Impact Resistance Of Fiber Reinforced Concrete Research Articles

Dynamic mechanical properties, interface structure evolution and deformation behaviors of PVA-carbon fiber reinforced concrete with negative Poisson’s ratio design

Based on the advantages of negative Poisson's ratio (NPR) materials in controlling deformation and absorbing energy, this paper combines NPR design with the preparation of fiber reinforced concrete (FRC) to optimize the anti-dynamic load performance of FRC. In this paper, a helical auxetic yarn (Hay) with NPR effect is obtained by wrapping carbon fiber (CF) on polyvinyl alcohol fiber (PVAF) at a certain angle, and it is mixed into concrete in different forms to obtain auxetic fiber concrete. In order to explore the influence of auxetic fiber on the anti-dynamic load performance of concrete, split Hopkinson pressure bar (SHPB) test and dropping ball impact test are carried out on different FRC. The impact resistance of FRC under different impact velocities is tested, and the impact resistance behavior of FRC is analyzed by digital speckle correlation method (DSCM). The results show that in SHPB test, the anti-impact strength of the layered auxetic fiber concrete is 19.1 % higher than that of the plain concrete (PC), and its fracture energy is increased by 25.8 %. In the dropping ball impact test, its fracture energy is 5 ∼ 9 times that of PC. In addition, the results of scanning electron microscopy (SEM) and DSCM test show that the incorporation of auxetic fiber has a positive effect on improving the generation and development of internal cracks in concrete, which is expected to provide a reference for the application of NPR materials in explosion resistance, penetration resistance and impact resistance of building structures.

The impact resistance of Fiber-Reinforced concrete with polypropylene fibers and GFRP wrapping

Developments in polymer technology have introduced new choices such as using fibers and fiber-reinforced polymers (FRP) to improve the impact behavior of concrete structures. In this research, 52 concrete samples (half of which wrapped with glass fiber-reinforced polymers-GFRP) with different compressive strengths (20, 30, and 40 MPa) and polypropylene fibers were constructed. These samples were subjected to weight dropping (46.7 kg and 66.8 kg). The number of weight droppings related to 30% weight loss was recorded. Results indicated that the impact resistance of the concrete samples, corresponding to the number of weight droppings, increased using higher-strength concrete, higher polypropylene ratios, or GFRP wrapping, separately and in application with each other. However, the effects of GFRP wrapping on the improvement of the impact resistance much higher than those of the polypropylene fibers or concrete strength.

Impact Resistance of Fibre-Reinforced Concrete

Fibre-reinforced composite materials are becoming important in many areas of technological application. In addition to the static load, such structures may be stressed with short-term dynamic loads or even dynamic impact loads during their lifespan. Impact loading of construction components produces a complex process, where both the characteristics of the design itself and the material parameters influence the resultant behavior. It is clear that reinforced concrete with fibers has a positive impact on increasing of the resistance to impact loads. Results of two different impact load tests carried out on drop-weight test machine are presented in this report.

Flexural strength and impact resistance study of fibre reinforced concrete in simulated aggressive environment

