[L. concretus, p. p. of concrescere to grow together; con- + crescere to grow; cf. F. concret.]
United in growth; hence, formed by coalition of separate; particles into one mass; united in a solid form
Verb (used with object), con·cret·ed, con·cret·ing.
Verb (used without object), con·cret·ed, con·cret·ing.
|الخرسانة /Arabic/||σκυρόδεμα /Greek/||concrete /Esperanto/||бетон /Russian/|
|具体 /Chinese/||בטון /Hebrew/||béton /French/||betón /Slovak/|
|beton /Croatian/||calcestruzzo /Italian/||betong /Norwegian/||concreto /Spanish/|
|beton /Czech/||コンクリ?`ト /Japanese/||beton /Polish/||betong /Swedish/|
|beton /German/||concrete /English/||concreto /Portuguese/||beton /Turkish/|
Timeline of the Development of Concrete
Cement has been around for at least 12 million years. When the earth itself was undergoing intense geologic changes natural, cement was being created. It was this natural cement that humans first put to use. Eventually, they discovered how to make cement from other materials.
Concrete and the technology surrounding it has come a long way since its discovery and development. From the great Pyramids at Giza to smart sensors for testing concrete temperature, maturity, etc.
Reactions between limestone and oil shale during spontaneous combustion occurred in Israel to form a natural deposit of cement compounds. The deposits were characterized by Israeli geologists in the 1960’s and 70’s.
Egyptians used mud mixed with straw to bind dried bricks. They also used gypsum mortars and mortars of lime in the pyramids. Chinese used cement like materials to hold bamboo together in their boats and in the Great Wall.
Greeks, Crete & Cyprus used lime mortars which were much harder than later Roman mortars. The Nabataeans possibly made waterproof cisterns in the Arabian deserts during this time.
Babylonians & as Syrians used bitumen to bind stones and bricks.
Nabataeans undoubtedly built countless cisterns with waterproof cement by this date in Arabia. Many of these cisterns are still intact and continue to be used today.
200 BC - 476 AD
Romans used pozzolana cement from Pozzuoli, Italy near Mt. Vesuvius to build the Appian Way, Roman baths, the Coliseum and Pantheon in Rome, and the Pont du Gard aqueduct in south France. They used lime as a cementitious material. Pliny reported a mortar mixture of 1 part lime to 4 parts sand. Vitruvius reported a 2 parts pozzolana to 1 part lime. Animal fat, milk, and blood were used as admixtures (substances added to cement to increase the properties.) These structures still exist today.
500 - 1500 The Middle Ages
The quality of cementing materials in europe deteriorated. The use of burning lime and pozzolan (admixture) was lost, but reintroduced in the 1300’s.
Joseph Moxon wrote about a hidden fire in heated lime that appears upon the addition of water.
Bry Higgins was issued a patent for hydraulic cement (stucco) for exterior plastering use.
Bry Higgins published “Experiments and Observations Made With the View of Improving the Art of Composing and Applying Calcereous Cements and of Preparing Quicklime.”
John Smeaton found that the calcination of limestone containing clay gave a lime which hardened under water (hydraulic lime). He used hydraulic lime to rebuild Eddystone Lighthouse in Cornwall, England which he had been commissioned to build in 1756, but had to first invent a material that would not be affected by water. He wrote a book about his work.
James Parker from England patented a natural hydraulic cement by calcining nodules of impure limestone containing clay, called Parker’s Cement or Roman Cement.
In France, a similar Roman Cement process was used.
Edgar Dobbs received a patent for hydraulic mortars, stucco, and plaster, although they were of poor quality due to lack of kiln precautions.
Louis Vicat of France prepared artificial hydraulic lime by calcining synthetic mixtures of limestone and clay.
Maurice St. Leger was issued patents for hydraulic cement. Natural Cement was produced in the USA. Natural cement is limestone that naturally has the appropriate amounts of clay to make the same type of concrete as John Smeaton discovered.
1820 - 1821
John Tickell and Abraham Chambers were issued more hydraulic cement patents.
James Frost of England prepared artificial hydraulic lime like Vicat’s and called it British Cement.
Joseph Aspdin of England invented portland cement by burning finely ground chalk with finely divided clay in a lime kiln until carbon dioxide was driven off. The sintered product was then ground and he called it portland cement named after the high quality building stones quarried at Portland, England.
I. K. Brunel is credited with the first engineering application of portland cement, which was used to fill a breach in the Thames Tunnel.
