Did the Romans invent concrete?
Ancient Roman architecture
Although concrete had been used on a minor scale in Mesopotamia, Roman architects perfected Roman concrete and used it in buildings where it could stand on its own and support a great deal of weight. The first use of concrete by the Romans was in the town of Cosa sometime after 273 BC. Ancient Roman concrete was a mixture of lime mortar, aggregate, pozzolana, water, and stones, and was stronger than previously-used concretes. The ancient builders placed these ingredients in wooden frames where they hardened and bonded to a facing of stones or (more frequently) bricks. The aggregates used were often much larger than in modern concrete, amounting to rubble.
Plasterwork
Modelled stucco was employed throughout the Roman Empire. The Romans used mixtures of lime and sand to build up preparatory layers over which finer applications of gypsum, lime, sand and marble dust were made; pozzolanic materials were sometimes added to produce a more rapid set. Following the fall of the Roman Empire, the addition of marble dust to plaster to allow the production of fine detail and a hard, smooth finish in hand-modelled and moulded decoration was not used until the Renaissance. Around the 4th century BC, the Romans discovered the principles of the hydraulic set of lime, which by the addition of highly reactive forms of silica and alumina, such as volcanic earths, could solidify rapidly even under water. There was little use of hydraulic mortar after the Roman period until the 18th century.
Roman concrete
Recent scientific breakthroughs examining Roman concrete have been gathering media and industry attention. Because of its unusual durability, longevity and lessened environmental footprint, corporations and municipalities are starting to explore the use of Roman-style concrete in North America, substituting the coal fly ash with volcanic ash that has similar properties. Proponents claim that concrete made with volcanic ash can cost up to 60% less because it requires less cement, and that it has a smaller 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.
Ancient Roman pottery
Fired clay or terracotta was also widely employed in the Roman period for architectural purposes, as structural bricks and tiles, and occasionally as architectural decoration, and for the manufacture of small statuettes and lamps. These are not normally classified under the heading 'pottery' by archaeologists, but the terracottas and lamps will be included in this article. Pottery is a key material in the dating and interpretation of archaeological sites from the Neolithic period onwards, and has been minutely studied by archaeologists for generations. In the Roman period, ceramics were produced and used in enormous quantities, and the literature on the subject, in numerous languages, is very extensive.
Concrete mixer
The concrete mixer was invented by Columbus, Ohio industrialist Gebhardt Jaeger.
Opus quadratum
This technique was used by the Romans from about the 6th century BC, and over time the precision and accuracy of the block cutting improved. The technique continued to be used throughout the age of the Roman Empire, even after the introduction of mortar, and was often used in addition to other techniques. The type of stone, the size of the blocks, and the way the blocks were put together can all be used to help archaeologists date structures that display the technique.
History of Roman and Byzantine domes
Rounded arches, vaults, and domes distinguish Roman architecture from that of Ancient Greece and were facilitated by the use of concrete and brick. By varying the weight of the aggregate material in the concrete, the weight of the concrete could be altered, allowing lighter layers to be laid at the top of concrete domes. But concrete domes also required expensive wooden formwork, also called shuttering, to be built and kept in place during the curing process, which would usually have to be destroyed to be removed. Formwork for brick domes need not be kept in place as long and could be more easily reused.
Modern architecture
French industrialist François Coignet was the first to use iron-reinforced concrete, that is, concrete strengthened with iron bars, as a technique for constructing buildings. In 1853 Coignet built the first iron reinforced concrete structure, a four-story house in the suburbs of Paris. A further important step forward was the invention of the safety elevator by Elisha Otis, first demonstrated at the Crystal Palace exposition in 1852, which made tall office and apartment buildings practical. Another important technology for the new architecture was electric light, which greatly reduced the inherent danger of fires caused by gas in the 19th century.
Ancient Roman architecture
When the framework was removed, the new wall was very strong, with a rough surface of bricks or stones. This surface could be smoothed and faced with an attractive stucco or thin panels of marble or other coloured stones called revetment. Concrete construction proved to be more flexible and less costly than building solid stone buildings. The materials were readily available and not difficult to transport. The wooden frames could be used more than once, allowing builders to work quickly and efficiently. Concrete is arguably the Roman contribution most relevant to modern architecture.
Core-and-veneer
The Romans started with basic emplekton masonry walls, but developed the technique one step further using temporary walls (forms), that were removed after the cemented rubble (concrete) had cured. This Roman technique was called "opus caementicium", and eventually led to modern ferroconcrete construction.
History of architecture
The Romans widely employed, and further developed, the arch, vault and dome (see the Roman Architectural Revolution), all of which were little used before, particularly in Europe. Their innovative use of Roman concrete facilitated the building of the many public buildings of often unprecedented size throughout the empire. These include Roman temples, Roman baths, Roman bridges, Roman aqueducts, Roman harbours, triumphal arches, Roman amphitheatres, Roman circuses palaces, mausolea and in the late empire also churches.
History of structural engineering
Again taking reinforced concrete design forwards, from 1892 onwards François Hennebique's firm used his patented reinforced concrete system to build thousands of structures throughout Europe. Thaddeus Hyatt in the US and Wayss & Freitag in Germany also patented systems. The firm "AG für Monierbauten" constructed 200 reinforced concrete bridges in Germany between 1890 and 1897 The great pioneering uses of reinforced concrete however came during the first third of the 20th century, with Robert Maillart and others furthering of the understanding of its behaviour. Maillart noticed that many concrete bridge structures were significantly cracked, and as a result left the cracked areas out of his next bridge design - correctly believing that if the concrete was cracked, it was not contributing to the strength. This resulted in the revolutionary Salginatobel Bridge design. Wilhelm Ritter formulated the truss theory for the shear design of reinforced concrete beams in 1899, and Emil Mörsch improved this in 1902. He went on to demonstrate that treating concrete in compression as a linear-elastic material was a conservative approximation of its behaviour. Concrete design and analysis has been progressing ever since, with the development of analysis methods such as yield line theory, based on plastic analysis of concrete (as opposed to linear-elastic), and many different variations on the model for stress distributions in concrete in compression
Technological history of the Roman military
However, the Romans made many significant technological advances, such as the invention of hydraulic cement and concrete. They used such new materials to great advantage in their structures, many of which survive to this day, like their masonry aqueducts, such as the Pont du Gard, and buildings, such as the Pantheon and Baths of Diocletian in Rome. Their methods were recorded by such luminaries as Vitruvius and Frontinus for example, who wrote handbooks to advise fellow engineers and architects. Romans knew enough history to be aware that widespread technological change had occurred in the past and brought benefits, as shown for example by Pliny the Elder's Naturalis Historia. That tradition continued as the empire grew in size and absorbed new ideas. Romans thought of themselves as practical, so small-scale innovation was common (such as the development of the ballista into the polybolos or repeating ballista). The traditional view is that their reliance on a plentiful slave labour force and a lack of a patent or copyright system have both been cited as reasons that there was little social or financial pressure to automate or reduce manual tasks. However, this view is being challenged by new research that shows they did indeed innovate, and on a wide scale. Thus the watermill had been known to the Greeks, but it was the Romans who developed their efficient utilisation. The set of mills at Barbegal in southern France were worked by a single aqueduct, which drove no fewer than 16 overshot mills built into the side of a hill. They probably were built by the army and supplied flour to a wide region. Floating mills were also used to exploit fast flowing rivers.
