Design of pipe cooling system in massive concrete structures
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Journal Title
Journal ISSN
Volume Title
Insinööritieteiden korkeakoulu |
Master's thesis
Authors
Date
2022-01-24
Department
Major/Subject
Mcode
Degree programme
Master's Programme in Building Technology (CIV)
Language
en
Pages
104+10
Series
Abstract
The construction of a massive structure requires a large amount of concrete. The amount of concrete used is proportional to the amount of heat emitted due to the hydration process of cement. In Finland, when the temperature of concrete during the hardening phase reaches over than 60 degrees Celsius, the structure is prone to cracking. Other factors that lead to cracking of concrete are internal and external restraints. Under the effect of temperature, a material expands when the temperature increases and contracts when the temperature decreases. So when the exterior contracts (due to low ambient temperature) and resists the interior to expand (due to hydration heat), thermal stress will appear. If the thermal stress exceeds the tensile strength of concrete, cracks will be created. Apart from the crack, high-temperature conditions will affect the properties and serviceability of concrete, creating difficulties in fresh concrete including decreased strength, decreased durability, increased rate of setting, and water demand. The need of controlling the emitted heat of concrete is necessary to ensure the quality of concrete. A variety of methods are presented throughout the thesis, divided into pre-cooling and post-cooling methods. The thesis serves as a guideline to users to control the generation of heat before/and after casting the concrete. The main focus of the thesis is the design of pipe cooling system, with water circulating in the pipes. A further study for this master thesis is to develop a three-dimensional finite element program to analyze the hydration heat of concrete with the use of pipe cooling system. An analysis of air cooling system can be studied, as well as the cost of the system.Description
Supervisor
Punkki, JouniThesis advisor
Paukku, ElinaVirtanen, Markku
Keywords
massive concrete structure, pipe cooling system, hydration process, pre-cooling method, post-cooling method