Masonry

Concrete additives Concrete and masonry Concrete mixes Concretes... 

Mashing-in Mashing-off Masking of odors Masks Masonite Mason number Masonry... 

N. Dobbs and co-workers, "Design of Steel, Masonry and Precast Concrete Stmctures to Resist the Effects of HE Explosions" in 17th Annual Dept, of Defense Explosive Safety Seminar,NT S, Springfield, Va., 1976. 

Urea—Formaldehyde and Urea-Based. In the 1970s and early 1980s, urea materials were in general use particularly for direct field retrofitting of cavity wall constmction of wood frame and masonry. However, because of formaldehyde odor and excess shrinkage under specific conditions, this ceUular plastic has limited use as an insulation. 

Mason s lime is a hydrated lime used in mortar for masonry purposes. 

A second form of limestone is finely pulverized limestone for masonry cement. This form is achieved by intergrinding roughly equal parts of limestone and cement clinker in a bad mill to which an air-entraining agent is added. 

Any of these mortars can be used for unit masonry or for stucco (exterior plaster). The finish coat in conventional interior plastering is composed of either neat time putty or a sanded putty, gauged with Keene s cement or gypsum-gauging plaster. The former is called a whitecoat finish the latter a sandfloat finish. 

Sealers. Mica is used in all types of sealers for porous surfaces, such as waHboard masonry, and concrete blocks, to reduce penetration and improve holdout (see Sealants). It permits a thicker film to be appHed and at the same time reduces sagging. Cracking is reduced by the reinforcing action of the flakes, and gaps and holes in rough masonry are bridged by the mica flakes. 

Acid cleaners based on sulfamic acid are used in a large variety of appHcations, eg, air-conditioning systems marine equipment, including salt water stills wells (water, oil, and gas) household equipment, eg, copper-ware, steam irons, humidifiers, dishwashers, toilet bowls, and brick and other masonry tartar removal of false teeth (50) dairy equipment, eg, pasteurizers, evaporators, preheaters, and storage tanks industrial boilers, condensers, heat exchangers, and preheaters food-processing equipment brewery equipment (see Beer) sugar evaporators and paper-mill equipment (see also Evaporation Metal surface treati nts Pulp). 

Water resistance is an important factor in concrete and masonry constmetion for the safety, health, and comfort of buUding occupants (see Cement). Several texts on concrete constmetion describe the methods for obtaining water resistance (72—76). The term waterproof describes concrete and masonry that is completely impervious to water and its vapor, whether or not the water is under pressure. Waterproof constmetion involves the use of some type of barrier that covers aU surface pores or capUlaries. Water repeUent describes concrete or masonry that repels water without significantly reduced permeabUity to water vapor. In this discussion, concrete and masonry are used synonymously. 

Barium carbonate prevents formation of scum and efflorescence in brick, tile, masonry cement, terra cotta, and sewer pipe by insolubilizing the soluble sulfates contained in many of the otherwise unsuitable clays. At the same time, it aids other deflocculants by precipitating calcium and magnesium as the carbonates. This reaction is relatively slow and normally requites several days to mature even when very fine powder is used. Consequentiy, often a barium carbonate emulsion in water is prepared with carbonic acid to further increase the solubiUty and speed the reaction. 

Masony cements are hydrauHc cements designed to have improved workabUity for use in mortar for masonry constmction. The standards are given in ASTMC91. 

Calcium Silicate Brick. Sand—lime brick is used ia masonry ia the same way as common clay brick. The bricks, molded from a wet mixture of sand and high calcium hydrated lime, are heated under pressure ia a steam atmosphere. Complex hydrosiUcates are formed that give the bricks high dimensional stabiUty (6). 

Most masonry cements are finely iaterground mixtures where Portland cement is a principal constituent. These cements also iaclude finely grouad limestones, hydrated lime, aatural cement, po22olans, clays, or air-entraining ageats. Secoadary materials are used to impart the required water reteatioa and plasticity to mortars. 

Masonry cements (80) are cements for use in mortars for masonry constmction. They are formulated to yield easily workable mortars and contain special additives that reduce the loss of water from the mortar to the porous masonry units. 

An appHcation where latex paints show outstanding performance is over masonry such as stucco or ciader block constmction. This performance results from saponification resistance ia the preseace of the alkaH from the cement. Furthermore because masoary surfaces are porous, having both small and large pores, the low viscosity external phase of a latex paint can penetrate rapidly iato the small pores, causiag a rapid iacrease ia the viscosity of the remaining paiat. The bulk paiat, ia turn, sinks iato the larger holes more slowly than a solution-based paint. Thus less latex paint is required to cover the same surface area as compared to alkyd paints. 

Metals, Alloys, Ores Timber, Air-diy Dry Rrrbble Masonry ... 

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