Brick
Early civilisations around the Mediterranean adopted the use of fired bricks, including the Ancient Greeks and Romans. The Roman legions operated mobile kilns, and built large brick structures throughout the Roman Empire, stamping the bricks with the seal of the legion.
History of construction
The invention of the waterwheel, sawmill, arch, and were by the Romans. The Romans also began using glass for architectural purposes after about 100 CE and used double glazing as insulated glazing. Roman roads included corduroy roads and paved roads, sometimes supported on raft or pile foundations and bridges. 
Vitruvius gives details of many Roman machines. The Romans developed sophisticated timber cranes allowing them to lift considerable weights to great heights. The upper limit of lifting appears to have been about 100 tonnes. Trajan's column in Rome contains some of the largest stones ever lifted in a Roman building, and engineers are still uncertain exactly how it was achieved.
History of structural engineering
In 1824, Portland cement was patented by the engineer Joseph Aspdin as ""a superior cement resembling Portland Stone"", British Patent no. 5022. Although different forms of cement already existed (Pozzolanic cement was used by the Romans as early as 100 B.C. and even earlier by the ancient Greek and Chinese civilizations) and were in common usage in Europe from the 1750s, the discovery made by Aspdin used commonly available, cheap materials, making concrete construction an economical possibility.
Precast concrete
Ancient Roman builders made use of concrete and soon poured the material into moulds to build their complex network of aqueducts, culverts, and tunnels. Modern uses for pre-cast technology include a variety of architectural and structural applications — including individual parts, or even entire building systems.
Roller-compacted concrete
In dam construction, roller-compacted concrete began its initial development with the construction of the Alpe Gera Dam near Sondrio in North Italy between 1961 and 1964. Concrete was laid in a similar form and method but not rolled. RCC had been touted in engineering journals during the 1970s as a revolutionary material suitable for, among other things, dam construction. Initially and generally, RCC was used for backfill, sub-base and concrete pavement construction, but increasingly it has been used to build concrete gravity dams because the low cement content and use of fly ash cause less heat to be generated while curing than do conventional mass concrete placements. Roller-compacted concrete has many time and cost benefits over conventional mass concrete dams; these include higher rates of concrete placement, lower material costs and lower costs associated with post-cooling and formwork.
Stone veneer
Thin stone veneer was first developed in the late 19th century, but there were materials developed much earlier that foreshadowed the use of stone veneer. Parts of the Roman Coliseum were made out of marble veneer that can no longer be seen. The holes in structure of the Coliseum are from the anchors of the veneer panels. Structures throughout the Roman Empire were made in part out of stone blocks, including the Segovia aqueduct in Spain, which was made out of granite blocks. People in the Roman Empire also developed concrete (out of cement and rubblestone), which helped builders expand structures greater than before. Stone was used as a part of the facings of these new concrete structures in the Roman Empire, as seen in the Coliseum.
History of construction
An example of a temple made of Roman concrete in the 1st century BC is the Temple of Vesta in Tivoli, Italy. The concrete was made of nothing more than rubble and mortar. It was cheap and very easy to produce and required relatively unskilled labour to use, enabling the Romans to build on an unprecedented scale. They not only used it for walls but also to form arches, barrel vaults and domes, which they built over huge spans. The Romans developed systems of hollow pots for making their domes and sophisticated heating and ventilation systems for their thermal baths. .
Alkaline earth metal
Lime has been used as a material for building since 7000 to 14,000 BCE, and kilns used for lime have been dated to 2,500 BCE in Khafaja, Mesopotamia. Calcium as a material has been known since at least the first century, as the ancient Romans were known to have used calcium oxide by preparing it from lime. Calcium sulfate has been known to be able to set broken bones since the tenth century. Calcium itself, however, was not isolated until 1808, when Humphry Davy, in England, used electrolysis on a mixture of lime and mercuric oxide, after hearing that Jöns Jakob Berzelius had prepared a calcium amalgam from the electrolysis of lime in mercury.
Reinforced concrete
Joseph Monier was a French gardener of the nineteenth century, a pioneer in the development of structural, prefabricated and reinforced concrete. François Coignet was the first to use iron-reinforced concrete as a technique for constructing building structures. In 1853, Coignet built the first iron reinforced concrete structure, a four-story house at 72 rue Charles Michels in the suburbs of Paris. Coignet's descriptions of reinforcing concrete suggests that he did not do it for means of adding strength to the concrete but for keeping walls in monolithic construction from overturning. In 1854, English builder William B. Wilkinson reinforced the concrete roof and floors in the two-storey house he was constructing. His positioning of the reinforcement demonstrated that, unlike his predecessors, he had knowledge of tensile stresses.
Concrete
Small-scale production of concrete-like materials dates to 6500 BC, pioneered by the Nabatean traders who occupied and controlled a series of oases and developed a small empire in the regions of southern Syria and northern Jordan. They discovered the advantages of hydraulic lime, with some self-cementing properties, by 700 BC. They built kilns to supply mortar for the construction of rubble-wall houses, concrete floors, and underground waterproof cisterns. They kept the cisterns secret as these enabled the Nabataeans to thrive in the desert. Some of these structures survive to this day.
