Too appropriately answer, we must travel back in time to when the first concrete mixes where used efficiently; Ancient Rome. Continued construction of what we know as the Roman Forum spanned over hundreds of years as the area was cultivated as center for commerce and entertainment. The immense concrete structures were raised by various Emperors to accommodate shopping and the congregation of the Roman people in a city center. These structures, for the most part, still exist. Withstanding hundreds of years of earthquakes, volcanic eruptions and daily weathering from wind, rain and snow, they are a testament to the strength of what one can build with a mix of sand, limestone, gravel and water. Naturally concrete is still made today with various mix designs of aggregates because of its durability.
The concrete mixes used by the Ancient Romans are widely believed to be the most durable building material in human history. Roman Concrete differs from its modern day counter part in that it utilized volcanic ash, which prevented cracks from spreading. Look around at driveways and sidewalks, it’s very easy to see cracks that have spread over time in current concrete applications. Used from 200 BCE, this volcanic ash aggregate mixture was improved upon until the Concrete Revolution in about the mid 1st Century ACE, where it truly came to form and was used to build the world’s largest unreinforced concrete dome which graces the Patheon. Two thousand years later, it still stands intact. Once again showing the true strength that concrete can build.
Aggregate used in Roman Concrete is similar to what we use now: the aggregate varied, but included limestone, pieces of various rock, sand, ceramic tile and brick rubble from the remains of buildings that were demolished. The Ancient Romans used gypsum and quicklime as binders. Volcanic sand, called pozzolana or “pit sand “was favored for durability if it could be found. Given the proximity of Rome to the volcanic coast of Southern Italy, it wasn’t difficult. Transport of this material was worth the effort in order to use it in concrete mixtures.
The Ancient Romans also produced a very durable marine concrete. To do this they mixed volcanic sand with quicklime, creating a concrete that when permeated by salt water, chemically reacted and created aluminous tobermorite crystals which resisted breakdown by salt water. This was obviously a key development in various ports and cities around Italy. Ancient Rome was a hub of commercial trade between Europe and the Far East; their port was the largest in operation in its hay day. Called Ostia Antica, it eventually silted over and a new port was built to the North. This marine concrete was also essential to the building of the city of Venice, whose founders sought military protection from their enemies by being surrounded by water. The foundations of buildings in Venice are actually built in the salt water.
Italy’s major cities, like many cities built in the Medieval Period, were built on river banks. Rivers were hugely important for transportation, as well as providing water for citizens. The bases of these bridges, similar to the Ponte Vecchio, Florence’s famed shopping bridge, have foundations consisting of Ancient Rome’s recipe for marine concrete as well as stones, sand and gravel aggregate. This bridge’s strength is amazing; it is literally lined on both sides of the span with shops and apartments. It used to house butchers, bakers and sellers of necessities. Now the shops house jewelry shops. Hundreds of tourists cram this span at a time. Given the shear weight of the buildings themselves, plus the people, plus the elaborate and expensive jewelry, it’s obvious that the city has faith in its strength…there are no weight restrictions.
To compare, the setting of Roman pozzolana cements is very similar to the setting of Portland cements, especially when a Portland cement is mixed with high silica aggregates such as blast furnace slag, fly ash or silica fume. Using blast furnace slag in today’s mixtures serves a dual purpose; it can strengthen the concrete when used as a cement, and it recycles a byproduct of the steel making process.
Shoreline Aggregate Solutions is a limestone, sand and gravel supplier that delivers quality state approved materials. Whether you are completing a large or small project, Shoreline has the aggregates for your project. From highway, residential or commercial projects, we offer state approved aggregates and rip rap. If you need to build a sports field, horse arena, golf course or keep it maintained, Shoreline delivers bunker sand, topdressing sand and divot mixes. Our objective is to provide customers with consistent and high quality products that will meet or exceed expectations. We strive to be unique and innovative with our products by offering creative solutions to customer requests and for setting the standard for quick responsive delivery.
If you have any questions regarding our products offered by Shoreline Aggregate Solutions, contact us. We will be glad to help.