Surface enhanced pulp fibers in fiber cement

Abstract

The present invention relates to a method of making a fiber-reinforced cementitious composite material which finds widespread applicability in a variety of construction and related applications. The composite comprises cellulosic fibrous material in order to provide the composite with the desired performance characteristics. Notably, at least a portion of the cellulosic fibrous material comprises surfaced enhanced pulp fiber, which desirably enhances the processing characteristics of the material, as well enhancing the characteristics of the finished composite product. The method of making a fiber-reinforced cementitious composite comprising the steps of providing a cementitious composition, and providing cellulosic fibrous material. The present method further includes blending the cementitious composition and the cellulosic fibrous material to form the cementitious composite. The surface enhanced pulp fiber preferably comprises approximately 1-10%, by weight, of the cellulosic fibrous material, and the cellulosic fibrous material exhibits an enhanced Bauer-McNett long fiber fraction. The cellulosic fibrous material preferably exhibits at least a 10% increase in length-weighted average fiber length (LWAFL), in comparison to a cellulosic fibrous material which is devoid of surface enhanced pulp fiber. The cellulosic fibrous material requires relatively reduced refining energy, in comparison to a cellulosic fibrous material which is devoid of surface enhanced pulp fiber, to reach a predetermined freeness CSF (Canadian Standard Freeness) value.