"Basically there is only one method for making concrete light i.e., by the inclusion of air in concrete. This is achieved in actual practice by three different ways. (a) By replacing the usual mineral aggregate by cellular porous or light-weight aggregate. (b) By introducing gas or air bubbles in mortar. This is known as aerated concrete. (c) By omitting sand fraction from the aggregate. This is called 'no-fines' concrete."