What Kind Of Concrete Did The Romans Use For Longevity?

 Concrete has a long history of withstanding tensile strain and is a crucial component of modern infrastructure. The combination of steel bars embedded in reinforced concrete and strength against tensile stress is the cornerstone of contemporary society. But one drawback of steel is that it rusts, which weakens the reinforcement and increases the amount of iron oxide that is produced as a byproduct. Due to the pressures caused by this expansion, the concrete finally cracks, spalls, and breaks.

The Romans circumvented this problem by using structural engineering methods like the arch and dome to reduce the need for reinforcement. Huge design was used to ensure that their structures could withstand water pressure without the need for reinforcement. Even today, this technique is used in large concrete dams, gravity structures, and arch structures that rely on their own weight and shape for stability.

The combination of seawater and volcanic ash used in ancient Roman concrete projects may have produced extraordinarily durable minerals that are uncommon in modern concrete, according to research published in 2017. However, this does not mean that strong concrete cannot be made in the modern period. The progress made in the field of mix design, or concrete formula science, was unimaginable to Roman engineers. One of the most important components of concrete’s chemistry is the proportion of water to cement. The importance of this ratio was known to the Romans, who used a technique that involved mixing concrete with as little water as possible and hammering it into position using specific tamping tools.

Modern techniques such as Roller Compacted Concrete (RCC) have close resemblance to the techniques employed by the ancient Romans. It uses components that are similar to regular concrete, but it uses a lot less water, therefore the mixture is quite dry. After RCC has been handled by earth moving equipment, it is crushed into place using vibratory rollers that resemble pavement. The fact that it usually contains ash makes it similar to Roman concrete as well.

Modern buildings such as highway overpasses and skyscrapers would not be possible without reinforced concrete. Viscous or soupy concrete is generally preferred because it is easier to work with and flows through complex formwork and pumps.

Superplasticizers and other chemical admixtures that reduce the viscosity of the concrete mix are now able to assist in resolving the problem of water content in concrete. This prevents cement dilution and results in a significantly stronger concrete cure by keeping concrete workable even at reduced water concentrations.

In this video, the process of mixing three batches of concrete is demonstrated. Following a week of curing, a hydraulic press is used to test the compressive strength of the first batch sample, which contained the amount of water needed for a typical mix. At about 14 MPa, or 2000 psi, the sample cracks, which is a pretty typical compressive strength for concrete that is seven days old.

The mixture is more difficult to work with and takes longer to pack into the mould because the second batch contains a lot less water. After a week of curing, the sample is stronger than the previous mix and doesn’t break until it is almost at its maximum pressure of 21 MPa, or 3000 psi.

It uses exactly the same amount of water as the last mix, and the final batch doesn’t flow at all. Even yet, after the concrete is combined with the superplasticizer, it flows easily in the hand. A concrete mix that is workable can frequently be made with 25% less water by using chemical admixtures.

One of the reasons concrete doesn’t last nearly as long as it should is economics. The extraneous elements of a structure that aren’t needed to meet design requirements need to be considered by engineers. Building to Roman standards is rarely impossible, but it is often more expensive than what the general public would consider acceptable. Most infrastructure is funded by taxes.

Since concrete technology is continually advancing, contemporary concrete is probably going to outlast that of the Romans. Before we can be certain, 2000 years will pass.