Frost-resistant material

By its thermo-mechanical properties the aromatic polysulfone on the basis of bisphenylolpropane takes intermediate place between polycarbonate and polyarylate of the same bisphenol. The glassing temperature of the polysulfone lies in the ranges of 190-195 °C, heat resistance on vetch is 185 °C. The given polysulfone is devised to be used at temperatures below 150 °C and is frost-resistant material (-100 °C). 

The history of siloxane rubber manufacture is related to the search for materials combining high heat- and frost-resistance with good physical-chemical performance. 

INHAM-3 [131] contains up to 97 wt% PE and copper in the metal-polymer with the formula [—CH2—CH2—]nCum, dispersed rubber. Cl, unsaturated hydrocarbons of oil and PE copolymer with polyformaldehyde. This material shows high impact viscosity (see Table 4.13), resistance to thermooxidative aging (the strength does not impair upon thermal aging) and frost resistance (down to —70°C). 

Bender W, Handle F (1992) Frost Resistance of ceramic building materials. In ZI Jahrbuch, Bauverlag GmbH Wiesbaden und Berlin,... 

Main fields of application frost-resisting cables, aircraft car interior, flooring, films, paints, food wrap, pharmaceutical coatings, packaging materials, medical, synthetic leather ... 

The hardened material has also been reported to possess good frost resistance, a thermal stability up to 1200°C, and a high resistance to chemical attack, including attack by free sulfuric acid (Lu, 1986). 

The addition of microsilica generally improves the frost resistance of concrete. However, at higher microsiUca additions the reduced permeability of the material may hamper moisture migration, and may cause a build-up of internal hydraulic pressure and cracking. To prevent this the amount of added microsiUca must not be excessively high. The use of an air-entraining admixture may also be necessary, to provide an adequate air-void system. 

The recipes of compositional materials on modified PP bases was alabo-rated with the help of this method dispersefilled PP with improved technological qualities, electrical conductive materials, eleetrical eonductive materials with inereased frost resistance and improved pressing charaeteristies. 

Schurecht Ratio. A term that has been used for saturation coefficient (q.v.) named from H. G. Schurecht (USA) who introduced this coefficient in his research on frost-resistance of terra cotta carried out at the National Bureau of Standards in 1926 but never published the term Schurecht Ratio was first applied by J. W. McBurney. Scleroscope. An instrument for determining the relative hardness of materials by a rebound method. 

The pores may be separated or interconnected by channels or microcracks in the matrix and the overall pore fraction is an important material characteristic. However, more precise information may be needed, e.g. pore diameter distribution and average distance between pores are often required to evaluate the material s frost resistance see. Section 6.5.2. In addition, aggregate grains themselves contain pores. 

For high freezing and thawing resistance, a very dense structure of material is required with an appropriate system of pores obtained by application of air-entraining admixtures. Also aggregate grains should exhibit adequate frost resistance. 

All these standard procedures of testing give valuable but only approximate indications as to the actual frost resistance, verified on many structures in severe climatic conditions. Their practical importance is also related to a possibility of testing different concretes to obtain comparative results and thus to select the best material for the purpose. 

Asbestos cement materials are widely used due to their good mechanical properties, low thermal conductivity and resistance to weathering, frost and rotting. The slurry of asbestos and cement can also be processed directly using a spray process, as so-called asbestos spray for fire-retarding layers as well as for thermal (hot and cold) and sound insulation. 

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