Thermal repair materials

However, the repair material is subject to the same stresses as the concrete with regard to temperature variation. Ultimately, the repair will prove most durable if the repair material has a similar coefficient of thermal expansion as the original material. 

Thermal variations also may lead to differential deformation between the repair material and the concrete substrate, especially in large and thick patches. To limit the risk of loss of bond, the thermal expansion coefficients of the two materials should be similar. 

It can also be seen from Table 6.1 that the coefficients of thermal expansion/contraction of resin-based repair systems may be two or three times that of the substrate concrete. If the repair is carried out at, say, 10 °C then a rise in ambient temperature to 25 °C will potentially induce a compressive strain in the repair material of the... 

The performance of many non-portland cement-based repair materials is dependent on the chemistry and physics of the system, the properties of the existing concrete, and the enviromnent. Thermal analysis techniques are increasingly being used to investigate the physico-chemical behavior of non-portland cement binders exposed to aggressive enviromnents. 

When thermally dissimilar materials are bonded together, residual thermal stresses are developed that usually detract the remaining strength available for transmitting mechanical loads. These phenomena occur whenever titanium edge members are bonded around the edges of composite panels to permit the use of mechanical fasteners during final assembly of the structure or to permit disassembly in service for inspections and repairs. These thermal stresses... 

Ziac foil coated with a conductive, pressure-sensitive adhesive is used for repair of other ziac coatings or for imparting corrosion resistance at field sites. The 0.08-mm ziac tape or sheet has a 0.025-mm coaductive adhesive. The laminate is cut to size and pressed tightly to activate the adhesive. Conductive tape can be wrapped around pipe, especially around welds or connections. The corrosion resistance of this material is iatermediate between galvanized or thermally sprayed coatings and zinc-filled paints (21,50). 

Polymer resins were first introduced in the early 1940s as an aesthetic alternative to repair defects in anterior teeth. Some of the first resins were unfilled polymers of methyl methacrylate. Presently, these unfilled resins have been replaced by filled composite materials that limit the problems associated with polymerization volume shrinkage, abrasion or wear resistance, mechanical properties, water sorption, solubility, and thermal expansion. Polymeric composite materials generally consist of a monomer resin, a ceramic filler, a polymerization initiator or initiating system, and a coupling agent which binds the polymer... 

Repair the damaged area or remove the damaged material if repair is not possible. Maintain aU thermal system insulation ACM and its covering in an intact state and imdamaged condition. 

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