Experimental Investigation of Projectile Impact Local Damage on Cementitious Composite Slabs

2013 ◽  
Vol 486 ◽  
pp. 301-306 ◽  
Author(s):  
Tomáš Vavřiník ◽  
Jan Zatloukal
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Experimental Program ◽  
Local Damage ◽  
Fiber Reinforced ◽  
Projectile Impact ◽  
Composite Slabs

This paper describes the projectile impact resistance of cement based composite slabs. The resistance is evaluated on the basis of the presented experimental program. In the experiment, local damage was inflicted by impact of defined projectiles on specimens made from normal strength concrete (NSC), steel fiber-reinforced concrete (FRC), ultra-high performance concrete (UHPC) and ultra-high performance fiber-reinforced concrete (UHPFRC) with different fiber content. Deformable ogive-nose projectiles with diameter of 7.92 mm and mass of 8.04 g with impact velocity about 700 m/s were in the experiment hitting center of the specimens. Data from the measured and visual evaluation of specimen damage were used for comparison of specimen projectile impact resistance in relation to the used material.

scholarly journals Resistance of an Optimized Ultra-High Performance Fiber Reinforced Concrete to Projectile Impact

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 63
Author(s):  
Anna L. Mina ◽  
Michael F. Petrou ◽  
Konstantinos G. Trezos
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Depth Of Penetration ◽  
Projectile Impact ◽  
High Performance Fiber

The scope of this paper is to investigate the performance of ultra-high performance fiber reinforced concrete (UHPFRC) concrete slabs, under projectile impact. Mixture performance under impact loading was examined using bullets with 7.62 mm diameter and initial velocity 800 m/s. The UHPFRC, used in this study, consists of a combination of steel fibers of two lengths: 6 mm and 13 mm with the same diameter of 0.16 mm. Six composition mixtures were tested, four UHPFRC, one ultra-high performance concrete (UHPC), without steel fibers, and high strength concrete (HSC). Slabs with thicknesses of 15, 30, 50, and 70 mm were produced and subjected to real shotgun fire in the field. Penetration depth, material volume loss, and crater diameter were measured and analyzed. The test results show that the mixture with a combination of 3% 6 mm and 3% of 13 mm length of steel fibers exhibited the best resistance to projectile impact and only the slabs with 15 mm thickness had perforation. Empirical models that predict the depth of penetration were compared with the experimental results. This material can be used as an overlay to buildings or to construct small precast structures.

Influence of Different Mechanical Properties to the Concrete Penetration Resistance

2014 ◽  
Vol 982 ◽  
pp. 119-124 ◽  
Author(s):  
Tomáš Vavřiník ◽  
Jan Zatloukal
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
High Speed ◽  
High Performance ◽  
High Performance Concrete ◽  
Penetration Resistance ◽  
Fiber Reinforced Concrete ◽  
Experimental Program ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete

This paper describes influence of different mechanical properties to the concrete penetration resistance. The resistance is evaluated on the basis of the presented experimental program. In the experiment, non-deformable ogive-nose projectiles with diameter of 7.92 mm and mass of 8 g with impact velocity of about 700 m/s were hitting center of the specimens. Determination of the concrete penetration resistance was than based on projectile residual velocity obtained from high-speed camera record. The specimens were made from high strength concrete, steel fiber-reinforced concrete, ultra-high performance concrete and ultra-high performance fiber-reinforced concrete with different fiber content. The concrete penetration resistance was evaluated on total 32 specimens. Influence of mechanical properties, addition of coarse aggregate and steel fibers were discussed. Mechanical properties of the tested materials were investigated on total 125 specimens. Data from the measurements were used for creation of new RHT concrete models in Autodyn. In order to confirm experiment's setup and results, numerical analysis was performed in Autodyn. Results of the numerical simulations were compared to the experimental program.

Behaviour of Uniaxial Reinforced Concrete Columns Strengthened with Ultra-High Performance Concrete and Fiber Reinforced Polymers

2021 ◽  
Vol 28 (2) ◽  
pp. 54-72
Author(s):  
Abd-al-Salam Al-Hazragi ◽  
Assim Lateef
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Columns ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced Polymers ◽  
Tension Zone ◽  
Fiber Reinforced ◽  
Group A ◽  
Group B

This article investigates the behaviour of strengthened concrete columns using jacketing ultra-high-performance fiber reinforced concrete (UHPFRC) and carbon fiber-reinforced polymer (CFRP) under uniaxial loaded. The jacket was connected to the column core using shear connectors and (CFRP) fixed as a strip on the tension zone between the column cores and the jacketing. Seven column samples of square cross-section (120 x120) mm at the midsection with overall length of 1250 mm were cast using normal strength concrete (NSC) and having similar longitudinal and transverse reinforcement. The samples were made and tested under axial load at eccentricity equal to 120 mm up to failure. Test parameters were the thickness of jackets (25 and 35) mm and the width of CFRP (0,8, and 12) cm. Column specimens were tested, one of them was reference without any strengthening, and the other specimens divided into two groups (A, and B), and each group included three specimens based on the parameters. Group (A) has UHPFRC jacket thickness 25 mm and CFRP width (0,8, and 12) cm respectively, and group (B) has UHPFRC jacket thickness 35 mm and CFRP width (0,8, and 12) cm respectively. The outcomes of the article show that increasing the thickness of jacket, and width of CFRP lead to increase in the load carrying capacity about (110.5%,168.4%, and 184.2%) for group A, and (157.9%,226.3%, and 263.2%) for group B compared with the reference column due to delay in the appearance of cracks and their distribution. The mid-height lateral displacement of columns was decreased about (66.6%,42.3%, and 35.9%) for group A, and (46.15%,38.46%, and 32.3%) for group B, also the axial deformation of specimens decreased about (71.7%,60.86%, and 55.86%) for group A, and (65.5%,60.5%, and 53.4) for group B compared with the reference column. The ductility of columns that were strengthened with UHPFRC jacket only was increased about (13.67%,19.66%) for thickness(25,35) mm respectively, because of that UHPFRC jacket was contented on steel fibers, and the percentage decrease of ductility was about (5.1%,and 12%) for group (A), (1%,and 9.4%) for group (B) when bonded CFRP in the tension zone with width (8 ,and 12) cm respectively. The results show improvement in the initial and secant stiffness when, increased the thickness of jacket, and width of CFRP because of increase in the size of columns and improvement in the modulus of elasticity. The toughness increase was about (273.97%,301.55%, and 304.5%) for group A, and (453.69%,511.93%, and 524.28%) for group B compared with the reference column because of increase in the size of specimens and delay the appearance of cracks.

