Effects of Partial Replacement of Cement with Selected Polymers on Sorption and Mechanical Properties of Rattan Cane Fibre-Reinforced Composite Roofing Tiles

Abstract

AbstractEnvironmental concerns about CO2 emissions during Portland cement manufacture have drawn attention to the need to minimise cement consumption. Mixing cement with relatively cheap and readily available polymers is one way of addressing the challenge. This study, therefore, investigated the effects of polymer–cement admixtures on selected properties of rattan cane fibre-reinforced roofing tiles. Mature rattan (Laccosperma secundiflorum) canes were sun-dried and hammer-milled. The fibres were treated with dilute NaOH (10% w/v). Three polymeric materials were used in polymer–cement admixtures—natural rubber latex; Cissus populnea gel extracted from the stem of cissus plant; and acrylic emulsion latex, a synthetic paint. Triplicate samples of 160 × 50 × 6 mm composite tiles were produced with 3% fibre content using 0.5 cement/water ratio. Based on preliminary studies, cement was partially replaced (w/w) with 5,7.5, 10% natural rubber latex;10, 20%, 30% acrylic emulsion latex; and 10,20,30% Cissus populnea gel in different composite samples cured under wet conditions for 28 days. The Density, Water Absorption, Thickness Swelling, Apparent Porosity, Modulus of Elasticity, and Modulus of Rupture of the samples were determined using standard methods. Composite densities ranged between 0.86 and 1.23gc/m3. All the three polymers, particularly natural rubber latex, significantly reduced the density (p ≤ 0.05). Water Absorption ranged between 0.62 and 1.66%. Though Cissus populnea gel significantly increased Water Absorption, the values still fell within acceptable limits. Thickness Swelling (0.54–2.76%) was relatively low. Apparent Porosity (11.6–28.5%) was also relatively low except in samples containing acrylic emulsion latex. The Modulus of Elasticity (930-4649 N/mm2) and Modulus of Rupture (1.12–4.58 N/mm2) were within acceptable limits. However, natural rubber latex had negative, while Cissus populnea gel had positive effects on both strength properties with the gel increasing the Modulus of Elasticity and Modulus of Rupture by approximately 100% of the control sample values. It was concluded that relatively strong and dimensionally stable rattan fibre-reinforced roofing tiles can be produced with Cissus populnea gel–cement admixtures at cement replacement levels of up to 30%.KeywordsRattan fibresPolymer–cement Cissus populnea Roofing tiles