The first production of lime and hydraulic cement took place in Canada.
The first systematic tests of tensile and compressive strength took place in Germany.
J. M. Mauder, Son & Co. were licensed to produce patented portland cement.
Isaac Johnson claims to have burned the raw materials of portland cement to clinkering temperatures.
Pettenkofer & Fuches performed the first accurate chemical analysis of portland cement**.**
The beginning of the era of portland cements of modern composition.
Blake Stonebreaker of England introduced the jaw breakers to crush clinkers.
Joseph Monier of France reinforced William Wand’s (USA) flowerpots with wire ushering in the idea of iron reinforcing bars (re-bar).
David Saylor was issued the first American patent for portland cement. He showed the importance of true clinkering.
J. Grant of England show the importance of using the hardest and densest portions of the clinker. Key ingredients were being chemically analyzed.
The first rotary kiln was introduced in England to replace the vertical shaft kilns.
Henri Le Chatelier of France established oxide ratios to prepare the proper amount of lime to produce portland cement. He named the components: Alite (tricalcium silicate), Belite (dicalcium silicate), and Celite tetracalcium aluminoferrite). He proposed that hardening is caused by the formation of crystalline products of the reaction between cement and water.
The first concrete reinforced bridge is built.
The addition of gypsum when grinding clinker to act as a retardant to the setting of concrete was introduced in the USA. Vertical shaft kilns were replaced with rotary kilns and ball mills were used for grinding cement.
George Bartholomew placed the first concrete street in the USA in Bellefontaine, OH which still exists today.
William Michaelis claimed that hydrated metasilicates form a gelatinous mass (gel) that dehydrates over time to harden.
Basic cement tests were standardized.
The first concrete high rise was built in Cincinnati, OH.
Thomas Edison built cheap, cozy concrete houses in Union, NJ.
Thomas Edison was issued a patent for rotary kilns.
Dr. Linus Pauling of the USA formulated a set of principles for the structures of complex silicates.
Air entraining agents were introduced to improve concrete’s resistance to freeze/thaw damage.
The first major concrete dams, Hoover Dam and Grand Coulee Dam, were built. They still exist today!
First concrete domed sport structure, the Assembly Hall, was constructed at The University of Illinois, at Urbana-Champaign.
Fiber reinforcement in concrete was introduced.
CN Tower in Toronto, Canada, the tallest slip-form building, was constructed. Water Tower Place in Chicago, Illinois, the tallest building was constructed.
Superplasticizers were introduced as admixtures.
Silica fume was introduced as a pozzolanic additive. The “highest strength” concrete was used in building the Union Plaza constructed in Seattle, Washington.
The tallest reinforced concrete building in the world was constructed at 311 S. Wacker Dr., Chicago, Illinois.
|Type I||Normal Portland Cement|
|Grey or White|
|Type II||Moderate Sulfate Resistance|
|Used for structures in water or soil containing moderate amounts of sulfate|
|Type II (MH)||Moderate Heat of Hydration and Moderate Sulfate Resistance|
|Used when heat build-up is a concern|
|Type III||High Early Strength|
|Used when high strength are desired at very early periods|
|Type IV||Low Heat Hydration|
|Used where the amount and rate of heat generation must be kept to a minimum|
|Type V||High Sulfate Resistance|
|Used where the water or soil is high in alkali|
Blended hydraulic cements:
|Type IL||Portland-Limestone Cement|
|Type IS||Portland-Slag Cement|
|Type IP||Portland-Pozzolana Cement|
|Type IT||Ternary Blended Cement|
|CSA||Cement high in Calcium Aluminum Sulfate Crystals|
|When used with Portland cement concrete, CSA generates a strong cementitious matrix that enhances the physical and chemical properties of the mix|
Other typws of cements:
|Rapid hardening Portland cement|
|Extra rapid hardening cement|
|Hydrophobic Portland cement|
|Quick setting Cement|
|High alumina cement|
|Air-entraining Portland cement|
During the last two decades, concrete technology has been undergoing rapid developments. In recent years, different concepts of concrete mixes have gained popularity and are steadily progressing from laboratory to the field of practice. A wide range of mix designs and add-ins produce concrete with different properties.
In our projects we use different types of concrete but mostly we use our Special UHPC Fiber-Reinforced (AR Glass and Carbon) Mix that has exceptional mechanical performance, in particular its tensile strength, resistance to compression and bending, its creep and shrinkage behavior, its fire-resistance, and its water impermeability unlike conventional concrete.
