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
Or, you know, you could just alter the cement chemistry for a chloride environment. Just like cement producers have been doing for decades in applications with high chloride exposure.
The stupid. It burns.
Haha, I’m in the cement industry, and you took the words right out of my mouth. The stupid really does burn with this story. They have no idea how how cement and concrete are made.
… and how long have you guys been trying to figure out how to make improved and corrosion proof reinforcing members? Like this is supposed to be “news.” (fyi, I’m sure they’re using the terms cement and concrete interchangeably… yes the stupid is strong there.)
The authors are civil and environmental engineers that, by virtue of this article, have sublimated into climate scientists. Thus, they’ve achieved infallibility.
The give-away is in the second sentence. “They predict about 60 percent of Boston’s buildings will have some structural deterioration by 2050.” The key word is ‘some’, which immediately fails to actually quantify the extent of the deterioration. How much is natural and expected? Is an extra crack or chip due to Climate Change? Nope. Not misleading at all.
With you there. Most cement made to standards is good but not all concrete is good. The reason for concrete “cancer” was the use of Calcium Chloride to give early strength growth. This has been banned. Other problems of using too much water, not enough cement in concrete mixes and insufficient cover over reinforcing, although in standards, is more difficult to police. There is good and bad concrete. Poor concrete is the fault of poor design, poor construction, & poor supervision it has nothing to do with climate or environment but government legislation and environmental restrictions on production and construction which raise costs (encouraging short cuts) are not helpful for getting a good outcome.
By the way the hydraulic lime used by the Romans was not all good quality nor were many of the structures built by the Romans. What remains was at the top of the quality curve. The dome of the Pantheon in Rome is an outstanding example.
@ Tucker –
My first job out of college was as a laboratory inspector for ASTM’s Cement and Concrete Reference Laboratory. Blaine and Wagner (you may have heard of them) were two of the first people associated with that organization.
I can honestly say that I’ve forgotten more about Portland cement and concrete than most people will ever know.
Nor do they understand the reinforced concrete design process. I hate to say this but these people are idiots.
Concrete loves hot and humid. A warmer climate would undoubtedly increase the life of concrete in Boston. It’s rapid temperature swings and corrosives concrete doesn’t like, which is why additives and sealants are used, and why reinforcing steel often has corrosion protection. There is no substitute for good maintenance and good design, no matter the weather and climate.
I was in the Coliseum in Rome last year, and was amazed at the condition of the concrete, which was actually quite good. The Coliseum was built with rubble, bricks and other waste materials, as filler. The dome of the Pantheon (126 AD) is all concrete and in great shape as far as I could tell. The benign (warm) climate, which seldom freezes, has played a big part in the life of these structures.
I am confident that the concrete in Boston will be just fine if it is properly maintained, and just as confident that it will not be.
But ya know, they are right. Once places that didn’t freeze before start the freeze thaw cycle, their lifespan will be reduced.
Ot the converse. They believe there will be less freeze/thaw
as the globe warms. freeze/thaw rips up concrete roads.
Not as bad for vertical surfaces I guess.
“Hey you guys, quit burning those Christians!”
Well, they’re gonna need SOMETHING to explain why that new Bay Bridge in SF fails waaay early.
Roman concrete is not the same concrete we use today. Today we use Portland cement. The Romans used lyme and volcanic ash. Their formula was vastly superior to the modern formulation. Today’s concrete has a relatively short lifespan.
http://www.romanconcrete.com/docs/spillway/spillway.htm
Glad you had something concrete to add to the discussion instead of just Roman around like the rest of us.
LOL. We still have a lot to learn from the ancients.
GROOAANNNNN
Way to kick some ash! 🙂
Mesopotamian hydraulic cement predated even the Romans use of pozzolans ground pumice, brick, pottery. The chemical resistance is in the hydraulic/non-hydraulic nature.
An acquaintance forms-carpenter told of earth collapsing under bridge forms and submerging them through the winter. Rather than blasting them, they were incorporated into the footings.
