Concrete men have long believed that it is dangerous to disturb the hardening of concrete once this process is definitely in progress. Although this opinion still prevails throughout the profession, there are a few dissenting views on the subject which may will form the nucleus of an entirely new school of thought. Evidence is accumulation which indicates that revibration may be something more than just a desperation measure which happily has no ill effects on concrete. The new point of view is that this unorthodox practice can actually improve some of the important characteristics of hardened concrete. Among the major claims being made is that under properly controlled conditions revibration can increase density and strength, remove air and water pockets, release water trapped beneath horizontal reinforcing steel, improve bond between concrete and steel, and substantially reduce honey-combing. The Bureau of Reclamation has taken official notice of revibration stating," Revibration has been found to be beneficial rather than detrimental, provided that the concrete is again brought to a plastic condition. It may be accomplished by immersion-type vibrators, by form vibration, or by transmittal of vibration through the reinforcement system."