It achieves this engineering feature by progressively absorbing the energy applied and efficiently dispersing it throughout the matrix.
These mechanical properties make it possible to create very slender structures with little or no passive steel reinforcement.
By adjusting a mix design we can control flow from none to completely self-consolidating.
It has micro-fine aggregates that make it extremely dense with less porosity, offering resistance to scratching and staining.
This super fine design matrix also produces a surface capable of intricate detail with unlimited surface textures, finishes and colors.
We have designed and programmed our own Concrete Mix Design Calculator with all the ingredients and parameters input, and we are able to easily make tailor-made concrete mix in just a few steps.
We are working with, researching and experimenting with all kinds of concrete variations, some of them are:
Regular Conventional Concrete
Mix of hydraulic cement, natural aggregate and water.
SCC - Self-Compacting / Self-leveling / Self-placing
Concrete is an extremely fluid mix with the following distinctive practical features.
HPC - High Performance Concrete
Concrete with strength and durability significantly beyond those obtained by normal means. HPC mixtures are composed of essentially the same materials as conventional concrete mixtures, but the proportions are designed, or engineered, to provide the strength and durability.
UHPC - Ultra-High Performance Concrete
It s a new class of concrete with exceptional properties of strength and durability. This innovative material produces concrete elements that are up to 10 times stronger than conventional concrete. The UHPC possesses unprecedented flexural strength, allowing for finer, thinner, lighter and more elegant designs. The chemistry is cutting edge while still embracing the natural qualities of concrete.
FRC - Fiber-Reinforced Concrete
Concrete containing fibrous material which increases its structural integrity (AR glass, polypropylene, aramid and carbon fibers).
UHPFRC - Ultra High-Performance Fiber-Reinforced Concrete
Owing to a densely packed structure, its compressive strength exceeding 150 MPa, tensile strength is higher than 7-8 MPa. W/B ratio for it is lower than 0.25, it has high content of binder, fibres to ensure a ductile behavior. Use of a quite large amount of super-plasticizers in order to obtain an acceptable work-ability is also a characteristic of the UHPFRC.
PMC / PPCC - Polymer-Modified Concrete
Developed by adding a polymer material to Portland-cement concrete with the interest of enhancing the fresh and hardened concrete properties (extensibility and tensile strength, impact resistance, abrasion resistance, durability and resistance to aggressive fluids, bond strength).
Concrete that uses a polymer binder in place of Portland cement (Epoxy, Polyurethane, Polyester).
Concrete with visible natural stone or artificial aggregate (washed or ground).
Thin Shell Concrete
Extremely thin concrete forms of special concrete mix and application (Air forms, Free forms, Fabric forms).
Thin Skin Concrete
Thin concrete overlay on different materials.
Concrete with added expansion additives that foam during hydration making lightweight concrete. We can control expansion through section to achieve different weight /strength ratios in one cast.
Ultra Light Concrete
Replacing part or whole aggregate with light aggregate such as expanded glass and perlite or synthetic pearls (EPS, XPS, perlite) concrete can become extremely lightweight and at the same time hard and resistant to moisture.
High Density Concrete
Radiation protection concrete with addition of heavy metals like barite, magnetite, steel or lead.
Concrete with recycled aggregate (crushed concrete, brick, plastic, rubber) + active waste ingredients from industry (micro-silica, slag, etc.) has the benefits of energy, CO2 and water savings.
Wear Resistant Concrete
Addition of corundum or quartz aggregate make it ideal for use in industrial floors.
Waterproof concrete is an impermeable concrete used for long-lasting, durable watertight construction.
Special mix design that leaves voids between large aggregate helps water drainage.
Fast Setting Concrete
It is a special blend of fast-setting cements, sand and gravel designed to set hard in approx. 20 to 40 minutes.
Light Transmitting / Translucent Concrete
Concrete with Fiber-optic glass and acrylic inserts that transmits light trough section.
Color Changing concrete
Temperature dependent color changing concrete.
Glow in the Dark Concrete
Addition of special self-illuminating aggregate and post processing (grinding / washing) makes concrete that glows in the dark or under UV light.
Water Sensitive Concrete
Changes color when wetted and different patterns or inscriptions become visible. It turns back to normal color after surface is dried out.
Decorative Metal concrete
An exclusive line of decorative metal powders and shavings-based concrete with unprecedented surface attractiveness (brass, bronze, copper, silver, corroded steel, stainless steel).