Hope this not too off-topic, but the Egyptians appear to have learned how to make concrete earlier still and (this is highly speculative) used the technology in the construction of their monuments.
Here’s a nice short article about the possibility that the Egyptians poured the blocks for the pyramids into molds, on site:
http://cementafriend.wordpress.com/2014/05/06/pyramids/
Actually, if I remember correctly (more questionable as time passes), there was an article several years ago by a Yugoslavian engineer (possibly in Science mag) that first claimed to have discovered the formula for a cement like substance used by the Egyptians to build their pyramids. He had produced several samples and claimed they were indistinguishable from the ‘stones’ used in the pyramids.
No poured blocks for the pyramids. The stone used is quite well characterized and sourced. The biggest mystery was always “how” the blocks were moved into place, and what became of the ramp afterward, which, of external would have massed nearly as much as the pyramid. Look up the “pyramid internal ramp hypothesis”. The idea is elegant and some recent supports the idea quite well. What is particularly elegant is that the ramp doesn’t have be removed since it was incorporated directly into the pyramid.
Did you draw these concrete conclusions from the aggregate data? Greater reinforcement may cement your thesis, before it all turns to mud….
Aging concrete is actually a huge issue.
http://www.usbr.gov/ssle/damsafety/TechDev/DSOTechDev/DSO-05-05.pdf
Cementafriend introduced me to the great engineer, John Smeaton (8 June 1724 – 28 October 1792). “He is important in the history, rediscovery of, and development of modern cement, because he identified the compositional requirements needed to obtain “hydraulicity” in lime; work which led ultimately to the invention of Portland cement. Portland cement led to the re-emergence of concrete as a modern building material, largely due to Smeaton’s influence.”
Now, as usual with disaster predictions from environmentalists, possible environmentalist regulations and sabotage of the compositional requirements for Portland cement would and could fulfill their own prophecies of failing cement.
Alan,
Lyme cement is not vastly superior to Portland cement. They each have their strengths and weaknesses, and the type used should be based on the purpose and need required. Therefore, one is not better than the other.
My first introduction to Lyme cement was the Tabby foundations used for the old houses in the Low Country of South Carolina. They were poured of lime, sand and water with broken/crushed oyster shells as aggregate. The lime was made by crushing and burning oyster shells.
You are of course correct. Steel re-enforced concrete has weakness too. If the steel is not clean of rust and not deep enough in the concrete it will oxidise, rust and will eventually cause the concrete to swell and fail. Also, it was the Romans who developed concrete that could set while in sea water.
The only thing that this sort of “research” seems to be doing is shortening the lifespan of a dollar bill in my wallet. It used to be able to rest there a day or two, but now it has a hard time getting to it in the first place.
This is true. Over-regulation, the continued use of special permits, and the banning of effective chemicals make it more and more difficult for most people to engage in commercial activity.
This then destroys culture, because the opportunities for individuals engaging in commercial activity naturally rewards hard work, innovation, and intelligence. Without commercial activity by all people, the welfare system rewards unemployment and drug use.
It also destroys purchasing power.
One more reason for the alarmists to start holding their breath.
I am at the point of starting a rumor “Global warmist who talk too much about this and that causing climate change are the cause of the climate change.” In other words I tired of hearing them. They make themselves look dumb.They wonder why you look at them like their crazy.
If you like their crazy, you can keep their crazy, There, there, those homeynyms (sic) will getcha every time, they’re everywhere.
Yep its gone from a lifespan of 2500 years from before Christ until 25,000 years with today’s technology
From the hyped “press corpse release” above ..
It is the SALT (mainly from the northeast’s need to spread salt over everything to prevent ice damage and clear roads and sidewalks of the frozen slush) that causes the steel to rust. It is NOT the CO2 that harms concrete or steel – instead the CO2 strengthens the concrete surface! (The article is correct on one point: A rust surface on carbon steel has a different, much larger crystal structure with substantial gaps and openings thattrap additional moisture and oxygen around the rusted material (Fe2 and Fe3 iron oxides) that does tend to expand and crack away (spall) the cover concrete from the rebar. But only if the rebar is set too shallow in the first place.
