Grading of sand refers to the particle size distribution of sand. It can greatly affect the properties of concrete, including workability, strength, and durability.

Workability of Concrete
Workability refers to how easily concrete can be mixed, transported, and placed without losing its homogeneity or segregation. The grading of sand affects workability by altering the amount of fine and coarse particles in the mix. A well-graded sand with a balanced proportion of fine and coarse particles can improve workability, while a poorly-graded sand can cause problems like excessive bleeding and difficulty in mixing.

Strength of Concrete
Strength refers to the ability of concrete to resist external forces and loads. The grading of sand can affect concrete strength by influencing the particle packing density, which in turn affects the void content and the water-cement ratio. A poorly-graded sand can cause a higher void content and a higher water-cement ratio, which can decrease the strength of the concrete.

Durability of Concrete
Durability refers to the ability of concrete to withstand weathering, chemical attack, and other forms of degradation. The grading of sand can influence the durability of concrete by altering the pore structure and permeability of the concrete. A well-graded sand can produce a more dense and less permeable concrete, which can improve durability. On the other hand, a poorly-graded sand can lead to a more porous and permeable concrete that is more susceptible to degradation.

In conclusion, the grading of sand can greatly affect the workability, strength, and durability of concrete. It is important to use a well-graded sand that produces a balanced particle size distribution to achieve optimal concrete properties.

Because grading effect the alll properties of concrete because all are properties which are simultaneously related by surface area of solids in void ratio available in concrete and these are parameters effected by grading of concrete, grading is referers to what is variation of sizes parties in mass