Category: Traditional Materials

Category: Traditional Materials Uses of Timber

Timber is used for the following works: 1. For heavy construction works like columns, trusses, piles. 2. For light construction works like doors, windows, flooring and roofing. 3. For other permanent works like for railway sleepers, fencing poles, electric poles and gates. 4. For temporary works in construction like scaffolding, centering, shoring and strutting, packing of materials. 5. For decorative

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Category: Traditional Materials Preservation of Timber

Preservation of timber means protecting timber from fungi and insects attack so that its life is increased. Timber is to be seasoned well before application of preservatives. The following are the widely used preservatives: 1. Tar 2. Paints 3. Chemical salt 4. Creosote 5. ASCO 1. Tar Hot coal tar is applied to timber with brush. The coating of tar

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Category: Traditional Materials Defects in Timber

Various defects which are likely to occur in timber may be grouped into the following three: (i) Due to natural forces (ii) Due to defective seasoning and conversions. (iii) Due to attack by fungi and insects. (i) Defects due to Natural Forces: The following defects are caused by natural forces: (a) Knots (b) Shakes (c) Wind cracks (d) Upsets (a)

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Category: Traditional Materials Seasoning of Timber

This is a process by which moisture content in a freshly cut tree is reduced to a suitable level. By doing so the durability of timber is increased. The various methods of seasoning used may be classified into: (i) Natural seasoning (ii) Artificial seasoning. (i) Natural Seasoning: It may be air seasoning or water seasoning. Air seasoning is carried out

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Category: Traditional Materials Properties of Timber

Properties of good timbers are: Colour: It should be uniform. Odour: It should be pleasant when cut freshly. Soundness: A clear ringing sound when struck indicates the timber is good. Texture: Texture of good timber is fine and even. Grains: In good timber grains are close. Density: Higher the density stronger is the timber. Hardness: Harder timbers are strong and

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Category: Traditional Materials Classification of Timber

Various bases are considered for the classification of timbers. The following are the important basis: (i) Mode of growth (ii) Modulus of elasticity (iii) Durability (iv) Grading (v) Availability. (i) Classification Based on Mode of Growth: On the basis of mode of growth trees are classified as (a) Exogeneous and (b) Endogeneous (a) Exogeneous Trees: These trees grow outward by adding distinct

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Category: Traditional Materials Timber

Timber refers to wood used for construction works. In fact the word timber is derived from an old English word ‘Timbrian’ which means ‘to build’. A tree that yields good wood for construction is called ‘Standing Timber.’ After felling a tree, its branches are cut and its stem is roughly converted into pieces of suitable length, so that it can be transported to

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Category: Traditional Materials Uses of Cement

Cement is used widely for the construction of various structures. Some of them are listed below: (i) Cement slurry is used for filling cracks in concrete structures. (ii) Cement mortar is used for masonry work, plastering and pointing. (iii) Cement concrete is used for the construction of various structures like buildings, bridges. water tanks, tunnels, docks, harhours etc. (iv) Cement is

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Category: Traditional Materials Physical Tests on Cement

(a) Soundness Test: It is conducted by sieve analysis. 100 gms of cement is taken and sieved through IS sieve No. 9 for fifteen minutes. Residue on the sieve is weighed. This should not exceed 10 per cent by weight of sample taken. (b) Setting Time: Initial setting time and final setting time are the two important physical properties of cement. Initial setting

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Category: Traditional Materials Properties of Ordinary Portland Cement

(i) Chemical properties Portland cement consists of the following chemical compounds: (a) Tricalcium silicate 3 CaO.SiO2 (C3S) 40% (b) Dicalcium silicate 2CaO.SiO2 (C2S) 30% (c) Tricalcium aluminate 3CaO.Al2O3 (C3A) 11% (d) Tetracalcium aluminate 4CaO.Al2O3.Fe2O3 (C3AF) 11% There may be small quantities of impurifies present such as calcium oxide (CaO) and magnesium oxide (MgO). When water is added to cement, C3A is

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