Take a simple drive from your home in the suburbs and into the city and you would be able to count hundreds, if not thousands, of concrete structures and resources along the way. Concrete is the very basis of much of our infrastructure, being used in roads, ports, buildings, bridges; you name it, it’s got concrete in it.
So there’s no surprise that scientists would like to better understand what the current change of climate will do to concrete, immediately and over the long run.
“In order to better understand how climate change might influence infrastructure maintenance and construction, we need to establish an accurate national database on the rate, and factors involved in, the deterioration of concrete infrastructure,” says the author of a new report, CSIRO Climate Adaptation Flagship’s Dr Xiaoming Wang.
“Failure to consider the effects of climate change may compromise the safety of concrete structures but, overcompensating in our efforts to adapt for climate change may unnecessarily increase costs.”
The report makes a number of recommendations for maintaining the existence of current concrete structures and for the design of new structures.
Concrete deterioration is caused by a variety of stimuli, including physical, mechanical and chemical factors. Two of the primary causes for deterioration are carbonation – which occurs when atmospheric carbon dioxide penetrates the structure and exposes steel reinforcements – and chloride penetration – which causes cracking, delamination, or spalling, specifically in marine and coastal areas.
“Both corrosion mechanisms are influenced by climate change but, the time it will take for climate change to exacerbate carbonation and chloride-induced corrosion of concrete structures will depend on their location and level of exposure to the elements,” Dr Wang said.
Wang said that the durability of concrete structures depends heavily on the manner in which they were constructed and the materials used, as well as the environmental conditions they are routinely exposed to.
“Currently, the primary assumption in construction designs is that environmental conditions will be similar to those of the past,” said Wang. “However, scientists and engineers from CSIRO, in collaboration with a colleague from the University of Newcastle, have shown that increased atmospheric CO2, in addition to a changing climate – including ‘chronic’ factors like increasing CO2 concentrations, temperatures and humidity, and ‘acute’ factors like extreme weather events – will alter environmental exposure of most concrete infrastructure over their relatively long lifetime.”
“This means that concrete structures will generally deteriorate faster with major implications for the safety, serviceability and durability of infrastructure, particularly in warmer inland and coastal areas.”