Tell it to the Romans, who used concrete to build The Colosseum, which is still standing.
From E&E newswire – h/t to Marc Morano
Concrete’s life span is shortened by climate change — study
Published: Wednesday, October 15, 2014
Climate change may reduce concrete’s durability, with long-term consequences for buildings, roads and bridges constructed with the common material, according to a recent study.
Matthew Eckelman and Mithun Saha of Northeastern University focused their research on how infrastructure in Boston will be affected by the most extreme climate change scenarios.
They predict about 60 percent of Boston’s buildings will have some structural deterioration by 2050. Eckelman and Saha published their study results in the journal Urban Climate.
“Starting in 2025 is when [we expect] to see the concrete cover on buildings start to fail, assuming they were built to code,” Eckelman said.
Concrete is considered one of the most solid structures humans have engineered. Modern concrete structures and roads are further reinforced with steel bars to make the material less brittle. However, over time both carbon dioxide and chloride ions seep into the concrete and corrode the steel bars, called rebar. This corrosion expands the concrete, destabilizing it. Eventually, the damage becomes visible when the facade of a building cracks or chunks of concrete break off.
The amount of carbon dioxide in the atmosphere is expected to increase with climate change, and Boston in particular is vulnerable to chloride because of its proximity to salt water.
Under current building codes in the United States, buildings’ concrete coverings have to be about an inch and a half thick for the structures to last three-quarters of a century. However, the researchers noted that these building codes don’t take into account how climate is likely to change over that amount of time. When climate change is considered, buildings built today will likely last between 50 and 60 years, roughly 25 years less than if temperatures remained the same, the researchers said.
Eckelman and Saha said the biggest effect will likely be higher construction costs to reduce corrosion, like adding 3 to 12 millimeters of thickness to buildings’ concrete cover. This could increase building costs by between 2 and 4 percent.
The buildings most at risk in the near term are those built in the 1950s and ’60s because they are built with weaker concrete.
The American Concrete Institute, which provides guidelines for setting building codes, is going over its standards while taking into account global warming (Kevin Hartnett, Boston Globe, Oct. 12). — NH
Calcium chloride is a widely used addition to concrete mix/pours, in areas where freezing temperatures are likely. It accelerates the ‘cure’, allowing finish troweling on the poured slabs and early covering with insulation materials to prevent freezing. If fresh poured concrete freezes before sufficient ‘green strength’ and dewatering/drying is achieved, the ice crystals expand and destroy the developing slab strength.
See http://www.calciumchloride.com/concrete.shtml and
http://www.ascconline.org/PositionStatements/PS31CalciumChlorideWebSC.pdf for details.
As a young feller, I worked as a laborer for a steel building contractor in central Wisconsin. We poured the concrete slabs and then put up the steel buildings, mostly for warehousing and manufacturing operations. CaCl was added to the concrete mixes during the winter months, to accelerate the cure times to less than half of untreated concrete mixes.
CaCl solution is, however, caustic to human skin. I found out the hard way when working the ‘strike off’ board’ during a large mid-winter slab pour. What is ‘strike off’, you ask? Two guys work crouched over, sliding the edge of a 2 inch X 6 inch X 16 foot ‘strike off board’ back and forth across the tops of the slab forms to rough level the wet concrete as it is poured. This is hard work, not only because you are crouched and bent over but also because you often are pushing/dragging excess piles of ‘mud’ in front of the strike off board as you move down the slab rough leveling it. Unbeknownst to me (at first – ahem), the seat of my blue jeans touched the wet top of the concrete and damped off the seat of my pants with CaCl + water. By mid afternoon, I was quite uncomfortable, with light caustic ‘burns’ on both cheeks.
It was a very looooong drive home from the job site, that day.
“The amount of carbon dioxide in the atmosphere is expected to increase with climate change, ”
No it isn’t. It is expected to increase as long as China is cranking out one coal burning plant a month. It will continue to increase even longer when India gets on the burn coal bandwagon followed by other 3rd world countries.
Unless by that statement they are now saying that warmer temperatures are increasing the CO2 …. which in part it is. That would be an interesting admission.
The Pantheon, in Rome, is made of concrete. Built almost 2,000 years ago it’s one of the world’s largest UNreinforced concrete domes. Some say it’s the largest.
http://www.history.com/news/the-secrets-of-ancient-roman-concrete
http://www.romanconcrete.com/docs/chapt01/chapt01.htm
It”s happening quicker than we thought-
“$300 million Las Vegas tower in peril MGM Resorts International wants to demolish a partially-completed tower on the Las Vegas strip. The developer says structural defects in the project, co-developed with Dubai World, are beyond repair”
It”s happening quicker than we thought… The developer says structural defects in the project, co-developed with Dubai World, are beyond repair”
And what’s happening all too quickly is the reflex to refer to this failure – almost certainly having nothing to do with CO2 – in the current discussion. Concrete structures fail for a lot of reasons, almost always arising from design or construction flaws. Perhaps a citation could be furnished, implicating CO2 as the culprit?
