کاربرد پذیری بتن تقویت شده با الیاف ترکیبی
Abstract
1- Introduction
2- Lab‑Based Experiment
3- Results of Lab‑Based Experiment and Discussion
4- Field Applications
5- Conclusions
References
Abstract
The aim of this research is to evaluate the protecting performance of hybrid fiber-reinforced concrete against lateral forces such as explosives or flying objects. The objective of this research is to better prepare this concrete for use in the ready-mix concrete industry. Even though the fiber addition gives it strong mechanical properties, it also decreases workability due to the inefficient dispersion of fibers. Therefore, it has been difficult to apply to the ready-mix concrete plant’s mixing, delivery and on-site placement. The authors have developed a combined steel and polyaramid fiber that gives the favorable protection needed against high-impact forces and provides a suitable workability for the ready-mix concrete system. To evaluate the required performance, the hybrid fiber-reinforced concrete specimen was subjected to high-speed projectiles and had its workability and performance tested on a construction site of an established ready-mix concrete company. The hybrid fiber-reinforced concrete successfully provided the protection capabilities sought for the finished product and provided a workable-ready mix applicability.
Introduction
When subjected to terrorism or warfare, everyone wants protection, which is why structures or facilities in areas that sufer from these attacks need to provide occupants with sufcient protection from shock waves or fying debris from bombs or other types of explosives. Plants that handle or manufacture explosive substances in highly populated areas also need to be housed in structures that can provide protection. For the lateral stress caused by an earthquake or explosion, fber-reinforced concrete (FRC) is known as a solution because of its high energy absorption capacity and high tensile strength (Li and Leung 1992; Yazıcı et al. 2007; Hsie et al. 2008). Compared to normal concrete without fber reinforcement, FRC, developed to control cracking, has a high tensile strength and toughness. Generally, for FRC, the fber content is the key to improving mechanical properties of the FRC mixture (Balaguru and Shah 1992). On the other hand, the addition of fber in a concrete mixture causes reduction of workability while increasing both viscosity and yield stress (Tattersall and Banfll 1983). It means FRC is still not suitable for on-site placement with a general ready-mix concrete system. Tus, for FRC, the fber content should be balanced between mechanical properties and workability. Te reinforcing fbers used to improve the performance of cementitious materials have diferent roles or performances depending on their aspect ratios (length-todiameter ratio), materials, or shapes (straight, bent, or hooked). Especially, regarding the materials, the reinforcing fber can be categorized into metallic and polymeric fbers (Balaguru and Shah 1992; Bentur and Mindess 2006). First, metallic fber, mainly steel fber, increases the mechanical properties such as tensile strength and toughness of the mixture.