scholarly journals Retrofitting unreinforced masonry by steel fiber reinforced mortar coating: uniaxial and diagonal compression tests

2020 ◽  
Vol 53 (6) ◽  
Author(s):  
Sara S. Lucchini ◽  
Luca Facconi ◽  
Fausto Minelli ◽  
Giovanni Plizzari
Keyword(s):  
Experimental Study ◽  
Steel Fiber ◽  
Mechanical Characterization ◽  
Thin Layers ◽  
Steel Fibers ◽  
Masonry Buildings ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Diagonal Compression ◽  
The University

AbstractThin layers of mortar reinforced with steel fibers can be applied on one or both sides of bearing walls as an effective seismic strengthening of existing masonry buildings. To assess the effectiveness of this technique, an experimental study on masonry sub-assemblages was carried out at the University of Brescia. This paper summarizes and discusses the main results of the investigation, which included mechanical characterization tests on masonry and its components as well as on the Steel Fiber Reinforced Mortar (SFRM) used to retrofit the masonry samples. Uniaxial and diagonal compression tests were carried out on both unstrengthened wallets and masonry samples retrofitted with 25 mm thick SFRM coating. Both single-sided and double-sided retrofitting configurations for application on wall surfaces were considered. The results highlighted the ability of the technique to improve the compressive and the shear behavior of masonry, even in case of single-sided strengthening. Moreover, no premature debonding of coating was observed. Lastly, the manuscript presents the results of a numerical investigation that was performed both to simulate the diagonal compression tests described in the first part of the paper and to predict the response of panels with different strengthening configurations.

Shear Capacity of Masonry Panels Reinforced with Inorganic Strengthening Systems

2019 ◽  
Vol 817 ◽  
pp. 486-492
Author(s):  
Marta Del Zoppo ◽  
Gennaro Maddaloni ◽  
Alberto Balsamo ◽  
Marco di Ludovico ◽  
Andrea Prota
Keyword(s):  
Composite Materials ◽  
Shear Capacity ◽  
Masonry Walls ◽  
Masonry Buildings ◽  
Compression Tests ◽  
Plane Shear ◽  
Diagonal Compression ◽  
The University ◽  
Fabric Reinforced Cementitious Matrix ◽  
Inorganic Composite

Unreinforced masonry buildings are particularly vulnerable to brittle failures during seismic events due to the poor in-plane shear capacity of masonry walls. The use of strengthening solutions with polymeric matrices is not often recommended for masonry buildings, due to breathability issues, and the adoption of inorganic matrices is sometimes considered preferable. In this paper, the use of inorganic composite materials for improving the in-plane shear capacity of tuff masonry walls is investigated. The experimental data from 83 diagonal compression tests carried out at the University of Naples Federico II in recent years have been collected and the main results are herein discussed to outline the main features of different strengthening techniques with inorganic composite materials such as Reinforced Plaster (RP), Composite Reinforced Mortar (CRM) and Fabric Reinforced Cementitious Matrix (FRCM).

scholarly journals Strain sensitivity of steel-fiber-reinforced industrial smart concrete

2019 ◽  
Vol 31 (1) ◽  
pp. 127-136 ◽  
Author(s):  
Erman Demircilioglu ◽  
Egemen Teomete ◽  
Osman E Ozbulut
Keyword(s):  
Cement Paste ◽  
Electrical Resistance ◽  
Steel Fiber ◽  
Steel Fibers ◽  
Gauge Factor ◽  
Cementitious Composites ◽  
Strain Sensitivity ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Concrete Mixtures

Self-sensing cementitious composites can enable structures that are capable of carrying the loads applied on them while monitoring their condition. Most of earlier research has focused on the incorporation of nanofillers or microfibers into cement paste or mortar composites. However, there have been very limited number of studies on the development of steel-fiber-reinforced cementitious composites with self-sensing capabilities. This study explores strain sensitivity of concrete mixtures that include coarse aggregates up to 15 mm diameter and steel fibers with a length of 13 mm and a diameter of 0.25 mm. Five different concrete mixtures with steel fibers at 0%, 0.2%, 0.35%, 0.5%, and 0.8% volume ratios were fabricated. Compression tests with simultaneous measurement of strain and electrical resistance were conducted on the cubic specimens. Gauge factor and percent linearity that is a measure of error in strain sensing were calculated. Concrete mixtures with 0.5% steel fibers possess a strong linear relationship between applied strain and electrical resistance change with a gauge factor over 20 times larger than that of traditional metal strain gauges. Phenomenological models for different resistivity and gauge factors of cement paste/mortar with respect to concrete with large aggregates and short–long fiber cement composites were presented.

