While concrete mixers as we know them today had not been invented yet, concrete was the Roman Empire’s construction material of choice. The world-famous, monumental buildings were created on the foundation of concrete, using ancient concrete mixers to assist their building journey.
While modern concrete structures, specifically structures built near the sea, have crumbled, ancient Roman buildings and monuments remain intact today. Concrete is convenient and functional, and provided a unique scheme in the production of ancient architecture.
It was the concrete revolution which the Romans developed that contributed to the structurally complicated forms of buildings that still stand today. Concrete was not invented by the Romans, but it played an important part in the development of the city of Rome. Read through this comprehensive guide to learn everything you need to know about concrete in the Roman empire.
Concrete use in Ancient Rome:
Roman concrete is also called opus caementicium and is based on a hydraulic-setting cement which includes a binder in the cement mixture. It was found that the Romans used their own form of concrete mixers to mix volcanic ash, lime and seawater, creating a mortar. Chunks of volcanic rock were then used as the aggregate, developing extremely strong and durable concrete.
Around 25BC a Roman architect and engineer recorded and distinguished different types of aggregate which were seen as appropriate for the preparation of lime mortars. He then recommended pozzolana, the volcanic sand from the beds of Pozzuoli, to be incorporated into the structural mortars. The engineer specified a ratio of 1 part lime to 3 parts pozzolana for cement used in buildings and a 1:2 ratio of lime to pozzolana for underwater work, which is essentially the same ratio mixed for concrete used in marine locations today.
Pozzolana includes a combination of chemicals which does not need to lose water through the evaporation process but rather is able to retain water in its structure. Because of this, Pozzolana mortars are able to be set in damp areas, leading it to be of great importance when waterproofing buildings. It is able to prevent decay and corrosion, leading to the buildings lasting longer than they usually would.
By the middle of the first century AD, underwater construction using concrete and concrete mixers was a method which was mastered by Roman builders, leading them to build the well-known city of Caesarea.
After an uncontrollable fire destroyed large parts of Rome in 64AD, brick-faced concrete was introduced, encouraging the development of brick and concrete industries. Romans used cement and concrete to build and repair the city while also using the building materials to create famous structures which remain intact today. A few examples of these famous concrete-based structures include:
• The Pantheon
• Trajan’s Markets
• The Colosseum
• The Arch of Constantine
• Church of Santa Costanza
The strength and longevity of Rome’s marine concrete is understood to benefit from the reaction of mixing seawater, volcanic ash and quicklime which creates a rare crystal called tobermorite. Tobermorite is resistant to fractures, thus when the concrete structure encountered seawater which collected in the tiny cracks of the Roman concrete, it created aluminous tobermorite crystals.
The reaction resulted in “the most durable building material in human history”. In contrast, modern concrete, which is exposed to seawater, deteriorates within decades. By comparison, Portland cement (the commonly used concrete blend) lacks the lime-volcanic ash combination and doesn’t bind as well as Roman concrete. Portland cement tends to wear away easily in saltwater, forcing it to have a service life of around 50 years.
Production of Portland cement leads to large amounts of carbon dioxide, which is considered one of the most damaging greenhouse gases, being released into the air. Roman cement is considered more sustainable to produce as it uses less lime, and the limestone is baked at 900 degrees Celsius rather than at 1,450 degrees Celsius like Portland cement.
Roman concrete takes time to develop its strength and harden from being exposed to seawater. Its drawbacks include having less compressive strength than Portland cement, however, it is for this reason that it is unlikely Roman concrete could become widespread but rather be used in particular contexts, such as building a tidal lagoon.
Low compressive strength means that the Roman concrete would not be able to tolerate large piles of weight placed atop a small space. This technique of piling large amounts of weight onto a small space is used in building skyscrapers, which are prominent in modern cities.
The Development of Concrete:
Romans were not the first to create concrete. The earliest concrete structures were in fact traced back to 6500 BC and were used by the Nabataea traders in regions of Syria and Jordan. Concrete was used to create floors, housing structures, and underground cisterns. It was used to bind the different building materials together, keep the houses warm in Winter and cooler in Summer, as well as reduce the need for a replacement building anytime soon.
During this period, concrete was discovered along the banks of the Danube River in Yugoslavia. Stone Age hunters and fishermen used it to make the floors of the huts they would live in. The floors consisted of 10 inches of concrete over a chalk base. Analysis indicates that a type of red lime was brought into the site from 200 miles upstream and was mixed with sand, gravel, and water to form the earliest concrete yet discovered in Europe.
