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Chemical property and characteristics of polymer
Published in S. Thirumalai Kumaran, Tae Jo Ko, S. Suresh Kumar, Temel Varol, Materials for Lightweight Constructions, 2023
A. Sofi, Joshua Jeffrey, Abhimanyu Singh Rathor
Kuralon and Vinylon are brand names for PVA fibers. The advantages of using fibers to make fiber-reinforced concrete products are as follows: high aspect ratio, high ultimate tensile strength, strong chemical compatibility with Portland cement, good affinity for water, faster drainage rate, and no health risks associated with their use [25]. Unitika Kasei Ltd, Japan, invented high-modulus Vinylon fiber, which has been hailed as one of the most promising new materials for replacing asbestos in fiber-reinforced cementitious composite materials. It possesses numerous appealing properties, including increased strength (1.23 GPa), high modulus (2.95 GPa), good alkali resistance, effective cement bonds, and a specific gravity of approximately 1.3.
Steel-reinforced concrete characteristics
Published in Brian Cherry, Green Warren, Corrosion and Protection of Reinforced Concrete, 2021
Fibre-reinforced concrete is defined as concrete made with hydraulic cement, containing fine or fine and coarse aggregate, and discontinuous discrete fibres. It is usually used without massive reinforcement. The fibres can be made from natural material (e.g. sisal, cellulose) or are a manufactured product such as glass, steel, carbon, and polymer (e.g. polypropylene, kevlar). The purposes of reinforcing the cement-based matrix with fibres are to increase the tensile strength by delaying the growth of cracks, and to increase the toughness by transmitting stress across a cracked section so that much larger deformation is possible beyond the peak stress than without fibre reinforcement. Short fibre reinforcement results in enhanced strength and toughness in flexure and enhanced toughness in compression. Fibre reinforcement improves the impact strength and fatigue strength, and also reduces shrinkage. The quantity of fibres used is small, typically 1–5% by volume as higher volumes decrease the workability substantially.
New advancement in durable segments for combined sewer overflow tunnels, USA
Published in Daniele Peila, Giulia Viggiani, Tarcisio Celestino, Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 2020
Ongoing research and continuous developments on macro synthetic fibre and macro synthetic fibre reinforced concrete have made it today being a modern and cost-efficient construction material. Eliminating durability issues with regard to corrosion of the primary reinforcement yields significant advantages for the design, since it is no longer governed by serviceability limits.
Performance evaluation of dispersed basalt fiber on strength of lightweight expanded clay concrete
Published in Cogent Engineering, 2022
Paschal Chimeremeze Chiadighikaobi, Dafe Aniekan Emiri, Mohamed Ibrahim Abu Mahadi, Kebba Camara, Foud Adnan Noman Abdullah Al-shaibani, Majeed M. Haidar, Lina Abass Saad
Concrete is one of the famous structural material, however one of its major disadvantages is it self-weight. Engineers have explored various ways to reduce the weight of concrete and still retain a high strength-durable relationship. Fiber-reinforced concrete can be used to overcome this challenge, examples of these fibers are composites, hybrid fiber, and plant fiber. These materials have unique features and disadvantages. Therefore, this paper analyzed research works and experiments of previous researchers on lightweight basalt-fiber concrete. The authors propose replacement of granite with expanded clay (EC) as aggregate thus reducing the weight of concrete while basalt fibers (BFs) is used to strengthen/reinforce the concrete. EC and BFs are pure, natural, and eco clean materials that are widely available within the earth surface, they are affordable yet durable. The analysis drawn from the various authors shows the effectiveness of EC and BF.
Impact of waste fibers on the mechanical performance of concrete composites
Published in The Journal of The Textile Institute, 2020
Muhammad Imran Khan, Muhammad Umair, Khubab Shaker, Abdul Basit, Yasir Nawab, Muhammad Kashif
Fiber reinforced concrete is concrete in which different type of fibers are added along with cement, coarse aggregate (crush) and fine aggregate (sand) by dispersing the fibers uniformly in the mixture. FRC containing fibrous material which can increase its mechanical properties (tensile, compressive, bending) depending upon the %age and type of fiber used. It contains short fibers that are uniformly dispersed and randomly oriented and most fibers used in FRC includes steel, glass, synthetic and natural fibers (Jute, hemp, sisal). The matrix for FRC is a mortar, having a specific formulation depending on the area of application. Fiber reinforced mortar (FRM) is a mortar in which different type of fibers are added along with cement, fine aggregate only. In a similar way, the FRM properties can be improved by adding different types of fiber in different proportions. The fibers used in the cement as a part of reinforcement, which acts as a bridge between the small cracks and prevent the further propagation of the larger cracks. This effect is called the sewing effect (Foti, 2011) which seems to stitch the matrix together and enhance the mechanical properties of the cement matrix. The cement matrix with dispersed fibers is called fiber reinforced cement composite (FRC).
Numerical validation of double punch test for the assessment of tensile strength in natural fiber reinforced concrete
Published in Mechanics of Advanced Materials and Structures, 2019
Laura Anania, Giuseppe D'agata
The tensile strength of fiber reinforced concrete can be determined either by direct pull on briquettes or by indirect tensile and bending tests. The fracture energy is evaluated from uniaxial tensile tests or bending tests using displacement control. The uniaxial tensile test is the most appropriate, but the test stability requires a very stiff closed-loop servo-controlled testing system [1] and [2] Direct tensile tests are difficult to carry out, because of the fragile nature of the concrete, but if performed correctly, it can provide very important information. Up till now different modes are proposed in the literature for direct tensile tests on fiber cementitious specimens [3] and [4]. Unfortunately, these tests lack in simplicity, reliability, or reproducibility. Thus, we need an alternative test method capable of overcoming these lacks. This need can be satisfied by the use of the double punch test (DPT). It was introduced, by Chen, in 1970 [5]–[7] that defined the relationship between the peak load applied on the tested specimen and the tensile strength of the material tested. Later, this relationship was developed accounting also for a nonlinear fracture mechanism approach [8]–[11].