Resistant Cements and Mortars

The industrial value of furfuryl alcohol is a consequence of its low viscosity, high reactivity, and the outstanding chemical, mechanical, and thermal properties of its polymers, corrosion resistance, nonburning, low smoke emission, and exceUent char formation. The reactivity profile of furfuryl alcohol and resins is such that final curing can take place at ambient temperature with strong acids or at elevated temperature with latent acids. Major markets for furfuryl alcohol resins include the production of cores and molds for casting metals, corrosion-resistant fiber-reinforced plastics (FRPs), binders for refractories and corrosion-resistant cements and mortars. 

Outlet through common wall permits trench to drain. Hanbrane continued through outlet and protected by sleeve set in acid-resistant cement and mortared to brick lining. 

The several manufacturers of chemical resistant mortars and cements publish extensive charts listing their products and various corrosive agents. Such charts indicate the degree of resistance of the cements and mortars. These manufacturers also publish details of corrosion resistant masonry construction. The technical representatives can be of help, however, the degree of expertise of these representatives varies widely from excellent to order taker so they are suspect until proven otherwise. 

Also to be considered are the specialty mortars derived from the acid-resistant cements. These mortars can be applied to steel or concrete to provide remarkable acid, alkali, and heat resistance. They may be reinforced with wire mesh to sustain the heavy thicknesses normally applied. Coefficients of expansion close to that of steel have been attained to resolve one of the major problems when applying inorganic materials on steel. These can be used as floors, tank interiors, in scrubbers, and other process equipment of clean interior design. 

Concrete, Mortar, and Plaster. Citric acid and citrate salts are used as admixtures in concrete, mortar, and plaster formulations to retard setting times and reduce the amount of water requited to make a workable mixture (172—180). The citrate ion slows the hydration of Portland cement and acts as a dispersant, reducing the viscosity of the system (181). At levels below 0.1%, citrates accelerate the setting rate while at 0.2—0.4% the set rate is retarded. High early strength and improved frost resistance have been reported when adding citrate to concrete, mortar, and plaster. 

Maximum chemical resistance of polyester mortars is obtained from cements made from isophthalic or biphenol resins. The biphenolic resins are preferred for alkaline and hypochlorite solutions. 

The reduction in porosity, decreased water content, and air entrainment that results when latexes are used in mortar and concrete mixes make them much more resistant to freezing and thawing conditions than conventional mortar and concrete. Figure 6.17 presents the freeze-thaw durability in water (-18 to 4°C) of combined water-and dry-cured SBR-, PAE- and EVA-modified mortars [98], The frost resistance of mortars made with these latexes is markedly improved even at polymer-cement ratios of 5%. However, an increase in the polymer-cement ratio does not necessarily produce further improvement in freeze-thaw resistance. EMM and EMC, when exposed to outdoor conditions involving freeze-thaw, UV radiation and carbonation show better weatherability when compared with conventional mortar and concrete. 

Acid resistant metals and alloys) pp 1534-36(Acid resistant carbon, graphite, cement, mortar, putty, ceramics and plastics)... 

Another version of Portland cement mortar or concrete is the replacement of some of the Portland cement with rice hull ash. This ash additive markedly improves the resistance of the mortar or concrete to food acids and similar chemicals. Flyash (pozzolanic admixture) meeting ASTM C618 has also been widely used to improve the properties and sulfate resistance of Portland cement... 

Use Wetting agent, furan polymers, corrosion-resistant sealants and cements, foundry cores, modified urea-formaldehyde polymers, penetrant, solvent for dyes and resins, flavoring. The polymer is used as a mortar for bonding acid-proof brick and chemical masonry. 

D. Btirchler, B. Elsener, H. Bohni, Electrical resistivity and dielectrical properties of hardened cement paste and mortar , in Corrosion of Rein-... 

J. A. Gonzales, Relation between resistivity and corrosion rate of reinforcements in carbonated mortar made with several cement types . Cement and Concrete Research, 1988, 8, 687. 

Figure 16.11 Dependence of resistivity of cement paste and mortar on water/cement ratio and relative humidity of the environment [20]...

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