In addition to being exposed to chloride and sulphate attacks, marine structures are subject to seismic and impact loads resulting from waves, impact with solid objects, and water transports. Therefore, the flexural behaviour and impact resistance of Fibre-Reinforced Concrete (FRC) in marine environment must be elucidated. However, such information is scarcely reported. Therefore, this study aims to explore the effects of simulated aggressive environments on flexural strength and impact resistance of FRC and to identify the relationship between the two parameters. Three types of fibres, namely, coconut fibre, Barchip fibre (BF), and alkali-resistant glass fibre, were used in this study. The fibre dosage ranged from 0.6% to 2.4% of the binder volume. All mixes have constant water/binder ratio of 0.37 and their compressive strengths were all exceeding 60MPa. The specimens were prepared and exposed to three different aggressive exposure environments, namely, tropical climate, cyclic air and seawater conditions, and seawater environment for up to 180days. Results indicate that flexural strength and impact resistance of FRC have a direct relationship with fibre content. Nonetheless, change in fibre type is more significant than increasing fibre dosage in enhancing flexural strength but alteration in both matters would significantly impact the impact resistance. Tensile strength of an individual BF (640MPa) is much higher than the flexural strength of the BFRC composite. Thus, failure of concrete matrix was observed to occur prior to the rupture of the fibre which in turn resulted in fibre pull out from the concrete matrix. Among the various FRC examined, FRC containing the highest BF content (2.4%) demonstrated the best flexural strength performance. The flexural strength of the Barchip FRC was observed to be increased by 11–13% in all exposure environments after 180days. The pre-crack energy absorptions, which were determined through impact load test were found to increase by 60–63% as compared to the control concrete, which exhibited no post-crack energy absorption. Meanwhile, the post-crack energy absorptions of the 2.4BF were found to range between 3.67J and 3.71J for various environmental exposure conditions. Analysis of variance (ANOVA) results showed that flexural strengths were significantly increased after six months of exposure to the various aggressive environment conditions, especially in seawater. This could be due to formation of salt crystals which contributed towards enhancing the fibre/matrix frictional bond. However, the exposure environments have no significant effect on impact resistance performance. A logarithmic relationship was found between flexural strength and total impact energy absorption.

Impact resistance of fibre-reinforced concrete

Fibre reinforcement increases the toughness of plain concrete under static compressive loading. The compressive toughness of fibre-reinforced concrete (FRC) under impact loading has not, however, previously been investigated. The current paper reviews the behaviour of high-strength fibre-reinforced concrete under uniaxial compressive impact loading. An instrumented drop weight impact machine was used to carry out compressive impact tests on various FRC systems with compressive strengths ranging from about 60 MPa to 120 MPa. The deformations of the FRC cylinders were determined using a high-speed video camera system. As expected, the compressive strength was found to increase with increasing drop height (or impact velocity). The dynamic compressive toughness was also found to increase with increasing drop height and with increasing matrix strength. It was observed that the mode of failure of the FRC was dependent upon the properties of the matrix and of the fibres, as well as on the drop height. Thus, the dynamic compressive toughness of FRC appeared to be dependent on the constitutive behaviour of the matrix, the fibre type and volume, the impact velocity and the mode of failure.

Effects of Silica Fume and Steel Fibers on Some Mechanical Properties of High-Strength Fiber-Reinforced Concrete

Abstract There are many test methods to measure the impact resistance of fiber-reinforced concrete that are complicated, time consuming, and expensive. A practical test method has been developed to measure the impact resistance of high-strength fiber-reinforced concrete (HSFRC). The equipment developed can also be used for testing aggregate impact values by simply changing the base plate of the machine. A machine was developed to measure the surface abrasion resistance of HSFRC. Testing fiber-reinforced concrete for surface abrasion resistance was found to be extremely difficult if realistic and practical results were desired. In this study the influence of silica fume on the properties of HSFRC was investigated by using silica fume at two different percentages and with three different hooked-end fibers, namely, 30/0.50, 60/0.80, and 50/0.60 length/diameter (mm/mm). Fibers were added to concrete in three different percentages of 0.5, 1.0, and 2.0% by volume of concrete. The results show that including fibers in high-strength concrete improves impact resistance, surface abrasion, and splitting tensile strength.

Strain-rate effects in fibre-reinforced concrete subjected to impact and impulsive loading

One of the most important properties of fibre-reinforced concrete is its considerably improved impact resistance compared to that of the unreinforced matrix. Although tests for determining the impact resistance can be tailored to suit practical situations, a more basic knowledge of the mechanical properties of the composite at the high strain-rates caused by impact would pave the way for more rational analysis and design of fibre-reinforced concrete structures subjected to impact. In this paper the tests conducted by various investigators to assess the impact resistance of fibre-reinforced concrete are reviewed, and some recent work conducted by the authors to obtain more basic material properties is presented.