Vattenfall has developed a special low-cement concrete mixture designed for hydropower applications, and the concrete will replace parts of a dam in Sweden. “The objective was to define a climate-smart concrete concept that is ready to be implemented at the start of construction,” said Erik Nordstrom, development engineer at Vattenfall R&D.
Vattenfall has developed a climate-smart hydropower concrete with less cement content that can reduce carbon dioxide emissions by around a quarter. The first major structures have recently been built on-site at Lilla Edet power station in Göta älv.
Cement production generates large carbon dioxide emissions. So a reduction in the cement content of construction concrete gives a direct reduction in the strain we’re putting on the environment. One standard way to reduce cement quantity and heat development internationally is to use by-products that react with cement. This method has been combined with lessons learned from Vattenfall’s major periods of expansion in the 1950s and ’60s to develop a modern, climate-smart concrete concept.
At Lilla Edet power station in Göta älv near Gothenburg in Sweden, Vattenfall will be replacing parts of the existing dam with a brand new one by 2024. Various methods have been investigated to reduce the amount of cement in construction concrete, thereby reducing both the burden on the climate and the need for cooling that comes with rough constructions. Extensive tests have been carried out to ensure that the concrete works for construction purposes and, above all, meets the requirements for dam safety and durability for over 100 years from now.
Lower temperature reduces risk of cracking
Casting rough concrete structures creates exacting demands for handling the temperature increase that occurs inside the concrete, otherwise it can cause cracks to appear. One common method is after-cooling via cooling pipes inside the rough concrete structures to reduce the temperature increase. However, the reduced amount of cement gives a lower temperature increase than usual.