Textile Fibre Composites in Civil Engineering By Thanasis Triantafillou

Textile Fibre Composites in Civil Engineering By Thanasis Triantafillou

Preface :

The use of brittle materials with low tensile strength, such as concrete or masonry, has been known for thousands of years. The idea of embedding fibers in brittle materials, so that cracking does not lead to failure, is also not new. Thousands of years ago straw was added to clay bricks in order to make them tougher. Later on, techniques were devised to strengthen concrete that were based on the use of metallic reinforcement. In recent decades, various methods have been developed to replace the conventional steel reinforcement in concrete structures through the use of short fibers (e.g. steel,

glass, or polymeric), with a recent development along these lines being the ultra ductile concrete. Another development is the use of fiber reinforced polymers (FRP), which are typically made of long, continuous fibers (e.g. carbon, glass, aramid) in a polymeric matrix, which yield reinforcing elements such as bars, strips, and sheets, for the reinforcement, strengthening, or seismic retrofitting of new or existing concrete and masonry structures. Considerations to combine continuous fibers with inorganic binders in the con struction of new structures began in the 1980s, and the first research efforts were made in Germany in the 1990s, leading to the product known as textile reinforced concrete (TRC). This material consists of textiles made of long woven, knitted, or even unwoven fiber rovings in at least two directions, embedded in an inorganic fine-grained binder (typically—but not necessarily cementitious). In the early 2000s, the textile-based composites were used successfully in the field of strengthening and seismic retrofitting of concrete and masonry structures, in an

attempt to solve problems associated with the use of polymeric resins in FRP products. At thebeginning, these new “textile fiber composite” materials were given (in Europe) the name “textile reinforced concrete” (TRC) or “textile reinforced mortar” (TRM).Strictly speaking,the inorganic matrix is not classified as “concrete”, due to the very small size of aggregates. More recently (in the USA), the materials were given the  name “fabric reinforced cementitious matrix systems” (FRCM).

The introduction of textile fiber composites to the market have been accompanied with an extensive expansion of research on TRC or TRM or FRCMs. Many research units worldwide deal with topics relevant to new constructions, as well as to the ret rofitting of existing ones. A wide variety of publications already demonstrate the worldwide interest in this innovative structural material, which is expected to grow rapidly.