So, the CO2 affects ONLY the outside 3 mm of the drying concrete. Which will NOT affect the steel rebar INSIDE the concrete covered by – what should be 2- 3 INCHES (75 mm) of concrete. Rebar 1/2 inch (25 mm) from the outside surface
More important to look for corrupt Boston city manager that managed to spend more time and effort building a single highway tunnel than was needed for the Hoover Dam, Golden Gate Bridge and Panama Canal. Combined. But those projects didn’t also enjoy roof panels that were not glued on right either.
Oxidation (rusting) of elemental iron creates iron oxides ( Fe2O3, Fe3O4, etc), an exothermically favorable reaction. A volumetric expansion occurs with formation of the iron oxides, causing shear forces and subsequent flaking and spalling of the developing oxide layer. This presents fresh iron surface to free oxygen atoms and the cycle continues until the iron is consumed. Oxy-acetylene ‘torch’ cutting of irons and steels is a (very!) accelerated form of this reaction.
As more oxides form on and around the ‘rusting’ iron surfaces, the continuing volumetric expansion during oxide formation can create sizable tensile forces in the concrete surrounding the rusting ‘rebar’.
Additional stresses are created from the differing thermal expansion/contraction properties of steel rebar vs concrete, as a result of the daily and seasonal changes in temperature cycles (day/night, summer/winter).
When the combined stresses exceed the local tensile strength of the concrete, the concrete cracks or even spalls off, allowing more direct exposure of the steel to oxidation and corrosion. And so it goes…..
2- 3 INCHES (75 mm) of concrete. Rebar 1/2 inch (25 mm)
I think that should read 50 – 75mm
& 1/2″ = 12.7mm
Technically, yes – if any field worker were measuring concrete and concrete forms with a calculator and micrometer instead of a yardstick, measuring tape, and 2×4’s …. one should convert 1/2 inch to 12.7 mm . But, that is not the real world case of pouring concrete and bending rebar with sledge hammers and crowbars to fit inside a form made of plywood and 2×12’s … 8<)
I saw electrical transmission lines in the Ukraine in the 1990s that were – unusual – to a western eye. Instead of wooden poles and yards they used reinforced concrete. Apparently there’s a dearth of tall-enough trees in the former Soviet Union and metal had other important uses. The lower three to five feet of many of these poles was bare re-bar. The repeated freezing and thawing caused the concrete to crumble at and below the common limits of the yearly snow accumulation. I found myself wondering what a high wind would do to a line in that condition.
Am I missing something, or isn’t this about increased CO2 levels, not climate change?
Bingo.
And the climate change they are predicting is rising CO2 levels – not temperature, storms or dying polar bears.
This makes sense. CO2 has risen consistently. Probably due to man and fossil fuels – near certainly in my opinion..
But even if not it has still been a consistent rise during the time of ~800 years post-MWP.
This “alarm” is reasonable. And so is the anticipated mitigation (thicker concrete).
Somewhat OT, but I read somewhere (possibly on this site) that when Mt Pinataubo (sp?) went up, it released more carbon dioxide than all human activity ever has. Is this correct, and if yes, could someone point me to a reference, please. When I throw these sorts of factoids into discussions with warmists, I like to make sure I can back the statements up (unlike many statements warmists parrot, that sheer logic should tell them couldn’t possibly be correct).
The amount of damage done by 0.04% of CO2 is so much bigger than that of acid rain.
Interesting new example of climate alarmism. Do they have any suggestions on how to halt climate change without perturbing every living thing on earth? An unchanging climate has never happened before but now it seems to be a critical necessity. Its for the concrete, people.
Assumes that Roman concrete is the same.
a SIMPLE google check and one would have avoided the knee jerk response of comparing the two
to discredit the study.
why roman concrete has lasted so long when its structurally weaker.
http://www.smithsonianmag.com/history/the-secrets-of-ancient-romes-buildings-234992/?no-ist
eye rolling?
more like eye’s shut.
