Research Papers - Department of Civil Engineering

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Subject: search.filters.subject.high strength concrete

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Now showing 1 - 3 of 3
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    PublicationOpen Access
    Effects of Manufactured Sand on the Properties of Normal and High Strength Concrete
    (SLIIT, 2022-02-11) Perera, J; Premadasa, R
    Manufactured Sand (MS) has been introduced as a very effective fine aggregate and is being widely used in various construction activities. Large amounts of Manufactured Sand Fines (MSF) that are less than 75 µm in particle size, are produced during the production process. Costs are incurred in separating these fines from the crushed stone and are then dumped in landfills, thus causing serious environmental issues. Studies on MSF are not well established and a handful has been done on High Strength Concrete (HSC). The key objectives of this study were to study and compare the effects that MSF have on the properties of Normal Strength Concrete (NSC) and HSC and to propose effective fines percentages that could be incorporated in them. Tests were carried out by partial replacement of MS with fines in proportions of 10%, 15% and 20% for C30 and C60 concrete and were compared with the control mixes that contained 3.36% MSF. It was identified that a 15% replacement of MSF produced effective results with the highest compressive, splitting tensile and flexural strength results and minimum water absorption in both NSC and HSC. At 15% fines content, a strength of 35.3 MPa and 63.3 MPa was achieved by the C30 and C60 concretes respectively. However, the increment of fines decreased the workability significantly. The microstructure analysis proved the densification of the microstructure at 15% MSF content. The cost analysis showed that the availability of high fines content can deduct the cost of NSC by 1.8% and HSC by 1.6%. The 10% - 15% range was identified as the most effective fines content range that can be incorporated in NSC and HSC. Results of this study can contribute to develop concrete with better performance while addressing several environmental and cost issues related to the concrete industry.
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    PublicationOpen Access
    Use of Natural Fibres to enhance tensile strength of concrete
    (ACADEMIC JOURNAL OF CIVIL ENGINEERING, 2017-07-21) Seneviratne, R.A.C.J; Tharmarajah, G; Archbold, p
    This paper discusses the influence of natural fibres on density, compressive strength and flexural strength of fibre reinforced concrete specimens. Coir fibre extracted from coconut husk was added to high strength concrete to produced 36 test cubes and 36 beam samples. Tests carried out on cube and beam samples show that compressive strength of high strength concrete reduces with addition of coir fibres. The reduction is noticed varying with the change of fibre content and fibre length. Further, comparison between cubes and beams indicate variation in density of the concrete as well. The test results show that a reduction in flexural strength in most cases except for 2% coir fibre reinforced concrete, where a slight enhancement was noticed in flexural strength.
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    PublicationOpen Access
    Experimental study On Addition of Pine Fibres to High Strength Concrete
    (researchgate.net, 2017-03) Seneviratne, R; Tharmarajah, G
    This study focuses on influence of pine fibres on unit weight, compressive strength and flexural strength of high strength concrete. Concrete mixes with 2%, 4% and 6% fibre content were produced while length of the fibres were varied from 10 mm to 40 mm. From the pine fibre reinforced mixes, 36 test cubes and 36 beam specimens were casted to identify the desired variations. Unit weight of the concrete showed significant variations in the test cubes. However, the variations of the unit weight observed in the beam specimens were low compared to the variations observed in test cubes. Compressive strength of the high strength concrete also reduced significantly with the addition of pine fibres. Also a reduction in flexural strength was observed. Variation of both compressive and flexural strength showed a relationship with the fibre content and fibre length as well.