scholarly journals Effect of Strengthening Methods on Two-Way Slab under Low-Velocity Impact Loading

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5603
Author(s):  
Sun-Jae Yoo ◽  
Tian-Feng Yuan ◽  
Se-Hee Hong ◽  
Young-Soo Yoon
Keyword(s):  
Reinforced Concrete ◽  
High Performance Concrete ◽  
Impact Load ◽  
Reaction Force ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Low Velocity Impact ◽  
Fiber Reinforced ◽  
Reinforced Concrete Slabs ◽  
The Impact

In this study, the performance of reinforced concrete slabs strengthened using four methods was investigated under impact loads transferred from the top side to bottom side. The top and bottom sides of test slabs were strengthened by no-slump high-strength, high-ductility concrete (NSHSDC), fiber-reinforced-polymer (FRP) sheet, and sprayed FRP, respectively. The test results indicated that the test specimens strengthened with FRP series showed a 4% increase in reaction force and a decrease in deflection by more than 20% compared to the non-strengthened specimens. However, the specimen enhanced by the NSHSDC jacket at both the top and bottom sides exhibited the highest reaction force and energy dissipation as well as the above measurements because it contains two types of fibers in the NSHSDC. In addition, the weight loss rate was improved by approximately 0.12% for the NSHSDC specimen, which was the lowest among the specimens when measuring the weight before and after the impact load. Therefore, a linear relationship between the top and bottom strengthening of the NSHSDC and the impact resistance was confirmed, concluding that the NSHSDC is effective for impact resistance when the top and bottom sides are strengthened. The results of the analysis of the existing research show that the NSHSDC is considered to have high impact resistance, even though it has lower resistance than the steel fiber reinforced concrete and ultra-high-performance-concrete, it can be expected to further studies on strengthening of NSHSDC.

scholarly journals Influence of Cracking on Oxygen Transport in UHPFRC Using Stainless Steel Sensors

2019 ◽  
Vol 10 (1) ◽  
pp. 239
Author(s):  
Ana Martínez-Ibernón ◽  
Marta Roig-Flores ◽  
Josep Lliso-Ferrando ◽  
Eduardo J. Mezquida-Alcaraz ◽  
Manuel Valcuende ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Oxygen Availability ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced ◽  
Ultra High Performance Concrete ◽  
Cracking Behavior

Reinforced concrete elements frequently suffer small cracks that are not relevant from the mechanical point of view, but they can be an entrance point for aggressive agents, such as oxygen, which could initiate the degradation processes. Fiber-Reinforced Concrete and especially Ultra High Performance Concrete increase the multi-cracking behavior, reducing the crack width and spacing. In this work, the oxygen availability of three types of concrete was compared at similar strain levels to evaluate the benefit of multi-cracking in the transport of oxygen. The types of concrete studied include traditional, High-Performance, and Ultra-High-Performance Fiber-Reinforced Concrete with and without nanofibers. To this purpose, reinforced concrete beams sized 150 × 100 × 750 mm3 were prepared with embedded stainless steel sensors that were located at three heights, which have also been validated through this work. These beams were pre-cracked in bending up to fixed strain levels. The results indicate that the sensors used were able to detect oxygen availability due to the presence of cracks and the detected differences between the studied concretes. Ultra High Performance Concrete in the cracked state displayed lower oxygen availability than the uncracked High Performance Concrete, demonstrating its potential higher durability, even when working in cracked state, thanks to the increased multi-cracking response.

scholarly journals Economic viability of ultra high-performance fiber reinforced concrete in prestressed concrete wind towers to support a 5 MW turbine

2017 ◽  
Vol 10 (1) ◽  
pp. 1-14 ◽  
Author(s):  
P. V. C. N. GAMA ◽  
T. N. BITTENCOURT
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Fiber Reinforced Concrete ◽  
Economic Viability ◽  
Fiber Reinforced ◽  
Limit States ◽  
Advantages And Disadvantages ◽  
High Performance Fiber

Abstract The Ultra-High Performance Fiber-Reinforced Concrete is a material with remarkable mechanical properties and durability when compared to conventional and high performance concrete, which allows its use even without the reinforcement. This paper proposes the design of prestressed towers for a 5 MW turbine, through regulatory provisions and the limit states method, with UHPFRC and the concrete class C50, comparing the differences obtained in the design by parametric analysis, giving the advantages and disadvantages of using this new type of concrete. Important considerations, simplifications and notes are made to the calculation process, as well as in obtaining the prestressing and passive longitudinal and passive transverse reinforcement, highlighting the shear strength of annular sections comparing a model proposed here with recent experimental results present in the literature, which was obtained good agreement. In the end, it is estimated a first value within the constraints here made to ensure the economic viability of the use of UHPFRC in a 100 m prestressed wind tower with a 5 MW turbine.

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