Properties of concrete in cores removed from massive hydraulic structures: Fid-Bau Portal

Properties of concrete in cores removed from massive hydraulic structures

Tonka, A. R.

Conclusions The results of core tests indicate that use of the Toktogul method of concreting massive dam structure [1] makes it possible to provide high-quality concrete and its placement.The high efficiency of the use of gliezh-portland cement and the combination of an SDB hydrophilizing additive and an SNV hydrophobizing additive in stiff mixes for the dam’s internal zone is shown. In combination with the use of controlled screening of the gravel and an aggregate containing six fractions, dam concrete corresponding to the design requirements ($ 250_{180} $ $ V8_{190} $ $ R16_{28} $ and $ 250_{180} $$ V8_{180} $$ R14_{28} $) is produced with grade 300 pozzolana portland cement contents of 200 and 180 kg/$ m^{3} $, respectively (a content of purely clinker portland cement of 145 and 130 kg/$ m^{3} $).A rapid increase in strength during the first year and one-half, exceedence of the modulus of elasticity as compared with data presented in the Construction Norms and Specific cations, an extremely high degree of impermeability, and a high crack resistance are characteristic for the concrete of the internal zone. All this is explained by an increase in the content of the colloidal phase in the hydration products stemming from formation of calcium hydrosilicates during interaction between the calcium hydroxide and siliceous gliezh, and also by the effect of favorable conditions of the mass and the specifics of the procedure of concreting by the Toktogul method on the development of these properties in the concrete.