Abstract
There is no question, due to the climate emergency, that the construction market needs to work into reducing its emissions and reserving natural resources. Work is being done into reducing the impact of concrete as one of the most used construction materials. In this study focus is on the low-cost aspect of the construction industry, as most of the new constructions take place in the developing world where 40% of the world’s population lives. If the new buildings are tackled with low-cost materials rather than over-use of cement, they can work into reducing the impact of the construction sector. Agricultural wastes (agro-wastes) were targeted for its abundance and self-inherit biodegradability, as such they were introduced to the construction industry from the beginning of civilisation. Nonetheless, their compatibility with modern construction materials needs to be studied in depth.In this study the target area was chosen to be Sudan and has the potential of being applicable in the African countries with comparable climate. Three agro-wastes were chosen for their abundance in the country: sorghum stalk, groundnut husk and corncobs. The study focused into identifying the best use of these wastes in construction industry for low-cost purposes.
The research developed an understanding of the raw materials’ properties before adding them in different forms to construction units, thus several physical and chemical characterisation tests were performed. The agro-wastes were then added in three forms: as-is, coated, and burnt into ashes. The first and second forms were introduced to compressed earth bricks in the first part of the study. The strength and thermal conductivity of the bricks were tested and compared with different standards. The second part of the study focused on the analysis of cement mortars with the addition of treated corncob granules. This part aimed into optimising the pre-treatment techniques to acquire the best mortar properties. The final part of the research focused in analysing the properties of the agro-waste ashes and their potential behaviour as pozzolanic materials.
The study showed an overall enhancement of the construction material properties with possible use as pozzolanic materials. Soil bricks prepared with agro-wastes had improved strength compared to the control specimens. In the second part, the strength of the mortars including agro-waste was reduced compared to the control mix. Nonetheless, their properties met the minimum requirements for masonry units and mortars. Hence, they can be used in low-cost construction, and the treatment of agro-wastes can further improve their functionality. The pozzolanic ash produced from groundnut husk was found to be nonreactive while that of sorghum stalks was found to be moderately reactive giving way to further study this type of ash as cement replacement.
| Date of Award | 28 Jun 2023 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Peter Walker (Supervisor), Kevin Paine (Supervisor) & Stephen Allen (Supervisor) |