Abstract
ABSTRACT In this study, the hydration behavior of gypsum paste mixed with bagasse and kenaf fibers as lignocellulosic material and fiberglass as inorganic material is evaluated. Moreover, the properties of gypsum-bonded fiberboard (GBFB) are examined using bagasse fibers (Saccharum officinarum.L), kenaf fibers (Hibiscus cannabinus.L) and industrial fiberglass. The weight ratios of fiberglass (at three levels 0, 3 and 6%), bagasse fiber (at three levels 0, 7.5 and 15%) and kenaf fiber (at three levels 0, 7.5 and 15%) to gypsum are used to make the gypsum-bonded fiberboard with the nominal density 1.10 g.cm-3 . After preparing the fiberboard, its flexural properties were examined. Response surface methodology (RSM) and artificial neural network (ANN) were used to model the bending strength of gypsum-bonded fiberboard. According to the hydration tests, it was determined that as the extractives in the lignocellulosic materials increased, the temperature of the mixture decreased and its setting time increased. According to the bending test results, it was determined that there is an ideal consistency between the predicted values and the observed data, so that as bagasse and kenaf fiber increased, the modulus of rupture (MOR) increased. Maximum MOR of panel was predicted to be 10.81 MPa and 11MPa by RSM and ANN at optimum condition. Based on the statistical analysis, the training and validation data sets of the studied models were compared by the coefficient of determination (R2), root mean squares error (RMSE) and mean absolute error (MAE). ANN model showed a much more accurate prediction than RSM in terms of the values R2, RMSE and MAE.
Highlights
Panels with mineral binders have extensive applications in flooring, inner lining of walls, ceiling and partition walls
The results showed that the final setting time of the gypsum increased at the maximum temperature at the presence of the lignocellulosic material or extractives from washing the lignocellulosic material (Figure 2), and the maximum temperature of the mixture decreased
The increase or decrease of the hydration at different times depends on the type of the lignocellulosic material and the extractives content
Summary
Panels with mineral binders have extensive applications in flooring, inner lining of walls, ceiling and partition walls. These panels, such as gypsum-bonded fiberboard, have a better linear stability than similar woodbased panels, and when exposed to fire, they show a higher resistance than other wood composite products. Organic fibers were added to gypsum, but artificial fibers were mainly used, such as fiberglass (Eve et al 2002). Fiberglass has a proper strength and stiffness, preserves its mechanical properties at high temperatures, has proper resistance to moisture and corrosion and is rather cheap. The relationship between adding natural fibers to gypsum matrix and the mechanical properties of the composites was evaluated (Coutts 1990, HernándezOlivares et al 1992)
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