An Investigation of the Debonding Mechanism between FRCM Composites and a Masonry Substrate

2017 ◽  
Vol 747 ◽  
pp. 382-389 ◽  
Author(s):  
Mattia Santandrea ◽  
Gilda Daissè ◽  
Claudio Mazzotti ◽  
Christian Carloni
Keyword(s):  
Failure Modes ◽  
Stress Transfer ◽  
High Strength ◽  
Steel Fibers ◽  
Vapor Permeability ◽  
Fiber Reinforced ◽  
Direct Shear Tests ◽  
Frp Composites ◽  
Load Carrying ◽  
Externally Bonded

Fiber reinforced cementitious matrix (FRCM) composites have recently become a hot topic in Europe as an alternative to traditional fiber reinforced polymer (FRP) composites for several strengthening applications of existing masonry buildings. The terrific success of this new retrofitting system is mainly due to some advantages that it offers when compared to FRP, such as the possibility of application of the composite to wet surfaces and the vapor permeability featured by the inorganic matrix. In this work, the stress transfer between FRCM composites and a masonry substrate is investigated. FRCM strips comprised of ultra-high-strength steel fibers embedded in a cementitious grout are externally bonded to masonry blocks. Single-lap direct shear tests are performed. Parameters studied are bonded length and density of the steel fibers. Load responses are presented and failure modes are discussed. Change in the bond behavior and load carrying capacity with increasing bonded length is analyzed to determine the effective bond length.

scholarly journals Some Key Aspects in the Mechanics of Stress Transfer Between SRG and Masonry

2020 ◽  
Vol 10 (20) ◽  
pp. 7303
Author(s):  
Giulia Baietti ◽  
Tommaso D’Antino ◽  
Christian Carloni
Keyword(s):  
Stress Transfer ◽  
High Strength ◽  
Active Role ◽  
Fiber Reinforced ◽  
Suitable Alternative ◽  
Existing Structures ◽  
Direct Shear Tests ◽  
Frp Composites ◽  
Mortar Matrix

The use of composite materials to strengthen masonry structures has become common practice within the civil engineering community. Steel-reinforced grout (SRG), which comprises high-strength steel fibers embedded in a mortar matrix, is part of the family of the fiber-reinforced cementitious matrix (FRCM) composites that represent a suitable alternative to fiber-reinforced polymer (FRP) composites for strengthening existing structures. Although studies on FRCMs have already reached a certain level of maturity, some key issues remain open, such as the role of matrix type and layout, substrate properties, and test rate. This paper focuses on some of these issues. The results of single-lap direct shear tests on masonry blocks strengthened with SRGs are presented to analyze the bond behavior between the composite material and the substrate. Four aspects are considered: (1) the change in the width of the SRG mortar matrix while keeping the width of the fiber sheet fixed; (2) the type of mortar used for the SRG; (3) the influence of the test rate, and (4) the type of substrate (i.e., concrete vs. masonry). The results obtained indicate the active role of the matrix layout and the importance of the test rate, encouraging further investigations to clarify these aspects.

Confinement of Masonry Columns with Steel and Basalt FRCM Composites

2017 ◽  
Vol 747 ◽  
pp. 342-349 ◽  
Author(s):  
Mattia Santandrea ◽  
Giovanni Quartarone ◽  
Christian Carloni ◽  
Xiang Lin Gu
Keyword(s):  
Compressive Load ◽  
Basalt Fiber ◽  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Vapor Permeability ◽  
Fiber Reinforced ◽  
Promising Alternative ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Externally Bonded

The rehabilitation of existing masonry elements by means of jacketing of columns using composite materials is becoming a remarkable technique in several applications that aim to increase the strength of existing masonry buildings. Fiber reinforced cementitious matrix (FRCM) composites are a newly developed strengthening system that consist of high-strength fibers embedded in a cementitious grout and externally bonded to the substrate. High resistance to fire and high temperatures, ease of handling during application, and vapor permeability with the substrate are some of the characteristics that make FRCMs a promising alternative to traditional organic composites such as fiber reinforced polymer (FRP) composites. This work presents the results of an experimental study carried out to understand the behavior of masonry columns with a square cross-section confined by steel and basalt fiber sheets embedded in a mortar matrix subjected to monotonic concentric compressive load. The effectiveness of the confinement is studied in terms of load-bearing capacity with respect to unconfined columns. The effect of corner radius for columns confined with basalt fibers is investigated.

