Caution: You may end up paying more for 'pure' aggregates because aggregates are sold in volumes. So, a given volume of 'pure' aggregates will give you less weight because of larger voids between the chips.

Reinforcing Steel Reinforcing steel contributes to the tensile strength of concrete. Concrete has low tensile, but high compressive strength. The tensile deficiency is compensated by reinforcing the concrete mass through insertion of plain or twisted mild steel bars. Both branded and unbranded bars are available. It is wise to buy good brands, the names of which are marked on the steel. During construction, make sure that steel reinforcement is provided exactly as the engineering design specifies.

Precautions:
Steel bars/rods should be reasonably clean and free of rust
Bars that cannot be easily bent manually or mechanically should be rejected
Optimum length bars must be chosen to reduce wastage in cutting
To avoid laps, shorter bars must not be accepted
Welded lengths of bars should not be accepted.

Water It is very important to use clean, potable water in quality concrete production. Brackish or salty water must never be used. Contaminated water will produce concrete and mortars with lower durability, erratic set characteristics and inconsistent colour.

Bricks Bricks are distinguished by their base (raw) material and size. Standard burnt clay bricks come in the size 10" x 5" x 3". Modular bricks, rarely used because they are not easily available, come in the size 200 mm x 100 mm x 100 mm (including mortar thickness.) Fly ash bricks, sometimes, also come in modular form.

Conventional bricks have a 'frog' (depressed/raised portion) on one of the larger surfaces bearing the manufacturer's brand. These also provide a good mechanical key for bonding (i.e. lockability) with mortar. The modular bricks do not have the 'frog' on them. Fly ash bricks exhibit almost similar mechanical properties as burnt clay bricks. Exposed brickwork with precise pointing is possible if the shapes are perfect.

How do you recognize good bricks?

They show uniform texture and colour
When broken, they leave no lumps and grit

Precautions: Ensure that bricks are not made from saline clay. Look for proper and uniform burning.

The four broad categories of bricks used in construction:

1st Class Bricks
Perfect in size/shape Red to cherry-red in colour Do not break when dropped from waist height Do not absorb more than 15 to 17% of their own weight if kept submerged for 1 hour under water Suitable for precision work such as exposed brickwork