The factors affecting the strength of the interlayer bond of 3D concrete, as well as factors affecting the ability of the printer nozzle to produce a controlled concrete thread of a particular composition, which is being investigated in the process of 3D printing technology, the main characteristics of the suitability of compositions for printing on a 3D printer, requirements for rheology, hydration and strength in an uncured form, are considered 3D concrete, the main mechanical test methods for determining the adhesion strength in concrete printed on a 3D printer. The possible shapes and nominal sizes of the samples used in the methods for determining the strength of concrete are given.

Keywords: 3D concrete, anisotropy of mechanical properties, extrusion, cold connection, interfacial coupling, deflocation, thixotropy, initial static viscosity, curing, three-point bending

The article deals with the question of injury to the enterprise "Rostvertol" for the period from 1999 to 2010. Discusses some indicators of the status of labour conditions and safety of employees. The analysis of data on the number of injured in accidents at work by gender, age and length of service in the organization. As well as the number of injured by type of accident and by profession. Analyzed data on the number of victims for reasons that have led to an accident in the workplace. On the basis of the study there are several main reasons. Such as the unsatisfactory organization of work and production violation of labor discipline.

Keywords: labor protection, labor conditions, injury, accident, industrial injuries, mechanical engineering enterprises mechanical contact