Mechanochemical Activation of Fly Ashes a Way to Make Concretes with High Levels of Substitution: Hybrid Concretes

D. VIEJO MARIÑO, A. PALOMO, A.M. FERNÁNDEZ-JIMÉNEZ & O. MALTSEVA; CABRERA, OSCAR ALFREDO

Praga

Congreso; 15th International Congress on the Chemistry of Cement; 2019

ICCC2019

The objective pursued in this study was to determine the mechanical properties and some technological characteristics of a few concrete formulations containing a high level of fly ash. Three concrete options were considered with respect the fly ash addition: i) concrete TO (prepared by adding original fly ash); ii) concrete TM (prepared with mechanically activated fly ash); iii) concrete TMA (prepared with mechano-chemical activated fly ash). The pozzolanic activity of the fly ash as function of the type of activation procedure (TO, TM or TMA) was determined by the Frattini method and also by the Activity Index. The effect of the fly ash in the hydration kinetics was also determined by conduction calorimetry. Finally the effect in the mechanical strength development was determined in a H-30 concrete. Results of this research indicate that the mechano-chemical treatment of the fly ash (TMA), allows to develop a compressive strength of 30 MPa at 28 days for a replacement level (fly ash for OPC) of 50%.