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The IUP Journal of Structural Engineering :
Influence of Glass Fiber and Fly Ash on the Mechanical Properties of Concrete
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Conservation of natural resources is the key requirement for maintaining ecological balance. Thus, there is a need to find alternate construction materials. In that direction, the present experimental investigation is carried out to investigate the mechanical properties of glass fiber reinforced fly ash concrete with fly ash replacement of 0%, 20% and 40% by weight of cement and addition of glass fibers of length 12 mm and diameter 14 micron in four different volume fractions of 0%, 0.5%, 1% and 1.5%. Compressive strength is measured by testing standard cubes (150 mm x 150 mm x 150 mm) at the age of 7, 28 and 56 days. Flexural strength is measured by testing standard prisms (100 mm x 100 mm x 500 mm) at the age of 28 and 56 days. Splitting tensile strength and modulus of elasticity are measured by testing standard cylinders (150 mm dia x 300 mm height) at the age of 28 and 56 days.

 
 

Concrete, the most widely used structural material, is prone to cracking for various reasons. These reasons may be attributed to structural or environmental factors, but most of the cracks are formed due to inherent weakness of the material to resist tensile forces. Concrete without any fibers will develop cracks due to plastic shrinkage, drying shrinkage and volume changes. The development of these micro-cracks causes elastic deformation of concrete. Plain concrete is a brittle material having the values of modulus of rupture and strain capacity is very low. In order to meet the required values of flexural strength and enhance the strain capacity of plain concrete, fibers are being used in normal concrete. The addition of fibers in plain concrete controls the cracking due to shrinkage and also reduces the bleeding of water. The addition of glass fibers in plain concrete shows higher flexural strength than plain concrete. The randomly oriented glass fibers assist in controlling the propagation of micro-cracks present in the matrix, first by improving the overall cracking resistance of the matrix and later by bridging across even smaller cracks formed after the application of load on to the member, thereby preventing their widening into major cracks.

 
 

Structural Engineering Journal, Fly ash, Glass fiber, Tensile strength, Reinforced concrete