1. We have observational evidence that the colliseum is made of “concrete”
2. We have a study that says more C02 may shorten the lifespan of buildings in Boston.
One person can read these two and conclude that they are in conflict
But where is the conflict?
1. Maybe roman concrete is different than Boston concrete
2. Maybe the Boston study is flawed
rolling your eyes means you’ve concluded that 1 is not possible. This is a bias.
On its face either or or 2 is plausible. So, before passing judgment and settling the issue, a good skeptic
reads more.
I agree wholeheartedly. We need to avoid jumping to conclusions.
+1
No.
Roman concrete is a totally, completely different chemical, applied and poured in position completely different from modern cast reinforced concrete (including no rebar that could rust and cause spalling!) and contributes NOTHING to the story except distraction. Plus a usual snide implication “our new stuff is not as good as the old stuff” revisionism …
Re-read the story: CO2 does NOT degrade concrete performance. It is the too-shallow steel rebar that rusts and causes the concrete to spall. IF the concrete was improperly poured in the first place.
Then, these idiots compound the problem by assuming a skim coat of 1/2 inch could be applied successfully to prevent rust damage – when 1/2 inch (12 mm) of re-applied cover coat concrete will INCREASE sub-surface water/salt/chloride retention and subsequent rusting.
CAGW by press release. Bad data. Bad writing, wrong conclusions, wrong solution. All written around the “Greater CO2 is going to cause more problems and kill people….Unless we stop all progress and force more people into poverty.”
I beg to differ. The post posited the argument that concrete is long lasting, citing Roman concrete as evidence, and then raised the issue as to whether climate change could have any effect on the longevity of concrete. But at Steve and I pointed out Roman concrete is not the same as modern concrete, so any arguments concerning the longevity of “concrete” based on the lifespan of Roman concrete is not applicable. This is not to argue that climate change has any effect on the longevity of modern concrete. But as I pointed out earlier in this post, there is an issue with aging concrete and needs to be addressed and attached a PDF that talks about it.
As I have pointed out modern concrete can be made to last up to 16,000 years! So maybe build structures might struggle, but I still roll my eyes about the future of modern concrete. Special coatings can also be applied to extend the life of concrete.
http://wattsupwiththat.com/2014/10/15/eye-roller-concretes-life-span-is-shortened-by-climate-change/#comment-1763284
I own a cement block house with re-inforced concrete pillars, beams and suspended floor slab. I was told it would have a life of 100 years, some said 60. I am aware of the lifespan issue.
My problem is this:
Why not a study that just tells us about concrete’s failures in the coming years? Grrrrrrrrr. I suppose it’s one one sure fire way to get your grant application approved el pronto. This is what I am sick and tired of.
The Romans used more than one form of concrete. Pozzolana made with volcanic dust was used to produce concrete that was required to set under water but this material was not available everywhere and had a cost premium. The modern equivalents use substitutes such as furnace fly ash and have very similar properties.
There are thousands of bridges and other structures across Europe that were built with other aggregates including the Pantheon in Rome which used volcanic materials such as Tufa and Pumice to produce light weight aggregates. The modern equivalent in the UK uses fly ash from coal fired power plants to produce lightweight stable concrete blocks with good thermal insulation properties usually referred to as breeze blocks
There is no evidence that we are heading into any of the climate extremes used in this analysis. There is no question though that concrete and steel are vulnerable to weathering and there’s nothing we can do about weathering. The intent of the report is to impart worry, not science. BTW, they place the blame on a warming climate, not more CO2.
“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.”
That’s fine, as long as the cost of fuel, electricity, cereals, dairy, beef, fruits, wood, light bulbs, shipping, restaurant operations, and everything else don’t rise because of environmentalist regs and unnecessary add-ons.
Oh wait…
You don’t have to thicken the concrete.
Just so long as the reo has sufficient cover, is all that’s required. (hint: the reo could be futher inside from the surface).
It’s still a brainless study, as engineeers have been designing concrete structures for decades with the environment and soil acidity in mind.