Concrete
Perhaps the greatest step forward in the modern use of concrete was Smeaton's Tower, built by British engineer John Smeaton in Devon, England, between 1756 and 1759. This third Eddystone Lighthouse pioneered the use of hydraulic lime in concrete, using pebbles and powdered brick as aggregate.
Architectural technology
Until the twentieth century, the materials used for building were limited to brick, stone, timber and steel to form structures, slate and tiles for roof coverings, lead and sometimes copper for waterproofing details and decorative roofing effects. The Romans used concrete, but it was virtually unknown as a building material until the invention of reinforced concrete in 1849. Modern construction is much more complex, with walls, floors and roofs all built up from many elements to include structure, insulation and waterproofing often as separate layers or elements.
Cement
Any preservation of this knowledge in literature from the Middle Ages is unknown, but medieval masons and some military engineers actively used hydraulic cement in structures such as canals, fortresses, harbors, and shipbuilding facilities. A mixture of lime mortar and aggregate with brick or stone facing material was used in the Eastern Roman Empire as well as in the West into the Gothic period. The German Rhineland continued to use hydraulic mortar throughout the Middle Ages, having local pozzolana deposits called trass.
Productivity improving technologies
Cement is the binder for concrete, which is one of the most widely used construction materials today because of its low cost, versatility and durability. Portland cement, which was invented 1824-5, is made by calcining limestone and other naturally occurring minerals in a kiln. A great advance was the perfection of rotary cement kilns in the 1890s, the method still being used today. Reinforced concrete, which is suitable for structures, began being used in the early 20th century.
History of structural engineering
Developments in concrete continued with the construction in 1848 of a rowing boat built of ferrocement - the forerunner of modern reinforced concrete - by Joseph-Louis Lambot. He patented his system of mesh reinforcement and concrete in 1855, one year after W.B. Wilkinson also patented a similar system. This was followed in 1867 when a reinforced concrete planting tub was patented by Joseph Monier in Paris, using steel mesh reinforcement similar to that used by Lambot and Wilkinson. Monier took the idea forward, filing several patents for tubs, slabs and beams, leading eventually to the Monier system of reinforced structures, the first use of steel reinforcement bars located in areas of tension in the structure.
Pozzuoli
The local volcanic sand, pozzolana (Latin: "pulvis puteolanus", "dust of Puteoli") formed the basis for the first effective concrete, as it reacted chemically with water. Instead of just evaporating slowly off, the water would turn this sand/lime mix into a mortar strong enough to bind lumps of aggregate into a load-bearing unit. This made possible the cupola of the Pantheon, which is still the world's largest unreinforced concrete dome.
The apostle Paul landed here on his way to Rome, from which it was distant. Here he stayed for seven days ("Acts" 28:13, 14) and then began with his companions his journey by the Appian Way to Rome.
Self-healing material
According to a 1996 study by H. L. Erlich in "Chemical Geology" journal, the self-healing ability of concrete has been improved by the incorporation of bacteria, which can induce calcium carbonate precipitation through their metabolic activity. These precipitates can build up and form an effective seal against crack related water ingress. At the First International Conference on Self Healing Materials held in April, 2007 in The Netherlands, Henk M. Jonkers and Erik Schlangen presented their research in which they had successfully used the "alkaliphilic spore-forming bacteria" as a "self-healing agent in concrete". They were the first to incorporate bacteria within cement paste for the development of self-healing concrete. It was found that the bacteria directly added to the paste only remained viable for 4 months. Later studies saw Jonkers use expanded clay particles and Van Tittlelboom use glass tubes, to protect the bacteria inside the concrete. Other strategies to protect the bacteria have also since been reported.
Pumice
Pumice is widely used to make lightweight concrete or insulative low-density cinder blocks. When used as an additive for cement, a fine-grained version of pumice called pozzolan is mixed with lime to form a light-weight, smooth, plaster-like concrete. This form of concrete was used as far back as Roman times. Roman engineers used it to build the huge dome of the Pantheon and as construction material for many aqueducts.
Edmond Coignet
Coignet was the son of industrialist François Coignet (1814-1888) and educated at the École Centrale des Arts et Manufactures (École Centrale Paris). He was the inventor of the agglomerated concrete to strengthen the cement with metal inserts. He permanently reoriented the family business to construction. In 1892 he applied his innovative construction methods on the aqueduct of Achères in Paris. Coignet was the first to use reinforced concrete piles and built with the architect Jacques Hermant some of the first Parisian buildings in this material.
Roman cement
The name is misleading as it is nothing like any material used by the Romans, but was a "natural cement" made by burning septaria – nodules that are found in certain clay deposits, and that contain both clay minerals and calcium carbonate. The burnt nodules were ground to a fine powder. This product, made into a mortar with sand, set in 5–15 minutes. The success of Roman cement led other manufacturers to develop rival products by burning artificial mixtures of clay and chalk.
Sanitation in ancient Rome
The Romans recycled public bath waste water by using it as part of the flow that flushed the latrines. Terra cotta piping was used in the plumbing that carried waste water from homes. The Romans were the first to seal pipes in concrete to resist the high water pressures developed in siphons and elsewhere. Beginning around the 5th century BC, aediles, among their other functions, supervised the sanitary systems. They were also responsible for the efficiency of the drainage and sewage systems, the cleansing of the streets, prevention of foul smells, and general oversight of baths.
Roman concrete
Roman concrete, also called opus caementicium, was a material used in construction during the late Roman Republic until the fading of the Roman Empire. Roman concrete was based on a hydraulic-setting cement. Recently, it has been found that it materially differs in several ways from modern concrete which is based on Portland cement. Roman concrete is durable due to its incorporation of volcanic ash, which prevents cracks from spreading. By the middle of the 1st century, the material was used frequently, often brick-faced, although variations in aggregate allowed different arrangements of materials. Further innovative developments in the material, called the Concrete Revolution, contributed to structurally complicated forms, such as the Pantheon dome, the world's largest and oldest unreinforced concrete dome.
Roman cement
James Frost is reported to have erected a manufactory for making of an artificial cement in 1826. In 1843, Aspdin's son William improved their cement, which was initially called "Patent Portland cement," although he had no patent. In 1848, William Aspdin further improved his cement and in 1853, he moved to Germany where he was involved in cement making. William Aspdin made what could be called meso-Portland cement (a mix of Portland cement and hydraulic lime).
