1.14, 1.15, 1.16].
Specific discussions of the historical developments of FRC with
various fiber types are included in Chapters 2 through 5.