Wood fiber surface treatment level effects on selected mechanical properties of wood fiber-cement composites

The objective of this study was to determine the effects of sodium (N) silicate, potassium (K) silicate, and silane (Si) treatment levels on newspaper and unbleached kraft fibers for enhancing selected mechanical properties of wood fiber-cement composites compared to untreated wood fiber-cement composites. Both wood fiber types were treated with selected aqueous solution strengths, air dried, and mixed with water and cement. The bending and compression properties of the specimens were determined after 28 days of hydration. Results of this study indicated that the aqueous chemical treatments of the wood fibers enhanced some of the mechanical properties of wood fiber-cement composites compared to the untreated wood fiber-cement composites. The enhancement depended on chemical treatment and wood fiber type. All three chemical treatments of newspaper fiber enhanced the normalized toughness values compared to the untreated newspaper fiber-cement composites. In addition, higher treatment levels using N silicate with newspaper fiber improved the compressive strength and bending modulus of the composites compared to the untreated newspaper fiber-cement composites. Kraft fiber treated with all three chemicals enhanced the compressive strength, bending modulus and bending strength compared to the untreated kraft fiber-cement composites. However, only silane-treated kraft fiber improved the normalized toughness values compared to the untreated kraft fiber-cement composites. The results of the study indicated that certain chemical treatments react better with different wood fiber types resulting in selected mechanical property enhancements.