Artificial cement: Development in the 1860s of rotating horizontal kiln technology brought dramatic changes in properties, arguably resulting in modern cement. Certainly it is difficult to define whether an old render was a natural cement (single source marl) or an artificial one, but there is no doubt as whether the cement was fired in a vertical or horizontal kiln. The names Natural cement or Roman cement then defines a cement coming from a single source rock. Early or Proto Portland cement could be used for early cement that comes from a number of sourced and mixed materials. There is no widely used terminology for these 19th-century cements. There had been, in order to rediscover this technology, two projects carried out by the European Union ROCEM and subsequently ROCARE (an ongoing project). Both these only deal with Natural cement - referred to as Roman cement without reference to the early artificial cements.
Types of concrete
Concrete has been used since ancient times. Regular Roman concrete for example was made from volcanic ash (pozzolana), and hydrated lime. Roman concrete was superior to other concrete recipes (for example, those consisting of only sand and lime) used by other cultures. Besides volcanic ash for making regular Roman concrete, brick dust can also be used. Besides regular Roman concrete, the Romans also invented hydraulic concrete, which they made from volcanic ash and clay.
George Bartholomew (inventor)
George Bartholomew was an American inventor who is credited with the invention of concrete pavement. In 1886, Bartholomew moved to Bellefontaine, Ohio, after having learned about cement production. Bartholomew found a good source of limestone and clay in the area; from this, he hoped to create an artificial stone for paving. Bartholomew founded the Buckeye Portland Cement Company and set about developing a new cement for pavement.
Pozzolana
The pozzolanic reaction is the chemical reaction that occurs in portland cement containing pozzolans. It is the main reaction involved in the Roman concrete invented in Ancient Rome. At the basis of the pozzolanic reaction stands a simple acid-base reaction between calcium hydroxide (as Portlandite) and silicic acid.
Ancient Roman architecture
The Romans made fired clay bricks from about the beginning of the Empire, replacing earlier sun-dried mud-brick. Roman brick was almost invariably of a lesser height than modern brick, but was made in a variety of different shapes and sizes. Shapes included square, rectangular, triangular and round, and the largest bricks found have measured over three feet in length. Ancient Roman bricks had a general size of 1½ Roman feet by 1 Roman foot, but common variations up to 15 inches existed. Other brick sizes in ancient Rome included 24" x 12" x 4", and 15" x 8" x 10". Ancient Roman bricks found in France measured 8" x 8" x 3". The Constantine Basilica in Trier is constructed from Roman bricks 15" square by 1½" thick. There is often little obvious difference (particularly when only fragments survive) between Roman bricks used for walls on the one hand, and tiles used for roofing or flooring on the other, so archaeologists sometimes prefer to employ the generic term ceramic building material (or CBM).
Rastra
Polystyrene concrete was invented in 1960. BASF, a German chemical conglomerate, originally created this product, but found no successful applications. An Austrian-Swiss-based company modified the product and created what is known as Rastra.
Roman engineering
Above that, there were the "rudens", which were made of ten inches of rammed concrete. The next layer, the "nucleus", was made of twelve to eighteen inches of successively laid and rolled layers of concrete. "Summa crusta" of silex or lava polygonal slabs, one to three feet in diameter and eight to twelve inches thick, were laid on top of the rudens. The final upper surface was made of concrete or well smoothed and fitted flint.
Roman engineering
Marble was mainly a decorative material. Augustus Caesar once boasted that he had turned Rome from a city of bricks to a city of marble. The Romans had originally brought marble over from Greece, but later found their own quarries in northern Italy.
Roman concrete
For an environment as prone to earthquakes as the Italian peninsula, interruptions and internal constructions within walls and domes created discontinuities in the concrete mass. Portions of the building could then shift slightly when there was movement of the earth to accommodate such stresses, enhancing the overall strength of the structure. It was in this sense that bricks and concrete were flexible. It may have been precisely for this reason that, although many buildings sustained serious cracking from a variety of causes, they continue to stand to this day.
Voided biaxial slab
While concrete has been used for thousands of years, the use of reinforced concrete is usually attributed to Joseph-Louis Lambot in 1848. Joseph Monier, a French gardener, patented a design for reinforced garden tubs in 1868, and later patented reinforced concrete beams and posts for railway and road guardrails.
Precast concrete
In the modern world, precast panelled buildings were pioneered in Liverpool, England, in 1905. The process was invented by city engineer John Alexander Brodie, a creative genius who also invented the idea of the football goal net. The tram stables at Walton in Liverpool followed in 1906. The idea was not taken up extensively in Britain. However, it was adopted all over the world, particularly in Eastern Europe and Scandinavia.
Shotcrete
Shotcrete, then known as gunite, was invented in 1907 by American taxidermist Carl Akeley to repair the crumbling façade of the Field Columbian Museum in Chicago (the old Palace of Fine Arts from the World's Columbian Exposition). He used the method of blowing dry material out of a hose with compressed air, injecting water at the nozzle as it was released. In 1911, he was granted a patent for his inventions, the "cement gun", the equipment used, and "gunite", the material that was produced. There is no evidence that Akeley ever used sprayable concrete in his taxidermy work, as is sometimes suggested. F. Trubee Davison covered this and other Akeley inventions in a special issue of "Natural History" magazine.
French architecture
The architecture of Ancient Rome at first adopted the external Greek architecture and by the late Republic, the architectural style developed its own highly distinctive style by introducing the previously little-used arches, vaults and domes. A crucial factor in this development, coined the Roman Architectural Revolution, was the invention of concrete. Social elements such as wealth and high population densities in cities forced the ancient Romans to discover new (architectural) solutions of their own. The use of vaults and arches together with a sound knowledge of building materials, for example, enabled them to achieve unprecedented successes in the construction of imposing structures for public use.
Fly ash
Owing to its pozzolanic properties, fly ash is used as a replacement for Portland cement in concrete. The use of fly ash as a pozzolanic ingredient was recognized as early as 1914, although the earliest noteworthy study of its use was in 1937. Roman structures such as aqueducts or the Pantheon in Rome used volcanic ash or pozzolana (which possesses similar properties to fly ash) as pozzolan in their concrete. As pozzolan greatly improves the strength and durability of concrete, the use of ash is a key factor in their preservation.
