The durability performance of waste cardboard kraft fibre reinforced concrete

Despite the high recycling rate of cardboard, a significant amount of this material is disposed of in landfill areas. The conversion of cardboard waste into kraft fibres (KFs) offers potential sus-tainability benefits when used in the building and construction industry. This study compre-hensively analyses the durability of KF reinforced concrete as a partial cement substitution. Durability testing was conducted, exploring the composites microstructure when integrating KFs derived from waste cardboard. Fibre and matrix modification techniques were utilised via silica fume (SF) and metakaolin (MK), respectively. Porosity analysis of the novel composites demon-strated connecting microstructural system, enhancing the knowledge of durable aspects of po-tential service life of the composites. SF reduced the water permeability of the novel composites as demonstrated via water absorption and immersion testing. At one year, there was a reduction of chloride ion transference for all fibre composites. Composites were aged via wet and dry cycles, then tested for their compressive and tensile strength at each interval. Compressive strength of all samples peaked at 60-80 day-cycles. Fibre Matrix modified composites demonstrated a tensile strength of 2.5 MPa when subjected to 100 day-cycles, with the control having 2.7 MPa.