The most important parameters used to interpret the particle size distribution curves are coefficient of uniformity and coefficient of curvature. These two parameters characterize the curve based three sizes, namely, D10, D30, and D60, where D10 indicates size of particles below which 10% of particles are lower than this size. In fact, these two parameters can be good inputs to represent gradations in equations / modelling exercise.

Thanks Mr. Anush 

In mining and cement industry usually the RRSB-PSD (Rosin-Rammler-Bennet) is used.

This is a double logarithmic graph of the function  ln ln(1/R)=n(ln(x)-ln(x´)),

whereby  R is the residue on a sieve with x (mm or µm) mesh size respectively the amount of particles bigger than x. In this graph the inclination (Steepmess of PSD) of the curve is n and x´ is the particle size where 36.8% of particles are bigger than x´.

Thanks mr Reinhard Assmus

The particle size distribution curves for gravel and sand (also called grading curves) show the relative percentage of particles by weight passing a particular sieve size. These grading curves help engineers design the most economical concrete using the aggregates in question. One uses established grading curves (target curves) from research and experience to determine the required mix proportions of the gravel and sand. By approximating the target curve one minimizes the pore content and therefore the required cement content of the mix. Minimizing the pore content means getting the highest concrete density and therefore the highest possible concrete strength.

Thanks Mr.Alex Mrema 

The amount of fines is also visible on this curve. dmin and DMax are also important and can be found on these curves. The finess modulus can be calculated with this curve.