Using Natural Raw Materials and CEM Approach for the Design of Andean Volcanic Self-Compacting Concretes

Abstract

Volcanic activity is characteristic of seismic zones. Consequently, volcanic material form part of the landscape in places where earthquakes are common natural phenomena. As volcanic wastes (VW) show pozzolanic activity, the substitution of manufactured Portland cement (PC) with VW is clearly a desirable option not only from an economical point of view but also to reduce the CO2 fingerprint. Therefore, designing concretes with volcanic Portland cements (VPC) clearly contributes to cleaner cement production. Construction and building activities in seismic zones need to use a specific kind of concrete—self-compacting concrete (SCC). The challenge we focused on was the design of SCC using VPC. The flow behavior of SCC is characterized by low yield stress, high plastic viscosity, and shear-thickening behavior at high shear. However, obtaining these striking properties of the concrete is not easy with traditional concrete flow tests (Abrams cone, etc.). Moreover, these methods are very costly in terms of time and material. An alternative that allows us to use absolute rheometry and which has been little explored consists in the substitution of concrete by an equivalent mortar. The so-named concrete equivalent mortar (CEM) approach was used in this study to obtain SCC formulations with VPC. Mini cone tests confirmed the absence of blend in some selected CEM formulations based upon the accomplishment of the criteria for SCC. Three concrete proposals were inferred from the respective CEM formulations. They adapted to the SCC European standard according to the Abrams cone spread test.