Roman cement
There has been recent resurgence of interest in Natural cements and Roman cements due mainly to the need for repair of façades done in this material in the 19th century. The major confusion involved for many people in this subject is the terminology used.
Roman cement was originally the name given, by Parker, to the cement he patented which is a Natural cement (i.e. it is a marl, or limestone containing integral clay, dug out of the ground, burnt and ground to a fine powder).
Structural clay tile
Clay tile in different capacities has been used for thousands of years. The Romans were among the first to use clay tile in construction by building clay pots to lighten vaulting loads. However the first recorded structural use of terra-cotta forms was in sixth-century Italy in the dome of the Church of San Vitale in Ravenna. Clay pots lined with plaster of paris lightened the load of the dome in a similar way to earlier Roman construction.
François Coignet
Coignet is the inventor of moulded concrete which is known as "Béton Coignet." He had much success at building with this type of concrete. He became a renowned building contractor and showed his many designs, including the molded concrete church of Le Vesinet near Paris. This church with its 130-foot spire is the first modern monumental building built in concrete.
History of art
Roman art is sometimes viewed as derived from Greek precedents, but also has its own distinguishing features. Roman sculpture is often less idealized than the Greek precedents, being very realistic. Roman architecture often used concrete, and features such as the round arch and dome were invented.
George Bartholomew (inventor)
In 1891, the Bellefontaine city council approved the use of Bartholomew's invention for paving a test strip on Main Street outside the Logan County courthouse. This experiment proved successful, and the council approved the pavement of Court Avenue. A section of Court Avenue remains paved today with Bartholomew's formula, celebrated as the first concrete paved street in America.
Concrete
In the Ancient Egyptian and later Roman eras, builders discovered that adding volcanic ash to the mix allowed it to set underwater.
Concrete
Modern structural concrete differs from Roman concrete in two important details. First, its mix consistency is fluid and homogeneous, allowing it to be poured into forms rather than requiring hand-layering together with the placement of aggregate, which, in Roman practice, often consisted of rubble. Second, integral reinforcing steel gives modern concrete assemblies great strength in tension, whereas Roman concrete could depend only upon the strength of the concrete bonding to resist tension.
Le Corbusier
During World War I, Le Corbusier taught at his old school in La-Chaux-de-Fonds, He concentrated on theoretical architectural studies using modern techniques. In December 1914, along with the engineer Max Dubois, he began a serious study of the use of reinforced concrete as a building material. He had first discovered concrete working with Auguste Perret in Paris, but now wanted to use it in new ways.
Roman engineering
The Romans were the first to exploit mineral deposits using advanced technology, especially the use of aqueducts to bring water from great distances to help operations at the pithead. Their technology is most visible at sites in Britain such as Dolaucothi where they exploited gold deposits with at least 5 long aqueducts tapping adjacent rivers and streams. They used the water to prospect for ore by unleashing a wave of water from a tank to scour away the soil and so reveal the bedrock with any veins exposed to sight. They used the same method (known as hushing) to remove waste rock, and then to quench hot rocks weakened by fire-setting.
Roman concrete
Gypsum and quicklime were used as binders. Volcanic dusts, called pozzolana or "pit sand", were favored where they could be obtained. Pozzolana makes the concrete more resistant to salt water than modern-day concrete. The pozzolanic mortar used had a high content of alumina and silica. Tuff was often used as an aggregate.
Concrete ship
Concrete ships are built of steel and ferrocement (reinforced concrete) instead of more traditional materials, such as steel or wood. The advantage of ferrocement construction is that materials are cheap and readily available, while the disadvantages are that construction labor costs are high, as are operating costs. (Ferrocement ships require thick hulls, resulting in a comparatively large cross-sectional area to push through the water, or less space for cargo.) During the late 19th century, there were concrete river barges in Europe, and during both World War I and World War II, steel shortages led the US military to order the construction of small fleets of ocean-going concrete ships, the largest of which was the SS "Selma". Few concrete ships were completed in time to see wartime service during World War I, but during 1944 and 1945, concrete ships and barges were used to support U.S. and British invasions in Europe and the Pacific. Since the late 1930s, there have also been ferrocement pleasure boats.
Pozzolan
Mixtures of calcined lime and finely rounded, active aluminosilicate materials were pioneered and developed as inorganic binders in the Ancient world. Architectural remains of the Minoan civilization on Crete have shown evidence of the combined use of slaked lime and additions of finely ground potsherds for waterproof renderings in baths, cisterns and aqueducts. Evidence of the deliberate use of volcanic materials such as volcanic ashes or tuffs by the ancient Greeks dates back to at least 500–400 BC, as uncovered at the ancient city of Kameiros, Rhodes. In subsequent centuries the practice spread to the mainland and was eventually adopted and further developed by the Romans. The Romans used volcanic pumices and tuffs found in neighbouring territories, the most famous ones found in Pozzuoli (Naples), hence the name pozzolan, and in Segni (Latium). Preference was given to natural pozzolan sources such as German trass, but crushed ceramic waste was frequently used when natural deposits were not locally available. The exceptional lifetime and preservation conditions of some of the most famous Roman buildings such as the Pantheon or the Pont du Gard constructed using pozzolan-lime mortars and concrete testify to both the excellent workmanship reached by Roman engineers and to the durable properties of the binders used.
Roman bridge
Roman bridges, built by ancient Romans, were the first large and lasting bridges built. Roman bridges were built with stone and had the arch as the basic structure (see arch bridge). Most utilized concrete as well, which the Romans were the first to use for bridges.
Bridge
The greatest bridge builders of antiquity were the ancient Romans. The Romans built arch bridges and aqueducts that could stand in conditions that would damage or destroy earlier designs. Some stand today. An example is the Alcántara Bridge, built over the river Tagus, in Spain. The Romans also used cement, which reduced the variation of strength found in natural stone. One type of cement, called pozzolana, consisted of water, lime, sand, and volcanic rock. Brick and mortar bridges were built after the Roman era, as the technology for cement was lost (then later rediscovered).
Concrete
Concrete, usually Portland cement concrete, is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens over time—most frequently a lime-based cement binder, such as Portland cement, but sometimes with other hydraulic cements, such as a calcium aluminate cement. It is distinguished from other, non-cementitious types of concrete all binding some form of aggregate together, including asphalt concrete with a bitumen binder, which is frequently used for road surfaces, and polymer concretes that use polymers as a binder.
