Physical, mechanical and durability properties of sugarcane ash enhanced compressed earth blocks stabilized with fly ash and lime powder
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Date
2019
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University of Zululand
Abstract
The construction sector is one of the principal component of anthropogenic activities and a major contributor of greenhouse gases (GHGs) emissions. Large quantities of solid wastes are being produced every year by industrial and agricultural industries which lead to environmental and health concerns such as flooding, air pollution and other public health scarce. These wastes have potential pozzolanic reactivity and may be used to develop cementitious materials that are sustainable, while maintaining requirements as affirmed in various standards. The sector is also an important economic sector that has a large environmental impact in terms of large quantities of construction and demolition wastes (C&DW) which are generated. These is mainly due to severe shortage of natural aggregates (NA) for the production of new concrete materials, and a boom in construction activities currently taking place worldwide. The utilization of recycled masonry and concrete (RCA) from C&DW will conserve the natural resources and reduce the environment impact of concrete manufacturing. Sugarcane bagasse ash (SCBA) is an industrial waste material obtained from sugar milling industry that can be used as pozzolanic material for the development of greenbricks. In this research, the application of various waste materials and the effects of fly ash and lime on the mechanical and durability properties of compressed earth bricks (CEBs) are investigated. Secondly, the applications of fly ash, recycled cement and masonry as industrial waste materials in construction industry are reviewed. Lastly, The SCBA greenbricks were developed using lime as a chemical stabilizer and tested for physical, mechanical and durability properties.
In addition, several agricultural by-product such as sugar cane bagasse (SCB) and soft wood (SW) were treated as wastes until recent times when researchers considered incorporating them in polymeric matrices to mainly avoid environmental pollution and cost of a new synthesis. The properties of untreated sugarcane bagasse (SCB) and soft wood (SW), their respective celluloses, and corresponding composites and blends with thermoplastics (polypropylene and polyethylene) were analysed by DMA, SEM, XRD, FTIR, DSC and TGA. Three degradation models, Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (OFW), and Kissinger (KGR) methods were employed to determine apparent activation energy values of untreated SCB and SW, and their respective celluloses. The apparent activation energy values obtained from OFW and KAS models vary with the degree of conversion, and showed similar trends. The activation energies TGA analysis shows that the untreated SCB and SW degrade earlier than their respective celluloses and the prolonged treatment affects the onset of main degradation. PP/SCB were least thermally stable compared to PP/SW composites. The addition of extracted cellulose decreased the thermal stability of PP/SCB composites at higher filler content due to poor interfacial bonding as compared to PP/SW composites. Likewise, the cellulose containing blend composites were thermally stable compared to untreated fibre, and are less stable compared to neat PP/PE blend. DMA of both PP/SCB and PP/SW composites indicated improvement in the storage modulus compared with neat PP. Similar results were obtained for all blend composites, with the cellulose containing blend composites displaying higher values than untreated fibre. SEM results confirmed a rough morphology and the presence of many voids resulting from fibre pull-out in composites, especially for the ones with higher fibre content. However, a stronger interaction between PP/PE/SW as compared to PP/PE/SCB took place in the blend composites. DSC analysis reveals that the introduction of SCB or SW did not significantly change the melting and crystallization behaviour of both the PE and PP.
Description
A thesis submitted in fulfillment of the academic requirements for the degree of Doctor of Philosophy in the Department of Chemistry in the Faculty of of Science, Agriculture and Engineering, University of Zululand, 2020.
Keywords
sugarcane ash, fly ash, lime powder, compressed earth blocks