Effect of modifier MB10-01 on the parameters of fracture mechanics of high-strength coarse-aggregate concrete
The mass production of high-strength concretes (HSC) in Russia is mainly associated with the use of organomineral modifiers of the MB series, containing in their composition micro silica, fly ash, super plasticizer C-3 and hardening regulator in different ratios. In our study we produced HSC samples, with the compressive strength of at least 100 MPa, with dimensions of 100x100x100 mm – four series, 100x100x450 mm – four series, 100x100x450 mm with the artificial crack of 25 mm deep in the middle of the span – four series, and also 100х75х450 mm (75 mm height was taken equal to the height of the section above the crack of the 2nd type of prisms) – four series. The actual HSC grade on compression, the tensile strength at bending, the strength at axial tension, the elasticity modulus, the cracking moment, and also the parameters of fracture mechanics, such as: the critical stress intensity factor and the critical energy release rate, at the curing periods of 7, 14, 28, 60 days, have been determined. We also evaluated the influence of crack in the bend element on the value of the cracking moment. The research results have been implemented in the construction of highrise buildings of the Moscow International Business Center "Moscow City", and in the reconstruction of the Engineering Faculty building of the RUDN University.
Keywords: Cracking moment, Critical energy release rate, Critical stress intensity factor, Tensile strength at bending, Strength at axial tension