Influence of Alkaline Environments on the Mechanical Properties of FRCM/CRM and their Materials

2019 ◽  
Vol 817 ◽  
pp. 195-201
Author(s):  
Valeria Rizzo ◽  
Antonio Bonati ◽  
Francesco Micelli ◽  
Marianovella Leone ◽  
Maria Antonietta Aiello
Keyword(s):  
Glass Fibers ◽  
Tensile Tests ◽  
Design Guidelines ◽  
Hydraulic Lime ◽  
System A ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Alkaline Environments ◽  
Externally Bonded ◽  
Direct Tensile

Fabric Reinforced Mortar (FRCM) used as Externally Bonded Reinforcements (EBR), provide a sustainable solution for retrofitting and repair of existing masonry structures. They are commonly made by fibrous meshes embedded in a cementitious/hydraulic lime matrix. This technique represents a valid alternative to the well-known FRP (Fiber Reinforced Polymer) composites, which show some limitations in heritage masonry applications. In this scenario, a new system known as CRM (Composite Reinforced Mortar) has been developed in the last years. In this system, a pre-cured FRP grid is utilized as internal reinforcement in a mortar layer. The system reproduces the traditional technique of reinforced plaster, where the steel grid is substituted by a non-metallic one. In masonry applications high compatibility with the substrate, sustainability and removability are commonly required in heritage construction. These goals are not easily achieved by using fibers immersed into a polymeric resin. Moreover, the inorganic matrix ensures the transpiration of substrates and consequently a higher durability of the whole strengthened system is expected. On the other hand, the recent use of these new materials in civil engineering needs appropriate design guidelines. The proposed paper focuses attention on the initial results of a large experimental study on the durability of FRCM/CRM systems and their single components (dry glass fibers, resin, pre-cured FRP grid and mortar). In particular, the influence of three alkaline environments solutions was studied. Exposure conditions were stressed by increasing the temperature of the three aqueous solutions. The mechanical retention of tensile properties was measured by performing direct tensile tests after different exposure times.

A proposed strengthening model considering interaction of concrete-stirrup-FRP system for RC beams shear-strengthened with EB-FRP sheets

2018 ◽  
Vol 37 (10) ◽  
pp. 685-700 ◽  
Author(s):  
Weiwen Li ◽  
Chengyue Hu ◽  
Zejie Pan ◽  
Wei Peng ◽  
Yong Yang ◽  
...  
Keyword(s):  
Effective Strain ◽  
Polymer System ◽  
Design Guidelines ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Externally Bonded

Many factors can affect the shear capacity of fiber-reinforced polymer in reinforced concrete beams shear-strengthened with externally bonded fiber-reinforced polymer composites. Undoubtedly, the interaction of concrete-stirrup-fiber-reinforced polymer system is one of the key factors. However, most of the existing fiber-reinforced polymer design guidelines do not take account of this important factor on predicting fiber-reinforced polymer shear capacity. This study provides an advanced strengthening model that comprehensively considers the interaction among concrete, stirrup, and fiber-reinforced polymer for calculating the fiber-reinforced polymer effective strain. The advanced strengthening model provides a more accurate prediction for the fiber-reinforced polymer shear contribution compared with existing design guidelines.

Strengthening of shear deficient RC deep beams using GFRP sheets and mechanical anchors

2021 ◽  
Vol 48 (1) ◽  
pp. 1-15 ◽  
Author(s):  
A. Kumari ◽  
A.N. Nayak
Keyword(s):  
Design Guidelines ◽  
Shear Capacity ◽  
Deep Beams ◽  
Reinforced Polymer ◽  
Glass Fibre Reinforced Polymer ◽  
Rc Deep Beams ◽  
Externally Bonded ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
Strengthened Beam

This paper presents the test results of an experimental study on shear deficient reinforced concrete (RC) deep beams strengthened with externally bonded glass fibre reinforced polymer (GFRP) sheets and mechanical anchors. A total of nine deep beams are prepared. One beam is kept as un-strengthened. Four beams are strengthened using GFRP sheets only at shear spans by varying the number of layers. The remaining four beams are strengthened using both GFRP sheets and mechanical anchors at shear spans. The shear capacity, failure mode, and deflections are studied with respect to the different strengthening techniques. The optimum enhancement in shear capacity of these beams is observed as 25.64% and 55.5% for GFRP strengthened beams and GFRP strengthened anchored beams, respectively with respect to the un-strengthened beam. Moreover, the experimental results are also compared with the results predicted from the design guidelines and models available in the literature, which shows good agreement.

