With the development of civil engineering material science and technology, concrete material has become the most widely used construction material in the world.
With the development of civil engineering material science and technology, concrete material has become the most widely used construction material in the world. The most famous advantage of concrete is its high compressive strength. However, concrete materials have defects such as low crack resistance, poor toughness and low tensile strength. When a concrete structure is damaged under load, the energy consumed is very limited and many cracks of varying sizes are produced. The higher the strength of concrete the more brittle it is. The presence of a large number of cracks has a significant negative impact on the mechanical properties and durability of the concrete structure and can lead to a shortened service life of the structure.
In order to overcome the defects of concrete materials, many researchers have conducted numerous studies to improve the properties of concrete, especially to improve the toughness of concrete. The use of fibers has been shown to improve the mechanical properties and durability of concrete. Over the past few decades, a great deal of research has been conducted to study the properties and advantages of fiber-reinforced concrete. Commonly used learn more, glass fibers, polyethylene fibers, polypropylene fibers, polyvinyl alcohol fibers, polyester fibers, basalt fibers, and natural fibers. The role of fibers on concrete are anti-cracking, reinforcement, toughening three roles. Crack resistance is the ability to limit and reduce the generation and development of shrinkage cracks in concrete. Reinforcement can be defined as the addition of fibers reduces the adverse effect of internal defects on the strength of concrete and improves the mechanical properties of concrete. Toughening action is defined as the bridging effect of fibers across internal cracks in concrete, which improves the toughness of concrete after cracking.
The purpose of this paper is to bring together researchers from industry and academia to report and explore new investigation techniques, new preparation methods and basic material properties, testing methods and standardization, fresh performance and constructability, shrinkage and creep, structural performance and modeling, functional coatings for buildings, durability and sustainability, and field applications of fiber-reinforced concrete materials in civil engineering, and to review the latest advances in the field.
Among the various fibers, steel fibers are the most well-known fibers used in concrete materials. Scientists have conducted an experimental study on the mechanical properties of high-strength fiber-reinforced concrete (HSFRC). In this study, they used three steel fiber contents and three steel fiber lengths. The results showed that the compressive strength, modulus of elasticity and tensile strength of mixtures of HSFRC with mixed steel fibers were similar to those of mixtures with single lengths of steel fibers. They compared the mechanical properties of different strength steel fiber concrete prepared using conventional mixing and vibratory mixing methods. Their results showed that vibratory mixing can effectively improve the distribution of steel fibers in concrete and increase the density of steel fiber concrete, so it effectively improves the mechanical properties of steel fiber concrete compared with the conventional mixing method. They investigated the mechanical properties of magnesium phosphate cement mortar reinforced with micro steel fibers. The results showed that the addition of microsteel fibers at 0% to 1.6% by volume significantly increased the compressive strength of the mortar, and the addition of microsteel fibers changed the bending damage mode of magnesium phosphate cement mortar from brittle to ductile.
Through a series of experiments, the mechanical properties of nano-silica and steel fiber-reinforced crumb rubber concrete have been investigated. According to their results, it is possible to improve the brittle damage and enhance the mechanical properties of crumb rubber concrete by adding steel fibers and nanosilica. In addition, steel fibers showed a more significant increase in the splitting tensile strength of modified gum powder concrete, while nano-silica had an important role in the enhancement of compressive properties. The chloride diffusion coefficient has been considered as the most important parameter for predicting chloride ion intrusion in concrete. Based on a series of chloride volume diffusion tests. Scientists proposed a suitable model to calculate the chloride diffusion coefficient of steel fiber concrete. The results showed that unstressed specimens of steel fiber concrete exhibited better chloride resistance and the chloride ion diffusion coefficient of steel fiber concrete decreased due to compressive stress, while no significant change was observed for plain concrete. The addition of steel fibers has greatly improved the chloride resistance of concrete. The model can provide a simple method to calculate the chloride diffusion coefficient of steel fiber concrete specimens under bending load.
The effect of applying hook-end steel fibers in helically restrained concrete with different pitches has been investigated. In their tests, standard concrete cylinders were helically restrained with steel reinforcement and with/without hook-ended steel fibers. Their results showed that the use of hook-ended steel fibers contributed significantly to the improvement of both compressive strength and ductility of the concrete.
Some short fibers can be added to cement composites to produce a high performance building material, often referred to as engineered cement composites (ECC). A new cement composite has been prepared using ceramic fibers and some experiments have been conducted to evaluate the high temperature resistance of the composite. Their results showed that hydrothermal curing had a positive effect on the ceramic fiber-reinforced refractory cement composite and achieved particularly excellent flexural strength before and after high temperatures. The scientists conducted an experimental study of the bending properties of ECC. It can be observed that the number of cracks increases with increasing stress level and most of the cracks are formed in the early stages of dynamic tests.
Several scientists have studied the effect of expansion admixtures on the mechanical properties of strain-hardened cementitious composites and investigated the structural properties of reinforced concrete (RC) beam specimens repaired with strain-hardened cement composites. They investigated the flexural properties of ECC-concrete composite beams, revealing the effect of bonding at the interface and fiber mesh reinforcement on flexural properties and cracking patterns. It can be concluded that the fiber mesh reinforcement can further improve the flexural performance regardless of the bonding conditions. Based on extensive tests, the effect of silica fume (SF) and ground blast furnace slag (GGBS) on the frost resistance of ECC containing large amounts of fly ash has been discussed. Their results showed that the relative dynamic elastic modulus and mass loss of ECC in freeze-thaw cycles in NaCl solution were greater than those in freeze-thaw cycles in tap water, and that the relative dynamic elastic modulus and mass loss of ECC in freeze-thaw cycles increased with increasing fly ash content during thaw cycles.
With the development of concrete technology, ultra-high performance concrete has been manufactured to meet the increasing requirements for concrete structures. Various waste mineral admixtures are used to prepare ultra-high performance concrete (UHPC).