Earthern construction as a tailored alternative to conventional carbon-intensive materials in construction

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Conventional, modern-day construction materials such as concrete and steel are known to result in high levels of carbon dioxide (CO2) emissions; it is estimated that the construction and processing of such materials contribute to 11% of global CO2 emissions. Earthen construction materials (ECMs) are often viewed as outdated and having inadequate mechanical properties; whilst improvements in durability are desired, ECMs have an extremely low embodied carbon. It is suggested that the widespread application of such materials can result in reduced levels of total embodied carbon, i.e., McAuliffe across all life cycle stages, from material extraction to end-of-life disposal.I would like the principal focus of my PhD to be the improvement of ECM durability, hence increasing the feasibility of ECMs as a modern-day, mainstream construction material. Although existing earthen structures are typically single-storey buildings, the material properties can be developed to allow for applications such as contemporary architecture, highways infrastructure or land regeneration. I intend to study tailored properties of ECMs and in turn, identify the most suitable applications. I aim to carry out trials ranging from small, laboratory-sized samples to full scale. Each study shall highlight how ECM durability can be improved through the impact of various material constituents, additives, or construction techniques.Durability and thus, longevity are key concerns with the widespread usage of ECMs. The longevity 10665199of an ECM is entirely governed by external factors, with water-induced erosion being the primary cause of failure. The effects of driving rain and high humidity levels result in unsaturated soils becoming more susceptible to erosion via hydromechanical weakening. Desired durability properties will vary with application; however, all external applications will require an improvement in water resistance. I suggest that durability against external weather conditions (investigated through abrasion resistance, freeze and thaw and water resistance), and the influence of aging (examined using accelerated aging and carbonisation techniques) are investigated further to determine how resilience can be improved. To promote a circular economy and maintain focus on low carbon materials and construction processes, waste products can be used. Waste streams can include, but are not limited to, construction and excavation waste, food waste and industrial waste. Additives can provide specific material enhancements; the type and quantity of waste additives will be studied to ensure beneficial impacts on ECM performance. For example, the hydrophobic effect of non-toxic oils can improve water resistance whereas ground granulated blast furnace slag (a by-product of the steel industry) can be utilised to improve compressive strength and reduce shrinkage. Non-hazardous excavation waste is usually recycled for aggregates or used for on-site retaining structures. Excavation waste generally comprises ECM constituents, if the waste material is deemed suitable for earthen construction, the fine gravel and earth can be utilised as the bulk ECM components.In order to verify the carbon benefit of proposed ECMs, the upfront and embodied carbon can be quantified through the completion of life cycle assessments.