Water Sorption of Vegetable Fiber Reinforced Polymer Composites

2016 ◽  
Vol 369 ◽  
pp. 17-23 ◽  
Author(s):  
L.H. de Carvalho ◽  
A.G. Barbosa de Lima ◽  
E.L. Canedo ◽  
A.F.C. Bezerra ◽  
W.S. Cavalcanti ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Polymer Composites ◽  
Water Sorption ◽  
Glass Fibers ◽  
Fiber Reinforced Polymer ◽  
Synthetic Fibers ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Vegetable Fiber

Despite the ever-growing worldwide interest in the use of lignocellulosic fibers as reinforcement in either thermoset or thermoplastic matrices, the use of these fibers to replace synthetic ones, is limited. The reasons for these limitations are associated with the vegetable fiber’s heterogeneity, lower compatibility to most polymers, inferior durability, flammability, poorer mechanical properties and higher moisture absorption when compared with synthetic fibers. Nevertheless, despite these drawbacks, vegetable fiber reinforced polymer composites are lighter in weight, more sustainable and can be used for non-structural products. Strategies to minimize these drawbacks include fiber and or matrix modification, the use of compatibilizers, fiber drying and the concomitant use of vegetable and synthetic fibers, for the production of hybrid composites, the latter being an unquestionable way to increment overall mechanical and thermal properties of these hybrid systems. Here we present data on the water sorption of polymer composites having thermoset and thermoplastic matrices as a function of vegetable fiber identity, content and hybridization with glass fibers. Our data indicates that, regardless if the matrix is a thermoset of a thermoplastic, water absorption tends to be relatively independent of vegetable fiber identity and to be significantly dependent of its content. Fiber drying prior to composite manufacturing and hybridization with glass fibers leads to lower overall water absorption and higher mechanical properties.

Externally bonded carbon fiber–reinforced polymer composites for seismic retrofit of reinforced concrete coupling beams designed according to old codes

2018 ◽  
Vol 22 (6) ◽  
pp. 1412-1425 ◽  
Author(s):  
Sara Honarparast ◽  
Georges El-Saikaly ◽  
Omar Chaallal
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Polymer Composites ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Externally Bonded ◽  
Carbon Fiber Reinforced

A large number of existing buildings have seismic-resistant systems designed according to old code provisions. These structural systems exhibit non-ductile behavior and can present a significant risk in the case of a moderate or significant seismic event. Reinforced concrete–coupled shear walls designed to old codes and standards are among those deficient structures that need to be seismically upgraded. This article aims to investigate a new retrofitting and upgrading method using externally bonded carbon fiber–reinforced polymer composites for existing or/and damaged reinforced concrete coupling beams that can improve the seismic performance of them during earthquakes. To this end, an experimental test was conducted to evaluate the seismic behavior of two identical reinforced concrete–coupled shear wall specimens under reverse cyclic loading. To simulate the old existing building, the specimens were designed and constructed according to the old 1941 National Building Code of Canada with a conventionally reinforced coupling beam. One of the specimens was tested as a control, and the other was strengthened using externally bonded carbon fiber–reinforced polymer composites to evaluate the improvement in its seismic performance. Results show that the retrofit using externally bonded carbon fiber–reinforced polymer resulted in significant enhancement in strength and energy dissipation capacity compared to the conventionally reinforced coupling beam from the control specimen. In addition, externally bonded carbon fiber–reinforced polymer sheets resulted in much improved hysteretic and ductile behavior and in lesser strength and stiffness degradation.

Processing and Mechanical Property Evaluation of Flax-Glass Fiber Reinforced Polymer Composites

2015 ◽  
Vol 766-767 ◽  
pp. 144-149 ◽  
Author(s):  
M. Ramesh ◽  
P. Sudharsan ◽  
K. Palanikumar
Keyword(s):  
Low Cost ◽  
Glass Fibers ◽  
Sem Analysis ◽  
Fiber Reinforced Polymer ◽  
Glass Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Fiber Reinforced Polymer Composites ◽  
Property Evaluation ◽  
Sustainability Principles

In the fast developing world, the concern for the environmental pollution and the prevention of non-renewable and non-biodegradable resources has attracted researchers seeking to develop new eco-friendly materials and products based on sustainability principles. The fibers from the natural sources provide indisputable advantages over synthetic reinforcement materials such as low cost, low density, non-toxicity, comparable strength, and minimum waste disposal problems. In the present experimental study, flax and glass fibers reinforced epoxy composites are prepared and the mechanical properties of these composites are evaluated. The samples were subjected to the mechanical testing such as tensile, flexural and impact loading. Scanning electron microscope (SEM) analysis is carried out to evaluate fiber matrix interfaces and analyze the structure of the fractured surfaces.

scholarly journals Durability of Externally Bonded Fiber-Reinforced Polymer Composites in Concrete Structures: A Critical Review

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 765
Author(s):  
Jovan Tatar ◽  
Sandra Milev
Keyword(s):  
Polymer Composites ◽  
Critical Review ◽  
Concrete Structures ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Interdisciplinary Approaches ◽  
Externally Bonded

