PURPOSE: To constitute the above method so that separation of ingredients at the time of conveyance is prevented and filling can be performed while twining round an iron reinforcing rod at the time of compaction of the inside of a concrete shuttering by making use of vibrator, by a method wherein cement, melamine resin, aggregate, a mixing material and water are mixed with one another and agitated by a mixer until high viscosity of such an extent that water on the surface of a matter obtained by batch-granulating a composition having specific slump value is not stuck to a hand.

CONSTITUTION: Cement, melamine resin, aggregate, a mixing material and water are mixed with one another and agitated by a mixer until high viscosity of such an extent that water on the surface of a matter obtained by batch-granulating a composition having a slump value of 9±3cm is not stuck to a hand. With this construction, a high-viscosity and high-strength concrete which can obtain compression strength of 300-1,200kg/cm2 is manufactured and unsolidified concrete is formed into a granular and lumpy state. Furthermore, it may be good that surface-active agent or a retarder, under certain circumstance a thickening agent is mixed into concrete which is formed into the granular and lumpy state or the surface active agent or the retarder, under certain circumstance the thickening agent is stuck to the granular and lumpy concrete.