scholarly journals Mechanical Optimization of Concrete with Recycled PET Fibres Based on a Statistical-Experimental Study

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 240
Author(s):  
Alejandro Meza ◽  
Pablo Pujadas ◽  
Laura Montserrat Meza ◽  
Francesc Pardo-Bosch ◽  
Rubén D. López-Carreño
Keyword(s):  
Reinforced Concrete ◽  
Aspect Ratio ◽  
Mechanical Performance ◽  
Tensile Tests ◽  
Superior Performance ◽  
Fibre Reinforced Concrete ◽  
Marine Fauna ◽  
Recycled Pet ◽  
Pet Bottles ◽  
Fibre Aspect Ratio

Discarded polyethylene terephthalate (PET) bottles have damaged our ecosystem. Problems of marine fauna conservation and land fertility have been related to the disposal of these materials. Recycled fibre is an opportunity to reduce the levels of waste in the world and increase the mechanical performance of the concrete. PET as concrete reinforcement has demonstrated ductility and post-cracking strength. However, its performance could be optimized. This study considers a statistical-experimental analysis to evaluate recycled PET fibre reinforced concrete with various fibre dose and aspect ratio. 120 samples were experimented under workability, compressive, flexural, and splitting tensile tests. The results pointed out that the fibre dose has more influence on the responses than its fibre aspect ratio, with statistical relation on the tensional toughness, equivalent flexural strength ratio, volumetric weight, and the number of fibres. Moreover, the fibre aspect ratio has a statistical impact on the tensional toughness. In general, the data indicates that the optimal recycled PET fibre reinforced concrete generates a superior performance than control samples, with an improvement similar to those reinforced with virgin fibres.

scholarly journals Shear Behaviour of RC Beams Strengthened by Various Ultrahigh Performance Fibre-Reinforced Concrete Systems

2020 ◽  
Vol 2020 ◽  
pp. 1-18 ◽  
Author(s):  
Walid Mansour ◽  
Bassam A. Tayeh
Keyword(s):  
Reinforced Concrete ◽  
Mechanical Performance ◽  
Experimental Studies ◽  
Element Model ◽  
Shear Behaviour ◽  
Fibre Reinforced Concrete ◽  
Rc Beams ◽  
Shear Span ◽  
Depth Ratio ◽  
Normal Strength

This study presents a numerical investigation on the shear behaviour of shear-strengthened reinforced concrete (RC) beams by using various ultrahigh performance fibre-reinforced concrete (UHPFRC) systems. The proposed 3D finite element model (FEM) was verified by comparing its results with those of experimental studies in the literature. The validated numerical model is used to analyse the crucial parameters, which are mainly related to the design of RC beams and shear-strengthened UHPFRC layers, such as the effect of shear span-to-depth ratio on the shear behaviour of the strengthened or nonstrengthened RC beams and the effect of geometry and length of UHPFRC layers. Moreover, the effect of the UHPFRC layers’ reinforcement ratio and strengthening of one longitudinal vertical face on the mechanical performance of RC beams strengthened in shear with UHPFRC layers is investigated. Results of the analysed beams show that the shear span-to-depth ratio significantly affects the shear behaviour of not only the normal-strength RC beams but also the RC beams strengthened with UHPFRC layers. However, the effect of shear span-to-depth ratio has not been considered in existing design code equations. Consequently, this study suggests two formulas to estimate the shear strength of normal-strength RC beams and UHPFRC-strengthened RC beams considering the effect of the shear span-to-depth ratio.

Les bétons renforcés de fibres d'acier et la multifissuration

2000 ◽  
Vol 27 (4) ◽  
pp. 774-784 ◽  
Author(s):  
Benoît Bissonnette ◽  
Yves Therrien ◽  
Richard Pleau ◽  
Michel Pigeon ◽  
François Saucier
Keyword(s):  
Reinforced Concrete ◽  
Large Scale ◽  
Intrinsic Property ◽  
Tensile Tests ◽  
Experimental Program ◽  
Fibre Reinforcement ◽  
Fibre Reinforced Concrete ◽  
Restrained Shrinkage ◽  
Test Results ◽  
Multiple Cracking

This paper presents the results of an investigation aimed at establishing if multiple cracking can be an intrinsic property of steel fibre reinforced concrete (SFRC) in the hardened state and identifying the conditions to obtain it systematically. For this purpose, uniaxial restrained shrinkage tests and tensile tests were performed on large-scale SFRC specimens. The parameters studied in the experimental program were the fibre content (0-100 kg/m3), the fibre geometry, and the water to cement ratio of the concrete matrix (w/c = 0.40-0.80). The test results tend to indicate that multiple cracking is not a property of SFRC as such, at least within the range of concrete matrices and fibre contents investigated and that were intended to be compatible with practical considerations. While it does not mean that fibre reinforcement is not effective in terms of crack control, it is important to be careful in the analysis of test results where the effect of the restraining and exposure conditions might have been significant.Key words: cracking, drying shrinkage, fibre-reinforced concrete, multiple cracking, repairs, restrained shrinkage, steel fibres, tension.

scholarly journals Recent advances in structural fibre-reinforced concrete focused on polyolefin-based macro-synthetic fibres

2020 ◽  
Vol 70 (337) ◽  
pp. 206 ◽  
Author(s):  
M. G. Alberti ◽  
A. Enfedaque ◽  
J. C. Gálvez ◽  
A. Picazo
Keyword(s):  
Reinforced Concrete ◽  
Reinforce Concrete ◽  
Tensile Tests ◽  
Environmental Benefits ◽  
Fibre Reinforced Concrete ◽  
Steel Fibres ◽  
Lower Weight ◽  
Steel Bars ◽  
Future Challenges ◽  
And Storage