Experimental Analysis of the Bond Behavior of Glass, Carbon, and Steel FRCM Composites

2014 ◽  
Vol 624 ◽  
pp. 371-378 ◽  
Author(s):  
Tommaso D'Antino ◽  
Carlo Pellegrino ◽  
Christian Carloni ◽  
Lesley H. Sneed ◽  
Giorgio Giacomin
Keyword(s):  
Stress Transfer ◽  
High Strength ◽  
Fiber Reinforced ◽  
Bond Behavior ◽  
Cementitious Matrix ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
The Matrix ◽  
Glass Carbon ◽  
Concrete Matrix

In recent decades, the construction industry has witnessed a rapid growth of interest in strengthening and retrofitting of existing reinforced concrete (RC) and masonry structures. Fiber reinforced polymer (FRP) composites have gained great popularity, and several studies are now available in the literature on their use in strengthening and retrofit applications. Promising newly-developed composite materials are represented by the so-called fiber reinforced cementitious matrix (FRCM) composites. FRCM composites are comprised of high strength fibers embedded within a cementitious matrix that is responsible for the stress transfer between the existing structure and the strengthening material. FRCM composites are still in their infancy, and very limited results are available in the literature on RC and masonry strengthening applications. This study presents an experimental campaign conducted on different FRCM composites comprised of glass, carbon, or steel fibers embedded within two different cementitious matrices and applied to concrete prisms. The single-lap direct-shear test was used to study the stress-transfer mechanism between the FRCM composite and the concrete substrate. Two different composite bonded lengths were investigated. Debonding occurred at the matrix-fiber interface for some of the composites tested and at the concrete-matrix interface for others. This work contributes to the study of the bond behavior of FRCM composites, which represents a key issue for the effectiveness of FRCM composite strengthening.

A New Pull-Out Test to Study the Bond Behavior of Fiber Reinforced Cementitious Composites

2017 ◽  
Vol 747 ◽  
pp. 258-265 ◽  
Author(s):  
Tommaso D'Antino ◽  
Francesca Giulia Carozzi ◽  
Pierluigi Colombi ◽  
Carlo Poggi
Keyword(s):  
Stress Transfer ◽  
High Strength ◽  
Fiber Reinforced ◽  
Bond Behavior ◽  
Direct Shear Tests ◽  
Pull Out ◽  
The Matrix ◽  
Set Up ◽  
High Strength Fiber ◽  
Fiber Reinforced Cementitious Composites

Fiber reinforced cementitious matrix (FRCM) composites are gaining increasing popularity in the civil engineering community. FRCM composites are comprised of high-strength fiber textiles embedded within inorganic matrices that are responsible for the stress-transfer mechanism between the composite and the substrate. Failure of FRCM composites including one layer of textile is generally reported to be debonding of the fibers from the embedding matrix. Therefore, the bond behavior of the matrix-fiber interface is of critical importance for these types of composites.This paper presents the results of an experimental campaign carried out to investigate the bond behavior of an FRCM composite comprising PBO fibers. Specimens were tested using a newly-developed pull-out test set-up. The results obtained are compared with those obtained by different authors on single-lap direct-shear tests with the same FRCM composite.

Destructive In Situ Tests on Masonry Arches Strengthened with FRCM Composite Materials

2017 ◽  
Vol 747 ◽  
pp. 567-573 ◽  
Author(s):  
Andrea Incerti ◽  
Mattia Santandrea ◽  
Christian Carloni ◽  
Claudio Mazzotti
Keyword(s):  
Failure Modes ◽  
High Strength ◽  
Vapor Permeability ◽  
Fiber Reinforced ◽  
In Situ Tests ◽  
Masonry Arches ◽  
Promising Alternative ◽  
Cementitious Matrix ◽  
Strengthening Technique

In the last few decades, fiber reinforced polymer (FRP) composites have been widely employed in several strengthening and rehabilitation applications of existing masonry buildings. Fiber reinforced cementitious matrix (FRCM) composites are a newly-developed strengthening technique comprised of high strength fibers embedded in a cementitious matrix. FRCMs usually offer several advantages such as the high resistance to fire and high temperatures or vapor permeability with masonry substrate, therefore they appear to be a promising alternative to traditional FRP strengthening systems. In this experimental work, the results of destructive in situ tests performed on existing masonry arches strengthened with FRCM composites are reported. FRCM strips consist of a balanced bi-axial mesh made of basalt fibers embedded in a cementitious grout. Three different configurations of the strengthening system have been considered. Load responses and failure modes are presented.

