scholarly journals Basalt reinforced concrete structures for retrofitting concrete surfaces

2018 ◽  
Vol 199 ◽  
pp. 09014
Author(s):  
Benjamin Wolf ◽  
Andrea Kustermann ◽  
Christian Schuler ◽  
Christoph Dauberschmidt ◽  
Ömer Bucak
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Load Capacity ◽  
Weather Conditions ◽  
Bending Test ◽  
Basalt Fibre ◽  
Bending Tests ◽  
Three Point Bending ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer

Reinforced concrete facades exist since decades exposed to natural weather conditions. Thus nowadays lot of them are damaged by carbonation induced corrosion and therefor require repairing and retrofitting. The aim of this research project is to investigate the possibilities of basalt fibre reinforced concrete as repairing material and also basalt rebars as additional strengthening reinforcement. Investigations with basalt fibre reinforced mortar prisms showed best results in 3 point bending tests, tensile strength and also compressive strength using 0.3 Vol.-% basalt fibres in mixture. The mechanical properties of basalt rebars made of basalt fibre reinforced polymer were tested, showing higher values in tensile strength and Young´s Modulus than comparable steel reinforcement samples. The basalt rebar reinforced concrete samples achieved higher ultimate loads in three-point bending test compared to SRC samples. But after failure in the bonding area no residual load capacity remained. Finally basalt reinforcement bars seems to be well suited for use as retrofitting material for facade elements, but numerous properties have to be examined in further investigations.

RETROFITTING PERFORMANCE OF REINFORCED CONCRETE ONE WAY SLAB

2016 ◽  
Vol 78 (5-3) ◽  
Author(s):  
Norliyati Mohd Amin ◽  
Nur Aqilah Aziz ◽  
Ilya Joohari ◽  
Anizahyati Alisibramulisi
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Bending Test ◽  
Strength Performance ◽  
Concrete Crack ◽  
Reinforced Polymer ◽  
Structural Capacity

Cracks in concrete structure have always been a big threat on the strength of the concrete. Crack is one of the common deterioration observed in reinforced concrete beams and slabs. Concrete cracking is a random process, highly variable and influenced by many factors. To restore the structural capacity of the concrete damages, retrofitting and strengthening are required. There are several techniques that are used for retrofitting and strengthening reported in the literature [1], [2], [3]. This paper investigates the strength performance of retrofitting and strengthening methods of reinforced concrete one-way slab. Flexural bending test are performed on three different concrete slab of size 1000 mm x 500 mm x 75 mm. The methods that are used for retrofit are epoxy injection and patching and for the strengthening is lamination of carbon fiber reinforced polymer. The slabs were loaded to a certain stage where the cracks were formed for retrofitting and strengthening procedure. The achieved failure mode and load capacity of the concrete slab were observed. The repaired techniques for restoring and improving the structural capacity of cracked concrete slabs were analyzed. The ultimate load achieved for the epoxy injection laminate was 19.60 kN followed by CFRP laminate and patching that were 17.64 kN and 17.03 kN respectively. While the deflection value for the three specimens were 14.42 mm, 4.49 mm and 7.036 mm.  

Effect of freeze–thaw cycling on the behaviour of reinforced concrete beams strengthened in flexure with fibre reinforced polymer sheets

2003 ◽  
Vol 30 (6) ◽  
pp. 1081-1088 ◽  
Author(s):  
Mark F Green ◽  
Aaron J.S Dent ◽  
Luke A Bisby
Keyword(s):  
Reinforced Concrete ◽  
Test Data ◽  
Concrete Beams ◽  
Design Guidelines ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Small Scale ◽  
Freeze Thaw ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer

Externally bonded fibre reinforced polymer (FRP) plates and sheets for strengthening and rehabilitating existing reinforced concrete structures have recently received a great deal of attention within the civil engineering community. Many tests have shown the benefits of FRP, but more information is required on their behaviour in cold regions. Twenty-seven small-scale concrete beams (100 mm × 150 mm × 1220 mm) were strengthened with FRP in flexure (and in some cases also in shear), subjected to up to 200 freeze–thaw cycles, and tested to failure in four-point bending. Test results were compared with those predicted by theoretical models and reasonable agreement between the tests and the models was obtained. Current design guidelines for FRP-strengthened beams were compared against the test data and were found to be adequate for the artificially aged beams. The test data also indicated that no significant damage to the glass or carbon FRP-strengthened concrete beams had occurred because of freeze–thaw cycling.Key words: concrete, rehabilitation, fibre reinforced polymers, FRP, beams, freeze–thaw, cold region engineering, flexure, external strengthening.

