Portland cement/aggregate brick

The masonry units used in the pulp and paper industry include fireclay, shale, and carbon brick, structural glazed tile and Portland cement/aggregate brick. Structural glazed tile and Portland cement/aggregate brick are relatively unique to this industry and have not been widely used outside of it. 

The bricks are manufactured by combining the Portland cement, aggregate, and water in carefully controlled proportions. The bricks are then pressed and cured under controlled conditions to form a Portland cement brick which is excellent for lining use. 

Portland cement brick is being manufactured and used to line some pulp and paper mill vessels. These bricks are composed of Portland cement and a highly alkali resistant aggregate. The Portland cement brick presently available measures 19.37 cm (7.625 inches) by 22.86 cm (9 inches) by 6.35 cm (2.5 inches). The aggregate is specially selected for its alkaline resistance and is sized to produce a brick of optimum density. The density achieved in the currently available brick is 2.2-2.3 g/cc (138-145 Ib/ft ). The compressive strength of these brick is approximately 4,220-5,625 kg/cm (6,000-8,000 psi) with a cold water absorption of 4-6 weight percent. 

Cement plaster It is a mixture of suitable plaster, sand, Portland cement and water which is normally applied to masonry interiors and exteriors to achieve a smooth smface. Walls constructed with stock bricks are normally plastered while face brick walls are not plastered. Various cement-based plasters are also used as proprietary spray fireproofing products. These usually use vermiculite as lightweight aggregate. Heavy versions of such plasters are also in use for exterior fireproofing, to protect LPG vessels, pipe bridges and vessel skirts. 

In addition to the cement gel, there is present in concrete an aggregate of crushed stone that acts as a filler material. The Portland cement paste serves to bond together the aggregate particles in much the same way as a bond material present in a refractory brick or an abrasive wheel. 

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