Ductility enhancement of autoclaved cellulose fiber reinforced cement boards manufactured using a laboratory method simulating the Hatschek process

Autoclaved fiber cement (FC) boards manufactured using the Hatschek process are commonly used as building products such as siding and shingles. Despite their advantages, these products may exhibit low ductility and volume instability. A common, yet expensive, method for improving ductility is increasing the fiber content. In this study, a procedure to manufacture FC boards in the laboratory was introduced, and alternative economical methods for increasing the boards' ductility were investigated. Ductility was measured using a 3-point or 4-point bending tests, while the microstructure of the boards was studied using scanning electron microscopy. The results show that ductility of FC boards was improved by reducing their matrix tensile strength. This was achieved by reducing the density (increasing porosity) of FC boards or by partially replacing Portland cement with fly ash. Fiber mineralization was not found to be the cause of brittleness in the investigated FC boards.