Concretebroker

Blog

article title image

Published on 7/9/2017

Published by marketing@concretebroker.com.au

Science Reveals The Secret To Ancient Rome's Indestructible Concrete

By George Dvorsky at GIZMODO.au


 

 

 

Science Reveals The Secret To Ancient Rome's Indestructible Concrete 

 

By George Dvorsky at GIZMODO.au

Roman concrete is famous for its durability, lasting for thousands of years and seemingly stronger with each passing year. New research has uncovered the chemical processes responsible for the sturdiness of this ancient building material — a finding that could inspire modern engineers to revive this forgotten technique.

If this news about ancient Roman concrete sounds familiar, it's probably because you're remembering work done by the same researchers a few years ago. Back in 2014, a research team led by Marie D. Jackson of the University of California at Berkeley showed how the recipe for Roman concrete — a mixture of volcanic ash, lime, and seawater combined with a volcanic rock aggregate — produced a chemical reaction that resulted in super-strong concrete. The trouble is, Jackson's team wasn't entirely sure how the Romans managed to facilitate this complex reaction.

 


Geologists drilling at a marine structure in Portus Cosanus, Tuscany. (Image: University of Utah)

 

In a follow-up study, published this week in American Mineralogist, the researchers have learned that it wasn't the Romans who facilitated this chemical reaction — at least not directly. Rather, the strengthening process was caused by the steady filtering of corrosive seawater through the concrete over time, which triggered the growth of rare, interlocking minerals that made the material even tougher.

Indeed, ancient Roman piers and breakwaters, some of which were constructed more than 2000 years ago, are thought to be stronger today than when they were first constructed. Modern marine concrete structures, made of rocks or gravel mixed with water and cement, crumble within a few decades.

Inspired by naturally-cemented volcanic ash deposits, the Romans learned how to make concrete — and they did so by exploiting the binding powers of what scientists now call a pozzolanic reaction. This reaction, named after the city of Pozzuoli in the Bay of Naples, causes minerals to grow between the aggregate and the mortar, in this case, a mixture of silica oxides and lime found in volcanic ash, which has the happy effect of preventing cracks from growing. Modern concrete also uses rock aggregate, but particles used today are deliberately kept inert to prevent reactions from taking place. Unfortunately, these nonreactive aggregates help cracks to grow and spread, resulting in steady deterioration.

As the previous work by Jackson's team revealed, the presence of a rare mineral in the Roman marine mortar, called aluminous tobermorite, allows mineral crystals to grow around the lime particles via the pozzolanic reaction. But this only happens at relatively high temperatures, so it wasn't obvious how the Romans managed to achieve this effect. It's tough for scientists to do this in the lab today, and when it is done, it can only be done in small batches.


 

 

This microscopic image shows the lumpy calcium-aluminium-silicate-hydrate (C-A-S-H) binder material that forms when volcanic ash, lime and seawater mix. Platy crystals of Al-tobermorite have grown amongst the C-A-S-H in the cementing matrix. (Image: M. D. Jackson et al., 2017)
Read more at https://www.gizmodo.com.au/2017/07/science-reveals-the-secret-to-ancient-romes-indestructible-concrete/#MZigd7tTtHObIb6b.99

 

Convinced that something else was responsible for the effect, the researchers took samples of aluminous tobermorite, and a related mineral known as phillipsite, to Berkeley's Advanced Light Source lab for X-ray scanning. They found that the aluminous tobermorite formed within pumice particles and pores in the cementing mix, but because it isn't possible to recreate this effect over short timescales without high heat, the researchers figured something else had to be responsible.

That something else, concluded the researchers, is the steady pounding of seawater. Instead of eroding the concrete, seawater sifts through the material, dissolving components of the volcanic ash. Over the course of hundreds of years, this allows minerals to grow from the highly alkaline fluids that are leaching out. This results in the proliferation of interlocking, crystal-shaped structures that increase the concrete's resistance to brittle fracture.

To a materials engineer working today, this process would represent a total nightmare. In fact, scientists spend a lot of time trying to prevent this sort of thing from happening in modern materials.

"We're looking at a system that's contrary to everything one would not want in cement-based concrete," said Jackson in a press release. "We're looking at a system that thrives in open chemical exchange with seawater."

So why don't we do as the Roman's did? For one, volcanic ash isn't the most accessible natural resource. But more importantly, we still don't have the precise recipe used by the Romans to make the concrete, nor do we have access to similar building materials.

"Romans were fortunate in the type of rock they had to work with," said Jackson. "They observed that volcanic ash grew cements to produce the [mortar]. We don't have those rocks in a lot of the world, so there would have to be substitutions made."

Jackson and others are currently working on a replacement recipe, and should it be developed, it could be put to good use — including a tidal lagoon that's slated to be built in Swansea, United Kingdom. This structure, which will be used to harness tidal power, will need to operate for 120 years in order for the construction costs to be recouped.

"You can imagine that, with the way we build now, it would be a mass of corroding steel by that time," said Jackson. Instead, using this ancient Roman technique, we could built a structure that would remain intact for centuries.

 

Check out this video from the University of Utah on how seawater strengthens Roman concrete:

 

 

Read more at : American Mineralogist

 

Concrete, or beaches? : https://www.concretebroker.com/Blog/View/48

So tell me. Is concrete environmentally sustainable? : https://www.concretebroker.com/Blog/View/40

 

 

HAVE A CONCRETING PROJECT?

If you are ready to go with your next concreting project fill out a quote form here and at concretebroker we can put you in touch with a concreting expert near you. In fact we'll go further, we'll match you with 3 concreting experts.  Assess their quotations, read about their business online at concrete broker, and make an impartial, calculated decision.