scholarly journals Resistance of an Optimized Ultra-High Performance Fiber Reinforced Concrete to Projectile Impact

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 63
Author(s):  
Anna L. Mina ◽  
Michael F. Petrou ◽  
Konstantinos G. Trezos
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Depth Of Penetration ◽  
Projectile Impact ◽  
High Performance Fiber

The scope of this paper is to investigate the performance of ultra-high performance fiber reinforced concrete (UHPFRC) concrete slabs, under projectile impact. Mixture performance under impact loading was examined using bullets with 7.62 mm diameter and initial velocity 800 m/s. The UHPFRC, used in this study, consists of a combination of steel fibers of two lengths: 6 mm and 13 mm with the same diameter of 0.16 mm. Six composition mixtures were tested, four UHPFRC, one ultra-high performance concrete (UHPC), without steel fibers, and high strength concrete (HSC). Slabs with thicknesses of 15, 30, 50, and 70 mm were produced and subjected to real shotgun fire in the field. Penetration depth, material volume loss, and crater diameter were measured and analyzed. The test results show that the mixture with a combination of 3% 6 mm and 3% of 13 mm length of steel fibers exhibited the best resistance to projectile impact and only the slabs with 15 mm thickness had perforation. Empirical models that predict the depth of penetration were compared with the experimental results. This material can be used as an overlay to buildings or to construct small precast structures.

scholarly journals The Assessment of Using CFRP to Enhance the Behavior of High Strength Reinforced Concrete Corbels

2021 ◽  
Vol 28 (1) ◽  
pp. 71-83
Author(s):  
Mazin Abdulrahman ◽  
Shakir Salih ◽  
Rusul Abduljabbar
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Strength ◽  
Load Capacity ◽  
High Strength ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Ultimate Load Capacity ◽  
Load Carrying ◽  
Externally Bonded ◽  
Effective Depth

In this research, an experimental study is conducted to investigate the behavior and strength of high strength reinforced concrete corbels externally bonded with CFRP fabric sheets and Plates with different patterns taking into account the effect of adopted variables in enhancing the ultimate strength; the effect of shear span to effective depth (a/d), configuration, type and amount of bonding. Eleven high strength reinforced corbels were cast and tested under vertical loads. Test results showed there was an improvement in the behavior and load carrying capacity of all strengthened corbels. An increasing in the ultimate strength of strengthened corbel by inclined CFRP strips reached to (92.1%) while the increasing reached to (84.21%) for using one horizontal CFRP Plates compared to un-strengthened reference specimen. Also, it can be conducted that the increase of (a/d) ratio from (0.6 to 0.8) resulted in decreasing by 21.05% in ultimate load capacity of corbels and from (0.4 to 0.6) by 31.25% and 58.69% in cracking and ultimate loads respectively Using CFRP .

INTERFACIAL AND TENSILE PROPERTIES OF HYBRID FRP COMPOSITES USING DNN STRUCTURE WITH OPTIMIZATION MODEL

2019 ◽  
Vol 27 (02) ◽  
pp. 1950099 ◽  
Author(s):  
AHMED ABDUL BASEER ◽  
D. V. RAVI SHANKAR ◽  
M. MANZOOR HUSSAIN
Keyword(s):  
Tensile Properties ◽  
Natural Fiber ◽  
Hybrid Composites ◽  
Research Work ◽  
Composite Plates ◽  
High Strength ◽  
Fiber Reinforced ◽  
Reinforced Concrete Structure ◽  
Shear Strengthening ◽  
Frp Composites

Fiber reinforced polymer (FRP) composites are appealing for use in structural building applications because of their high strength-to-weight and stiffness-to-weight proportions, corrosion resistance, lightweight, possibly high durability, along with free design characteristics. The aim of this research work was to develop high strength natural fiber-based composite plates for the possible application in the shear strengthening of the reinforced concrete structure. In the experimental modeling, the composites were fabricated using glass, flax and kenaf fibers in treated and untreated conditions. This paper studied and analyzed the interfacial and tensile properties of fiber reinforced hybrid composites such as flax/glass and kenaf/glass by using the simulation approach, i.e. Deep Neural Network (DNN) with weight optimization. For optimizing the weights in DNN, Oppositional based FireFly Optimization (OFFO) is proposed. All the optimal results exhibit in the way that the accomplished error values between the output of the experimental values and the predicted qualities are firmly equivalent to zero in the designed system.

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