Combined effect of sustained load and freeze–thaw cycles on one-way concrete slabs reinforced with glass fibre – reinforced polymer

2013 ◽  
Vol 40 (11) ◽  
pp. 1060-1067 ◽  
Author(s):  
Hizia Bellakehal ◽  
Ali Zaidi ◽  
Radhouane Masmoudi ◽  
Mohamed Bouhicha
Keyword(s):  
Reinforced Concrete ◽  
Shear Capacity ◽  
Concrete Slabs ◽  
Thermal Cycles ◽  
Bending Tests ◽  
Freeze Thaw ◽  
Reinforced Concrete Slabs ◽  
Reinforced Polymer ◽  
Significant Difference ◽  
Fibre Reinforced Polymer

Flexural behaviour of reinforced-concrete slabs has been widely investigated to characterize properties and behaviour of fibre-reinforced polymer (FRP) materials as reinforcement for concrete structures. However, the short- and long-term thermal effects on FRP bars owing to the significant difference between the bars’ coefficients of thermal expansion in the transverse and longitudinal directions are still to be evaluated and may affect the bond properties and the concrete cover thickness after multiple exposures to freeze–thaw cycles. This paper presents the thermostructural behaviour of one-way concrete slabs reinforced with glass FRP (GFRP) that have previously been subjected to mechanical loads of 20% and 30% of the ultimate flexural capacity of reinforced-concrete slabs, simultaneously with short freeze–thaw cycles. Series tests were conducted on FRP-reinforced concrete slabs 500 mm wide, 195–215 mm thick, and 2500 mm long. The thermal cycles were varied from −30 to 60 °C. Four-point bending tests were conducted up to failure of the slabs. The results show that the thermomechanical load applied before bending tests increases the performance of reinforced-concrete slabs, particularly the concrete shear capacity. The deflection predicted from CSA code and ACI guidelines are very close to those obtained from experimental tests; however, the CSA code overestimates the deflection at the service load. The applied thermal cycles have no big influence on the behaviour before shear failure of concrete slabs reinforced with GFRP bars.

Development of rectangular hybrid-stiffened-plate structural system with fibre-reinforced polymer fabric composite in tension zone

2020 ◽  
pp. 136943322094875
Author(s):  
Inderpreet Kaur Dhindsa ◽  
Hardeep Singh Rai ◽  
Harvinder Singh
Keyword(s):  
Reinforced Concrete ◽  
Strength Parameter ◽  
Stiffened Plate ◽  
Basalt Fibre ◽  
Inelastic Analysis ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Collapse Failure ◽  
Plate System

Reinforced concrete plates stiffened by the beams in the orthogonal directions are widely used in bridges and buildings. Local failure occurs due to stiff beams whereas shallow beams cause global collapse failure in the plate. A theoretical model using inelastic analysis (yield line analysis) has been formulated to predict the behaviour of the rectangular hybrid-reinforced concrete-stiffened-plate system which recognized the benefits of different types of fibre-reinforced polymer fabric and ferrocement in tension side. Parametric study was also conducted to capture the influence of different parameters such as number of panels, plate aspect ratio and beam strength parameter on the flexural capacity of plate system. Designer can select the proportionate hybrid-stiffened-plate system which fails globally to avoid negative yield lines through design chart. In the experimental study, four rectangular hybrid-stiffened-plate structural systems were developed with two internal beams in each perpendicular direction incorporating ferrocement and unidirectional carbon fibre–reinforced polymer fabric, unidirectional basalt fibre–reinforced polymer fabric and bidirectional glass fibre–reinforced polymer fabric sheet on the bottom side. The experimental ultimate load was recorded maximum in unidirectional carbon hybrid–stiffened-plate system, however, unidirectional basalt hybrid–stiffened-plate system gave the best performance with respect to the cost analysis. The numerical analysis had a reasonable consistency with experimental and analytical results.

