Experimental Investigation on the Fracture Energy and Mechanical Behaviour of Hemp and Flax Fibre FRC Compared to Polypropylene FRC

2022 ◽  
Author(s):  
Ana Caroline Da Costa Santos ◽  
Paul Archbold
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Fracture Energy ◽  
Natural Fibre ◽  
Embodied Energy ◽  
Polypropylene Fibres ◽  
Flax Fibres ◽  
Flexural Tensile Strength ◽  
Hemp Fibres ◽  
Interesting Approach

Natural fibre reinforced concrete is been studied for many years as a more sustainable option to current reinforced concrete used in industry. The most common fibre materials currently adopted are steel, glass and synthetic fibres. Apart from the high oxidation and cost, their environmental impact is a serious issue as they are petroleum-based materials. This study assesses the feasibility of replacing polypropylene fibre with hemp and flax fibres. According to the inventory of carbon and energy (ICE) the embodied energy of polypropylene (PP) is 95.4MJ/kg and the embodied carbon is 4.98kgCO2/kg during its lifetime. It represents approximately 3 times more than the estimated values for vegetable fibres. For this, Different concrete mixtures reinforced by 0.5% to 1.0% of hemp, flax and polypropylene fibres were tested, and their post-crack flexural tensile strength, elastic’s modulus, compressive strength and fracture energy were evaluated. The mixtures containing hemp fibres presented properties equivalent to those containing polypropylene under the same proportion. Although both compressive and tensile strength were reduced for the mixes containing flax fibres, the Young’s modulus was 49% smaller and could be an interesting approach for applications that require better elasticity from the concrete, such as industrial floors and structures that may be submitted to impact.

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 Effect of Jute Fibre Orientation and Percentage on Strength of Jute Fibre Reinforced Concrete

2020 ◽  
Vol 9 (3) ◽  
pp. 1767-1770
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Dynamic Properties ◽  
Low Cost ◽  
Plain Concrete ◽  
Natural Fibre ◽  
Fibre Reinforced Concrete ◽  
Jute Fibre ◽  
Micro Cracks ◽  
Crack Arrester

The demerits of plain concrete are its lesser tensile strength, not significant ductility and poor resistance to cracking. Due to propagation of internal micro cracks in plain concrete causes decrease in tensile strength, hence leads concrete to brittle fracture. Addition of fibres behaves like crack arrester and enhances the dynamic properties of concrete. In India natural fibres such as bamboo, coir, jute, sisal, pineapple, banana, ramie etc are high available. Jute is a useful natural fibre for concrete reinforcement due to its easy availability and low cost. In this research, the experiments related to Jute fibre reinforced concrete (JFRC) are done by taking different fibre percentage and the compressive strength and modulus of rapture value observed. This JFRC can replace plain concrete and wood in many cases for example in door and window panels, inclined roof slabs, partition walls etc

scholarly journals Performance of ultra-high performance fibre reinforced concrete plates under impact loads

2021 ◽  
Author(s):  
Hesham Othman
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Fracture Energy ◽  
High Performance ◽  
Steel Reinforcement ◽  
Fibre Content ◽  
Fibre Reinforced Concrete ◽  
Concrete Plates ◽  
High Performance Fibre

The next generation of concrete, Ultra-High Performance Fibre Reinforced Concrete (UHP-FRC), exhibits exceptional mechanical characteristics. UHP-FRC has a compressive strength exceeding 150 MPa, tensile strength in the range of 8-12 MPa, and fracture energy of several orders of magnitudes of traditional concrete. The focus of this research is to investigate and analyze the advantage of using UHP - FRC in impact resistance structures. To achieve these goals, two experimental testing programs and major numerical investigations have been conducted. The material experimental investigation has been conducted to determine the effects of strain rate on UHP - FRC. Two parameters are investigated, namely: compressive strength (80, 110, 130, and 150 MPa); and steel fibre content (0, 1, 2, and 3%). Experimental results showed that the rate sensitivity decreases with the increase in the compressive strength ; and the dynamic enhancement of tensile strength is inversely proportional to the fibre content. The structural impact testing program focuses on the dynamic response of full - scale reinforced concrete plates as well as generating precise impact measurements. Twelve reinforced plates with identical dimensions are tested under high-mass low-velocity multi-impacts. The investigated parameters include: concrete type (NSC, HSC, and UHP - FRC), fibre volume content, and steel reinforcement ratio. The results showed that the use of UHP -FRC instead of NSC or HSC is able to change the failure mode from punching to pure flexural; and UHP -FRC containing 3% fibre has superior dynamic properties. For plates with identical steel reinforcement, the total impact energy of UHP-FRC plate containing 3% fibres is double the capacity of UHP - FRC plate containing 2% fibres , and 18 times the capacity of NSC plate. A three-dimensional finite element analysis has been performed using ABAQUS/Explicit to model multi-impacts on RC plates and the applicability is verified using existing experimental data. Concrete damage plasticity (CDP) model is adapted to define UHP - FRC. The CDP constitutive model parameters for the new material are calibrated through a series of parametric studies. Computed responses are sensitive to CDP parameters related to the tension, fracture energy, and expansion properties. The analytical results showed that the existing CDP model can predict the response and crack pattern of UHP - FRC reasonably well.

