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Confirmation of Candidature - Candidate : Piumika Ariyadasa

Assessing Long-Term Performance and Durability of Geopolymer Concrete Mortar for Sewage Pipe Coating Applications
08 JUN 2022
9.00 AM - 10.30 AM

Microbial induced concrete corrosion (MICC) is the most prevalent threat to concrete components exposed to aggressive sewage conditions, causing gradual degradation, compromising the structure's integrity, and resulting in a significant economic loss. Among the various technologies being used to alleviate and control this issue, barricading contact with a protective coating under the trenchless approach for rehabilitating sewerage pipes is gaining attention. However, an acceptable binder formulation with a satisfactory impact on suppressing the aggressive MICC has yet to be identified; thus, there is a growing demand for sustainable repair materials. Alkali activated geopolymer (GP) is a cement-free solution that excels in acid resistance and is a viable replacement candidate for Ordinary Portland Cement (OPC) in many applications. Since only limited attempts have been made for GP on durability studies, there are no adequate results to validate GP against adverse exposure conditions, which is critical in structural rehabilitation where components with longer lifespans are preferred. 

The proposed project will combine extensive experimental studies to evaluate the long-term performance and durability of low calcium-based geopolymer cement mortar in simulated aggressive conditions. The class F fly ash (FA) will be used as the precursor for GP mortar. The proposed approach will address objectives, including the development, characterisation and shortlisting of optimal FA geopolymer (FA-GP) mortar mixes, evaluating bond strength and investigating the behaviour of mortars under laboratory-induced conditions simulating MICC and external sulphate attack. Theoretical/empirical formulas will be developed subsequently to predict the long-term properties of FA-GP mortars and the Analytical Hierarchy Process (AHP) to determine the optimal FA-GP mix design. Sewer service life will be estimated based on material deterioration and the residual bearing capacity of the optimal FA-GP mortar coating. 
Keywords: MICC, Trenchless sewer rehabilitation, coating materials, geopolymer, aluminosilicates, fly ash, synthesis, mechanical properties, durability, long-term performances

For more information, please contact the Graduate Research School.