Steel-Reinforced Polymers and Steel-Reinforced Composite Mortars for Structural Applications—An Overview (original) (raw)
Related papers
2019
Due to its low tensile strength and brittle behavior, the use of concrete as structural material has required the use of tensile reinforcement, traditionally on the form of reinforcing bars placed on the locations in which high tensile stresses are expected. In previous decades, the use of steel, glass, or plastic fibers dispersed randomly on the fresh concrete mix for the total or partial replacement of reinforcing bars has shown to provide significant increase on the tensile and flexural strength, abrasion resistance, permeability, toughness and durability of concrete. The use of this composite material, known as fiber reinforced concrete (FRC) or mortar (FRM), for industrial pavement, tunnel linings, and hydraulic and precast structures has shown satisfactory results. More recently, the use of FRC and FRM for the strengthening of existing concrete and masonry structures has caught the attention of researchers worldwide. Unfortunately, experimental evidence on the topic is still s...
Use of steel fiber reinforced mortar for seismic strengthening
Construction and Building Materials, 2011
The objective of this research was to develop an economical, structurally effective, and practically applicable steel fiber reinforced mortar (SFRM) which could be applied onto the hollow brick infills of a reinforced concrete (RC) structure. Masonry walls were almost converted into strong and rigid infills with the application of SFRM. Two different mix proportions were produced with the composition of Portland cement, fine aggregate, water, and plasticizer or bonding agent as the chemical admixture. Tests were carried out to determine the optimum steel fiber content (1%, 2%, or 4% by volume) and to clarify the use of plasticizer or bonding agent in the mortar in the context of sticking ability, flexural, compressive, and adhesion strengths. As a result, mortar with plasticizer and 2% steel fiber (by volume) came out to be the optimum mortar mixture as strengthening material. The performance of RC frame strengthened with SFRM containing plasticizer and 2% steel fiber by volume was compared to those of the hollow brick infilled RC frame without strengthened mortar and the hollow brick infilled RC frame with reference mortar. It was observed that the specimen strengthened with the optimum mortar mix satisfied the target objectives of this study.
EXPERIMENTAL ANALYSIS OF MASONRY ARCHES STRENGTHENED BY INNOVATIVE COMPOSITE LAMINATES
The present research project presents an experimental study aimed to investigate the efficiency of utilizing innovative composite materials, based on high strength twisted steel wires embedded in either an epoxy (Steel Reinforced Polymer) or cementitious matrix (Steel Reinforced Grout), to strengthen masonry arches. The aim of such a strengthening method is to combine to the traditional advantages (very low weight, easiness of application, durability, etc.) proper of Fiber Reinforced Polymers (FRP) the performances of this new family of composite materials, able to allow the same applications, inducing an increase of ductility and reducing installation and material costs particularly when a cementitious matrix is used. For these reasons the use of these materials could become extremely interesting in the restoration of the historical building, and, more so, of masonry arches, as well as in road, rail, and waterway infrastructures, according to the principles of the most rigorous maintenance of historical patrimony and according to the most effective criterions of use of the modern technologies. In the UK, for instance, there are over 40,000 masonry arch bridges, the majority of which, being at least 100 years old, are in need of repair due to natural deterioration or lack of maintenance, or in need of strengthening due to ever increasing traffic volume and vehicle weight. In response to this situation an experimental study on the behavior of masonry arches strengthened with composite laminates is here presented. The influence of the type of fibers (steel and carbon), matrix (epoxy and cementitious), their location (intrados, extrados, both intrados and extrados) and boundary conditions are investigated in the laboratory on a series of nine specimens of arches built by concrete bricks arranged in a single skin (100 mm of thickness). The results have pointed out the enhancement in strength and ductility of the arches strengthened with SRG/SRP and the influence in the ultimate strength of the mechanical anchoring.
Construction and Building Materials
The objective of this research was to develop an economical, structurally effective, and practically applicable steel fiber reinforced mortar (SFRM) which could be applied onto the hollow brick infills of a reinforced concrete (RC) structure. Masonry walls were almost converted into strong and rigid infills with the application of SFRM. Two different mix proportions were produced with the composition of Portland cement, fine aggregate, water, and plasticizer or bonding agent as the chemical admixture. Tests were carried out to determine the optimum steel fiber content (1%, 2%, or 4% by volume) and to clarify the use of plasticizer or bonding agent in the mortar in the context of sticking ability, flexural, compressive, and adhesion strengths. As a result, mortar with plasticizer and 2% steel fiber (by volume) came out to be the optimum mortar mixture as strengthening material. The performance of RC frame strengthened with SFRM containing plasticizer and 2% steel fiber by volume was compared to those of the hollow brick infilled RC frame without strengthened mortar and the hollow brick infilled RC frame with reference mortar. It was observed that the specimen strengthened with the optimum mortar mix satisfied the target objectives of this study.
