4 manufacture of bricks from clay contd contd firing

Unformatted text preview: ring of Bricks: Bricks are burnt either in a periodic kiln or a continuous tunnel kiln - In a periodic kiln bricks are loaded in after initial drying, fired, cooled, and In unloaded; and the process is repeated after a certain period (say a month) - In a continuous tunnel kiln the bricks are loaded onto special railcars that pass continuous continuously through various processes to emerge at the other end fully burned continuously Stages of burning: Water-smoking and dehydration (drives off the remaining water from clay at 40o to 150o C) - Oxidation and Vitrification: Temperature of water Oxidation furnace rises to 1000o to 1300o C - Clay transformed to a ceramic material furnace Flashing: Fire is regulated to create a reducing atmosphere in the kiln that develops Flashing a color variation in the bricks - Cooling: Bricks are cooled under controlled Cooling: Bricks conditions to achieve the desired color and to avoid any thermal cracking - The entire process of firing takes from 40 to 150 hours Color of a brick: Depends on the chemical composition of clay, temperature, and chemistry of fire - Iron in clay turns to red in oxidizing fire and to purple in reducing fire - Calcium oxides gives creamy/white color - For bright colors, all faces of bricks can be glazed like pottery during normal firing or during subsequent firing can Brick Masonry - Sizes and Shapes No standard size Normal coursing - 3 bricks = 8” Larger sizes Custom Shapes & Colors 26 9.5 SIZES, GRADES AND TYPES OF BRICKS No single standard size available - Size varies Modular Brick: 3 1/2” x 7 1/2” x 2 1/4” (Actual size) Standard Brick : 3 1/2” x 8” x 2 1/4” Engineer Modular : 3 1/2” x 7 1/2” x 2 3/4” Engineer Standard : 3 1/2” x 8” x 2 3/4” Close Modular : 3 1/2” x 7 1/2” x 3 1/4” Roman : 3 1/2” x 11 1/2” x 1 5/8” Norman : 3 1/2” x 11 1/2” x 1 5/8” Brick may be solid, cored, hollow or frogged - This allows even drying of Brick solid, bricks bricks Custom-shaped bricks are often required for building for providing special details details 9.5 SIZES, GRADES A...
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