Abstract: A hydraulic composition comprising (a) a cement composition prepared by subjecting size-adjusted cement having its particle size distribution adjusted to have a 50% pass particle diameter of from 2 to 7 .mu.m and a ratio of a 90% pass particle diameter to a 10% pass particle diameter of from 25 to 40 to a water-spraying treatment to increase the loss on ignition thereof by 0.5 to 2.0% by weight and (b) a water reducing agent; and a process for producing a concrete pile by using a mixture of the hydraulic composition and from 18 to 25% by weight of water based on the hydraulic composition. A mortar or concrete mixture of the hydraulic composition exhibits sufficient fluidity and provides a hardened product having a greatly improved compressive strength. The concrete pile produced by using the hydraulic composition has a compressive strength of 800 kgf/cm.sup.2 or higher at one day age.