Why are the CAGWers fearmongering about the shortened lifespan of concrete? If they had their way, we wouldn’t be using ANY concrete, since the production releases CO2 to the envrionment.
http://en.wikipedia.org/wiki/Environmental_impact_of_concrete#Carbon_dioxide_emissions_and_climate_change
“…The cement industry is one of two primary industrial producers of carbon dioxide (CO2), creating up to 5% of worldwide man-made emissions of this gas, of which 50% is from the chemical process and 40% from burning fuel.[“
Since it won’t last very long anyway… Yet one more reason not to make cement. A twofer! 😉
Alan don’t forget steel works they use carbon to extract oxygen bubbles from steel. The waste gas is co2
Stop.Just freaking stop climateers. What next, erectile dysfunction? Those of us that visit this site frequently know it’s responsible for psychotic breaks as is obvious by this article. But concrete? Please.
I thought that was already on the list.
Climate change does cause more rape (at least it has been said); so that speaks against erectile dysfunction.
Hey, I read that freezing weather damages concrete.
You hada ask.
—-
Agency: Environmental Protection Agency [2010]
A Human Health Perspective on Climate Change: Summary [Brochure]
http://www.globalchange.gov/browse/reports/human-health-perspective-climate-change-report-outlining-research-needs-human-health
The “study” confuses and conflates climate change, warming, increased CO2, and salt corrosion. Epic FAIL.
The answer to corrosion which is primarily from salt is stainless steel rebar. The increased upfront costs are paid for eventually by increased lifespan of the structure.
Eeek, does that also mean the 800 tons of concrete under each wind turbine.
http://docs.wind-watch.org/Cracks-in-onshore-wind-turbine-foundations.pdf
Oh no , they were right, it’s already happening.
Ok I’m not a chemist, so could somebody explain to me how CO2 effects steel. Chloride ions I get. CO2 not so much.
Copy and Paste from Wikipedia:
And those formations break apart the surface of the structure.
And this reaction can be prevented with the addition of a pozzolan such as metakaolin that reacts with the calcium hydroxide hydration product to produce more cementious material, negating the reaction with carbon dioxide, making the concrete stronger, denser, less porous and eliminating efflorescence. Further, the addition of acrylic polymers and other admixes provides an anti-corrosive coating to reinforcing steel and also makes the concrete less porous. The addition of crystallization admixes can make concrete virtually impermeable to water. Further still, various fiber additives eliminate even the need for steel reinforcement in many applications. With these kinds of additives, my concrete constructions will outlast my great-great grandchildren. Modern concrete formulations are nothing like those of the past.
According to my late uncle – a civil engineer/contractor – the recipe for the mortar is the main determinant in how concrete endures.
all alarmist stories with might, may and could are meant for the dustbin,
“Climate change may reduce concrete’s durability”
Brian R – Steel and iron corrode when there are 3 things present: iron, oxygen, and water. CO2 has little to do with it. CO2 *will* affect the lime (calcium hydroxide) turning it into calcium carbonate and making it gradually crumble – unless precautions have been taken. The Romans used volcanic ash (Pozzolan) in their concrete to stabilize the lime and improve the “cementitious qualities”. The Minoans knew this trick, and passed it along through the Greeks.
The Colosseum wasn’t built out of concrete, it was built out of stone with metal clamps to keep it in place (no mortar).
However, if you want to talk about impressing Roman concrete structures, you can’t go past the Pantheon, with it’s un-reinforced domed roof approaching 2,000 years old.
The Romans, as Alan noted above, used their own Roman cement, the chemical formula of which eludes us to this day. It’s worth noting that Roman concrete tends to be unreinforced, unlike today’s construction materials, and so doesn’t suffer from concrete cancer.
Help is at hand.
http://www.concretenetwork.com/concrete/concrete_cracks/preventing_concrete_cracks.htm
Even better help at hand
http://crystalfix.com.au/content/how-mr-crystal-works.html
and
http://xypexwaterproofing.com/products/concentrate.html
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.
[i]60 percent of Boston’s buildings will have some structural deterioration by 2050[/I]
I am sure there will be structural deterioration of buildings in Boston in Boston over the next 36 years. It’s called lack of sea spray, entropy and lack of maintenance.
