Additives: Reinforcement is the main additive and there are also some fibers, and micro rebar which can increase the weight of the concrete.
Wire Mesh: Generally, wire mesh is provided in the slabs which can increase the weight of the slab.
Rebar: Any structural components contain rebar like shear walls, columns, beams, etc. It acts as the major weight inducer material in the concrete. The size of the rebar depends on the structural analysis calculation. It basically adds near about half a ton or more than the weight of a concrete wall.
Weight of concrete = Volume of concrete x Density of concrete
The volume of concrete can be calculated by multiplying the length, width, and height of the concrete. Once you have the volume, you can multiply it by the density of the concrete to get the weight.
For example, let's say you want to calculate the weight of a concrete slab that is 5 meters long, 3 meters wide, and 0.1 meters thick.
The volume of the concrete would be:
Volume = length x width x height = 5m x 3m x 0.1m = 1.5 cubic meters
Assuming the density of the concrete is 2,400 kg/m³, the weight of the concrete would be:
Weight of concrete = Volume of concrete x Density of concrete = 1.5 m³ x 2,400 kg/m³ = 3,600 kg
So, the weight of the concrete slab would be 3,600 kilograms or 7,937 pounds approximately.