Elliott Brothers (builders merchant)
By 1864, Thomas Elliott and Robert Young before him had been manufacturing Roman cement on the banks of the Itchen for over 40 years. Roman cement is a natural product and its manufacture does not generate particularly obnoxious fumes. However, in 1864, Elliott started producing Portland cement, the manufacture of which releases pollutants, notably sulphur dioxide. As a result of complaints from neighbours, Elliott was taken to court. Whilst three hearings were taking place in late 1865 Elliott implemented measures designed to reduce the nuisance. These were found sufficient for the case to be dismissed. However, at the same time, a further summons was taken out against him and, this time, he was fined £5 with costs.
The costs were much greater than the fine itself for, all told, Elliott was the poorer by £150.
Cement
The word "cement" can be traced back to the Roman term "opus caementicium", used to describe masonry resembling modern concrete that was made from crushed rock with burnt lime as binder. The volcanic ash and pulverized brick supplements that were added to the burnt lime, to obtain a hydraulic binder, were later referred to as "cementum", "cimentum", "cäment", and "cement". In modern times, organic polymers are sometimes used as cements in concrete.
Charles Pasley
In 1826, as lecturer in architecture and engineering at the Royal School of Military Engineering at Chatham, he began research and experiments on artificial hydraulic cement, attempting to match or make an improvement over natural or "Roman" cement, invented by James Parker in 1796. In 1830, he succeeded and with chalk and Medway clay, produced a hydraulic lime equal to the natural "Roman" cement and similar to that produced by Joseph Aspdin in Wakefield.
Building material
Bricks were laid in lime mortar from the time of the Romans until supplanted by Portland cement mortar in the early 20th century. Cement blocks also sometimes are filled with grout or covered with a parge coat.
History of structural engineering
The ancient Romans made great bounds in structural engineering, pioneering large structures in masonry and concrete, many of which are still standing today. They include aqueducts, thermae, columns, lighthouses, defensive walls and harbours. Their methods are recorded by Vitruvius in his De Architectura written in 25 BC, a manual of civil and structural engineering with extensive sections on materials and machines used in construction. One reason for their success is their accurate surveying techniques based on the dioptra, groma and chorobates.
Calcium
Calcium compounds were known for millennia, although their chemical makeup was not understood until the 17th century. Lime as a building material and as plaster for statues was used as far back as around 7000 BC. The first dated lime kiln dates back to 2500 BC and was found in Khafajah, Mesopotamia. At about the same time, dehydrated gypsum (CaSO·2HO) was being used in the Great Pyramid of Giza; this material would later be used for the plaster in the tomb of Tutankhamun. The climate of present-day Italy being warmer than that of Egypt, the ancient Romans instead used lime mortars made by heating limestone (CaCO); the name "calcium" itself derives from the Latin word "calx" "lime". Vitruvius noted that the lime that resulted was lighter than the original limestone, attributing this to the boiling of the water; in 1755, Joseph Black proved that this was due to the loss of carbon dioxide, which as a gas had not been recognised by the ancient Romans.
Louis Vicat
Vicat studied the setting of mortars and developed his own. The first building using the modern mortar is the bridge of Souillac (Dordogne) erected in 1818.
The material was popular but was superseded by Portland cement. He also invented the Vicat needle that is still in use for determination of setting time of concretes and cements. His son, Joseph Vicat, founded Vicat Cement, which is today a large international cement manufacturing company.
Edison Portland Cement Company
Somewhat ahead of his time Edison believed that concrete would have a wide range of applications, but in the early 20th century its production was not sufficiently economical. He envisioned a future with concrete houses filled with concrete furniture, refrigerators, and pianos. While none of these items were made Edison did create concrete phonograph cabinets. Edison investigated the use of formwork molds that could repeatedly be used to create concrete houses, experimenting in 1910 by casting a garage and a gardener's cottage at his mansion in New Jersey. He decided to donate the patented information to qualified builders rather than charge for it, generating significant publicity in the process.
Self-healing material
The ancient Romans used a form of lime mortar that has been found to have self-healing properties. By 2014, geologist Marie Jackson and her colleagues had recreated the type of mortar used in Trajan's Market and other Roman structures such as the Pantheon and the Colosseum and studied its response to cracking. The Romans mixed a particular type of volcanic ash called Pozzolane Rosse, from the Alban Hills volcano, with quicklime and water. They used it to bind together decimeter-sized chunks of tuff, an aggregate of volcanic rock.
As a result of Pozzolanic activity as the material cured, the lime interacted with other chemicals in the mix and was replaced by crystals of a calcium aluminosilicate mineral called Strätlingite. Crystals of platey strätlingite grow in the cementitious matrix of the material including the interfacial zones where cracks would tend to develop. This ongoing crystal formation holds together the mortar and the coarse aggregate, countering crack formation and resulting in a material that has lasted for 1,900 years.
Roman cement
Roman cement is a substance developed by James Parker in the 1780s, being patented in 1796.
Roman engineering
Cement was made of hydrated lime (calcium oxide) mixed with sand and water. The Romans discovered that substituting or supplementing the sand with a pozzolanic additive, such as volcanic ash, would produce a very hard cement, known as hydraulic mortar or hydraulic cement. They used it widely in structures such as buildings, public baths and aqueducts, ensuring their survival into the modern era.
Opus signinum
Opus signinum ('cocciopesto' in modern Italian) is a building material used in ancient Rome. It is made of tiles broken up into very small pieces, mixed with mortar, and then beaten down with a rammer. Pliny in his Natural History describes its manufacture: "Even broken pottery has been utilized; it being found that, beaten to powder, and tempered with lime, it becomes more solid and durable than other substances of a similar nature; forming the cement known as the "Signine" composition, so extensively employed for even making the pavements of houses." Pliny's use of the term "Signine" references "Signia (modern Segni), the name of a town in Latium which was famous for its tiles."
Roman concrete
Vitruvius, writing around 25 BC in his "Ten Books on Architecture", distinguished types of aggregate appropriate for the preparation of lime mortars. For structural mortars, he recommended pozzolana ("pulvis puteolanus" in Latin), the volcanic sand from the beds of Pozzuoli, which are brownish-yellow-gray in color in that area around Naples, and reddish-brown near Rome. Vitruvius specifies 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, essentially the same ratio mixed today for concrete used in marine locations.