60 percent of Boston’s buildings will have some structural deterioration by 2050
I am sure there will be structural deterioration of buildings in Boston over the next 36 years. It’s called lack of sea spray, entropy and lack of maintenance.
60 percent of Boston’s buildings will have some structural deterioration by 2050
I am sure there will be structural deterioration of buildings in Boston over the next 36 years. It’s called sea spray, entropy and lack of maintenance.
Doh!!
Robert, my question on the ’60 percent will have’ statement was – What is the current percent of Boston’s building that already have structural deterioration?
OK This argument is as follows: time causes ageing
Who’d a figured?
Hmmm, is that why my hair is turning grey, and my wind machines need overhauls?
“Climate change may reduce concrete’s durability,…”
You’ve got to love it when the greens use the word “may” in the hypothesis of their pseudo science.
“May” implies anything could be true. So how about “The Elevated Roman Warm Period Temps May Have Caused Roman Era Cement To Be So Long Lived” as a title instead?
Or how about “Modern Global Temperature Stability The Past 18 Years May Cause Obama’s Ears To Grow Even Larger” after all it “may” all be true.
Last Winters extreme cold and snow caused excessive damage in the eastern half of the US, including tens of billions to to concrete roads. Chicago had its coldest Winter ever since records started in 1880. Detroit, it’s snowiest.
http://www.rejournals.com/2014/04/16/property-damage-from-winter-2014-can-emerge-in-spring-prepare-for-next-year/
But we found out last January from Dr. John Holdren, that global warming caused it:
“A growing body of evidence suggests that the kind of extreme cold being experienced by much of the United States as we speak is a pattern that we can expect to see with increasing frequency as global warming continues,” Holdren asserts. Watch it:
http://www.motherjones.com/blue-marble/2014/01/john-holdren-video-polar-vortex
It is idiotic to build concrete roads in areas with cold winters and extensive frost heaving. It has been tried again and again and it doesn’t work. Asphalt that is slightly resilient and much easier to repair/re-use is much better.
It’s Already Happening. Be afraid. Be very afraid.
http://kelsoindustrial.com/kelso-industrial-group/news/elliot-lake-disaster-a/
And look at the Colosseum! Pretty shabby condition. In fact, most Roman buildings are just ruins, now. Isn’t that PROOF of Climate Change?
“The buildings most at risk in the near term are those built in the 1950s and ’60s because they are built with weaker concrete.”
Are there any left? And if so, why haven’t they been knocked down already?
My local shopping area used to be called Piccadilly Arcade. This got knocked down and replaced with a mall. The mall got knocked down and replaced with a new (smaller) shopping arcade and apartments. This all happened in a span of 50 years.
I noted that no one made any mention of the quality of concrete used today versus that of about 50 years ago.
We replaced my mom’s back yard about 50 years ago, and only recently (last 5 years or so) noted hairline cracks, but nor heaving.
Mom had some front sidewalk replace about 5 years ago, and it’s already got cracks.
I’ve noticed the same on sidewalks poured within the pas 5 years arount new buildings where I work.
Don’t tell Dr Dave Viner about this because…..In the Future…..Children just aren’t going to know what concrete is…..
Post-tension anyone?
A lot of concrete fortifications were built in Europe in 1939-45, usually hastily and with substandard materials. They are dam’ near impossible to destroy even 70 years later.
Nearby I have one of the oldest major concrete bridges in Scandinavia. It was built in 1910 and has had minimal maintenance (the (metal) handrails have been replaced once). It shows virtually no signs of deterioration.
On the other hand the Öland bridge, built in 1967-72 has required repeated large-scale and very expensive repairs because slightly brackish water was used for the concrete “to save money”. It is chloride ions (=salt) that destroys concrete, not CO2.
What a bunch of garbage looking for a grant. The formation of the calcium oxide will most assuredly be the limiting chemical reaction. Not the reaction of CaO with CO2. More runaway global warming nut jobs.
This will be most fun to watch. MSCE Structural.
Oh no!!! The sky is falling. Think of the children….