“However, over time both carbon dioxide and chloride ions seep into the concrete and corrode the steel bars, called rebar”.
Spaghetti Junction, Birmingham UK. A class example of re-bar BS for motorway intersections
Most any concrete (pure) spends it time setting. A very long hardening process
Compo to hold bricks…just washes out as we know……And?
Add:
We use Portland cement from South England. The Romans used something better I think…its a freaking tough thing anyway….is it from the Pompeii area?
“However, over time both carbon dioxide and chloride ions seep into the concrete and corrode the steel bars, called rebar”
They actually said that? It’s O2 that causes the corrosion if the rebar is not propery prepared and covered with concrete.
Most any concrete (pure) spends it time setting. A very long hardening process
Someone who worked on the maintenance end at the Hoover Dam during the 1980s-1990s told me 10 years ago that the cement still hadn’t hardened. It was built in what, 1935? He said it was going to take another 75 years. That was in 2004.
http://www.history.com/topics/hoover-dam
“When climate change is considered, buildings built today will likely last between 50 and 60 years, roughly 25 years less than if temperatures remained the same, the researchers said.”
Good, that way buildings will need to be rebult in time for them to be rebuilt slightly higher to stay ahead of sea level rise.
While buildings may have a design life of 70 or 80 years, many will probably not last that long anyway and will be demolished to make way for other buildings. I know of many concrete buildings that get demolished after 30 or 40 years because they are no longer represent the best use of the land they stand on. Same is true of roads – how many roads last 80 years? The real practical impact of this is minimal. The only issue would be iconic buildings that have a heritage value.
The purpose of the steel reinforcement is to provide tensile strength to the structural element. It is not to make the concrete ” material less brittle”. So many other errors. They appear to not have basic engineering skills.
However, the researchers noted that these building codes don’t take into account how climate is likely to change over that amount of time.
But the ‘researchers’ didn’t bother to note that concrete structures, reinforced and unreinforced, have stood splendidly under a vast range of temperatures and environmental situations for centuries, and that sealing them against intrusion of rebar-corrosive substances has been understood and applied for at least a century. It’s a standard part of specifications for concrete mixes. Such seals can be retroactively applied as well.
NB – that ” inch and a half thick” cover over the rebar is to protect it against heat-weakening in case of fire. Even the dreaded global warming has a ways to go before approaching that sort of temperatures.
“Starting in 2025 is when [we expect] to see the concrete cover on buildings start to fail, assuming they were built to code,” Eckelman said.
this was happening back in 2000
http://ihbc.org.uk/context_archive/65/deterioration/supportingcols.html
“Deterioration of 20th century concrete buildings
Brian Morton looks at causes of, and solutions to, structural problems with concrete buildings”
Saha and Eckelman provide this statement in the conclusion to their paper:
“This increase in corrosion phenomena is driven more by increases in atmospheric CO2 concentration in which there is high confidence, and less by the less accurate projections in temperature and relative humidity. Even under the control emission scenario with stable CO2 concentrations and temperature, the increase in damage risks over the 21st century will still be significant and cannot be ignored, particularly for chlorination-induced corrosion of structures located on the coast.”
A review of their concrete carbonation model formulas appears to be industry standards. Like they point out, the output from the equations are much more dependent on CO2 concentration than on a couples of degrees of temp variation.
Further, their assumption that pCO2 will continue to rise is quite reasonable, while the calculations are relatively insensitive to temperature changes of a few degrees, which are well within concrete expected range of lifetime temperatures.
All in all, I find this study quite reasonable in its conclusions and should not be dismissed. The conclusions are largely independent of temperature rises.
Further the first level effects are from chlorination, the Cl- ion, since the detrimental impacts from that occurs sooner. There is no doubt the SST off Boston has risen by several degrees in the last 30 years. Since Boston is of course situated on a large harbor with frequent damp marine air, their chlorination modeling based on some various 1 or 2 degree rise in temp is quite reasonable, as most of the building they examined were built in the 1950’s and 1960’s. Further, Boston,like all big east coast cities uses copious amounts of salt in de-icing streets, bridges and walkways.