Mortar (masonry)
Historically, building with concrete and mortar next appeared in Greece. The excavation of the underground aqueduct of Megara revealed that a reservoir was coated with a pozzolanic mortar 12 mm thick. This aqueduct dates back to c. 500 BCE. Pozzolanic mortar is a lime based mortar, but is made with an additive of volcanic ash that allows it to be hardened underwater; thus it is known as hydraulic cement. The Greeks obtained the volcanic ash from the Greek islands Thira and Nisiros, or from the then Greek colony of Dicaearchia (Pozzuoli) near Naples, Italy. The Romans later improved the use and methods of making what became known as pozzolanic mortar and cement. Even later, the Romans used a mortar without pozzolana using crushed  terra cotta, introducing aluminum oxide and silicon dioxide into the mix. This mortar was not as strong as pozzolanic mortar, but, because it was denser, it better resisted penetration by water.
Pozzolana
Pozzolanas such as Santorin earth were used in the Eastern Mediterranean since 500–400 BC. Although pioneered by the ancient Greeks, it was the Romans that eventually fully developed the potential of lime-pozzolan pastes as binder phase in Roman concrete used for buildings and underwater construction. Vitruvius speaks of four types of pozzolana: black, white, grey, and red, all of which can be found in the volcanic areas of Italy, such as Naples. Typically it was very thoroughly mixed two-to-one with lime just prior to mixing with water. The Roman port at Cosa was built of pozzolana-lime concrete that was poured underwater, apparently using a long tube to carefully lay it up without allowing sea water to mix with it. The three piers are still visible today, with the underwater portions in generally excellent condition even after more than 2100 years.
Ferrocement
The inventors of ferrocement are Frenchmen Joseph Monier who dubbed it "ciment armé" (armored cement) and Joseph-Louis Lambot who constructed a batteau with the system in 1848. Lambot exhibited the vessel at the Exposition Universelle in 1855 and his name for the material "ferciment" stuck. Lambot patented his batteau in 1855 but the patent was granted in Belgium and only applied to that country. At the time of Monier's first patent, July 1867, he planned to use his material to create urns, planters, and cisterns. These implements were traditionally made from ceramics, but large-scale, kiln-fired projects were expensive and prone to failure. In 1875, Monier expanded his patents to include bridges and designed his first steel-and-concrete bridge. The outer layer was sculpted to mimic rustic logs and timbers, thereby also ushering Faux Bois (wood grain) concrete. In the first half of the twentieth century Italian Pier Luigi Nervi was noted for his use of ferro-cement, in Italian called "ferro-cemento".
Pepper Pot, Brighton
The main building material was said to be cement by English Heritage in its listing description, but research undertaken during the 2011 restoration work discovered that the core of the Pepper Pot is made of a pioneering type of concrete known as "Ranger's Artificial Stone" or "Ranger's Lime Concrete"—making it one of the oldest buildings in England to use this material. William Ranger, a builder from the nearby village of Ringmer, invented this in the early 19th century.
Arch bridge
Roman engineers were the first and until the industrial revolution the only ones to construct bridges with concrete, which they called Opus caementicium. The outside was usually covered with brick or ashlar, as in the Alcántara bridge.
History of construction
No timber structures survive (roofs, floors etc.), so our knowledge of how these were put together is limited. The spans are, in the main, limited and suggest very simple beam and post structures spanning stone walls. For the longer spans it is uncertain if the Greeks or Romans invented the truss but the Romans certainly used timber roof trusses. Before 650 B.C.E. the now famous ancient Greek temples were built of wood, but after this date began to be built of stone. The process of a timber structure being repeated in stone is called petrification or "petrified carpentry".
Roman concrete
It is uncertain when Roman concrete was developed, but it was clearly in widespread and customary use from about 150 BC; some scholars believe it was developed a century before that.
Environmental impact of concrete
Italian company Italcementi designed a kind of cement that is supposed to fight air pollution. It should break down pollutants that come in contact with the concrete, thanks to the use of titanium dioxide absorbing ultraviolet light. Some environmental experts nevertheless remain skeptical and wonder if the special material can 'eat' enough pollutants to make it financially viable. Jubilee Church in Rome is built from this kind of concrete.
Francis Petre
Petre's early speciality was his work in mass concrete, at the time a novel building material in New Zealand. Widely used by the ancient Romans the formula for making it was lost and a new one only invented in the 18th century. Three of Petre's earliest projects were all constructed in this material: Judge Chapman's house (today known as "Castlamore"), the clifftop villa nicknamed Cargill's Castle in 1876, and St. Dominic's Priory in 1877. However, according to the whims of his patrons, he did also work with more conventional building materials.
Ancient technology
Roman engineers build monumental arches, amphitheatres, aqueducts, public baths, true arch bridges, harbours, dams, vaults and domes on a very large scale across their Empire. Notable Roman inventions include the book (Codex), glass blowing and concrete. Because Rome was located on a volcanic peninsula, with sand which contained suitable crystalline grains, the concrete which the Romans formulated was especially durable. Some of their buildings have lasted 2000 years, to the present day. Roman society had also carried over the design of a door lock with tumblers and springs from Greece. Like many other aspects of innovation and culture that were carried on from Greece to Rome, the lines between where each one originated from have become skewed over time. These mechanisms were highly sophisticated and intricate for the era.
François Coignet
Coignet started experimenting with iron-reinforced concrete in 1852 and was the first builder ever to use this technique as a building material. He decided as a publicity stunt, and for promotional purposes of his cement business, to build a house made of "béton armé", a type of reinforced concrete. In 1853 he built the first iron reinforced concrete structure anywhere, a four-story house at 72 rue Charles Michels. This location was near his family cement plant in St. Denis, a commune in the northern suburbs of Paris. The house was designed by local architect Theodore Lachez.
Legacy of the Roman Empire
Some of the more famous examples are the Roman aqueducts (some of which are still in use today), Roman roads, water powered milling machines, thermal heating systems (as employed in Roman baths, and also used in palaces and wealthy homes) sewage and pipe systems and the invention and widespread use of concrete.
Types of concrete
Limecrete or lime concrete is concrete where cement is replaced by lime.
One successful formula was developed in the mid-1800s by Dr. John E. Park.
