Properties and performance of high strength fibre reinforced concrete by using steel and polypropylene fibres

Wan Jusoh, Wan Amizah (2019) Properties and performance of high strength fibre reinforced concrete by using steel and polypropylene fibres. Doctoral thesis, Universiti Teknologi Malaysia.


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Many reinforced concrete structures suffer severe degradation due to the effect from freezing and thawing, shrinkage and expansion, aggressive environment, earthquake and drastic increase of live loads. The most common sign of deterioration in concrete is cracking. Plain or unreinforced concrete is characterised by its low tensile strength, low strain capacities and brittle in nature. The tensile strength of plain concrete is considered lost once cracking occurred. Discrete short fibre reinforcement is being considered to be used for structural applications since it can reduce cracking phenomena, improve ductility and failure mode, and to some extent improve the durability of reinforced concrete. Fibre added in concrete has also been found to be effective in controlling cracks due to plastic and drying shrinkage. Shrinkage in concrete is greatly influenced by the surrounding environment and types of fibre included. Therefore, the aim of this research is to investigate the engineering and shrinkage properties of reinforced concrete containing a combination of steel and polypropylene fibres under different exposure conditions. In this study, the physical and engineering properties of fibre reinforced concrete (FRC) are investigated by using steel fibre (SF) type hooked end and polypropylene fibre (PPF) type virgin fibrillated. The objectives of the study are to assess the effect of hybrid fibres on its engineering properties, shrinkage properties under the influence of tropical climate and finally the structural performance of the FRC beams. Laboratory testing program is first conducted to determine the physical properties of the fibres. Then, the fibre reinforced concrete were tested to determine the engineering properties include compressive strength, tensile splitting strength, flexural strength, toughness, Modulus of Elasticity and shrinkage. The desired optimum mix is evaluated by the volume fractions (Vf) of 0.5%, 1.0% and 1.5%., and the combination of SF 100% + PPF 0%, SF 75% + PPF 25%, SF 50% + PPF 50%, SF 25% + PPF 75%, SF 0% + PPF 100%. The engineering properties and structural performance are then determined based on the optimum percentage using high strength concrete grade C60 to simulate concrete strength of sample manufactured at the factory. Test on the efficiency of fibres in limiting the shrinkage deformation for indoor and outdoor exposure are performed. The results indicated that the best combination of fibres is for concrete containing SF 75% + PPF 25%. The combination of SF and PPF fibres in concrete is able to enhance the engineering properties and controlling the growth of cracks in concrete. The results also indicated that concrete with both SF and PPF produced higher tensile and flexural strengths as compared with the control by 77% and 170%, respectively. The variation in relative humidity and temperature was found to have small effect on the drying shrinkage of the FRC. Results for the FRC beam test show that the percentage proportion of SF 75% + PPF 25% give the best flexural performance compared to other beams. Thus, the use of hybrid fibres, SF 75% + PPF 25%, was found to enhance the performance of either plain concrete or reinforced concrete.

Item Type: Thesis (Doctoral)
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA401-492 Materials of engineering and construction. Mechanics of materials
Depositing User: Mrs. Sabarina Che Mat
Date Deposited: 05 Aug 2021 03:14
Last Modified: 05 Aug 2021 03:14

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