Concrete is a composite material composed of aggregate bonded together with a fluid cement that cures to a solid over time. Concrete is the second-most-used substance in the world after water, and is the most widely used building material. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminium combined.
A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Concrete is the most widely used material in existence and is behind only water as the planet's most-consumed resource.
Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and is usually made from limestone. It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, and then grinding the clinker with the addition of several percent gypsum. Several types of portland cement are available. The most common, historically called ordinary portland cement (OPC), is grey, but white portland cement is also available. Its name is derived from its resemblance to Portland stone which is quarried on the Isle of Portland in Dorset, England. It was named by Joseph Aspdin who obtained a patent for it in 1824. His son William Aspdin is regarded as the inventor of "modern" portland cement due to his developments in the 1840s.
Angel food cake, or angel cake, is a type of sponge cake made with egg whites, flour, and sugar. A whipping agent, such as cream of tartar, is commonly added. It differs from other cakes because it uses no butter. Its aerated texture comes from whipped egg white. Angel food cake originated in the United States and first became popular in the late 19th century. It gained its unique reputation along with its name due to its light and fluffy texture and white color.
In chemistry, efflorescence is the migration of a salt to the surface of a porous material, where it forms a coating. The essential process involves the dissolving of an internally held salt in water or occasionally, in another solvent. The water, with the salt now held in solution, migrates to the surface, then evaporates, leaving a coating of the salt.
Ready-mix concrete (RMC) is concrete that is manufactured in a batch plant, according to each specific job requirement, then delivered to the job site "ready to use".
Air entrainment in concrete is the intentional creation of tiny air bubbles in a batch by adding an air entraining agent during mixing. A form of surfactant it allows bubbles of a desired size to form. These are created during concrete mixing, with most surviving to remain part of it when hardened.
The water–cement ratio is the ratio of the mass of water to the mass of cement used in a concrete mix:
Metakaolin is the anhydrous calcined form of the clay mineral kaolinite. Rocks that are rich in kaolinite are known as china clay or kaolin, traditionally used in the manufacture of porcelain. The particle size of metakaolin is smaller than cement particles, but not as fine as silica fume.
Coal combustion products (CCPs), also called coal combustion wastes (CCWs) or coal combustion residuals (CCRs), are categorized in four groups, each based on physical and chemical forms derived from coal combustion methods and emission controls:
Self-consolidating concrete or self-compacting concrete (SCC) is a concrete mix which has a low yield stress, high deformability, good segregation resistance, and moderate viscosity.
A defoamer or an anti-foaming agent is a chemical additive that reduces and hinders the formation of foam in industrial process liquids. The terms anti-foam agent and defoamer are often used interchangeably. Strictly speaking, defoamers eliminate existing foam and anti-foamers prevent the formation of further foam. Commonly used agents are insoluble oils, polydimethylsiloxanes and other silicones, certain alcohols, stearates and glycols. The additive is used to prevent formation of foam or is added to break a foam already formed.
Fly ash brick (FAB) is a building material, specifically masonry units, containing class C or class F fly ash and water. Compressed at 28 MPa(272 atm) and cured for 24 hours in a 66 °C steam bath, then toughened with an air entrainment agent, the bricks can last for more than 100 freeze-thaw cycles. Owing to the high concentration of calcium oxide in class C fly ash, the brick is described as "self-cementing". The manufacturing method saves energy, reduces mercury pollution in the environment, and often costs 20% less than traditional clay brick manufacturing.
Concrete is produced in a variety of compositions, finishes and performance characteristics to meet a wide range of needs.
The environmental impact of concrete, its manufacture, and its applications, are complex, driven in part by direct impacts of construction and infrastructure, as well as by CO2 emissions; between 4-8% of total global CO2 emissions come from concrete. Many depend on circumstances. A major component is cement, which has its own environmental and social impacts and contributes largely to those of concrete.
Continuous foam separation is a chemical process closely related to foam fractionation in which foam is used to separate components of a solution when they differ in surface activity. In any solution, surface active components tend to adsorb to gas-liquid interfaces while surface inactive components stay within the bulk solution. When a solution is foamed, the most surface active components collect in the foam and the foam can be easily extracted. This process is commonly used in large-scale projects such as water waste treatment due to a continuous gas flow in the solution.
The pozzolanic activity is a measure for the degree of reaction over time or the reaction rate between a pozzolan and Ca2+ or calcium hydroxide (Ca(OH)2) in the presence of water. The rate of the pozzolanic reaction is dependent on the intrinsic characteristics of the pozzolan such as the specific surface area, the chemical composition and the active phase content.
Foam concrete, also known as Lightweight Cellular Concrete (LCC) and Low Density Cellular Concrete (LDCC), and by other names, is defined as a cement-based slurry, with a minimum of 20% foam entrained into the plastic mortar. As mostly no coarse aggregate is used for production of foam concrete the correct term would be called mortar instead of concrete; it may be called "foamed cement" as well. The density of foam concrete usually varies from 400 kg/m3 to 1600 kg/m3. The density is normally controlled by substituting all or part of the fine aggregate with the foam.
The cement industry in the United States produced 82.8 million tonnes of cement in 2015, worth US$9.8 billion, and was used to manufacture concrete worth about US$50 billion. The US was the world's third-largest producer of cement, after China and India. The US cement industry includes 99 cement mills in 34 states, plus two plants in Puerto Rico. The industry directly employed 10,000 workers in 2015. Ten percent of the cement used in the United States in 2015 was imported.
3D concrete printing, or simply concrete printing, refers to digital fabrication processes for cementitious materials based on one of several different 3D printing technologies. 3D-printed concrete eliminates the need for formwork, reducing material waste and allowing for greater geometric freedom in complex structures. With recent developments in mix design and 3D printing technology over the last decade, 3D concrete printing has grown exponentially since its emergence in the 1990s. Architectural and structural applications of 3D-printed concrete include the production of building blocks, building modules, street furniture, pedestrian bridges, and low-rise residential structures.
Bubbles do not cover entire surface
Bubbles cover entire surface
