Researchers at AUST Re-engineer Earth-based Composites for Low-cost Housing Solutions

Evaluation of mechanical properties of fibres A Doctoral candidate in the Materials Science and Engineering Department in AUST, Emeso Ojo, has engineered earth-based composites that have the potentials to meet increasing infrastructural demands in tandem with the present global drive towards achieving sustainability in the building construction sector. Her research, which is part of a collaborative partnership between the Pan African Materials Institute (PAMI) of AUST, and Research Nucleus on Materials for Biosystems of University of São Paulo, Brazil, focuses on the alkali activation of clays typically found in soils as binding mechanism alongside the inclusion of natural and synthetic fibres as reinforcements to improve mechanical properties of this class of materials. She also explored the adaptability of this technology for industrial-scale production using extrusion moulding as a processing technique. The research presented a comparative analysis of the reinforcing effect of different fibre types (sisal, Eucalyptus pulp microfibers and polypropylene), in an alkali-activated stabilized soil, to give insight on the effect of fibre type and content on physical and mechanical properties of the composites. The results show that fibres and alkaline activators significantly improve properties of earth-based composites through distinct fibre-soil interactions which control composite performance.

Conducting nano-indentation tests on soil-fiber She adopted a multi-scale approach using nano-indentation and macro-mechanical testing to study the mechanical behaviour of the composites to further understand the strengthening and toughening contributions of natural and synthetic fibres for this class of materials. The understanding gained from this approach will help expand the scope of application of earth-based building materials and ultimately inspire engineers to design composites for a wide range of structural applications. In countries like Nigeria and Brazil, these building materials have the potential to meet increasing housing demands in line with targets set by the sustainable development goals (SDGs). ‘I am motivated by the abundant natural resources in these parts of the world and seek to apply insights from studies on material behaviour for the design of sustainable and robust building materials particularly for low-cost housing solutions’, she says.