摘要:
A presente invenção trata do uso mais eficiente de concretos a fim de mitigar as emissões de CO2 na cadeia do concreto/cimento. A presente invenção revela uma mistura de finos, compreendendo um cimento Portland e um primeiro fíler ou um segundo fíler ou uma mistura dos mesmos. O cimento Portland compreende uma fração de 50 a 90% da mistura, sendo preferencialmente de 60 a 80%, sendo de forma ainda mais preferível, a fração de 65 a 75% de cimento Portland na mistura. Um ou ambos os fíleres compreendem uma fração de 10 a 50% da mistura, sendo preferencialmente a referida fração de 20% a 40%, sendo de forma ainda mais preferível, a fração de 25% a 35% de um ou ambos os fíleres na mistura. O fíler da presente invenção é um material inorgânico proveniente da moagem de sua matéria prima ou obtido por classificação granulométrica da sua matéria prima. O primeiro fíler possui uma área superficial BET menor ou igual a 6 m 2 /g e possui distribuição granulométrica com área média definida pela faixa de 4µm 2 /g e uma distribuição granulométrica de área média de 6µm
摘要:
There is provided a cement composition, comprising: a portland cement (comprising a clinker; limestone; and gypsum); a layered double hydroxide; and, optionally, an additional amount of powdered limestone and/or gypsum, where the portland cement composition and the additional amount of powdered limestone and/or gypsum, when present, are taken as 100 wt%, wherein the total amount of limestone in the composition is from 3.0 to 20.0 wt%; total amount of gypsum in the composition is from 4.0 to 8.0 wt%; and amount of the layered double hydroxide in the composition is from 0.35 to 6.0 wt%, relative to the 100 wt% of the portland cement composition and, when present, the additional amount of powdered limestone and/or gypsum.
摘要:
A concrete mix for producing freeze-thaw durable concrete having enhanced strength properties, like compressive strength, abrasion resistance, impact strength, toughness, is disclosed. The novel concrete mix contains deformable solid elements in place of 4-8% entrained air for good durability of concrete under freeze-thaw cycles.
摘要:
New methods for synthesizing boron-modified silazanes, their use as polymer-derived ceramic precursors, and polymer-derived ceramics and composites formed therefrom are disclosed. The polymeric ceramic precursors comprise a boron-modified silazane that is a room temperature liquid-phase polymer comprising a backbone having recurring monomeric repeat units comprising boron-nitrogen bonds. Nanocomposites comprising polymer-derived ceramics and carbon nanotubes are also disclosed.
摘要:
The present invention is of a cementitious composition containing Ordinary Portland Cement (OPC), calcined gypsum, a source of amorphous silica and a source of amorphous alumina. The ratio of calcium sulfate hemihydrate to OPC is 0.7:1.0 to 1.8:1.0, the ratio of amorphous silica and amorphous alumina to OPC is 0.26:1.0 to 0.4:1.0, and the ratio of amorphous alumina to amorphous silica is 0.3:1.0 to 1.5:1.0. The cementitious composition, by itself and mixed with aggregates, is fast-setting and exhibits good early compressive strength and very high compressive strength after hydration. Despite the high content of calcium sulfate relative to prior art OPC formulations, the cementitious composition according to the present invention is essentially waterproof and exhibits excellent strength characteristics, even after 2 years under water. The use of calcined gypsum in place of alumina cement or even OPC is of great economic advantage, and in addition, provides the cementitious composition with quick-setting characteristics. Soluble anhydrite can replace some or all of the calcined gypsum.
摘要:
A carbon black for coloring cement which has been surface-treated with an aqueous solution containing humic acid dissolved therein and which has humic acid adsorbed thereon, preferably a carbon black having humic acid adsorbed thereon which is prepared by wet granulating a carbon black powder using an aqueous solution containing humic acid dissolved therein as a granulation water, followed by drying; and a method for coloring a molded article of cement using the carbon black which comprises adding an aqueous suspension of a carbon black having humic acid adsorbed thereon to a cement slurry, followed by mixing, or adding a carbon black having humic acid adsorbed thereon directly to a cement slurry, followed by mixing. The carbon black for coloring cement is excellent in dispersibility into a cement slurry and has high adhesiveness to a cement matrix, and also is excellent in coloring properties and strength properties of the resulting cement article.
摘要:
In order to obtain maximum shielding from heat and radiation, a radiation protective casing (2) is provided with a wall area (2a-2z) that is made of radiation protective concrete (22a-22z) that includes a first aggregate containing boron with a particle size of up to 1 mm, in addition to a second metal aggregate with a particle size of up to 7 mm. In a first embodiment, the amount of the first aggregate containing boron included in the radiation protective concrete is at least 5.0 wt. % and more particularly at least 7.8 %. In a second embodiment, the proportion of the second metal aggregate in the radiation protective concrete (22b) is 80-90 wt. %, more particularly 85-90 %. In the gap, the proportion of the first aggregate containing boron can range from 1.0 to1.5 wt. %.
摘要:
A corrosion-inhibiting composition for application to a metal substrate, such as steel, silver, copper or aluminum, includes a film-forming organic polymer component and a dispersed pigment phase of a stable unitary hybrid which contains organic and inorganic solid phase constituents interfaced at a micro-crystalline level, which are inseparable by physical separation procedures and which display uniphase behavior. The inorganic phase includes a cation selected from Zn, Al, Mg, Ca, Sr, Ti, Zr, Ce and Fe and an anion selected from phosphates, polyphosphates, phosphites, molybdates, silicates and cyanamides. The organic phase includes zinc or alkyl-ammonium (for example: cyclohexyl-ammonium, di-cyclohexyl-ammonium, octyl-ammonium) salts of organic mercapto- and thio- compounds or their alkyl-substituted derivatives, as follows: mercaptobenzothiazole, mercaptothiazoline, mercaptobenzimidazole, mercaptoimidazole, 2,5-dimercapto-1,3,4-thiodiazole, 5,5-dithio-bis(1,3,4-thiadiazole-2(3H)-thione, mercaptobenzoxazole, mercaptothiazole, mercaptotriazole, mercaptopyrimidine, mercaptopyridine, mercaptoquinoline, alkyl- and cyclo-alkyl mercaptanes, -alkyl- or N-cycloalkyl-dithiocarbamates, O-alkyl- or O-cycloalkyl-dithiocarbonates, O,O-dialkyl- and O,O-dicycloalkyl-dithiophosphates.