Even in a cooling climate if one wishes to take the contrarian view of Climate Change (me, for example), more winter-tme snow and ice means more de-icing salt use in the coming decades. AnNyone who has seen the cracked eroded concrete bridges and structures along Boston’s major highways and turnpikes knows what chloride ions do to the rebar steel inside concrete. Once the salt penetrates through the outer skin of cement to the steel rebar inside, rust expansion and concrete spalling can in short order seriously compromise integrity of columns and beams. Thicker cement skins is the only cost effective approach..
My BSci is in Civil Engineering. Although I never pursued CE as a career, I always found working civil engineers to be quite conservative and realistic in their assumptions on building standards. Both Saha and Eckelman are Civil Engineers, not climate change wonks yelling alarms of thermageddon doom.
Conclusion: This study should not be dismissed as simply as part of the Climate Change gravy train, rent-seeking engineers. The findings of Saha and Eckelman are worthy of serious consideration by the engineering committees who set building standards and best engineering practices for the design of concrete structures.
as civil engineers I am sure they would be familiar with –
“…then it is possible to reduce the effect on the structure by surface treatment of the rusting reinforcement and on anti-carbonation treatment applied to the surface of the concrete.”
That’s all well and good, but the article starts out:
“Climate change may reduce concrete’s durability, with long-term consequences for buildings, roads and bridges constructed with the common material, according to a recent study.”
So if they’re going to start out claiming that it’s about climate, when it’s about CO2, are you surprised at the cold reception? A little more honesty and candor, please.
That was the overhyped presser from E&E. Not from the study authors.
The underlying study by Saha&Eckelman I find quite sound and based on reasonable assumptions of increasing CO2 and additional Chlorine (which I think will come from a colder climate needing more de-icing). Saha and Eckelman simply used the IPCC CO2 emission scenarios to model the increases in CO2. Yes they also used the temp increases too, but concrete is quite insensitive to minor changes in average temperature of a few degrees.
And if you think about it, Saha-Eckelman’s conclusion, that we need to use more concrete is actually counter to the Climate Change Fraud that we must reduce CO2 emissions. If anything, their recommendations will drive more CO2 emissions, as Portland cement production is a major source of anthropogenic CO2 emissions.
So these guys (Saha and Eckelman) are not on the “CO2 is bad and causing global warming” band-wagon with this paper.
The Climate Change believers that we must reject are the ones who say we must drastically and rapidly cut CO2 emissions to prevent some climatological catastrophe. Those folks are McKibbenites, AlGore, Mann, etc.
They’ve villified concrete because of the CO2 produced. Few seem to realize that it is normal for the CO2 calcined out to make cement (and lime) to gradually be resorbed back into concrete. The human contribution of CO2 includes the calcined CO2 but they tend to be mum about the resorption that is going on even now with structures that were built 50 years ago. Maybe we are in equilibrium on this. The CO2 for firing, of course isn’t resorbed. Maybe a peak at the future of concrete in Boston is to be found in Halifax today. To me freezing and thawing is a bigger factor in deterioration of concrete. Engineers were a bastion of common sense until recently. I note they say it will add 2-4% on to construction – piffle!
You can roll eyes some more I suppose. They always find a problem where there is no problem.
MIT researchers say that by adding silica fumes concrete can be made to last for up to 16,000 years “if made with an ultra-high-density (UHD) concrete.”
Also special sealers such as epoxy coatings are available to extend the life of concrete.
Here is an article from Caltech.
Abstract
“Extending the Life of Concrete Structures with Solid Stainless Steel Reinforcing Bar”
The last reference is from cartech and not Caltech.
Stainless steel rebar? $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
Carbon nanotubes?
“may”? That is science? I’m so tired of their doomsday conjecture.
May, Possibly, Could, Might, etc. etc. etc. ad nauseum. Either it will or it won’t and if you can’t say it definitively and lend your credibility to your statement then don’t bother us until you actually do enough research to tell us something worth knowing .
It’s not even climate change that’s behind the claim. It’s increased CO2. The climate is irrelevant.
if they were civil engineers they would be last on my list of go to for information-
http://en.wikipedia.org/wiki/Concrete_cancer
lists concrete buildings suffering and treatment.
would hate to investigate this one –
“Many of the raised concrete freeways in Sicily around Palermo”
Starting in 2025, I wonder it that date is in anyway related to the time when they expect they will no longer be in the profession so they can be reminded of their claims ?
Okay, rain water on average contains about 0.000012 moles/L of carbonic acid. When the average content of the atmosphere reaches 500 ppm we can expect rain water to contain about 0.000017 moles/L carbonic acid. Are they sure that concrete structures simply won’t dissolve in a flash? -sarc
I’ve noticed climate change is very good at causing B.S. to spread uncontrollably!
