Browsing by Author "De Silva, SGHMJ"

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    item: Conference-Abstract
    Finger joints and their structural performance in different exposure conditions
    Vievek, S; Sudhira, DS; Muthumala, GHMJ; De Silva, SGHMJ; Muthumala, CK
    Timber is widely used as a construction material in Sri Lanka for different application. Finger joint is one of the efficient method to minimize the timber wastages arising in the timber industry. In this study main objectives are to determine the best combination of timber materials for timber joints in different environmental conditions as well as their structural performance. Seven locally available timber species Mahohany, Kumbuk, Grandis, Teak, Jack, Banyan and Pinus were selected for the study. The physical properties (shrinkage and swelling) related to moisture content were investigated in different environment condition by using temperature and humidity chamber to choose best combination of timber materials. In addition different strength tests bending and tension were conducted for those selected combinations. Average moisture contents of timber specimens were around 12%.In wet condition all the samples shows increase in moisture content as well as volume. Modulus of elasticity varies 800 MPa - 2200MPa, modulus of rupture varies 10 MPa – 22 MPa, Similarly other test parameters were investigated and presented in the paper.
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    item: Conference-Abstract
    Incorporating natural fibres for precast slab panels
    Kumara, WGL; De Silva, S; De Silva, SGHMJ
    The addition of small closely spaced and uniformly dispersed fibres to concrete can act as a crack arrester and improves its static and dynamic properties. This is known as fibre reinforced concrete, which can also be defined as the concrete containing fibrous materials which increases its structural performance. So usage of coconut coir as a replacement material for steel reinforcement cage in reinforced precast concrete slab panel will be investigated. At the initial stage concrete cubes, cylinders and prisms were casted with different coconut coir compositions (0.5%,1.0% &1.5%) for water cement ratio of 0.3. From that it has observed that 1% of coconut coir would give the optimum result for concrete having 0.3 water cement ratio. Two sets of slab specimens as control specimen (without coconut coir) and with optimum percentage (1.0%) of coconut coir were casted and subjected to center-point line loading test (ASTM C 293) and dropping weight test (ASTM D 1557) to evaluate structural suitability and impact energy absorption of precast slab panel. Concrete permeability apparatus used to compare the water permeability between plain concrete and coconut coir mixed concrete.
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    item: Conference-Abstract
    Incorporating recycled pet fibers for green roof slab panel
    Prasanthan, T; Sudhira, DS; Subashi, DS; De Silva, SGHMJ
    High consumption of plastics leads to production of large amounts of plastic waste in today’s world and plastic is non-biodegradable so its disposal has been a problem. In order to resolve this problem, recycled PET fibers were proposed to be used as reinforcement in concrete and recent studies show that they can be accepted as successful building material. This paper has discussed the effect of adding recycled plastic fiber (PET) to the precast concrete green roof panels. This research consists of two main stages. In first stage, different volumes of recycled PET fibers, i.e. 0%, 0.5%, 1.0% and 1.5% have been added as percentages of concrete by volume. The results show that the maximum volume of PET fiber for a desired compressive and tensile strength was 1.0%. It was observed that 15.3 % of increase in compressive, 22.44% of increase in flexural strength and 18.77% of increase in split tensile strength for the addition of 1% PET fibers to the concrete. In second stage, optimum fiber percentage (1.0%) selected from stage-1 was used to produce precast concrete panels. To check the structural performance of this slab panel, center-point line loading test and dropping weight test were conducted. Finally, permeability test was conducted to compare the permeability of plain concrete and recycled PET fiber introduced concrete.