Is wollastonite capable of improving the properties of wood fiber-cement composite?

Abstract

Effects of wollastonite substitution were investigated relative to the mechanical, physical, and microstructural properties of a wood fiber-cement composite. Wollastonite content of 0%, 3%, 6%, and 9% and lignocellulosic material (kraft fibers) content of 10%, 20%, and 30% were used based on the dry weight of cement. Then the lignocellulosic material and the resulting board samples were compared to a control (without wollastonite). Modulus of rupture (MOR), modulus of elasticity (MOE), water absorption, and fire resistance tests were conducted to examine the characteristics of the board composite. The results showed that the mechanical properties of wood fiber-cement composite were improved by the 9% wollastonite substitution. The fire-resistance of the composite board was improved when the wollastonite content was increased. Furthermore, cement boards with 9% wollastonite exhibited lower water absorption in comparison to the other specimens. Scanning electron microscopy (SEM) results showed that the calcium hydroxide formed hydrated calcium silicate gel (C-S-H gel) after the addition of wollastonite. The SEM images showed that the micro-structure of the boards were improved by increasing the nano-wollastonite content.