Abstract: A forced kneading concrete mixer including a or a plurality of mixing members such as paddles or blades disposed at fixed positions within a rotating pan or cylindrical vessel. The mixing member is carried by a support which is movably mounted on a stationary member and which is subjected to a vertical oscillation having an amplitude of from 2 to 5 mm and a frequency of 3500 to 6000 cycles per minute. A fluid charge comprising ingredients to form concrete is mulled and oscillated by the cooperation of the vessel and the mixing member. When subjected to the oscillation, the individual particles of cement contained in the oscillating fluid charge are dispersed and acquire moisture on their surface. The load on the mixing member is reduced inasmuch as the consistency is increased due to a temporary tendency of the charge to fluidize.