แสดงบทความที่มีป้ายกำกับ Silicon Nitride Produc แสดงบทความทั้งหมด
แสดงบทความที่มีป้ายกำกับ Silicon Nitride Produc แสดงบทความทั้งหมด

วันพุธที่ 10 เมษายน พ.ศ. 2556

Types of modern cement


Portland cement blends

Portland cement blends are often available as inter-ground mixtures from cement producers, but similar formulations are often also mixed from the ground components at the concrete mixing plant.[35] Portland blastfurnace cement contains up to 70% ground granulated blast furnace slag, with the rest Portland clinker and a little gypsum. All compositions produce high ultimate strength, but as slag content is increased, early strength is reduced, while sulfate resistance increases and heat evolution diminishes. Used as an economic alternative to Portland sulfate-resisting and low-heat cements.Portland flyash cement contains up to 35% fly ash. The fly ash is pozzolanic, so that ultimate strength is maintained. Because fly ash addition allows a lower concrete water content, early strength can also be maintained. Where good quality cheap fly ash is available, this can be an economic alternative to ordinary Portland cement Portland pozzolan cement includes fly ash cement, since fly ash is a pozzolan, but also includes cements made from other natural or artificial pozzolans. In countries where volcanic ashes are available (e.g. Italy, Chile, Mexico, the Philippines) these cements are often the most common form in use.. High Temperature Insulation  Portland silica fume cement. Addition of silica fume can yield exceptionally high strengths, and cements containing 5–20% silica fume are occasionally produced.

However, silica fume is more usually added to Portland cement at the concrete mixer. Masonry cements are used for preparing bricklaying mortars and stuccos, and must not be used in concrete. They are usually complex proprietary formulations containing Portland clinker and a number of other ingredients that may include limestone, hydrated lime, air entrainers, retarders, waterproofers and coloring agents. They are formulated to yield workable mortars that allow rapid and consistent masonry work. Subtle variations of Masonry cement in the US are Plastic Cements and Stucco Cements. These are designed to produce controlled bond with masonry blocks. Expansive cements contain, in addition to Portland clinker, expansive clinkers (usually sulfoaluminate clinkers), and are designed to offset the effects of drying shrinkage that is normally encountered with hydraulic cements. This allows large floor slabs (up to 60 m square) to be prepared without contraction joints. White blended cements may be made using white clinker and white supplementary materials such as high-purity metakaolin. Colored cements are used for decorative purposes.
High Temperature Cement

In some standards, the addition of pigments to produce "colored Portland cement" is allowed. In other standards (e.g. ASTM), pigments are not allowed constituents of Portland cement, and colored cements are sold as "blended hydraulic cements". Very finely ground cements are made from mixtures of cement with sand or with slag or other pozzolan type minerals that are extremely finely ground together. Such cements can have the same physical characteristics as normal cement but with 50% less cement particularly due to their increased surface area for the chemical reaction. Even with intensive grinding they can use up to 50% less energy to fabricate than ordinary Portland cements.

วันพฤหัสบดีที่ 21 มีนาคม พ.ศ. 2556

What Is Mastic Adhesive?



Ceramic tile adhesive is mainly available in two forms: mastic and thin set. Mastic adhesive is a premixed adhesive that can be directly applied, while thin set is a powder that must be mixed and left to sit for several minutes before using. The premixed adhesive is applied in areas where moisture will not be an issue, such as backsplashes in kitchens or wall tile. Thin set is applied in bathrooms because it is moisture-resistant. It is not typically used on walls because it takes longer to bond.
Mastic is only suitable for ceramic tile because other types, such as porcelain or marble, are porous. Over time, the adhesive could seep into the tiles and cause them to discolor. Ceramic tile is often used on walls in restaurants and homes. Mastic works well in these applications because it creates an extremely tight bond with the wall. It also sets quickly, which is an advantage when working with vertical designs because the need to stand and hold each tile while it dries is greatly reduced. High Temperature Adhesive

What Is Mastic Adhesive?



