DEVELOPMENT OF COIR FIBRE CEMENT AND CASHEW NUT SHELL LIQUID BONDED COMPOSITE BOARDS

Abstract

There are enormous Agricultural Residues (AR) such as Coir Dust (CD), Coir Fibre (CF), and cashew nut shells, which are sources of environmental pollution in Nigeria. However, these residues can be deployed in Cement Composite (CC) production as alternative building material. Ce0ment composites are however susceptible to unwarranted dimensional instability which can be curtailed by the incorporation of polymeric substances such as Cashew Nut Shell Liquid (CNSL). Literature on properties of CCs produced from AR with the incorporation of CNSL is sparse. Therefore, this study was designed to investigate the properties of CCs made from CD, CF and CNSL. Cashew nuts were collected from a local site at Ogbomoso, milled to about 3.35 mm sizes. The CNSL was chemically extracted from the milled particles using IS methods, while coconut husk were reduced to obtain CF and CD using IS and ASTM methods. Cement composites were produced at four levels of CF (5.0, 7.5, 10.0 and 15.0%), four levels of CD (5.0, 7.5, 10.0 and 15.0%) and four levels of CNSL (2.5, 5.0 7.5, 10.0%) based on cement weight at 2:1 cement: water ratio following the preliminary tests. A CC board machine was developed and tested for the production of CC boards using Schaum’s Machine Design methods. The physical and sorption properties such as density, Water Absorption (WA), Thickness Swelling (TS) were determined using ASTM standards. The mechanical properties such as, Compressive Strength (CS), Modulus of Rupture (MOR), Modulus of Elasticity (MOE), and Impact Strength (IS) were evaluated using ASTM standards. Data were analysed using ANOVA at 0.05. A 5.5 kW electrically operated CC board machine developed has an amplitude of 2 mm; frequency of 350 rpm; CC size of and capacity of 360 CCs per hour. The densities, WA and TS of CF composites without CNSL ranged from 1350.00 to 1690.00 kg/m3, 33.1 to 69.5% and 1.1 to 3.2%, respectively. Their respective CS, MOR, MOE and IS in Nmm-2 were 5.72–11.43, 4.37–5.34, 813.24– 1428.85, and 1.19–4.35. The densities, WA and TS of CD composite without CNSL ranged 1030.00–1480.00 kg/m3, 27.5– 69.1% and 1.9–5.1%, respectively. Their respective CS, MOR, MOE and IS in Nmm-2 were 0.9–11.16, 1.6–3.79, 330.64– 1916.31 and 0.86 – 2.18. However, composites with CNSL had densities, WA and TS that ranged from 1310.00 to 1510.00 kg/m3, 7.1 to 17.8% and 0.9 to 2.7%, respectively. Their respective CS, MOR, MOE and IS in Nmm-2 were 2.18–7.25, 1.71– 2.36, 306.01 - 1054.09 and 1.09 to 2.57. The incorporation of CNSL significantly affected the physical, sorption and mechanical properties of the manufactured CCs and can be utilised in both indoor and outdoor applications. There was significant differences in the properties of CC produced from CF, CD and those treated with CNSL. Cashew nut shell liquid enhanced the properties and performance of cement bonded composites made from coconut coir fibre and dust for indoor and outdoor applications.