Silica Fume Effects on the Pull-Out Behavior of Randomly Oriented Steel Fibers from Concrete

1987 ◽  
Vol 114 ◽  
Author(s):  
Parviz Soroushian ◽  
Ziadz Bayasi
Keyword(s):  
Silica Fume ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Steel Fiber Reinforced Concrete ◽  
Pull Out ◽  
Fiber Concrete ◽  
Pull Out Strength

ABSTRACTSilica fume is known to improve the pore system of cementitious pastes and their adhesion capacity to fibers and other mix inclusions. This study has been mainly concerned with the effect of silica fume on the pull-out strength of randomly oriented steel fibers from concrete. Silica fume effects on the fresh mix workability and the overall flexural and compressive behavior of steel fiber reinforced and plain concretes were also assessed. The only variable in different fibrous and plain mixes was the fraction of portland cement substituted with silica fume. This fraction ranged from 0% to 20%.The workability of plain and fibrous mixes were obtained by slump and inverted slump cone tests, respectively. In both the flexure and compression tests on fiber concrete, the complete load-deformation relationship was obtained. The pull-out strength of randomly oriented fibers was assessed through analysis of the flexural test data.All aspects of the fresh and hardened steel fiber reinforced concrete performance considered in this study, especially the pull-out strength of randomly oriented fibers from concrete, were observed to improve with the increase in silica fume-cementitious ratio up to a certain limit, after which the trends in silica fume effects were reversed.

Properties of steel fiber reinforced shotcrete

1994 ◽  
Vol 21 (4) ◽  
pp. 564-575 ◽  
Author(s):  
Nemkumar Banthia ◽  
Jean-Francois Trottier ◽  
Denis Beaupre ◽  
David Wood
Keyword(s):  
Key Words ◽  
Steel Fiber ◽  
Steel Fibers ◽  
Significant Enhancement ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Flexural Toughness ◽  
Dry Process ◽  
Wet Process ◽  
Compressive And Flexural Strengths

Five commercially available steel fibers with different geometries were investigated both in dry-mix and in wet-mix shotcretes. In the dry process, bulk-bin bags with dry premixes were used. In the wet process, ingredients were wet-mixed centrally in a batching plant and then transported to the shooting site in ready-mix trucks. Mixes were shot on wooden forms and the rebound characteristics of the fibers and other ingredients were determined. Once hardened, shotcrete panels were sawed and cored to obtain beam specimens for flexural toughness tests and cylinders for compression tests. Hardened shotcrete specimens were also tested for boiled absorption and permeable voids. The boiled absorption and permeable voids data indicated that an adequately dense in-place shotcrete was obtained for both processes. The rebound of fibers in the dry process was found to be much higher than that in the wet process. Both compressive and flexural strengths were found to be improved because of the addition of fibers. Fibers also led to a significant enhancement in the toughness of shotcrete. Key words: shotcrete, wet mix, dry mix, steel fibers, rebound, toughness.

Experimental Study on the Flexural Impact Properties of Fiber Reinforced Lightweight Aggregate Concrete

2014 ◽  
Vol 488-489 ◽  
pp. 696-699
Author(s):  
Jian Gang Niu ◽  
Bin Wu ◽  
Jian Bao
Keyword(s):  
Experimental Study ◽  
Energy Dissipation ◽  
Steel Fiber ◽  
Lightweight Aggregate ◽  
Steel Fibers ◽  
Lightweight Aggregate Concrete ◽  
Fiber Reinforced ◽  
Aggregate Concrete ◽  
Impact Properties ◽  
Plastic Steel

Through experimental study on the flexural impact properties of different dosage of plastic-steel fiber and steel fiber reinforced lightweight aggregate concrete, the results show that energy dissipation of cracking and damaging of steel fiber reinforced lightweight aggregate concrete increase with the increase of fiber ratio. However, energy dissipation of cracking and damaging of plastic-steel fiber concrete increases in early stage and decreases later with the increase of plastic-steel fibers. Enhancement effect of energy dissipation of damaging of plastic-steel fiber is higher than steel fibers.

