Evaluación de la reactividad árido-álcali en diversos áridos silicatados alternativas para minimizar esta reacción

Abstract

Siliceous aggregates are characterized for presenting certain chemical reactivity opposite to the calcium hydroxide liberated in the hydration of the Portland cement. The consequence of this reaction between the aggregate and the components of the intermediate concrete phase is the formation of gels very eager for water that can generate important disruptive pressures in the deeper structure of concrete. We have assessed the potential reactivity of several siliceous aggregates (granites, gneiss, hornfels, quartzite and serpentine) by means of the accelerated method in concrete bars (normalized method) and the superficial reactivity method, observing by scanning electron microscopy (SEM) the formation of silica calcium alkaline gels. On the other hand, we explore the way of minimizing this disruptive reaction employing ground clay bricks and cement type CEM IV UNE-EN 197-1.