reaction. the pozzolanic reaction is the chemical reaction that occurs in portland cement upon the addition of pozzolans.it is the main reaction involved in the roman concrete invented in ancient rome and used to build, for example, the pantheon.the pozzolanic reaction converts a silica-rich precursor with no cementing properties, to a calcium silicate, with good cementing properties.
solid mechanics extensively uses tensors to describe stresses, strains, and the relationship between them. solid mechanics is a vast subject because of the wide range of solid materials available, such as steel, wood, concrete, biological materials, textiles, geological materials, and plastics.
pharmaceutical formulation, in pharmaceutics, is the process in which different chemical substances, including the active drug, are combined to produce a final medicinal product. the word formulation is often used in a way that includes dosage form . formulation studies involve developing a preparation of the drug which is both stable and .
concrete degradation may have various causes.concrete can be damaged by fire, aggregate expansion, sea water effects, bacterial corrosion, calcium leaching, physical damage and chemical damage from carbonatation, chlorides, sulfates and non-distilled water .this process adversely affects concrete exposed to these damaging stimuli.
superplasticizers sp's , also known as high range water reducers, are additives used in making high strength concrete. plasticizers are chemical compounds that enable the production of concrete with ca. 15% less water content. superplasticizers allow reduction in water content by 30% or more. these additives are employed at the level of a few weight percent.
superplasticizers sp's , also known as high range water reducers, are additives used in making high strength concrete.plasticizers are chemical compounds that enable the production of concrete with ca. 15% less water content. superplasticizers allow reduction in water content by 30% or more.
this article is about pouring concrete in moving forms. see slipform stonemasonry for another type of slip forming, and slipcasting for manufacture of ceramic vessels.. slip forming, continuous poured, continuously formed, or slipform construction is a construction method in which concrete is poured into a continuously moving form. slip forming is used for tall structures such as bridges .
hydrophobic concrete is produced in a variety of ways that fall under two categories; coatings or admixtures. both allow the crystal structures to form in the presence of water. when creating hydrophobic concrete through a coating process, a coating is sprayed or brushed onto a porous surfaces. in most cases, it is applied to a regular concrete .
ultra-high-performance concrete. ultra-high-performance concrete is a new type of concrete that is being developed by agencies concerned with infrastructure protection. uhpc is characterized by being a steel fibre-reinforced cement composite material with compressive strengths in excess of 150 mpa, up to and possibly exceeding 250 mpa.
a developing country or a low and middle income country lmic , less developed country, less economically developed country ledc , or underdeveloped country is a country with a less developed industrial base and a low human development index hdi relative to other countries. however, this definition is not universally agreed upon. there is also no clear agreement on which countries fit .
lunarcrete, also known as 'mooncrete', an idea first proposed by larry a. beyer of the university of pittsburgh in 1985, is a hypothetical aggregate building material, similar to concrete, formed from lunar regolith, that would reduce the construction costs of building on the moon.
polymer concrete is a type of concrete that uses polymer to replace lime-type cements as a binder.in some cases the polymer is used in addition to portland cement to form polymer cement concrete pcc or polymer modified concrete pmc . polymers in concrete have been overseen by committee 548 of the american concrete institute since 1971.
asphalt concrete is recyclable and is the most widely reused construction material in the world. very little asphalt concrete — less than 1 percent, according to a survey by the federal highway administration and the national asphalt pavement association conducted annually since 2009 — is actually disposed of in landfills.
the term '3d printing' originally referred to a process that deposits a binder material onto a powder bed with inkjet printer heads layer by layer. more recently, the popular vernacular has started using the term to encompass a wider variety of additive-manufacturing techniques such as electron-beam additive manufacturing and selective laser .
there are a variety of 3d printing methods used at construction scale, with the main ones being extrusion concrete/cement, wax, foam, polymers , powder bonding polymer bond, reactive bond, sintering , and additive welding. 3d printing at a construction scale will have a wide variety of applications within the private, commercial, industrial and public sectors.
concrete dust released by building demolition and natural disasters can be a major source of dangerous air pollution. the presence of some substances in concrete, including useful and unwanted additives, can cause health concerns due to toxicity and usually naturally occurring radioactivity.