Mastic adhesive is made from the sticky resin of the mastic tree, which grows in the Mediterranean. Because of its sticky nature, it is used as a bonding agent in many commercial applications. Some types include construction adhesive, industrial adhesive, and ceramic tileadhesive. Depending on the application, the adhesive is available in thin liquid, thick glue, or paste form.
When used in construction, mastic adhesive is typically in liquid form and applied with a caulking gun. The adhesive is squeezed out by hand in a thin line along wall or ceiling joints. The strength of the adhesive helps hold load-bearing walls in place. In ceilings, the quick-setting adhesive eliminates the need to support heavy drywall for extended periods of time. Construction adhesive is also used as a temporary hold for fixtures so they can be nailed or screwed in place by one person.
Industrial uses for this adhesive include repairing duct work in the heating and air industry. This is due to its heat resistant properties and the ability to seal and form and a strong bond. The adhesive also bonds with most any material, so repairs to concrete, brick, or mortar are also possible. The adhesive for industrial uses comes in a finely ground powder that is mixed to form a paste. It is smeared onto the repair area and allowed to dry.

วันพุธที่ 18 กรกฎาคม พ.ศ. 2555

Masonry heater


          A masonry heater (or masonary stove, ceramic stove, tile stove) is a device for warming an interior space by capturing the heat from periodic burning of fuel (usually wood), and then radiating the heat at a fairly constant temperature for a long period . The technology has existed in different forms: from the Roman hypocaust to the Austrian/German kachelofen. The hypocaust is a system for heating the floors and walls of buildings (especiallybaths) using the smoke and exhaust of a single fire. In Eastern and Northern Europe and North Asia, these kachelofens (or steinofens) evolved in many different forms and names: for example the Russian Stove/Fireplace (Russian: Русская печь), the Finnish Stove (in Finnish: pystyuuni or kaakeliuuni, "tile oven") and the Swedish Stove (in Swedish: kakelugn, "tile stove" or "contra-flow stove") associated with Carl Johan Cronstedt. The Chinese developed the same principle into their Kang bed-stove. The masonry heater has gained renewed domestic popularity recently because of its heating efficiency.


Thank for Info : http://en.wikipedia.org

Porcelain tile


          Porcelain tiles are ceramic tiles with a water absorption rate of less than 0.5 percent that are used to cover floors and walls. They can either be unglazed or glazed.
          The hardness of the tile is rated from zero to five according to the ASTM C1027 (or ISO 10545-7) test for surface abrasion resistance of glazed tile. This rating, (sometimes mistakenly called the PEI rating) determines the tiles suitability for various end use conditions.
          Large-scale production of porcelain tile is undertaken in many countries, with the major producers being China, Italy, Spain and Turkey. There are also countries undertaking small-scale production, such as Australia and strong growth in developing countries such as Brazil.
         Porcelain Tile is also a very common trend in tile installation. There are many different styles of porcelain tiles on the market and they have proved to outperform ceramic tile in durability and looks.
          It is important to note that the differences of the body of the porcelain tile, as it relates to ceramic tile, has caused many "job failures" of tile installations. Tile setters that are self trained and novices to the industry will often use cements or mastic to install the impervious body of the porcelain tile to a substrate only to have delamination occur rather quickly. Highly Modified cements are necessary for installation of this material due to the very qualities that make it such a durable long lasting decorative surface. Those specifications are determined by and dictated as industry standards by the Tile Council of America, and supported by the Tile Contractors Association.

Thank for Info : http://en.wikipedia.org

วันอาทิตย์ที่ 15 กรกฎาคม พ.ศ. 2555

High temperature insulation wool


          In the 1950s, the term “Refractory Ceramic Fibre” was coined for the aluminium silicate fibres developed at this time. On account of their chemical purity and resistance to high temperatures (classification temperature >1000 °C) as well as on the basis of their use in other applications, this definition was made to differentiate aluminium silicate wools from the conventional “mineral wools”. Because of the ambiguity of the term “ceramic” and the development of new materials for the high temperature range, the nomenclature was changed to High Temperature Insulation Wool (HTIW) at the end of the 1990s.
          Basically, there are two types of inorganic HTIW. In addition to the more commonly used amorphous HTIW (Alumino Silicate Wool ASW/RCF and Alkaline Earth Silicate Wool (AES)), Polycrystalline Wool (PCW) is also available. Owing to the costly production and limited availability compared to mineral wool, HTIW products are almost only used in industrial applications and processes up to 1800 °C.

Thank for Info : http://en.wikipedia.org