Design equations for axially loaded reinforced concrete columns strengthened with fibre reinforced polymer wraps

2000 ◽  
Vol 27 (5) ◽  
pp. 1011-1020 ◽  
Author(s):  
Michèle Thériault ◽  
Kenneth W Neale
Keyword(s):  
Reinforced Concrete ◽  
Load Capacity ◽  
Axial Loading ◽  
Concrete Columns ◽  
Experimental Investigations ◽  
Reinforced Concrete Columns ◽  
Reinforced Polymer ◽  
Axial Load Capacity ◽  
Fibre Reinforced Polymer ◽  
Future Work

Step-by-step design procedures are proposed for the axial load capacity enhancement of circular and rectangular reinforced concrete columns confined with fibre reinforced polymer (FRP) wraps. The design methods are intended for practicing engineers in that they are relatively simple to apply and are made readily available in a design code format. Commentaries are presented to explain the design philosophy and rationale leading to the various design equations. For purposes of validation, numerical results based on the proposed design equations are compared against available experimental data. Strengthening limits, as governed by creep and fatigue phenomena, are also proposed. Whenever test data are found to be too limited, conservative approaches are adopted. Various experimental investigations are suggested for future work to further validate and update the design equations.Key words: FRP strengthening, concrete columns, axial loading, confinement, design.

scholarly journals Report on laboratory tests of sandstone and porphyry for rock fracture analysis

2020 ◽  
Vol 19 (2) ◽  
pp. 087-100
Author(s):  
Jakub Gontarz ◽  
Jacek Szulej
Keyword(s):  
Tensile Strength ◽  
Rock Fracture ◽  
Strain Energy Release ◽  
Mechanical Tests ◽  
Bending Test ◽  
Compression Tests ◽  
Bending Tests ◽  
Three Point Bending ◽  
Bending Of Beams ◽  
Brazilian Method

The paper presents the results of mechanical tests of three types of rocks from stone mines in Poland. Compression tests of cubic samples, three-point bending tests of beams, bending of beams with notch and testing of tensile strength using the quasi-Brazilian method were performed. Based on the tests, the compressive strength, tensile strength, Young's modulus, and Poisson's ratios were determined. The stress intensity factor and critical strain energy release rate in mode I were determined from the bending test of the notched beams. The determined values were used as parameters of computer models which are used to verify the authors’ method of predicting the crack propagation in the Abaqus FEA system.

scholarly journals Static and Dynamic Stiffness of Reinforced Concrete Beams Strengthened with Externally Bonded CFRP Strips

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 910
Author(s):  
Michał Musiał ◽  
Tomasz Trapko ◽  
Jacek Grosel
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Stiffness ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Bending Test ◽  
Experimental Investigations ◽  
Cross Sectional ◽  
Three Point Bending ◽  
Reinforced Polymer ◽  
Externally Bonded

This paper presents experimental investigations of reinforced concrete (RC) beams flexurally strengthened with carbon fiber reinforced polymer (CFRP) strips. Seven 3300 mm × 250 mm × 150 mm beams of the same design, with the tension reinforcement ratio of 1.01%, were tested. The beams differed in the way they were strengthened: one of the beams was the reference, two beams were passively strengthened as precracked (series B-I), two beams were passively strengthened as unprecracked (series B-II) and two beams were actively strengthened as unprecracked (series B-III). Moreover, the strengthening parameters differed between the particular series. The parameters were: CFRP strip cross-sectional areas (series B-I, B-II) or prestressing forces (series B-III). The beams were statically loaded, up to the assumed force value, in the three-point bending test and deflections at midspan were registered. After unloading the beams were suspended on flexible ropes (the free-free beam system) and their eigenfrequencies were measured using operational modal analysis (OMA). The static measurements (deflections) and the dynamic measurements (eigenfrequencies) were conducted for the adopted loading steps until failure. Static stiffnesses and dynamic stiffnesses were calculated on the basis of respectively the deflections and the eigenfrequencies. The qualitative and quantitative differences between the parameters are described.

