EFFECTS OF WOOD:CEMENT RATIO ON MECHANICAL AND PHYSICAL PROPERTIES OF THREE-LAYERED CEMENT-BONDED PARTICLEBOARDS FROM LEUCAENA LEUCOCEPHALA

Three-layered cement-bonded particleboards (CBPs) from 8- and 16-year-old Leucaena leucocephala trees were manufactured in the laboratory and examined for suitability as a construction material. Four wood—cement ratios, i.e. 1:1.75, 1:2.0, 1:2.25 and 1:2.5 were used. A combination of aluminium sulphate and sodium silicate was used as cement accelerator. Wood particles retained at 2 mm sieve size were used for the core layer and a combination of 1 and 0.5 mm were used for the outer layers. The mechanical and physical properties of the boards were evaluated based on MS 544:2001. The modulus of rupture ranged from 7.68 to 11.22 MPa and modulus of elasticity, 2981 to 4002 MPa. The internal bond ranged from 0.59 to 0.90 MPa. The water absorption and thickness swelling after 24 hours soaking in water ranged from 12.42 to 19.04% and 0.38 to 0.70% respectively. Generally, the CBPs produced from 8-year-old trees gave better mechanical strength than the 16-year-olds. Papan serpai tiga lapis berikatan simen (CBP) yang dihasilkan daripada Leucaena leucocephala berusia 8 tahun dan 16 tahun dihasilkan di makmal dan dikaji kesesuaiannya sebagai bahan binaan. Empat nisbah kayu:simen iaitu 1:1.75, 1:2.0, 1:2.25 dan 1:2.5 digunakan. Campuran aluminium sulfat dan natrium silikat digunakan sebagai pencepat penghidratan simen. Serpai kayu yang tidak melepasi tapisan bersaiz 2 mm diguna untuk menghasilkan lapisan teras dan campuran serpai kayu bersaiz 1 mm dan 0.5 mm diguna untuk menghasilkan lapisan luar. Ciri-ciri fizikal dan mekanik papan dinilai berdasarkan MS 544: 2001. Nilai modulus kepecahan berjulat antara 7.68 MPa hingga 11.22 MPa manakala nilai modulus kekenyalan antara 2981 MPa hingga 4002 MPa. Nilai kekuatan ikatan dalaman adalah antara 0.59 MPa hingga 0.90 MPa. Nilai serapan air dan pembengkakan ketebalan setelah sampel direndam selama 24 jam di dalam air masing-masing berjulat antara 12.42% hingga 19.04% dan 0.38% hingga 0.70%. Secara umumnya, CBP yang dihasilkan daripada pokok berusia 8 tahun mempunyai kekuatan mekanik yang lebih baik daripada pokok berusia 16 tahun.