USE OF OPAL-CRYSTOBALITE-TRIDIMITE MICRO-FILLER IN DENSE AGGREGATE CONCRETE
Opal-cristobalite-tridimite micro-filler (OCTMF) as a component of dense aggregate concrete (DAC), obtained by grinding of sedimentary siliceous rock – abiomorphic silicite fractions of 0.315-0.63 mm was studied considered. The chemical-mineral composition and microstructure of the of OCTMF particles were determined. Comparative analysis of the relationship between particle size distribution, average particle diameter, specific surface area of OCTMF particle and grinding period in shock-abrasive and cavitation mills was carried out. The conductometric express method was applied to study the effect of the OCTMF specific surface area on hydration activity of cement system. The optimal value of OCTMF specific surface area was (880–900 m2/kg), achieved as a result of cavitation dispersion for 5–10 minutes, that provides increasing in t hydration activity of cement system by 52–54 %. The effect of the consumption of components on strength of the DAC after 28 days of hardening was determined using mathematical statistics method. That allows predicting this parameter by varying the component composition of the concrete mix. An assessment of the OCTMF efficiency was made. It was established, the maximal effect of the OCTMF is at concentration up to 5 % (by wt. of cement), that provides an increasing the design compressive strength of DAC up to 126 %.