Introducing a New shape of Steel Fibres and Studying its Effect on the Mechanical Properties of Concrete.

Abstract

The marked brittleness with low tensile strength of plain concrete can be overcome by the addition of steel fibres (SF). This paper investigates the mechanical properties of steel fibre reinforced concrete (SFRC) and spiral steel fibre reinforced concrete (SSFRC). The properties included compressive and splitting tensile strength, modulus of rupture, and toughness index. The steel fibres were hook-ended shape with aspect ratio (l/d=50). The introduced shape was spiral steel fibres (SSF) with diameter of spiral=1.5 cm. The two shapes of steel fibres were added at the volume fraction of 0.5%, 1.0%,2.0%, and 3.0%. All the mechanica1 properties of SFRC enhanced up to 2.0% volume fraction of fibers, whereas the mechanical properties of SSFRC enhanced up to 3.0% volume fraction. The compressive strength of SFRC and SSFRC enhanced by 43.4% and 65% respectively relative to plain concrete. The splitting tensile strength of SFRC and SSFRC enhanced by 52.6% and 147% respectively relative to plain concrete. The modulus of rupture of SFRC and SSPRC enhanced by 137.5%, and 62.5% respectively relative to plain concrete. The toughness index of SPRC improved with increasing the fraction up to 2.0%. The indices I 5 , I 10 , and I 20 registered values of 10.7, 20.5, and 35.1 at 2.0% fraction. The toughness index of SSFRC improved with increasing the fraction up to 3.0%. The indices I 5 , I 10 , and I 20 registered values of 9.76, 18.78, and 35.8, respectively, at 3.0% volume fraction.

Improvement Concrete Barriers to Resist Pentration of Missiles

“…The results are reported in Table (7), and Figures (12), (13), (14) and (15). The impact resistance at initial cracking of SFC (compared to plain concrete) increased from about 2.5 times with 1.0% fibers content by volume to 5 times with 2.0% fibers content, but decreased to about 4.5 times with fibers content 3.0%, as shown in figures (12), (14).…”

“…The results are reported in Table (7), and Figures (12), (13), (14) and (15). The impact resistance at initial cracking of SFC (compared to plain concrete) increased from about 2.5 times with 1.0% fibers content by volume to 5 times with 2.0% fibers content, but decreased to about 4.5 times with fibers content 3.0%, as shown in figures (12), (14). using SSFC, the impact resistance at initial cracking increased from about 3 times with 1.0% fibers content by volume to 4 times with 3.0% fibers content by volume, also impact resistance at failure increased greatly from 90 times to 97.5 times to about 100 times with fibers contents 1.0%, 2.0% and 3.0% by volume, respectively as shown in figures (13), (15).…”

Using Ferrocement to Resist Penetration of Hyper-Velocity Objects

“…Numerous studies were conducted on behavior of reinforced concrete target subjected to missile impact; studies were mostly focused on concrete properties, and how to prevent excessive local damage and collapse of the target [7][8][9][10], that's by enhancement of concrete properties. Different from plain concrete in which mainly the strength dominates its ability of resisting penetration, reinforced concrete may be influenced by both the concrete strength and the amount of reinforcement.…”