EXPERIENCE IN USING ULTRA HIGH PERFORMANCE FIBER REINFORCED CONCRETE ELEMENTS

2021 ◽  
pp. 41-50
Author(s):  
Maxim MARCHENKO ◽  
Igor CHILIN ◽  
Nikita SELYUTIN
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
High Performance ◽  
Economic Effect ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Common Solution ◽  
Flexural Tensile Strength ◽  
High Performance Fiber

The article presents examples of the use of ultra-high performance fiber reinforced concrete for load-bearing structures in Russia. Using this material with limits of compressive strength 150 MPa, flexural tensile strength 21 MPa, tensile strength 8.5 MPa, external post-tensioned structures of bridges and tanks are made instead of common solution with the steel anchors. Full-scale tests of anchors were carried out, which did not reveal signs of deformations and destruction of elements during the tension of strands, at the level of design and ultimate loads - before strands rupture. It was concluded that it is advisable to replace steel anchors with anchors from the material, which, with high strength characteristics, has ultra-low permeability and high frost resistance corresponding to the F21000 class. The estimated economic effect of such a replacement is determined by the reduced cost of these elements of structures made of ultra-high performance fiber reinforced concrete in comparison with steel.

Natural Fibre/Polypropylene Wrap Spun Yarns and Preforms for Structured Thermoplastic Composites

2011 ◽  
Vol 675-677 ◽  
pp. 427-430 ◽  
Author(s):  
Jin Hua Jiang ◽  
Ze Xing Wang ◽  
Nan Liang Chen
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Hot Pressing ◽  
Mechanical Performance ◽  
Great Influence ◽  
Natural Fibre ◽  
Thermoplastic Composites ◽  
Flax Fibres ◽  
Fibre Composites ◽  
Spun Yarns

In the past decade, natural fibre composites with thermoplastic matrices had attracted many composites manufactures for the superiority of lightweight and low-cost. A major challenge for natural fibre composites was to achieve high mechanical performance at a competitive price. Composites constructed from yarn and fabric structure preforms were better than composites made from random nonwoven mats. However, the twist structure of conventional ring spun yarns prevented the full utilization of fibre mechanical properties in the final composites. In this paper, the wrapped yarns were produced by wrap spun method with flax and polypropylene (PP), in which all flax fibres were twistless, then woven to be fabric preforms. The PP fibres served as a carrier for flax fibres during processing and became the polymer matrix in the final composites. The homogenous distribution of fibre and thermoplastic matrix in preforms could be achieved before hot pressing, so that not lead to impregnate difficultly, and prevented damage to the reinforced nature fibres during processing. Composites made from the wrapped yarn demonstrated significant tensile and peeling properties. The fabric structures (include plain, twill, and basket weave) and yarn tensile orientation (in 0°, 90°, 45°), had great influence on tensile strength and elongation of preforms. The cavity thickness of hot pressing mould had different influence on the tensile strength and peeling strength of thermoplastic composites, and the mechanical properties were superior when the thickness was 0.8-1.2 mm. The microstructure of thermoplastic composites showed uniform infiltration between layers, and had good bonding interface between flax fibre and PP matrix in composites.

scholarly journals Material Analysis of Steel Fibre Reinforced High-Strength Concrete in Terms of Flexural Behaviour. Experimental and Numerical Investigation

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1631 ◽  
Author(s):  
Czesław Bywalski ◽  
Maciej Kaźmierowski ◽  
Mieczysław Kamiński ◽  
Michał Drzazga
Keyword(s):  
Tensile Strength ◽  
Fracture Energy ◽  
High Strength Concrete ◽  
Steel Fibre ◽  
High Strength ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Strength Concrete ◽  
Flexural Tensile Strength ◽  
Crack Tip Opening

The paper presents the results of tests for flexural tensile strength (fct,fl) and fracture energy (Gf) in a three-point bending test of prismatic beams with notches, which were made of steel fibre reinforced high-strength concrete (SFRHSC). The registration of the conventional force–displacement (F–δ) relationship and unconventional force-crack tip opening displacement (CTOD) relationship was made. On the basis of the obtained test results, estimations of parameters fct,fl and Gf in the function of fibre reinforcement ratio were carried out. The obtained results were applied to building and validating a numerical model with the use of the finite element method (FEM). A non-linear concrete damaged plasticity model CDP was used for the description of the concrete. The obtained FEM results were compared with the experimental ones that were based on the assumed criteria. The usefulness of the flexural tensile strength and fracture energy parameters for defining the linear form of weakening of the SFRHSC material under tension, was confirmed. Own equations for estimating the flexural tensile strength and fracture energy of SFRHSC, as well as for approximating deflections (δ) of SFRHSC beams as the function of crack tip opening displacement (CTOD) instead of crack mouth opening displacement (CMOD), were proposed.

scholarly journals Fracture Energy of Engineered Cementitious Composites

Proceedings ◽  
2020 ◽  
Vol 63 (1) ◽  
pp. 8
Author(s):  
Anamaria Cătălina Mircea ◽  
Tudor Panfil Toader
Keyword(s):  
Tensile Strength ◽  
Fracture Energy ◽  
Ductile Material ◽  
Cementitious Composites ◽  
Engineered Cementitious Composites ◽  
Preliminary Results ◽  
Strength Limit ◽  
Flexural Tensile Strength ◽  
Strength Tests ◽  
Material Fracture

The aim of this paper is to present preliminary results regarding Engineered Cementitious Composites (ECC) and their behavior when experimentally assessing their fracture energy, by measuring the flexural tensile strength (limit of proportionality, residual). As a characteristic of a ductile material, fracture energy is an important parameter when assessing ECC post-cracking residual stresses. With 2% fibers addition in the mixtures, the crack width can be controlled and the material’s ability to bear a tensile strain-hardening capacity has been assessed. Ninety days flexural tensile strength tests were performed in order to obtain preliminary results on ECC prismatic specimens.

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