Construction sealant selection

Cure time is very important for sealants as well as adhesives. Often the sealant will be required to function as a barrier or resist the movement of substrates very soon after it is applied. With construction sealants, for example, it may not be possible to delay the environmental conditions until after the adhesive cures. Thus, curing time becomes a critical parameter in selection of the sealant. ASTM C 679 covers a method for determining the time that a mechanic can work the sealant into the joint before the sealant starts to skin or solidify. 

British Standards Institution, Guide to the Selection of Construction Sealants, BS 6213, BSI, London, 2000. 

The following is a description of the selection of the appropriate sealant, then proper joint design and installation for construction sealant/ caulk applications. 

Filter pack. Filter pack is the term used to describe the materials placed in the annular space between the screen and the formation (Figure 1). Aller et al. and Driscoll provide a discussion of the purpose and selection of filter pack materials. The filter pack serves a number of important mechanical functions. During well construction, it helps to keep the well screen centered in the borehole and acts to block the sealant from entering the well screen. The filter pack also improves hydraulic conductivity between the well screen and the formation, prevents formation materials from migrating to the well screen by acting as a filter, and helps support the screen and borehole. ... 

Abstract Single-chamber solid oxide fuel cells (SC-SOFCs) immerse the entire cell in a mixture of fuel and oxidizer gases within a single chamber, which eliminates the need for high temperature sealant, simplifies construction, and increases reliability over traditional double-chamber cells. However, there are challenges, such as low fuel utilization and electrode catalytic selectivity, that need to be overcome. This brief review paper looks at recent improvements in materials, processing, and operation of SC-SOFCs, which are rapidly approaching the performances of the double-chamber fuel cells and may become attractive for specific fuel cell applications. 

The annual cost of corrosion consists of direct costs and indirect costs. The direct costs related to corrosion consist of (i) costs of design, manufacturing, and construction (ii) material selection (iii) additional material such as increased wall thickness for corrosion allowance (iv) materials such as coatings, inhibitors, sealants, cathodic protection to prevent corrosion (v) application including cost of labor and equipment. 

The term primer is used to describe any liquid preparation used to modify the surface of an adherend. While there are some primerless systems, the sealants used in construction often require primers as the surface condition may be extremely variable (See Sealant joint design, Seaiants in doubie giazing and Selection of joint sealants). 

Performance of primers has been studied both in general construction and water-retaining structures.Further information may be found in articles on Selection of joint sealants. Sealant joint design, Paint primers and Primers for adhesive bonding. 

In determining the appropriateness of a sealant or caulk for an application, many factors need to be considered. The generic polymer technology, the physical form, sealant classification, specifications and performance properties are all important features of a sealant or caulk. Table 22 outlines some basic performance properties of the sealant types reviewed in this chapter. As seen in Table 22, most of these sealant types are utilized in construction applications. As described earlier in this chapter, sealants and caulks can be classified in low, medium, and high movement categories, and selection is primarily decided on the basis of movement capability, adhesion, life expectancy, and material cost. Table 23 reviews the typical applications for these types of sealants and caulks. 

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