In the work it is proposed to use the principle of zonal placement of materials in prefabricated-monolithic bending structures with the use of light concrete, as well as combined reinforcement. The upper (monolithic) layer is preferably made of light concrete of low strength, and the lower (prefabricated elements) - of steel fibre concrete based on light concrete of higher strength. Rod and fibre reinforcement are located in prefabricated elements, which under operating loads will be in stretched zone of bent elements.The results of experimental studies of crack resistance and deformation of steel-fibre-fluorophobetone (SFTB) prefabricated monolithic bending elements on the basis of shoe filler of Kamenskoe deposit of Kabardino-Balkan Republic are presented in the work. Based on analysis of obtained data correlation dependence is derived and character and degree of influence of various factors on crack resistance and deformability of assembled monolithic combined reinforced bending elements is revealed. The following conclusions have been drawn: reinforcement of prefabricated elements of flexable monolithic structures made of tuphobetone with rods and fibres allows to significantly increase their crack resistance; Parameters of combined reinforcement of prefabricated elements, assignment of their geometrical dimensions, as well as dimensions of sections of bent prefabricated-monolithic structures from tuphobetone as a whole can be assigned taking into account correlation dependencies for evaluation of crack resistance obtained from the results of these studies.

Keywords: Stalefibrotaphobetone, monolithic assembly, zonal arrangement, combined reinforcement, reduced reinforcement, strength of monolithic concrete, correlation dependence, crack resistance, deformability, factors, parameters of combined reinforcement

Short data on efficiency of a fibrobeton on the basis of heavy quartz sand are provided in work. Taking into account existence of huge reserves of natural porous fillers (the tufa, pumice, pummitsit, etc.) in various regions of Russia and also the fillers received on the basis of industry waste the relevance of a research of a stalefibrobeton with easily concrete matrixes is proved. Experimental selection of optimum composition of concrete on the basis of tuff filler of the Kamensk field of Kabardino-Balkar Republic regarding his use as a matrix of a stalefibrotufobeton (SFTB) is executed . The picked-up structure has been used for creation of skilled combined and monolithic samples of beams which should be tested. During formation of beams control samples of a stalefibrotufobeton have been selected and tested. Results of tests of control samples for compression, stretching and a bend demonstrate that fiber reinforcing exerts significant positive effect on strength and deformativny properties of a tufobeton. Data of experimental research confirm a possibility of using tufobeton in the stalefibrobetonnykh designs.

Keywords: Stalefibrotufobeton, steel fiber, matrix, volume percent of fiber reinforcing, stretching, compression, bend, dynamic influences, zone placement