Title NOTES BCEM (U-1).pdf ✅

RUNGTA COLLEGE OF ENGINEERING AND TECHNOLOGY, BHILAI Department of Civil Engineering 2 CIVIL DARSHAN  Factors depend for colours- 1. Natural colour of clay and its chemical composition. 2. Natural colour of sand during moulding. 3. Temperature during burning & type of fuel used for burning. 4. State of dryness before burning. S. no. Colour Responsible Constituents 1 Red Iron 2 Dark blue/ purple Large portion of iron oxide burning at high temperature 3 Yellow or orange Magnesia and iron 4 Brown Excess in lime 5 Black Manganese and large proportion of iron  Qualities of a good brick- 1. Bricks should be table moulded with sharp edges and corners, free from surface crack. 2. It should be uniform in shape and standard size. 3. It should be well burnt in kiln so as to give uniform bright red colour. 4. It should give clear ringing sound when stuck against each other. 5. The surface should be hard enough so that there will be no impression left when scratched with a finger nail. 6. Brick when broken should show homogeneous and compact structure. 7. Brick should not absorb water more than 15% of its dry weight, when immersed in water for 24 hrs. 8. Brick soaked in water for 24 hrs shold not show deposits of white salt on drying in shade. 9. No bricks should have crushing strength less than 5.5 N/mm2 . 10. The brick should not break into pieces when dropped on hard ground from a height of about one meter. 11. Bricks should have low thermal conductivity and should be sound proof.  Quality of good brick depend on following factors – 1. Chemical Composition of clay 2. Preparation of clay.
RUNGTA COLLEGE OF ENGINEERING AND TECHNOLOGY, BHILAI Department of Civil Engineering 3 CIVIL DARSHAN 3. Method of moulding, drying and burning.  Brick frogs - Frog is a depression on the top face of a brick, which usually contain a brick manufacturer's stamp. Uses- 1. Frog is a key created to be filled up by mortar during laying and will impart the bond strength to the brick work. 2. It also shows the manufacturer company name. Brick frog size (100 x 40 x 10-20)mm  Composition (or ingredients of good brick earth)- S.no. Ingredients Percentage (%) Benefit (= %) Excess (> %) 1 Silica 50-60 1. Prevents cracking, shrinkage,warping of raw bricks 2. Uniform shape to bricks 3. Provide hardness, resistance to heat and durability 1. It destroys cohesion between particles and bricks become brittle. 2 Alumina 20-30 1. It is plastic in nature when wet and it helps to mould in any shape and on drying it looses its plasticity and becomes hard. 1. If it is excess with inadequate quantity of sand, raw bricks shrinks,cracks and warps during drying and becomes too hard when burned. 3 Lime 2-5 1. It reduces shrinkage on drying. 2. It act as a flux during burning, enabling silica particles to melt & thus 1. It cause vitrification of bricks, it cause bricks to melt, as more amount of silica will fuse. The bricks lose their shape.
RUNGTA COLLEGE OF ENGINEERING AND TECHNOLOGY, BHILAI Department of Civil Engineering 4 CIVIL DARSHAN binding the brick particles together. 4 Oxide of iron 5-7 1. Same as lime and gives hardness and strength. 2. It increases durability and impermeability of bricks. 1. Red oxide gets converted into black oxide during burning, which on combining with silica provides dark brown or dark blue colour which is not good. 5 Magnesia <1 1. It imparts yellow tint and decreases shrinkage. 1. It causes brick to decay.  Harmfull constituents of brick earth- 1. Pebbles of gravel and stone 2. Vegetation and organic matter 3. Alkalies 4. Lime stone and kankar 5. Iron pyrite 6. Reh or Kallar & carbonaceous matter  Manufacturing of Bricks- 1. Preparation of brick earth 2. Moulding of bricks 3. Drying of moulded bricks 4. Burning of dried bricks 1. Preparation of brick earth- 1. Unsoiling- Scraping top layer of soil about 150-250 mm depth, because it contain impurities. 2. Digging- After unsoiling, the brick earth is then dug upto 0.6-1.2 m. 3. Cleaning and powdering- Then brick earth is cleaned of stones, pebbles, kankar and the excavated lumps of soil are broken to reduce them in powdered form. 4. Weathering- The process of softening of dug out clay by little water and exposing it to the atmosphere is known as weathering. It improves plasticity and strength of the bricks. 5. Blending- It is then mix with sandy soil and other deficient content and then mix thoroughly. 6. Tempering- The process of kneading brick earth by water to get homogeneous mass and plasticity.