Composite materials with recycled fibers: Evaluation of the effect of different fibers on gypsum composites

The use of alternate more sustainable materials in building construction products has been a focus for the last two decades. Defining new methods to utilize materials destined for landfill while not increasing cost and discovering beneficial reuse for such materials is commended in today’s industry. This work explores three types of fibers (paper, hemp and fiberglass) with the goal of improving overall performance and sustainability of wallboard by means of making gypsum-fiber composites. Circular composite disks containing 0–2 wt% fibers in gypsum were tested with a biaxial bending apparatus. Fracture toughness was also calculated in the case of 1.5 wt% fiber loading. When recycled paper fibers were utilized in composites, the resulting composite exhibited a shift towards a less brittle material. The improvement in load resistance and deflections in the biaxial bending test was comparable to those of gypsum composites with high-energy manufactured fiberglass. Within the range investigated, hemp fibers, while sustainable, did not provide improved performance and may need to be refined further, which would add more cost. Fracture toughness improved with all fiber loadings with fiberglass revealing the highest toughness. SEM images suggest that the paper fibers had good surface bonding with the gypsum matrix, while the fiberglass appeared less, indicating different mechanisms to achieve improved performance.