On axial compressive behavior of steel fiber reinforced concrete confined by FRP

2021 ◽  
pp. 136943322098165
Author(s):  
Hossein Saberi ◽  
Farzad Hatami ◽  
Alireza Rahai
Keyword(s):  
Reinforced Concrete ◽  
Experimental Test ◽  
Steel Fiber ◽  
Experimental Tests ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Test Results ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Frp Confinement

In this study, the co-effects of steel fibers and FRP confinement on the concrete behavior under the axial compression load are investigated. Thus, the experimental tests were conducted on 18 steel fiber-reinforced concrete (SFRC) specimens confined by FRP. Moreover, 24 existing experimental test results of FRP-confined specimens tested under axial compression are gathered to compile a reliable database for developing a mathematical model. In the conducted experimental tests, the concrete strength was varied as 26 MPa and 32.5 MPa and the steel fiber content was varied as 0.0%, 1.5%, and 3%. The specimens were confined with one and two layers of glass fiber reinforced polymer (GFRP) sheet. The experimental test results show that simultaneously using the steel fibers and FRP confinement in concrete not only significantly increases the peak strength and ultimate strain of concrete but also solves the issue of sudden failure in the FRP-confined concrete. The simulations confirm that the results of the proposed model are in good agreement with those of experimental tests.

scholarly journals Strength And Durability Properties Of Steel Fiber Reinforced Self Compacting Concrete

2021 ◽  
Vol 12 (5) ◽  
pp. 818-826
Author(s):  
Sumith Vangara, S Siva Rama Krishna, Venu Malagavelli, K.Tarunkumar, A. Jagadish Babu
Keyword(s):  
Steel Fiber ◽  
Design Procedure ◽  
Steel Fibers ◽  
Second Phase ◽  
Initial Surface ◽  
Fiber Reinforced ◽  
Acid Attack ◽  
Self Compacting Concrete ◽  
Surface Absorption ◽  
Durability Properties

In this present study the durability characteristics of Steel fiber reinforced Self compacting concrete (SFRSCC) is determined for M30 and M40 grade concrete mixes. Along with durability strength and sorptivity is carried out and comparison is made with Plane self-compacting concrete (SCC) by chemical resistances, Initial Surface Absorption Test (ISAT). In the present study, the rational mix design procedure for self-compacting concrete is used. SCC mixes contains large quantity of powder (material whose parcel size is 0.125 mm) to maintain the plastic yield of the properties of fresh concrete as per the general guidelines for design of SCC mixes given in the EFNARC (2005). The present project consists of two phases. In the first phase, SCC mixes for different grades are developed without steel fibers and with steel fibers. The mechanical properties like compressive strength of the different grades were studied. In the second phase, based on the experimental results, durability properties were studied with the using of specimens of size 100 mm × 100 mm × 100 mm. Durability studies like Acid attack factors, Acid-Durability factors, Sulphate attack factors, Sorptivity are studied for the Plain SCC and steel Fiber Reinforced SCC and a comparison is made.

Study on Retrofitting and Strengthening of Reinforced Concrete Beams Using Fibrous Concrete

2021 ◽  
Vol 9 (8) ◽  
pp. 1676-1684
Author(s):  
Natalia Sharma
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
Cement Matrix ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete

Abstract: Reinforced concrete structures are frequently in need of repair and strengthening as a result of numerous environmental causes, ageing, or material damage under intense stress conditions, as well as mistakes made during the construction process. RC structures are repaired using a variety of approaches nowadays. The usage of FRC is one of the retrofitting strategies. Steel fiber reinforced concrete (SFRC) was used in this investigation because it contains randomly dispersed short discrete steel fibers that operate as internal reinforcement to improve the cementitious composite's characteristics (concrete). The main rationale for integrating small discrete fibers into a cement matrix is to reduce the amount of cement used. The principal reason for incorporating short discrete fibers into a cement matrix is to reduce cracking in the elastic range, increase the tensile strength and deformation capacity and increase the toughness of the resultant composite. These properties of SFRC primarily depend upon length and volume of Steel fibers used in the concrete mixture. In India, the steel fiber reinforced concrete (SFRC) has seen limited applications in several structures due to the lack of awareness, design guidelines and construction specifications. Therefore, there is a need to develop information on the role of steel fibers in the concrete mixture. The experimental work reported in this study includes the mechanical properties of concrete at different volume fractions of steel fibers. These mechanical properties include compressive strength, split tensile strength and flexural strength and to study the effect of volume fraction and aspect ratio of steel fibers on these mechanical properties. However, main aim of the study was significance of reinforced concrete beams strengthened with fiber reinforced concrete layer and to investigate how these beams deflect under strain. The objective of the investigation was finding that applying FRC to strengthen beams enhanced structural performance in terms of ultimate load carrying capacity, fracture pattern deflection, and mode of failure or not.

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