Before concrete was discovered by the Egyptians, they were using mud mixed with straw to bind dried bricks. By 3000 BC, they possibly used concrete mixers to form gypsum mortars and mortars of lime to create the world-famous pyramids. Gypsum mortar is a mixture of plaster and sand and is quite soft. The Chinese also used cement around this time to build the Great Wall of China and cover their boats to prevent water from leaking in.
Around 600 BC, the Greeks began using pozzolan concrete in their building structures. They also created and mixed a pseudo-concrete that preceded real concrete. It consisted of roughly broken stone held together with a mortar of lime and sand. However, this mixture was too weak to bind the whole together into a compact mass for serious building purposes.
During the same period around 600 BC, the Romans began incorporating concrete into their building designs. By 200 BC, concrete was successfully implemented into the majority of their construction. Volcanic ash, lime and seawater was most likely incorporated using cement mixers and the mixture was then packed into wooden forms. Once hardened, the concrete blocks were stacked like bricks.
During the Middle Ages, technology crept backwards and after the fall of the Roman Empire in 476 AD, the recipe or technique for making pozzolanic concrete was lost. As the Roman empire declined, shipping declined, and the need for seawater concrete declined too.
The original Roman concrete structures were argued to have been built so well that once they were in place, they didn’t need to be replaced. All concrete constructions for the next 1300 years used lime mortars and concrete rather than pozzolanic concrete. It wasn’t until the discovery of the old concrete manuscripts in 1414 that the interest in building with concrete was rekindled.
Building structures with concrete was as convenient as it was practical. With regards to labour, the majority of the workers needed to build the Roman structures did not require skills or education. The only highly skilled workers needed were those involved with the projects such as the architect, the master masons and the master carpenters.
The tasks of mixing, carrying, hauling and pouring the concrete were performed by unskilled labourers. The timetable of the workers was based on the drying of the concrete. Some Roman architecture was possibly built from stone, but this required workers to have the skills of being able to dress the stones to the exact dimensions, which is much more challenging compared to using concrete mixers and pouring the material into shape. The ease of using concrete made it a more prevalent type of building technology in Ancient Rome.
More About BS Suppliers and Concrete Uses:
We at B&S Power Commercial Suppliers encourage individuals to not limit themselves into thinking concrete mixers are only for commercial use. The machinery is able to speed the process of concrete production, allowing for excellent quality concrete to be made at a high speed and in larger quantities.
Concrete is generally associated with construction sites, creating foundations and flooring for buildings. Concrete can be used for just about anything, ranging from creating exotic water fountains to glamourous patios which can be used for entertaining guests.
Concrete is extremely durable, impact-resistant, fire-resistant and strong. It offers cost savings for the initial build, as well as maintenance and efficiency savings later. Concrete is resistant to erosion, rotting, rusting, and weathering, making it the perfect material for outdoor use, both in and around the ocean.
Concrete can be used to create many different garden ornaments and structures. Here are just a few examples:
• Pot plants
• Stepping- stones
• Retaining walls
• Garden furniture
Many modern house designs include concrete in some form, whether it be to create flooring, a feature wall, the ceiling, or room dividers. Concrete can do it all. The material is easy to work with, it is affordable, more environmentally- friendly compared to other building material alternatives, and only takes 24- 48 hours to dry, making it an extremely attractive building option.
We are ready to assist you in achieving your building and construction goals, providing excellent quality commercial construction equipment at the click of a button. Our headquarters are based in Cape Town, however, we are able to supply equipment to anyone in South Africa through online shopping and delivery.
Our products range from chainsaws and high-pressure washers to concrete mixers and generators. We currently offer three types of user-friendly concrete mixers which range from 360L to 500L. Each concrete mixer is fitted with a Baumax RX200 2:1 6.5HP engine and has semi-solid wheels for movement.
The chassis is constructed from channel iron and folded metal to ensure safety and durability. Drum rotation differs per concrete mixer and each drum has a thickness of 3mm. A ring gear cover and an enclosed engine cabin have been installed on each cement mixer to ensure operator safety.
We have a concrete mixer guide available on our website and enquiries are welcome to be sent through email or via Whatsapp Messenger.