scholarly journals ACCURACY ANALYSIS OF DESIGN METHODS FOR CONCRETE BEAMS REINFORCED WITH FIBER REINFORCED POLYMER BARS / KOMPOZITAIS ARMUOTŲ BETONINIŲ ELEMENTŲ PROJEKTAVIMO METODŲ TIKSLUMO ANALIZĖ

2014 ◽  
Vol 5 (3) ◽  
pp. 123-133 ◽  
Author(s):  
Edgaras Timinskas ◽  
Rūta Jakštaitė ◽  
Viktor Gribniak ◽  
Vytautas Tamulėnas ◽  
Gintaris Kaklauskas
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Design Methods ◽  
Steel Reinforcement ◽  
Design Codes ◽  
Basalt Fibre ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Innovative Materials ◽  
The Moment

Traditional steel reinforcement does not resist corrosion and its resources are limited; therefore, carbon, glass, aramid and basalt fibre reinforced polymer bars were developed. The composite reinforcement has a high tensile strength and resistance to electromagnetic fields. Different kinds of materials and application of various surface coatings are used in the production of the composite bars. This results in different adhesion to concrete and mechanical properties of composite bars. In comparison with steel reinforcement, glass, aramid and basalt fibre reinforced polymer bars have a lower modulus of elasticity. Thus, structural rigidity provided by these bars is smaller in respect to reinforced concrete elements. Current reinforced concrete design codes and recommendations are based on empirical and simplified methods of strain evaluation, which may be inadequate for design of structures with composite bars. In this paper, an adequacy of the empirical models was checked against the experimental data of concrete beams reinforced with composite bars. The moment-curvature data of 52 beams reported in the literature and conducted by the authors were used for assessment of accuracy of design methods. In order to perform the analysis, different methods from design codes (European (LST 2007), American (ACI Committee 318 2011) and Russian (NIIZhB 2006)) and recommendations (Italian (CNR 2007) and American (ACI Committee 440 2006)) have been selected. The results of the investigation will provide engineers with more information on design of concrete beams with fibre reinforced polymer bars. This will encourage an extensive use of these innovative materials in different types of structures. Santrauka Tradicinė plieninė armatūra nėra atspari korozijai, jos iŠtekliai yra riboti, todėl buvo sukurti polimeriniai strypai, armuoti anglies, stiklo, bazalto arba aramido pluoŠtu. Ši kompozitinė armatūra pasižymi dideliu tempiamuoju stipriu ir atsparumu elektromagnetiniam laukui. Kompozitinių strypų gamyboje naudojamos skirtingos medžiagos ir taikomi įvairūs pavirŠiaus dengimo būdai, skiriasi jų mechaninės bei sukibimo su betonu savybės. Lyginant su plienine armatūra, stiklo, aramido ir bazalto kompozitiniai strypų tamprumo modulis yra mažesnis, todėl tokiais strypais armuotų konstrukcijų standumas taip pat yra mažesnis nei gelžbetoninių konstrukcijų. Dabartiniuose gelžbetoninių konstrukcijų projektavimo reglamentuose taikomi empiriniai supaprastinti deformacijų nustatymo metodai gali būti netinkami konstrukcijoms, armuotoms polimerine armatūra, projektuoti. Šiame darbe, naudojant mokslinėse publikacijose surinktų 46 eksperimentinių tyrimų ir autorių atliktų 6 sijų bandymų duomenis, buvo įvertintas kompozitais armuoto betono elementų įlinkių skaičiavimo metodų tikslumas. Analizei atlikti buvo pasirinkti Europos (LST EN 1992-1-1:2005), JAV (ACI 318M-11) ir Rusijos (SP 52-101-2003) armuotojo betono konstrukcijų projektavimo normų bei Italijos (CNR-DT 203/2006) ir JAV (ACI 440.1R-06) projektavimo rekomendacijų metodai. Gauti analizės rezultatai suteiks projektuotojams iŠsamesnę informaciją apie kompozitais armuotų betoninių elementų projektavimą, skatins didins Šių inovatyvių medžiagų naudojimo apimtį įvairiose statybinėse konstrukcijose.

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