Riddle solved: Why was Roman concrete so durable?

[crimsonaudio]

I find this amazing!

Riddle solved: Why was Roman concrete so durable?

Researchers have discovered ancient Roman concrete-manufacturing strategies that incorporated self-healing. Applying this knowledge toward modern cement production, they hope to improve the material’s environmental impact.

news.mit.edu

 

[dtgreg]

THis is wonderful and decades (at least) overdue. I wonder if rebar will be discontinued?

 

[seebell]

Ancients were pretty darn smart!

 

[bamaga]

I find this amazing!

Riddle solved: Why was Roman concrete so durable?

Researchers have discovered ancient Roman concrete-manufacturing strategies that incorporated self-healing. Applying this knowledge toward modern cement production, they hope to improve the material’s environmental impact.

news.mit.edu

I find it amazing as well. Being in the construction business, we can’t make concrete bridges last 50 years, the Pantheon has stood intact for 2000 years.

 

[Padreruf]

Amazing...sometimes progress isn't progress...

 

[4Q Basket Case]

Just curious, and hoping some of our architects and structural engineers can enlighten me:

1. If quicklime is the key ingredient, and hot mixing is the key process, and together they make for both quicker construction and a longer-lasting finished product, why did engineers move away from them?

2. Having re-discovered the advantages, is there any reason modern engineers wouldn't start using quicklime and hot mixing?

 

[Ole Man Dan]

Just curious, and hoping some of our architects and structural engineers can enlighten me:

1. If quicklime is the key ingredient, and hot mixing is the key process, and together they make for both quicker construction and a longer-lasting finished product, why did engineers move away from them?

2. Having re-discovered the advantages, is there any reason modern engineers wouldn't start using quicklime and hot mixing?

COST. It would cost more to heat the material, and it would take longer to make. but make more money for contractors.

 

[DzynKingRTR]

COST. It would cost more to heat the material, and it would take longer to make. but make more money for contractors.

yep. clients want cheap and fast

 

[Go Bama]

Very cool! And high time.

Am I the only one who didn't know what a "clast" is?

 

[OakMtn4Bama]

I read one time that the ancients could do pretty much everything the "moderns" could do just about as well up until the invention of the steam engine.

 

[mdb-tpet]

THis is wonderful and decades (at least) overdue. I wonder if rebar will be discontinued?

Rebar is also used to create compression in concrete, since the compressive strength in concrete is stronger than the tensile strength. The clasts won't heal a crack fast enough (weeks vs. microseconds) to stop failure in concrete in tension.

But this forgotten technique could reduce the need for rebar.

 

[mdb-tpet]

Very cool! And high time.

Am I the only one who didn't know what a "clast" is?

Nope. I didn't know what a clast was either.

 

[mdb-tpet]

I wonder how many times throughout history someone has disregarded an old "sloppy manufacturing technique" that turned out to be the exact key ingredient to the original formula like this?

 

[Bamabuzzard]

Extending the time for return revenue will be what halts this process. Does anyone remember when weedeaters used to last more than three years and now if you get one to last more than two you've gotten a "good one"? The engineers were told to shorten their life. They were lasting too long so they shortened the revenue cycle by shortening how long the weedeater would last.

 

[dtgreg]

Extending the time for return revenue will be what halts this process. Does anyone remember when weedeaters used to last more than three years and now if you get one to last more than two you've gotten a "good one"? The engineers were told to shorten their life. They were lasting too long so they shortened the revenue cycle by shortening how long the weedeater would last.

Planned obsolescense.

 

[dtgreg]

Rebar is also used to create compression in concrete, since the compressive strength in concrete is stronger than the tensile strength. The clasts won't heal a crack fast enough (weeks vs. microseconds) to stop failure in concrete in tension.

But this forgotten technique could reduce the need for rebar.

The Romans never used rebar. I'm sure they thought of it but iron was needed for weapons and they didn't have the Bessemer process or anything like it (although, damascus steel?). Iron rusts so any use in concrete circumscribes the lifespan of said concrete.

The Romans were thinking of a multi-millenial empire. They built structures and roads to stand the test of time. They wanted to be remembered forever. We build boomtowns with wooden telephone poles running our utilities and worry about the next quarter.

 

[crimsonaudio]

The Romans were thinking of a multi-millenial empire. They built structures and roads to stand the test of time. They wanted to be remembered forever. We build boomtowns with wooden telephone poles running our utilities and worry about the next quarter.

This is perfect.