Enhanced Mechanical and Durability Performances of Low Cement Concrete with Natural Pozzolan Addition

The decarbonization of concrete structures sector is a priority due to the world climate. Since Portland cement is responsible for approximately 7% of the anthropogenic emissions worldwide, it is decisive to partially replace it by products with lower environmental impact. Fly ash has become highly demanded, due to its proven advantages, however, has announced end by the developed countries. The purpose of this research is to develop and characterize low cement concrete (LCC) with natural and ecological pozzolan additions as an alternative to fly ash. The main objectives are: define several structural concrete mixtures with low cement dosage, ranging from 125 to 175 kg/m(3); characterize the workability and the mechanical properties, beyond the durability performance of those concretes; study the influence of pozzolans additions on LCC performance, as an alternative to fly ash; assess the service life of structures produced with the developed LCC. It is possible to produce LCC with natural pozzolan additions, instead of fly ash, with improved mechanical properties and enhanced durability performances. Results also show that the structural LCC produced with pozzolan from Cape Verde provide a great protection against steel corrosion, achieving values 50% higher than concrete with fly ash, and even higher margins when compared with the minimum concrete covers recommended by standards, which highlights the benefits of its use from the sustainability point of view.