Earth-Based Construction Materials Reinforced with Tropical Plants and Recycled Waste Cellulose Pulp Fibre: Performance and Durability Assessment
Due to the growing concern of deforestation, renewable materials such as recycled cellulosic waste and non-wood fibres provide an alternative solution for partial replacement of wood resources as a reinforcement agent in building blocks. This study consists of exploring the feasibility of producing cellulose pulp and nanofibrillated cellulose (NFC) from plants widespread in Tropical region; raffia fibre (Raphia vinifera), cassava bagasse (Manihot esculenta), ambarella (Spondias dulcis), and bamboo (Bambusa vulgaris); to assess their suitability as a source of reinforcing agent for composites. The recycling process of municipal waste fibres was also studied to promote the conservation of plant resources, as well as the circular economy. Bamboo organosolv pulp (BOP) and recycled waste carton pulp (RWCP) were used as a reinforcement phase in an earth-based matrix at varying fibre contents (0, 5, 7.5, and 10%wt.) to assess their performances and durability for civil engineering construction applications. Fibres were produced using both organosolv and soda methods to assess the effect of processing on fibre properties. The composites were manufactured by the extrusion process and tested after 28 days. The results show that the inclusion of RWCP fibre in the soil matrix significantly improved the performance of the composites compared to matrices reinforced with BOP fibres. Addition of 5 %wt. of RWCP, showed an improvement in flexural strength (56%), specific energy (614%), fracture toughness (57%), wear resistance (48%), and thermal insulation (21%) compared to the control sample. The inclusion of RWCP in earth-based matrix increases the moisture loss, the drying shrinkage and behaves as a water reservoir for earth-based materials. It has been concluded from this study that RWCP has the potential to serve as a suitable reinforcement for the promotion of lightweight earthen wall block materials (reduction of bulk density up to 21% after the inclusion of 10% of RWCP), where flexural strength, ductility, and thermal insulation performance are the primary requirements. Besides, the successful replacement of virgin BOP fibres with RWCP fibres reduces the environmental footprint of the building material. Therefore, the use of this RWCP in the construction industry will be an attractive alternative as it will solve both energy and environmental concerns.