Fibre-cement Composites from Brazilian Agricultural and Industrial Waste Materials

摘要

Fibre-cement composites in which either the reinforcement or the matrix or both were derived from Brazilian waste materials were produced using a slurry vacuum de-watering technique followed by air-curing. Ground iron blast furnace slag (BFS), activated by mixtures of gypsum and lime, was examined as a lower-cost alternative to ordinary Portland cement (OPC) as a matrix material. The BFS-based composites reinforced with chemically pulped Pinus radiata fibre were generally weaker and less stiff than corresponding OPC-based materials, but possessed comparable toughness. Permeable void volume and hence water absorption values were greater than those of the OPC-based composites, with water absorption exceeding 30% w/w at a fibre content of 12% w/w. Reject Eucalyptus grandis fibre from a kraft pulp mill and laboratory prepared chemi-thermomcchanical pulps of sisal and banana crop residues were tested as reinforcements in the BFS matrix. Optimum strength and toughness values were obtained at fibre contents in the range 8% to 12% by mass. At these fibre levels, strengths of approximately 18 MPa and toughness values in the range 0.51―1.25 kJ m~(-2) were obtained. The performance of the waste-derived materials may be acceptable for their use in applications such as low-cost housing construction.