My Engineering

Brick Work

Normally the bricks are tested for Compressive strength, water absorption, dimensional tolerances and efflorescence. However at small construction sites the quality of bricks can be assessed based on following, which is prevalent in many sites.
• Visual check - Bricks should be well burnt and of uniform size and color.
• Striking pf two bricks together should produce a metallic ringing sound.
• It should have surface so hard that can’t be scratched by the fingernails.
• A good brick should not break if dropped in standing position from one metre above ground level.
• A good brick shouldn’t absorb moisture of more than 15-20% by weight, when soaked in water For example, a good brick of 2 kg shouldn’t weigh more than 2.3 to 2.4 kg if immersed in water for 24 hours.

53 grade Cement?

The Bureau of Indian Standards (BIS) has classified Cement in three different grades The classification is mainly based on the compressive strength of cement-sand mortar cubes of face area 50 cm2 composed of 1 part of cement to 3 parts of standard sand by weight with a water-cement ratio arrived at by a specified procedure. The grades are
(i)33 grade
(ii)43 grade
(iii)53 grade
The grade number indicates the minimum compressive strength of cement sand mortar in N/mm2 at 28 days, as tested by above mentioned procedure.
The strength of cement is expressed in terms of pressure a standard cube can withstand. The Ordinary Portland Cement, commonly called OPC is available in three grades namely 33, 43 & 53 grades. Thus, for a 43 grade cement a standard cement & sand mortar cube would give a minimum strength of 43 MPa when tested under standard curing conditions for 28 days.

Steel Reinforcement?

Steel reinforcements are used, generally, in the form of bars of circular cross section in concrete structure. They are like a skeleton in human body. Plain concrete without steel or any other reinforcement is strong in compression but weak in tension. Steel is one of the best forms of reinforcements, to take care of those stresses and to strengthen concrete to bear all kinds of loads.
Mild steel bars and Cold-worked steel high strength deformed bars are commonly used. Grade Fe 415 is being used most commonly nowadays. This has limited the use of plain mild steel bars because of higher yield stress and bond strength resulting in saving of steel quantity.

Some companies have brought thermo mechanically treated (TMT) and corrosion resistant steel (CRS) bars with added features.

Bars range in diameter from 6 to 50 mm. Cold-worked steel high strength deformed bars start from 8 mm diameter. For general house constructions, bars of diameter 6 to 20 mm are used.

Tyres are in black colour?????

Reasons is presence of carbon black

Tyres are black due to carbon black Carbon black is added because the polymer of tyres react with the UV rays and Sunlight and degrade very fast, so to prevent degradation, manufactures add carbon black so it will react with UV rays and heat is generated and easily dissipated. So after long use the tyres become grey, due to the reaction with carbon black and wasting of carbon black.

In 20’s tyres are in white colur as in the link below
http://www.autogallery.org.ru/k/o/04olds…

Uses:
Increases the strength of tyres
Resistant towards ultra violet rays by converting U.V. radiations into heat.
withstand the friction n stress of the road
helps to maintain the pressure inside the tyre
improves the puncture strength and tread wear resistance to rubber.