Fibre-reinforced concrete (FRC) allows reduction in, or substitution of, steel-bars to reinforce concrete and led to the commonly named structural FRC, with steel fibres being the most widespread. Macro-polymer fibres are an alternative to steel fibres, being the main benefits: chemical stability and lower weight for analogous residual strengths of polyolefin-fibre-reinforced concrete (PFRC). Furthermore, polyolefin fibres offer additional advantages such as safe-handling, low pump-wear, light weight in transport and storage, and an absence of corrosion. Other studies have also revealed environmental benefits. After 30 years of research and practice, there remains a need to review the opportunities that such a type of fibre may provide for structural FRC. This study seeks to show the advances and future challenges of use of these polyolefin fibres and summarise the main properties obtained in both fresh and hardened states of PFRC, focussing on the residual strengths obtained from flexural tensile tests.

Mechanical Properties and Fracture Energy of Concrete Beams Reinforced with Basalt Fibres

2022 ◽  
Author(s):  
Ana Caroline Da Costa Santos ◽  
Paul Archbold
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Fracture Energy ◽  
Mechanical Performance ◽  
Plain Concrete ◽  
Natural Fibre ◽  
Bending Test ◽  
Natural Material ◽  
Fibre Reinforced Concrete ◽  
Steel Fibres

Fibre-reinforced concrete (FRC) is widely employed in the construction industry, with assorted fibre types being used for different applications. Typically, steel fibres give additional tensile strength to the mixture, while flexible fibres may be used in large sections, such as floor slabs, to control crack width and to improve the handling ability of precast sections. For many reasons, including durability concerns, environmental impact, thermal performance, etc, alternatives to the currently available fibres are being sought. This study examines the potential of using basalt fibres, a mineral and natural material, as reinforcement of concrete sections in comparison to steel fibres and plain concrete mix. Mixes were tested containing 0.5% and 1.0% of basalt fibres measuring 25mm length, 0.5% of the same material with 48mm length and steel fibres measuring 50mm by 0.05%, 0.1%, 0.15% and 0.2% of the concrete volume. For the mechanical performance analysis, the 3-point bending test was led and the fracture energy, Young’s modulus and tensile strength in different moments of the tests were calculated. When compared to the control mixtures and the steel-fibre-reinforced concrete, the mixes containing basalt had a reduction in their elastic modulus, representing a decrease in the concrete brittleness. At the same time, the fracture energy of the mixtures was significantly increased with the basalt fibres in both lengths. Finally, the flexural strength was also higher for the natural fibre reinforced concrete than for the plain concrete and comparable to the results obtained with the addition of steel fibres by 0.15%.

scholarly journals Experimental and Numerical Investigation on the Size Effect of Ultrahigh-Performance Fibre-Reinforced Concrete (UHFRC)

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5714
Author(s):  
Andreas Lampropoulos ◽  
Demetris Nicolaides ◽  
Spyridon Paschalis ◽  
Ourania Tsioulou
Keyword(s):  
Reinforced Concrete ◽  
Size Effect ◽  
Numerical Models ◽  
Tensile Tests ◽  
Tensile Behaviour ◽  
Fibre Reinforced Concrete ◽  
Direct Tension ◽  
Flexural Tests ◽  
Direct Tensile ◽  
Efficiency And Reliability

In the last few years, there has been increasing interest in the use of Ultrahigh-Performance Fibre-Reinforced Concrete (UHPFRC) layers or jackets, which have been proved to be quite effective in strengthening applications. However, to facilitate the extensive use of UHPFRC in strengthening applications, reliable numerical models need to be developed. In the case of UHPFRC, it is common practice to perform either direct tensile or flexural tests to determine the UHPFRC tensile stress–strain models. However, the geometry of the specimens used for the material characterization is, in most cases, significantly different to the geometry of the layers used in strengthening applications which are normally of quite small thickness. Therefore, and since the material properties of UHPFRC are highly dependent on the dimensions of the examined specimens, the so called “size effect” needs to be considered for the development of an improved modelling approach. In this study, direct tensile tests have been used and a constitutive model for the tensile behaviour of UHPFRC is proposed, taking into consideration the size of the finite elements. The efficiency and reliability of the proposed approach has been validated using experimental data on prisms with different geometries, tested in flexure and in direct tension.

The Study of Using Fly Ash to Produce Ultra High Performance Fibre Reinforced Concrete

2012 ◽  
Vol 535-537 ◽  
pp. 1889-1892 ◽  
Author(s):  
Valeria Corinaldesi
Keyword(s):  
Reinforced Concrete ◽  
Fly Ash ◽  
Ceramic Material ◽  
High Performance ◽  
Mechanical Performance ◽  
Steel Fibers ◽  
Fibre Reinforced Concrete ◽  
Mineral Addition ◽  
Tension Tests ◽  
High Performance Fibre

Ultra High Performance Fibre Reinforced Concrete (UHPFRC) is a cement-based material, which behaves like a low-porosity ceramic material with excellent mechanical performance. This work was aimed to study soft cast (flowable at casting time) UHPFRCs and, in particular, UHPFRC mechanical performance was monitored by means of compression, bending and splitting tension tests. Two different kinds of mineral addition were compared: silica fume and fly ash. In the case of fly ash, several water to cement ratios were tested ranging from 0.20 to 0.25. Moreover, steel fibers and acrylic-based superplasticizer were employed to prepare the UHPFRC mixtures.

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