Rebar, or rebar, is the reinforcement used to strengthen and strengthen concrete under tension. It's usually made of steel, but fiberglass is popular for some projects because it won't corrode and is nonmagnetic.

The following are common uses for each rebar size:
#3 – This thin and cost-effective low-carbon rebar material adds strength to concrete roads, driveways or patios. It is also common in poured concrete swimming pools to provide shape and strength to the pool walls.
#4 — Thicker #4 bars are great for adding strength to highways and can add strength to columns and slabs.
#5 — This type of rebar is commonly used in bridges and highways.
#6 — Commonly found on foundations, retaining walls, roads or highways.
#7 – This rebar size provides support for structures such as multi-storey car parks and bridges.
#8 – #8 rebar is ideal for medium to heavy duty commercial applications. It can be used for slabs, seawalls, columns and beams.
#9 – This thick, durable material is the reinforcement of choice for high-rise building projects, seawalls and retaining walls.
#10 - Ideal for medium to heavy duty commercial use projects, this size provides structural support for beams, columns, etc.
#11 — This heavy steel bar is thick and strong, so it is often used in load-bearing structures.
#14 – One of the heaviest and thickest rebar in the standard size, the #14 rebar size is ideal for bridges, parking structures, high-rise buildings and piers.
#18 – This large, strong steel bar size is used in large buildings, industrial facilities, and other large constructions.

Steel grade
Knowing the difference between yield strength and tensile strength is necessary to assess what grade of rebar you need.

Think of yield strength and tensile strength as the minimum and maximum stress ranges for a particular rebar grade. Yield strength is the minimum stress a material can withstand before it begins to deform permanently. In contrast, tensile strength measures the maximum stress a material can sustain before it permanently damages and fractures.

Rebar grades are set by ASTM. The grade designation is equal to the minimum yield strength in kilopounds per square inch (KSI). Common grades are 40, 60, 75, 80 and 100. The designation of the grade represents the yield strength of the reinforcement. For example, grade 40 rebar has a minimum yield strength of 40 KSI, which equals 40,000 PSI, while grade 80 rebar has a minimum yield strength of 80 KSI, or 80,000 PSI.
Rebar is an essential material for reinforced concrete. Selecting the proper size, grade and type of rebar is critical to the success of any project. Proper and even spacing is also important.