Valorisation de la bentonite de M’Zila dans la formulation des bétons autoplaçants

Abstract

The construction in general is a major consumer of the raw materials to a cement base. These products pose three main problems: 1. Their environmental impact resulting strong releases of CO2 during the manufacture of cement as well as the greenhouse gases. 2. The technical difficulty to put in place the products that, by their low plasticity and their instability, impose formulations less optimized with respects to the real need of the final work. 3. Their cost price in a context of strong growth of the energy cost which affects that of the cement. In the face of this, the prospect of partial substitution of cement by bentonite (natural clay of montmorillonite type) after calcination is a promising solution that has the plastic properties missing at the cement while participating in the reactions of hardening needed to obtain the required resistance. In addition, the production of the bentonite produces less CO2, which is in fact an interesting product from an environmental point of view. This study aims to contribute to the enhancement of the bentonite of M’Zila, (county of Mostaganem, west of Algeria) after calcination in partial substitution of the cement as artificial pozzolana. This work shows the influence of this adding on mortars and selfcompacting concretes (SCC). The bentonite has been calcined to become active and added with defined proportions to cement (0, 5, 10, 15, 20, and 25% of cement weight). The self-compacting concretes (SCC) have likewise formulated with different proportions of calcined bentonite (0, 10, 20 and 30%). The SCC formulated with different percentages of calcined bentonite are characterized by specific tests in the fresh state, such as the slump test with the cone of Abrams, the L-box test, the sieve stability test and in the hardened state by the test of the resistance to compression. The self-compacting concretes produced have proved to be very satiosfactory in their mechanical resistance and in their durability, particularly for the percentage of 10% of adding calcined bentonite.