We Finally Know Why Ancient Roman Concrete Outlasts Our Own (2024)

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We Finally Know Why Ancient Roman Concrete Outlasts Our Own? ›

Ancient artisans built it all out of a concrete mix that displays “self-healing” properties. That's right — MIT, Harvard University, and Italian and Swiss labs all think ancient Roman concrete has outlasted modern concrete by millennia because it can repair itself after hardening.

Roman concrete's resistance to seawater erosion is attributed to its unique interaction with the environment, where seawater percolates through the concrete and promotes the growth of rare minerals like aluminous tobermorite and phillipsite.

You may wonder why we don't use Roman concrete today if that is the case; well, one of the reasons as to why is because, although it gets stronger over time and withstands erosion from water, when this cement is still young and has not had time to develop its strength from seawater, it likely does not have the ...

The lime clasts had aided in a chemical process that resulted in “self-healing.” Meanwhile, an identical chunk of concrete without the lime-clast structure never healed, and the water just kept flowing through the sample.

By 200 B.C.E., concrete was used in the majority of their construction projects. Roman concrete consisted of a mixture of a white powder known as slaked lime, small particles and rock fragments called tephra ejected by volcanic eruptions, and water.

It was a formidable tool of Roman engineering know-how. Yet, for all its advantages, concrete had one major defect: it was unsightly. Once the wooden formwork was removed, it showed an ugly surface. In the beginning, its use was mainly restricted to substructures where noone would see it.

The research team discovered that while modern concrete is made to be inert, the Roman version interacts with the environment. When seawater interacts with the mixture, it forms rare minerals aluminous tobermorite and phillipsite which are believed to strengthen the material.

We do know that Emperor Hadrian's engineers adjusted the concrete recipes, using more volcanic ash than rock to make the dome lighter, and more rock aggregate in the walls for heavier reinforcement. But when the Roman Empire fell in 476 CE, the unprecedented Roman recipe for concrete was lost to the world.

It also has a reduced environmental footprint due to its lower cooking temperature and much longer lifespan. Usable examples of Roman concrete exposed to harsh marine environments have been found to be 2000 years old with little or no wear.

A calcium-rich lime clast (in red), which is responsible for the unique self-healing properties in this ancient material, is clearly visible in the lower region of the image. The hot mixing allows lime clasts—characteristically brittle nanoparticulate, an easily fractured and reactive calcium source—to develop.

Can concrete last 1000 years? ›

Modern concrete—used in everything from roads to buildings to bridges—can break down in as few as 50 years. But more than a thousand years after the western Roman Empire crumbled to dust, its concrete structures are still standing.

When the ancient Romans made mortar, they heated up the lime to turn it into a substance called "quicklime" – a very reactive chemical sibling to limestone. And, because they introduced water to the quicklime during mixing, the heat it produced set up a chemical foundation that could strengthen the concrete later.

Self-healing is a well-established and well-known property of concrete due to its innate autogenous healing properties [1]. After a period of time, fissures may mend due to the ongoing hydration of clinker minerals or carbonation of calcium hydroxide (Ca(OH)₂).

6500BC – UAE: The earliest recordings of concrete structures date back to 6500BC by the Nabataea traders in regions of Syria and Jordan. They created concrete floors, housing structures, and underground cisterns. 3000 BC – Egypt and China: Egyptians used mud mixed with straw to bind dried bricks.

Literatures have shown that concrete's compressive strength developed as the concrete's age increases [11], [12], [13], [14] this is attributed to the ongoing chemical reactions during the curing process, which continue to evolve over time, leading to changes in the concrete's microstructure [15], [16].

Meanwhile, ancient Roman concrete is still standing strong after thousands of years, and not only does it resist damage, but the salt water actually makes it stronger. X-ray examinations have found the key to the mixture's incredible longevity, which could help improve modern recipes.

The sports stadiums we see today, with their oval shapes and tiered seating, derive from the basic idea the Romans developed. The arches of the Colosseum are made out of cement, a remarkably strong building material the Romans made with what they had at hand: volcanic ash and volcanic rock.

Roman concrete differs from modern concrete in that the aggregates often included larger components; hence, it was laid rather than poured. Roman concretes, like any hydraulic concrete, were usually able to set underwater, which was useful for bridges and other waterside construction.

Roman concrete, in many cases, has proven to be longer-lasting than its modern equivalent, which can deteriorate within decades.