aviratdhodare - Answers

APPEARANCE

• The stone to be used for facework must have uniform and pleasing color.
• It must be free from cavities, crack, flaws and patches of loose and soft materials.

STRENGTH

• A good bldg stone should have sufficient crushing strength to withstand the load of superstructure.
• It should ≮ 1000 kg/cm².

HARDNESS, TOUGHNESS AND RESISTANCE TO ABRASION

• The stone to be used in stone pavements, as railway ballast or road metal must be sufficiently hard, tough, resistance to abrasion.
• It must be able to resist wear and tear.

DURABILITY

• A good bldg stone must be durable enough to resist the effect of weathering against eg., rain, wing, temp, etc.
• It should have fine grained, compact, and crystalline structure.

TEXTURE

A good bldg stone should have a closed grained and compact texture.

WORKABILITY

The stone to be used for ornamental craving and architectural appearance should be easily and economically dressed.

SEASONING

The stone to be used for an imp interior work should be well seasoned. Presence of moisture makes the stone soft and it is liable to an early decay when used in structural work.

POROSITY

• A good bldg stone should be less porous.
• It should not absorb more than 5% of water.
• Any stone absorbing 10% of water should be rejected.

RESISTANCE TO FIRE

• A good bldg stone should be able to resist high temp.
• Its minerals constitutes should have equal coeff for expansion.

SPECIFIC GRAVITY

• The stone to be used on heavy engg works, docks, harbours, gravity dams, etc must have high specific gravity.
• Its varies from 2.4 – 2.8.

RESISTANCE TO ELECTRICITY

• A good bldg stone should be non-absorbent like marble and slate etc.
• It can offer good resistance to electricity.

Resection Method.

This method is used for establishing the instrument stations or after completing the traverse surveying the important object cannot be located due to difficulties & missed the station. PROCESS:-

1. Select the two stations P & Q on the ground & measure the length PQ & plot to a scale pq on a suitable scale.
2. Set the table at P , Centre, & level the table so that the point p is over the P.
3. Place the alidade along pq, orient the table by turning the board until the signal at Q is bisected, & then clamp it.
4. With the alidade touching at p sight the station R & draw a ray p to r.
5. Shift the table at R. & make the center & level & sight the point P by back sighting & clamp the table.
6. With the alidade centered on q, sight the station Q & draw a ray. The point of intersection of this ray & that previously drawn from p gives the reqd point r.

The cube test is the Remove the specimen from water after specified curing time and wipe out excess water from the surface. Place the specimen in the machine in such a manner that the load shall be applied to the opposite sides of thecube cast. Align the specimen centrally on the base plate of the machine.

Precautions for Tests The water for curing should be tested every 7 days and the temperature of the water must be at 27+-2oC. Procedure for Concrete Cube Test Remove the specimen from the water after specified curing time and wipe out excess water from the surface.

Cube Testing The cubes are generally tested at 7 & 28 days unless specific early tests are required, for example to remove a concrete shutter safely prior to 7 days. Usually 1 cube will be tested at 7 days and 2 cubes at 28 days, however this may vary depending of the requirements, check the design first.