Kualitas Papan Semen dari Sekam Padi (Oryza sativa Linn)

Abstract

INTRODUCTION: Recently, plenty of waste of paddy as a lignosellulosic organic material was obtained due to increasing. However, utilization of rice hull still not optimally done and it has low economic value. In some countries, the lignosellulosic waste becomes a problem because it pollutes the environment. Many researches showed that rice hull can be used in several necessity product, such as, alternative energy source, particle board, and cement bonded board and this research was to find out the substitution of solid wood and it may solve environmental problem. The objective of the study was to evaluate the effect of cement portion variation on the physical and mechanical properties of cement bonded boards from rice hull. MATERIAL AND METHOD: The cement bonded board were manufacture using rice hull particles (Oryza sativa,L.), portland cement, calcium chloride, and water. The rice hull particles were immersed in cold water for 24 hours prior to board manufacture. The rice hull-cement-water ratios applied were 1,00 : 2,75 : 1,38 ; 1,00 : 3,00 : 1,50, and 1,00 : 3,25 : 1,63 with used calcium chloride at 2 % of total weight. Manufacturing process the cement bonded board from rice hull can be divided into several operations including: the preparation of a raw material, mixing, mat forming (30 cm x 30 cm x 1 cm) at target density was 1,2 g/cm³, pressing (35 kgf/cm²), setting (60ºC for 24 hours), hardening (room temperature for 2 weeks), drying (80ºC for 10 hours), conditioning (2 weeks) and the test of physical and mechanical properties of cement bonded board. This experiment was designed using a Completely Randomized Design (CRD) with one treatment and three replicates. RESULT: Result showed that moisture content of cement bonded board is 8,01- 9,33%, density 1,15-1,26 g/cm³, for immersion period of 2 hours showed thickness swelling 0,12-0,35%, linear expansion 0,21-0,32%, and water absorption 20,98-24,78% while the immersion period of 24 hours thickness swelling 0,32-0,51%, linear expansion 0,29-0,33%, and water absorption 24,89-28,14%, modulus of elasticity 14.324,16-22.488,66 kgf/cm², modulus of rupture 22,99-29,63 kgf/cm², internal bond 0,45078-0,58797 kgf/cm², and screw holding strength 19,75-23,39 kgf. Physical properties of the boards requirement fulfilled the JIS A 5417 (1992) standard and Bison (1975) while mechanical properties of the boards were MOE, MOR, IB, screw holding strength did not fulfill the JIS A 5417 (1992) standard and Bison (1975). Result of research showed that increase in cement portion did not significantly effect the properties of cement bonded board from rice hull.