We know that lime has been used since Roman Times either as mass foundation concretes or as lightweight concretes using a variety of aggregates combined with a wide range of pozzolans (fired materials) that help to achieve increased strength and speed of set. This meant that lime could be used in a much wider variety of applications than previously such as floors, vaults or domes.
Over the last decade, there has been a renewed interest in using lime for these applications again. This is because of environmental benefits and potential health benefits, when used with other lime products.
Ancient Roman architecture
A crucial factor in this development, which saw a trend toward monumental architecture, was the invention of Roman concrete ("opus caementicium"), which led to the liberation of shapes from the dictates of the traditional materials of stone and brick.
Dome
Roman concrete used an aggregate of stone with a powerful mortar. The aggregate transitioned over the centuries to pieces of fired clay, then to Roman bricks. By the sixth century, bricks with large amounts of mortar were the principle vaulting materials. Pozzolana appears to have only been used in central Italy. Brick domes were the favored choice for large-space monumental coverings until the Industrial Age, due to their convenience and dependability. Ties and chains of iron or wood could be used to resist stresses.
Pavement (architecture)
Segmental pavers have been used for thousands of years. The Romans built roads with them that are still there. But it was not until the mid-1940s that pavers began to be produced out of concrete. It started in the Netherlands where all the roads are made to be flexible because the country is below sea level and the ground shifts, moves and sinks. Poured concrete is not an option because it will crack. Individual units not set in concrete, and placed in sand perform far better than concrete. Before the paver was made from concrete, either real stone or a clay product was used.
Concrete
Portland cement is the most common type of cement in general usage. It is a basic ingredient of concrete, mortar and many plasters. British masonry worker Joseph Aspdin patented Portland cement in 1824. It was named because of the similarity of its color to Portland limestone, quarried from the English Isle of Portland and used extensively in London architecture. It consists of a mixture of calcium silicates (alite, belite), aluminates and ferrites – compounds which combine calcium, silicon, aluminum and iron in forms which will react with water. Portland cement and similar materials are made by heating limestone (a source of calcium) with clay or shale (a source of silicon, aluminum and iron) and grinding this product (called "clinker") with a source of sulfate (most commonly gypsum).
Roman cement
From around 1807 a number of people looked to make artificial versions of this cement (or more strictly hydraulic lime as it was not burnt at fusion temperatures). Amongst these were James Frost who had about twenty patents from 1811 to 1822 including one for "British Cement" and in 1824 Joseph Aspdin, a British bricklayer from Leeds, with his now famous patent for a method of making a cement he called "Portland cement". This was done by adding various materials together to make an artificial version of natural cement. The name "Portland cement" is also recorded in a directory published in 1823 being associated with William Lockwood, Dave Stewart, and possibly others.
There then followed a number of independently discovered or copied versions of this "Portland cement" (also referred to as Proto Portland cement). Proto Portland cement had a different chemical makeup from other natural cements being produced at the same time: It was burnt at a higher temperature than other Natural cements and thus crosses the barrier between traditional Vertical Kiln fired Natural cement and the later Horizontal Kiln fired Artificial cements. This cement is not, however, the same as the modern ordinary Portland cement, which can be defined as artificial cement.
Pozzolan
Much of the practical skill and knowledge regarding the use of pozzolans was lost at the decline of the Roman empire. The rediscovery of Roman architectural practices as described by Vitruvius in "De architectura", also led to the reintroduction of lime-pozzolan binders. Particularly the strength, durability and hydraulic capability of hardening underwater made them popular construction materials during the 16th–18th century. The invention of other hydraulic lime cements and eventually Portland cement in the 18th and 19th century resulted in a gradual decline of the use of pozzolan-lime binders, which develop strength less rapidly.
Roman concrete
Compressive strengths for modern Portland cements are typically at the 50 MPa level and have improved almost ten-fold since 1860. There are no comparable mechanical data for ancient mortars, although some information about tensile strength may be inferred from the cracking of Roman concrete domes. These tensile strengths vary substantially from the water/cement ratio used in the initial mix. At present, there is no way of ascertaining what water/cement ratios the Romans used, nor are there extensive data for the effects of this ratio on the strengths of pozzolanic cements.
Ancient Roman architecture
Marble is not found especially close to Rome, and was only rarely used there before Augustus, who famously boasted that he had found Rome made of brick and left it made of marble, though this was mainly as a facing for brick or concrete. The Temple of Hercules Victor of the late 2nd century BC is the earliest surviving exception in Rome. From Augustus' reign the quarries at Carrara were extensively developed for the capital, and other sources around the empire exploited, especially the prestigious Greek marbles like Parian. Travertine limestone was found much closer, around Tivoli, and was used from the end of the Republic; the Colosseum is mainly built of this stone, which has good load-bearing capacity, with a brick core. Other more or less local stones were used around the empire.
Concrete
The long-term durability of Roman concrete structures has been found to be due to its use of pyroclastic (volcanic) rock and ash, whereby crystallization of strätlingite and the coalescence of calcium–aluminum-silicate–hydrate cementing binder helped give the concrete a greater degree of fracture resistance even in seismically active environments. Roman concrete is significantly more resistant to erosion by seawater than modern concrete; it used pyroclastic materials which react with seawater to form Al-tobermorite crystals over time.
The widespread use of concrete in many Roman structures ensured that many survive to the present day. The Baths of Caracalla in Rome are just one example. Many Roman aqueducts and bridges, such as the magnificent Pont du Gard in southern France, have masonry cladding on a concrete core, as does the dome of the Pantheon.
Formwork
Some of the earliest examples of concrete slabs were built by Roman engineers. Because concrete is quite strong in resisting compressive loads, but has relatively poor tensile or torsional strength, these early structures consisted of arches, vaults and domes. The most notable concrete structure from this period is the Pantheon in Rome. To mould this structure, temporary scaffolding and formwork or falsework was built in the future shape of the structure. These building techniques were not isolated to pouring concrete, but were and are widely used in masonry. Because of the complexity and the limited production capacity of the building material, concrete’s rise as a favored building material did not occur until the invention of Portland cement (and developments by the Edison Portland Cement Company) and reinforced concrete.
Types of concrete
Similar concretes have not only been used in Ancient Rome (see Roman cement), but also in the former Soviet Union in the 1950s and 1960s. Buildings in Ukraine are still standing after 45 years.