95 PHYSICO-MECHANICAL PROPERTIES OF CEMENT BONDED BOARD FROM MIXTURE OF AGRO-WASTE. 1 Ajayi Babatunde, 2 Taiwo A.A, 1 Olufemi B 1 Akinbodunse V.A, 1 Adamolekun O. R. 1 Department of Forestry and Wood Technology, Federal University of Technology Akure and 2 Department of Architecture, Federal University of Technology PMB 704 Akure, Ondo State, Nigeria. E-mail: babatundeajayi2000@yahoo.com ABSTRACT Physico-mechanical properties of cement bonded board produced from rice chaff and maize stalk at the blending proportions (BP) of 100:0, 75:25, 50:50, 25:75, 0:100; and mixing ratio (MR) of cement to agro- waste at 2:1 and 3:1 were investigated. The influence of BP and MR on the water absorption (WA), thickness swelling (TS), modulus of rupture (MOR) and modulus of elasticity (MOE) were determined. Increase in BP and MR caused decrease in WA and TS and increase in MOR and MOE. Board produced from 100% rice chaff (100:0) has the lowest physico-mechanical properties than that from maize stalk (0:100). Board produced from BP 25:75 and MR 3:1 exhibits highest properties. The WA, TS, MOR and MOE were significantly affected by the MR and BP. The agro-waste residues are suitable raw material for the manufacture of value- added panel products for core and social housing for low income citizens. KEYWORDS: Blending proportion, Mixing ratio, Physical and Mechanical Properties, Agro-waste and Cement Bonded Board INTRODUCTION The advent of technology provides solutions to environmental health and economic implications of bio- residues such as wastes from agriculture and wood processing outfits by the production of value added panel products (Ajayi, 2000 and 2006a) for economic growth and use. These requirements justified a series of research efforts aimed at achieving different objectives in the judicious use of agricultural residues and wastes, In 2006, the annual global production of lignocellulosic fibres from agricultural crops was about 4 billion tons, of which roughly 60% came from agricultural crops and 40% from forests (Justiz-smith et al; 2008). There is the growing need therefore to use these non-valuable huge agricultural wastes for the production of value- added boards. The benefits derivable include: increase farmers’ income and alleviate poverty, increase raw material supplies for construction, create job opportunities, increase food production and reduce pressure on other forest resources (Ajayi 2006a). Agricultural residues have been steadily gaining popularity as alternative sources of raw materials for the manufacture of cement-bonded boards (Ma et al; 2000 Ndazi et al; 2005; and Ajayi, 2011a). These agricultural wastes and residues include bagasse, banana stem, maize stalk, yam stem; coffee chaff and cotton stalk among others (Ajayi 2003, Adewopo, 2007, Ajayi, 2006a and 2006b). A cement-bonded particleboard is a value-added composite material made from wood/ agriculture particles, inorganic binder and a catalyst. The product can be formed into different shapes to meet specific end uses. The development and manufacture of this product is due to: 1) recognition of the suitability of a wide range of raw materials for board production, 2) desires to increase bio-wastes resources, 3) acceptability of the new products in the market and construction industry, and 4) the desire to protect forest biodiversity (Ajayi, 2006a). Cement-bonded board is considered to be a suitable raw material for internal and external buildings construction due to its inherent qualities such as resistance to insect, termite and fungal attack; high resistance to moisture, freezing and fire; good insulation properties, durability and nailing ability and because its dust is