This climate change hysteria (the new name for global warming alarmism) gets better by the day.
There is a famous Australian “bush” poem called ‘Said Hanrahan’. Hanrahan is a farmer and no matter what the weather does ” ‘we’ll all be rooned’, said Hanrahan” is the refrain – at the end of each verse. Of course none of it comes to pass and the battling farmers get by each challenge … but that never deters Hanrahan. Now even the concrete will ‘all be rooned’. LOL. I am not religious by dear God Almighty what will these nutters come up with next.
To paraphrase that great line in Cool Hand Luke, what we have here with ‘climate change’ is not a failure to communicate but an addiction to communicate the first thought that twitters its way into the hysterical consciousness, to shout out ‘we’ll all be rooned’ at every opportunity as junk science and hack journalism merge into an intellectual ebola.
BTW, here in Oz on October 17 last year we had raging bushfires in the Blue Mountains west of Sydney. This year on the 15th wouldn’t you know it – 6 inches of SNOW. Isn’t mother nature just a gorgeous old bitch! They’ll all be ‘rooned’ you know if they keep living in those Blue Mountains.
You mean the captured Jewish revoutionaries against Rome in the 66-73 AD war, don’t you? It is they who built it.
All climate alarmism repsupposes that humanity is going to sit back and watch trillions of dollars of infrastructure be destroyed by concrete rot, sea level rise etc etc. The only solution warmists can see is to reduce the amount of carbon dioxide in the atmosphere and all these problems will miraculously be solved.
As the article points out , steel is concretes downfall . As concrete dries out it shrinks . Corners are concretes enemy and the colosseum was round or oval. An archway is way stronger then a square opening. Hear’s the real smoking gun regarding cement . http://www.unep.org/chemicalsandwaste/Mercury/PrioritiesforAction/MercuryreleasesfromtheCementIndustry/tabid/106181/Default.aspx
Mercury the second deadliest element none to man, by putting it in our mouths and in vaccines they cover their asses from litigation. The felt hat industry used mercury to stiffen the felt, that’s were the term made as a hatter came from, they went crazy before they died.
It is interesting that one of the symptoms of mental break down, or madness, is an irrational fear of and fixation with mechanical objects.
For example, in the onset of schizophrenia, people experience extreme reactions to wind-up clocks.
Perhaps this explains certain populations’ fears of, and obsessions with, buildings and airplanes as sources of death and madness, and a compulsive need to communicate this obsession on all occasions to others.
One of the first signs of sycosis is no empathy . We live in a world were everybody thinks their the ONE instead of ONE of many .
No, I do have empathy for you. The irrational fear of technology and modern machinery is, I believe, counterproductive for you in your life. You do not have to live this way, in constant fear of machines.
I actually suspect that some of these phobias and fixations with mechanical and technological devices are related to cannabis use at a young age. These drugs are highly correlated to madness and stunted academic and emotional development.
Besides, if it is mercury you wish to avoid, do not use any CFL bulbs. These contain more mercury in each bulb than is considered safe in most states. CFLs also use mercury in its volatilized form as well, and are known to leak and spontaneously combust. It is a good idea to avoid these.
All righty then, more CO2 could lead to more cracks in concrete allowing more moisture to enter and rust the steel rebar quicker. The issue for rebar is moisture, especially moisture with a high salt content. I am assuming the Romans did not have rebar so readily available and avoided the rebar rusting issue.
So there is the process, which is used to jump a shark or two and conclude concrete lasting 25 years less. Concrete BTW that apparently already does not last too long at 75 years. Before the climate apocalypse, were the people who invested millions of dollars into buildings notified that the cement lasts 75 years in only “optimum” CO2 levels? Are new home purchasers notified the foundation their home sits upon was going to start rotting in 75 years but now that we are at the dawn of the climate apocalypse will only last 50? Somehow context or some relation to practical reality is missing in the research article.
Meanwhile it is hard to believe there is no chemical in the world that could be added to concrete or was already added to cement in high salt moisture regions that prevents the chemical reaction leading to premature cracks in the concrete.
In the past, only politicians could get paid well for activism thru obfuscating, now climate researchers have joined them.
Everyone here seems to have an important fact. Inside of buildings the CO2 level is typically much higher than the outside levels. The minor increase in global CO2 levels pales in comparison to the indoor levels.
… seams to have missed…
If you think about it, with GW you won’t have to worry about freeze and thawing. Let’s add another positive check mark to the position that warmer is better.