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Roman Engineering and Construction Techniques We Could Still Learn From

Posted by: Joseph Readman
The Industry – What You Really Want to Know

There’s been a lot of talk lately about how old Roman engineering and construction techniques are far greater than modern day engineering and construction techniques. I for one agree that there are many things we could learn from the Romans! These days, we use tried and tested ways of doing things to create buildings and structures. However, the Romans didn’t have that luxury. It seems they simply got creative, used their imaginations, and then honed their technique to get it right. Some of the things they created as a result are truly astonishing!

Modern day v Roman Concrete

Let’s start by taking a look at modern day concrete. Some modern concrete structures tend to fall apart within decades and yet 2000-year-old Roman piers stand strong, and seem to get stronger every day. This isn’t an exaggeration either! Many studies and tests have been performed on these things, and it turns out chemical reactions are actually happening to the concrete long after the mixture has hardened.

One example of this is a University of Utah geologist found that seawater filtering through Roman concrete leads to the growth of interlocking minerals that lend the concrete added strength and cohesion. This means that when seawater permeated through the concrete mixture after it had hardened, it dissolved components of the volcanic ash that was used in the mixture, and allowed new minerals to grow from the highly alkaline leached fluids, particularly Al-tobermorite and phillipsite. In short: the seawater dissolved the volcanic crystals and glasses, and aluminous tobermorite and phillipsite crystallised in their place.

These minerals helped to reinforce the concrete, preventing cracks from growing, with structures becoming stronger over time as the minerals grew. This is why Roman concrete doesn’t have any cracks that you can see. The minerals are filling in the cracks and gaps, and the mixture is actually becoming far stronger. Whether the Romans knew that this would happen or it was sheer luck is anybody’s guess, however, I would not put it past them to have figured this out.

For modern materials, the described process would wreak havoc and eventually break them down unlike the Roman mixture that thrives on an open chemical exchange with seawater. Modern day concrete is not designed to change after it hardens, which is why when cracks occur. If only we had invented magical self-fixing concrete!

What is the Special Roman Concrete Formulae?

Romans made this magical concrete mixture by mixing volcanic ash with lime and seawater to make a mortar, then incorporating that mortar into chunks of volcanic rock. This produces something called a ‘pozzolanic reaction’ (named after the city of Pozzuoli, in Naples). This mixture was used in many architectural structures, including the Pantheon.

You’re probably wondering, ‘hey, if this mixture is so great and magical, why isn’t it used more often?’ The truth is, the recipe was lost over time. Many civil engineers and historians have poured over ancient Roman texts, and nobody has yet uncovered the precise methods to recreate the marine mortar as it stands today. It is unlikely in modern times that this recipe would become widespread anyway, as it features less compressive strength than typical Portland cement. However, it could be extremely useful in certain situations, for example, to build the Seawall for the proposed Swansea lagoon, or any other method that requires concrete to be durable when in constant contact with seawater and the elements.

Roman Engineering and Building Achievements

If I were to talk about all of the Roman engineering feats and achievements, I’d be here all day. Let’s just have a quick recap!

They invented both concrete and cement.

They created many roads, many of which are still in use today as they are so well constructed.

They created grand aqueducts - designed to channel water into the city from the surrounding countryside.

They made creating a domed ceiling look simple.

The most amazing thing about the Romans is probably that they did not have a coherent theory of mechanical physics to guide them in their endeavours. They simply relied on trial and error, fine tuning their approach, and then learning from the result. The results of which we can see to this day, and is enough to inspire any newly qualified or experienced engineer, be it civil, design and planning!

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