Hairy Fabric Concrete
Concrete made in special molds that leaves micro fabrics on the concrete surface that looks like hairs.
Concrete never had magnetic properties until now. We are replacing gravel and sand by coarse and fine magnetic fillers merging the worlds of construction and electromagnetism.
Porous concrete with biologically nutrients, lime and organic materials (straw, sawdust, hypertufa, flower sponge, cork) suitable for the growth of moss and plants.
Concrete with the addition of essential oils and perfumes that evaporates through time.
Thermal Conductive Concrete
Concrete with addition of different types of graphite that conduct heat for different applications.
Thermal Insulating Concrete
It is made with special lightweight expanded aggregates or foam and has ability to provide excellent acoustic and thermal insulation properties.
Temperature Resistant Concrete
Using thermally resistant cement and aggregate, with special care made during and after hydration to dry resistant moisture from concrete, concrete can resist high heat.
Electrically Conductive Concrete
Concrete that conducts electrical energy can be used for raised computer floors to dissipate static electricity.
Sound Absorbing Concrete
Using different layers of concrete mixtures with different sound properties are making it sound absorbing or sound reflecting.
Impact and Blast Proof Concrete
With a use of special plastic behaviour and ductile systems it achieves protection by absorbing the blast load energy as strain energy upon deformation.
Flexible / Bendable Concrete
Special mix of fibers with different properties and addition of flexible polymers in concrete makes material that does not crack but bends on load.
Concrete with advanced mechanical and dynamic properties, and benefit of using recycled rubber material.
Internal Self-Curing Concrete (SCUC)
Addition of polyethylene-glycol helps hydration of cement to occur because of the availability of additional internal water that is not part of the mixing water, optimizing the performance of concrete.
Concrete with addition of sodium silicate that reacts with calcium hydroxide to form calcium silica hydrate helps heals cracks and pores in structure.
Self-Cleaning Air-Purifying Concrete
Contains titanium dioxide, a photo-catalytic material that removes the nitrogen oxides from the air and converts them into harmless nitrate with the aid of sunlight. The nitrate is then rinsed away by rain leaving concrete structure clean.
Depending on project demands and concrete mix design, different types of applying methods are available:
• Casting in rigid or flexible molds (fabric forming)
• Application by hand
• Rolling of fresh concrete
• Pressure pumping (top-down / bottom-up)
• Bending (1 axis or 2 axes)
• Spraying (dry or wet mix - Shotcrete / Gunite)
• Rotational molding (centrifugal / template)
• 3D concrete printing
Fabric Forming - our favorite
Fabric formwork uses flexible textile membranes in place of the rigid formwork panels that are usually used in concrete forming. When wet concrete is contained by a thin formwork membrane, the flexible fabric container naturally deflects into a repertoire of precise tension geometries. This produces naturally efficient structural curves, unprecedented sculptural forms, and extraordinary surface finishes.
From a sculptural / architectural perspective, the use of flexible formworks links concrete to its fluid origins, introducing a new horizon for architectural form and expression.
Fabric formworks can be used to form columns, walls, beams, slabs and panels in both precast and in-situ construction. It has a significant potential for construction and engineering technology in both advanced and basic building economies.
Fabric forming combined with high-end technology, enables us to create virtually any shape or form.
Concrete finishing is a process that strives to create a desired, durable surface. When finishing concrete, timing is crucial and close attention to the condition of concrete is vital.
It can be done on fresh concrete:
• Smooth finish
• Broom finish
• Salt finish
• Exposed aggregate
• Troweling / floating
• Staining / pigmentation
• Hardening / densifying
Or on hardened and cured concrete:
• Off form
• Hand sanding
• Acid etching
• Edge grinding and polishing
• Laser engraving
• Moss growing
Depending on their location and use, concrete structures are exposed to a wide range of different aggressive conditions – from normal atmospheric carbonation to aggressive influences in polluted urban and industrial environments, plus marine atmosphere and liquid or gaseous chemicals, along with influencers that can damage or attack the concrete and embedded steel reinforcement.
Different high quality protection systems are applied to concrete to protect it from surface damage, corrosion, carbonation, chloride attack, staining and graffiti.
Penetrating sealers / Stain repellents
They block the pores in concrete to reduce absorption of liquids.
• Invisible hydro- & oleo-phobic (silane / silicates / siloxane)
Sealers / Film forming
They form an impermeable layer which prevents liquids from passing.
Without protection, concrete changes during its lifetime, which can also have its special charm.