 

Concretebroker provides the tools, information and resources to purchase and pour concrete.
Find what you need to know for your next concreting project here 

 

  HOW MUCH CONCRETE, STEEL AND ACCESSORIES DO I NEED?
   And how much do concrete slabs cost in Australia?

 

 

 

 

  WHAT MAKES A GOOD CONCRETER?
   Are you cut out to be a good concreter?

 

 

 

 

  HOW TO POUR A CONCRETE DRIVEWAY IN THE USA
  How to Pour a Concrete Driveway by Sciulli Concrete
  

 

 

 

 

  
  I'VE NOW GOT PROBLEMS WITH MY SLAB
  What was the cause?
  And how can I prevent it from happening next time?

 

 

 

  HERE'S TEN "DON'T DO'S" WHEN IT COMES TO POURING AND FINISHING CONCRETE
  Inadequate concrete finishing can lead to surface imperfections

 

 

 

 

  WHY DID MY CONCRETE CRACK?
  Who's fault is it?

 

 

 

 

  

  HOW TO POUR A CONCRETE SLAB BY THE FAMILY HANDYMAN
  Watch this clip for some Do It Yourself tips ideal for your next pour

 

 

 

  
  HOW TO BUILD FORMWORK
  With our friends at Bunnings Warehouse we'll show you the basics for building formwork for a concrete slab

  

 

 


  HOW TO LAY A CONCRETE SLAB
  Follow Cement Australia's comprehensive step by step guide to laying your own slab

 

 

 

 TO SEAL OR NOT TO SEAL
 Thinking of sealing or resealing your concrete? Find out what you need to know here

 

 

 

 

  DID YOU KNOW THERE’S A DOZEN THINGS TO CONSIDER WHEN ORGANISING YOUR CONCRETE POUR?
  Check in with concretebroker’s dozen before your next concrete pour. Before it’s too late

 

 

 

 

  

  I NEED CONCRETE. HOW DO I CHOOSE A CONCRETE PLANT?
  Concretebroker gives you half a dozen things to look out for when choosing a  concrete plant

 

 

 

  SHOULD I POUR CONCRETE TODAY?
  Every day concretors and construction managers tear their hair out unsure of whether they should or shouldn't pour concrete due to the weather  
  conditions

 

 

 

 

 SO TELL ME, IS CONCRETE ENVIRONMENTALLY SUSTAINABLE?
 Now running the Association’s National Precast Concrete Association office from  Adelaide, Sarah Bachman gives us some insight

 

 

 

  
  CAN I POUR CONCRETE IN THE RAIN?
  We hear much these days about pouring concrete on hot, dry windy day. But what about when it's raining?

 

 

 

  THE CONCRETEBROKER DICTIONARY VOLUME 1 (AUSTRALIAN EDITION)
 Your comprehensive guide to the most popular abbreviations, definitions, phrases, slang and terms used within the industry.

 

 

 

 

  HERE'S HALF A DOZEN HINTS TO HELP YOU BEFORE ORDERING A CONCRETE PUMP
  Concrete pumps can save man hours, time and therefore money, but there are some important things to consider before you hire one

 

 

 

 

  TEN (THATS 10) MINUTE CRACK REPAIR. YOUR'E KIDDING AREN'T YOU? Cracks in Concrete - forget about them in ten minutes - just watch this
  video

 

 

 

 

  

  WOOD CONCRETE - HOW TO MAKE CONCRETE LOOK LIKE WOOD FLOORING
   Is that concrete? Or a timber floor? Watch this video to find out....

 

 

 

  HOW TO LAY A SMALL CONCRETE PAD
  Another look at how to lay a small concrete slab from DIY Network.com

 

 

 

 

 LETS TALK ABOUT STEEL FIBRES
 Mesh sits in the middle of your concrete slab and is quite cumbersome. What do steel fibres do?

 

 

 

 

  EVER THOUGHT ABOUT PLACING A PATTERN ON YOUR CONCRETE?
  BRICKFORM show how to properly stamp concrete from start to finish

 

 

 

 

  HOW TO POUR AND FINISH CONCRETE
 YouTube handyman and alround good guy Russ Richards shows us how to finish a slab properly

 

 

 

 

  NEED A CONCRETE TEST
  Check in with Valley Civilab, our latest member for all your concrete, soil and aggregate testing needs

 

 

 

 

  

  CONCRETE CAN BE A SPONGE FOR AIR POLLUTION
  Concrete surfaces can remove sulfur dioxide, a major contributor to air pollution, from the air, new research suggests

 

 

 

  
  FLOOR COATINGS EXPLAINED
  An overview of floor coatings and a quick look at whats happening in the floor coating market overseas

 

 

 

 
 COLORED CONCRETE IS TAKING OVER AND WE'RE VERY INTO IT
  Pink? Blue? A watercolory ivory? You choose!

 

 

 

 

  TALK TO ME ABOUT CONCRETE AND STEEL ACCESSORIES
  What accessories are used in the standard concrete slab? And where do I buy them from?

 

 

 

  BEWARE THE COLD JOINT
  Cold joints in concrete are your worst nightmare. But how do they occur and how do we prevent them from happening?

 

 

 

 


Tags: AmericanMineralogist Ancient Rome cement concrete Concrete science GIZMODO.au Pozzolans


This article was written by marketing@concretebroker.com.au all rights reserved. The views and opinions expressed in this article are those of the author(s) and do not necessarily reflect those of concretebroker.com