Browsing by Author "Jathunarachchi, P.N."

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    Development of a Composite Board by Mixing Cement, Coir Fiber and Calcium Carbonate
    (Uva Wellassa University of Sri Lanka, 2013) Jathunarachchi, P.N.; Withanage, N.S.; Fernando, J.A.K.M.
    Coir fiber products have a great potential in domestic and international market in view of the world trend towards natural products. Now a days coir fiber reinforced cement boards are becoming more popular than harmful synthetic fiber reinforced cement boards. Their natural abundance, relative cheapness and instantaneous replacing ability are the strongest arguments to utilize them in the construction industry in Sri Lanka. In the Acetylene plant, calcium carbonate is the waste material. Due to its excellent filling ability and the availability, it can be used in composite board manufacturing. For the development of the coir industry and to add value to the wasting coir surplus and calcium carbonate waste from acetylene plant, it is required to investigate the possibility of using coir fiber and calcium carbonate in composite board manufacturing. This research was aimed at developing a coir fiber reinforced composite board by mixing cement, coir fiber and calcium carbonate via the determination of weight fraction of the constituents of the boards. In addition to that, the effect of various coir fiber types (Bristle fiber, Mattress fiber and Baby fiber) as well as various calcium carbonate ratios (10%, 20% and 25%) on board properties such as dry weight, thickness, density, water absorption and flexural strength were also determined. Then the possibility of using these composites in ceiling sheet manufacturing was studied. Methodology Three types of coir fibers (Bristle fiber, Mattress fiber and Baby fiber), Calcium Carbonate (CaCO3) and Ordinary Portland cement (OPC) were obtained locally. Calcium carbonate precipitates were ground and sieved using 0.5 mm sieve to obtain the calcium carbonate in powder form. Then bristle fiber and the mattress fiber were cut into 2 cm length in pieces. Preliminary studies were conducted to find out the suitable composition for the development of composite board using cement, coir fiber andcalcium carbonate. In the preliminary trials ten different composites were manufactured and evaluated its weight and other physical properties and it was observed that the composite C34B was not acceptable condition. Accordingly nine composite mixtures were selected for further testing of the physico-mechanical properties. Compositions of mixtures were given in table no 1. Ordinary Portland cement and calcium carbonate in various ratios were manually mixed with water and also coir fiber. The mixing of these ingredients was continually done until the cement, calcium carbonate and fiber paste were uniformly distributed. Then the mixture was spread out in a metal frame placed on a polythene sheet to form a board using mason’s trowel. The board was inserted in between the two plates of hydraulic press machine and it was densified by compressing it to a desired thickness using a hydraulic press. The pressure was maintained for 24 hours. The boards were removed from the press after 24 hours and soaked in the water for 7 days for curing and conditioning. The cement: calcium carbonate ratios were varied in 400:160,400:120,400:50 while cement and CaCO3 to fiber ratio was kept at a constant (10%) and the fiber types were also changed. The amount of water was fixed at 400ml per board.
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    Development of a Lightweight Composite Board by Using Coir Fiber and Calcium Carbonate
    (Uva Wellassa University of Sri Lanka, 2013) Jathunarachchi, P.N.
    Composite boards like ceiling sheets, partition boards are vital raw materials in the construction industry. These are commonly made up using asbestos fibers and cement which lead to a high cost of production and health hazards. But, there is a possibility of using coir fiber to make the composite boards as value added products in the coir industry. Therefore, this research was conducted to develop a lightweight composite board. Calcium carbonate was used as a filler to utilize the waste of acetylene plant, to reduce the cement usage further. There are nine treatment levels (C 10B, C1 OM C25Y) with three different coir fiber types (Bristle fiber, Mattress fiber and Baby fiber) and three different calcium carbonate weight ratios (10%, 20% and 25%). The experimental design was two-factor factorial with three replicates. Mechanical properties such as dry weight, thickness, density, water absorption and flexural strength were tested according to the SLS 9: Part 1: 2001. Properties of the developed boards were compared with the accepted properties of asbestos cement ceiling sheets to select the best composite board. Results revealed that, there is a significant influence from fiber type on thickness, density, water absorption and bending strength of the boards. Calcium carbonate weight ratios significantly influence on dry weight, thickness, and density and bending strength of the boards. Interaction of fiber type and calcium carbonate significantly influence only on bending strength of the boards. Except the bending strength, all tested properties of the board having Cl OB treatment have achieved the standard values of currently using composite boards made with asbestos fibers and cement. Therefore, the ClOB (board with bristle fiber and 10% of the calcium carbonate weight ratio) can be used to produce suspended ceiling boards or interior partition boards. Key words: Composite board, Cement, Coir fiber, Calcium carbonate, Mechanical properties