Externally bonded fiber-reinforced polymer composites have been in use in civil infrastructure for decades, but their long-term performance is still difficult to predict due to many knowledge gaps in the understanding of degradation mechanisms. This paper summarizes critical durability issues associated with the application of fiber-reinforced polymer (FRP) composites for rehabilitation of concrete structures. A variety of factors that affect the longevity of FRP composites are discussed: installation, quality control, material selection, and environmental conditions. Critical review of design approaches currently used in various international design guidelines is presented to identify potential opportunities for refinement of design guidance with respect to durability. Interdisciplinary approaches that combine materials science and structural engineering are recognized as having potential to develop composites with improved durability.

Processing of Agricultural Biomass for Producing Reinforced Polymer Composites

2019 ◽  
Author(s):  
Birce Dikici ◽  
Samarth Motagi ◽  
Prahruth Kantamani ◽  
Suma Ayyagari ◽  
Gustavo Villarroel ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Vinyl Ester ◽  
Building Materials ◽  
Natural Fiber ◽  
Agricultural Waste ◽  
Tensile Tests ◽  
Tensile Fracture ◽  
Environmentally Sustainable ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites

Abstract Fast growing plants or biomass wastes can be used as affordable and environmentally sustainable alternatives to synthetic insulation materials. The aim of this study was to investigate the mechanical properties (tensile strength and Young’s modulus) of natural fiber reinforced polymer composites as potential building materials. As a natural fiber, Bermuda grass seeds, conifer cones and pinecones are selected. The fundamental processes to develop nanofiber reinforced resin by processing agricultural waste fibers into nanocellulose is also investigated. Tensile tests are conducted to define stress/strain relationship. SEM tests are conducted to evaluate the surface topologies after fracture. The tensile fracture surfaces of composites were investigated. With the addition of Bermuda fibers, the stiffness of the vinyl ester sample was observed to increase by 624.2% compared to neat vinyl ester sample. With the addition of nanocellulose fibers, the stiffness of the composite was observed to increase by 53.3% compared to neat vinyl ester sample.

Assesment of Proposed Models for Determining Allowable FRP Tensile Strain for Mitigation of Debonding Failure in FRP-Strengthened RC Beams

2011 ◽  
Vol 311-313 ◽  
pp. 1945-1948
Author(s):  
Gui Bing Li ◽  
Yu Gang Guo ◽  
Xiao Yan Sun
Keyword(s):  
Polymer Composites ◽  
Failure Mode ◽  
Tensile Strain ◽  
Failure Modes ◽  
Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Externally Bonded ◽  
High Level

intermediate crack-induced debondingis one of the most dominant failure modes in FRP-strengthened RC beams. Different code models or provisions have been proposed to mitigateintermediate crack-induced debondingfailure.However, these code models or provisions cannot mitigate this failure mode properly. Recently, mew models have been proposed.Out of all the existing proposed models, five typical ones are investigated in the current study. These main available proposed models for mitigating debonding failure of externally bonded fiber reinforced polymer composites appliedto concrete is evaluated based on data obtained from experimental programs. It is shown that all the evaluated proposed models exhibit a high level of dispersion, they are not suitable for limiting the allowable tensile strain at the initiation of debondingof FRP laminates.

scholarly journals Disintegration and Recycling of Multi-layered Glass Fiber Reinforced Polymer Composites via Superheated Steam

2019 ◽  
Vol 264 ◽  
pp. 03003
Author(s):  
Chi Hoong Chan ◽  
Minato Wakisaka ◽  
Haruo Nishida
Keyword(s):  
Glass Fiber ◽  
Polymer Composites ◽  
Large Scale ◽  
Superheated Steam ◽  
Glass Fibers ◽  
Fiber Reinforced Polymer ◽  
Glass Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Fiber Reinforced Polymer Composites

To increase viability of recycling of robust and large-scale multi-layered glass fiber reinforced polymer composites (GFRPs), disintegration of the multi-layered GFRPs and recovery of fibers/resin-derived materials were investigated using superheated steam (SHS) under normal pressure where a very quick heat transfer to GFRP was possible. The SHS treatment of 4 different types of multi-layered GFRP products were conducted at 350 °C in an oxygen-free environment up to 3 hours. The SHS treated GFRPs were easily disintegrated into each layer. The separated layers were divided into components: glass fibers, oligomers, and inorganic fillers after subsequent thermal and ultrasonication processes. Finally, clear glass fibers were recovered, and matrix resin was also recovered as soluble oligomers consisting of phthalates, glycols, and styrene units due to partial chain cleavage of cured resin. These results clearly showed the viability for the recycling of actual large-scale multi-layered GFRP products.

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