Long-term durability testing of concrete in low and intermediate level waste repositories
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Journal Title
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Insinööritieteiden korkeakoulu |
Master's thesis
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Authors
Date
2023-06-12
Department
Major/Subject
Concrete Technology
Mcode
Degree programme
Master's Programme in Building Technology (CIV)
Language
en
Pages
82+32
Series
Abstract
In Low and Intermediate Level Waste (LILW ) repositories, the reinforced concrete barriers used must be able to resist their environments for hundreds of years. The reinforced concrete structure can be subjected to various degradation mechanisms, such as carbonation and chloride induced corrosion, sulfate and thaumasite attend acks, portlandite and sulfate leaching, alkali silica reaction. The objective of the research is to examine the environmental effects on different concrete mixes stored for 25 years in environments that simulate the conditions expected in LILW repositories and assess the performance of those concrete mixes. Concrete specimens casted between 1997 and 1998 were stored for 25 years in environments similar to LILW repository conditions were tested in this study, and their mechanical capabilities, as well as their durability to various environmental conditions. The tested concrete specimens were stored in various different solutions and had different mix compositions. The concrete specimens showed high strength properties, with a slight increase compared to their previous results in 2010. The petrographic analysis of the specimens only showed very minor instances of degradation, mostly being local, and no significant damage was observed. The chloride content increased slightly in aggressive solutions, but it is still below the determined threshold for submerged specimens. The sulfate and magnesium results were sporadic, but they were mostly low. This research proves that long term studies are important in studying the behavior of concrete structures in LILW environments. Therefore, it is essential to analyze and investigate these structures effectively, to ensure that such critical concrete structures serve their purpose.Description
Supervisor
Punkki, JouniThesis advisor
Al-Neshawy, FahimKeywords
corrosion, reinforced concrete, LILW repositories, chloride attack, sulfate attack, mechanical properties