E-Thesis 93 views
Sustainable concrete for innovation in rail construction / JAMES HOLLIMAN
Swansea University Author: JAMES HOLLIMAN
Abstract
With concrete used so much in the industry, there is a significant problem with CO2 emissions when concrete is made. These emissions can be lowered when Portland cement is replaced with another material. Previous work has focused on single replacements to identify one material, which has all the ele...
| Published: |
Swansea University, Wales, UK
2025
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| Institution: | Swansea University |
| Degree level: | Master of Research |
| Degree name: | MSc by Research |
| Supervisor: | Wood, C. |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa70066 |
| Abstract: |
With concrete used so much in the industry, there is a significant problem with CO2 emissions when concrete is made. These emissions can be lowered when Portland cement is replaced with another material. Previous work has focused on single replacements to identify one material, which has all the elements needed for effective cement. However, up to now, it has been found that this single-material approach can only replace small amounts of cement ( less than 10%). Hence, this thesis started with the concept of using two replacement materials where the ratio between them was constructed based on elemental data and particularly the Ca:Si ratio. To start the research, several industry by-products (ashes of rice husk, sugar beet, palm leaf, sunflower, straw or wood, cockle and oyster shells, ground glass, limestone dust and basalt) were selected and analysed using optical microscopy, X-ray diffraction, infrared spectroscopy and scanning electron microscope-energy dispersive spectroscopy. From this data, seven mixes were designed based on the Ca:Si ratio and assuming a 20% replacement versus control cement. These samples were used to make Evaluated Variable 1, including one control mix and one mix with 20% less cement as control samples. All mixes were a success, with the cockle shell and ground glass mix being the strongest (83.88MPa).Based on Evaluated Variable 1s data, Evaluated Variable 2 was designed with four mixes consisting of cockle shell and micro silica, cockle shell and basalt, limestone dust and basalt and a control mix but swapping the M1000 metakaolin for opacilite metakaolin. These mixes were also a success, but none matched the strength of the cockle shell and ground glass mix.Finally, Evaluated Variable 3 tested the cockle shell and ground glass mixture at different replacement levels to explore the optimum replacement percentage. It was learned that the cutoff percentage was 40% as any more replacement mixture caused the compressive strength to be weaker than the control mixture and the 100%replacement mixture could only be de-moulded after seven days and when left to cure for 28 days it dissolved in the water tub.Overall, the data in this thesis show that using combinations of more than one replacement material alongside elemental data to determine the mix ratio can produce much stronger concrete at 20% replacement and similar strength concrete to control mix at 40% replacement. |
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| Item Description: |
A selection of content is redacted or is partially redacted from this thesis to protect sensitive and personal information. |
| Keywords: |
Sustainable Concrete, biomass, by-products, civil engineering |
| College: |
Faculty of Science and Engineering |
| Funders: |
Global Centre of Rail Excellence |