Research on Structural Characteristics of Self-Consolidating Concrete Reinforced with Steel Fibers and Utilizing Recycled Aggregate

Research on Structural Characteristics of Self-Consolidating Concrete Reinforced with Steel Fibers and Utilizing Recycled Aggregate

Syed Peer Kagaji Shaik1, N. Dedeepya2

1PG Scholar, Dept. of Civil Engineering, Chebrolu Engineering College, Chebrolu, Guntur, A.P, India.

2Asst. Professor, Dept. of Civil Engineering, Chebrolu Engineering College, Chebrolu, Guntur, A.P, India.

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Abstract - Shear failure is characterized by a rapid and brittle breakdown that happens suddenly and without notice. Reinforcing concrete beams using stirrups at tighter spacing depending on design helps to prevent these sorts of failures. When working with Reinforced Concrete (RC) components like columns, beams, and slabs, it may be challenging to use mechanical vibrators to crush concrete into all corners of the formwork due to the crowded arrangements of rebars and stirrups. Inappropriate vibration and compaction may cause macropores and empty spaces within concrete, which can reduce the material's mechanical strength and longevity. Okamura had a brilliant idea when he created Self-Compacting Concrete (SCC) in 1986 to address all of these issues. The term "self compacting concrete" (SCC) says it all: this kind of concrete compacts itself under its own weight, without the need for any outside force. Traditional reinforced concrete beams often break at the shear span due to concrete tensile failure. This is why shear failure is often abrupt and brittle; to counteract this and boost the beams' shear strength, shear reinforcement in the shape of stirrups is commonly used. The post-cracking behavior and flexural-tensile strength of concrete are both improved by adding steel fibers to the mix. The use of short steel fibers in concrete has grown substantially in the last several years. The ability of the fibers to bridge the fracture faces, when present in enough quantity, gives composite materials like steel fiber reinforced concrete (SFRC) improved post cracking behavior. Sustainable building practices are essential to prevent the further depletion of natural resources, as the construction sector inherently isn't eco-friendly. The building industry's reliance on cement and natural aggregate has grown substantially in recent years. Limestone and other natural aggregates are becoming increasingly scarce, so there's a pressing need to find alternatives to cement and aggregates made from locally available waste, such as mineral admixtures (flyash, GGBS, silica fume) for cement and recycled concrete for coarse and fine aggregates instead of natural ones.

Part - I: Research on the effects of different amounts of steel fibers on the fresh and hardened properties of self-compacting concrete with different concrete grades (M30, M50, and M70) and different dosages (0%, 0.25%, 0.5%, 0.75 %, and 1% by volume of concrete) in order to establish the ideal dosage of steel fibers. Among the mechanical qualities are the strengths in compression, splitting tensile, and flexure.

Part - II: Finding out how various steel fiber contents affect the strength of SCC and reusing concrete waste as coarse aggregate are the goals of this project. There were three different volumes of steel fibers (SF) used to strengthen the SCC (0, 0.5, and 1% of the concrete volume), and there were five various levels of recycled coarse aggregate (RCA) utilized to replace the natural coarse aggregate (NCA): 0, 25, 50, 75, and 100%. We measured the hardened SCC specimens' compressive and tensile strengths. According to the study's experimental findings, adding steel fiber to SCC improves its mechanical qualities, especially its tensile strength. A twenty percent improvement in compressive strength was achieved by including fifty percent recycled particles into the concrete mixture. The combination of recycled aggregates and steel fibers resulted in concrete that met or exceeded all expectations, surpassing those of regular concrete. The disposal of concrete debris also has a beneficial impact, since it helps the economy and lessens environmental damage.

Key Words:  Shear failure, Self-Compacting Concrete, steel fiber reinforced concrete, flyash, GGBS, silica fume.