Journal of Composites for Construction, 2016
Steel Reinforced Polymer (SRP) systems have recently emerged as an attractive solution for the external strengthening of reinforced concrete structures. They entail unidirectional fabrics made out of high tensile strength steel cords that can be externally bonded to the substrate via wet lay-up, using either epoxy or polyester resin. Currently, research about the behavior of SRP strengthening systems for concrete structures is evolving but further systematic and comprehensive studies are still needed to ensure the consistency and reliability of the studies performed to date. The present paper contributes to expanding the existing knowledge by presenting the results of an extensive experimental program devoted to investigate the bond behaviour between SRP and concrete substrate. To this purpose, a number of SRP strips were bonded to concrete blocks by a thixotropic organic matrix and the lap joint was subsequently subjected to direct shear tests performed in displacement control. Besides the concrete strength, the following study parameters were considered: (a) the concrete surface roughness in the bonded region, (b) the density of the steel fabric, (c) the ratio of the epoxy covered concrete surface width to the SRP strip width, and (d) the bonded interface length.
Strengthening of Concrete Structures using Steel Wire Reinforced Polymer
Synopsis: Synopsis: Synopsis: Synopsis: Synopsis: This paper deals with a new material for external reinforcement: Steel Wire Reinforced Polymer (SWRP). It consists of thin high-strength steel fibres embedded in a polymer laminate. This innovative material combines the advantages of steel plates and CFRP, which are already used today. The material cost of SWRP is relatively low, and the laminate is quite flexible. In the feasibility part, the practical use of SWRP is studied. Further, the available design model for externally bonded reinforcement for concrete elements is confronted with the results of an experimental program, carried out at the Reyntjens Laboratory of KULeuven. The model is adapted accordingly.
Review of strengthening techniques for masonry using fiber reinforced polymers
Composite Structures, 2017
Various studies have been done over a number of years to develop strengthening techniques which will improve the performance of masonry structures. Many unreinforced masonry structures are seismically deficient and several research studies have been conducted to improve the seismic performance of these structures. Strengthening methods such as the addition of new structural elements, steel plate bonding, external post tensioning, steel bracing and many more have been applied with some degree of success. However, an innovative retrofitting technique using Fiber Reinforced Polymer (FRP) has gained recognition and acceptance. FRP materials have light weight, excellent durability, and high strength, yet are lightweight and are easy and quick to install. All these properties make FRP materials attractive for strengthening and rehabilitating of reinforced and unreinforced masonry structures. Different strengthening techniques are available to increase the flexural and shear strength and ductility of masonry structures using FRP materials. This paper reviews these strengthening techniques, their advantages, disadvantages and limitations.
Structural Performance of Concrete: Exploring the Limits of Steel Fiber Reinforcement
International Journal for Multidisciplinary Research, 2024
Concrete is one of the most extensively utilized construction materials today. Its popularity stems from its ready availability, ease of moulding into various shapes, cost-effectiveness, and high compressive strength. Despite these advantages, concrete is known for its low tensile strength and poor performance in harsh conditions, which is a significant drawback for any construction material. To mitigate these weaknesses, concrete is typically combined with steel reinforcement. Steel fibers are added to concrete to improve the structural properties, particularly tensile and flexural strength. Plain, straight and round fibers were found to develop very weak bond and hence low flexural strength. In this research, steel binding wires were used as steel fibers which are locally available at very cheap cost. Steel fibers were added in different percentage i.e. 0%, 0.5 %, 1%, 1.5%, 2%, 2.5% and 3%. The primary focus of the research was to calculate compressive and tensile strengths of various samples and determine the maximum amount of Steel fibers that can provide the maximum strength. To achieve this, cubes and cylinders were cast and tested using a Universal Testing Machine for their compressive and tensile strengths. The findings indicated a slight increase in compressive strength, while the addition of steel fibers resulted in a more significant increase in tensile strength.
A Review study on use of Steel Fiber as Reinforcement Material with Concrete
Reinforcement is defined as the process of mixing various materials whether chemical, natural or artificial for improving the strength and durability of parent substance. Now a days there exists many reinforcement techniques for improving the strength of those materials which lacks load carrying and less durable capacity. Use of steel fiber to enhance the strength and reduce maintenance is an effective technology established in recent times.Fiber reinforced polymer (FRP) application is very effective way to repair and strengthen structures that have become structurally weak over their life span. FRP repair system provides an economically viable alternative to traditional repair system and material.