Influence of Porous Structure of Non-Autoclaved Bio-Based Foamed Concrete on Mechanical Strength

This study examines the impact of the porous structure on the density and mechanical behavior of a new foamed concrete incorporating hemp shives. The specific aim is to gain a better understanding of how the inclusion of hemp shiv, as well as different additions and foaming methods, influence the density and mechanical strength of the concrete. A total of eight batches of foam concrete were produced and tested, made with a protein-based surfactant agent, with cement, ground granulated blast furnace slag, and metakaolin as binders and hemp shiv as natural aggregates. The effect of several parameters is studied, including elaboration method (direct and preformed), amount of pozzolanic additions (0% and 30 of cement weight%), and incorporation of hemp shiv (5 and 15 vol%) on the resulting physical properties, microstructure, porous structure and mechanical behavior of the concrete. Pozzolanic additions improve slightly the uniformity of pore sizes, which increases the mechanical resistance, especially at 28 days. While hemp shiv incorporation results in increased concrete porosity and air bubble radius, it also decreased uniformity, mechanical strength, and lower cohesion with the cement matrix compared to standard concrete. The results contribute to the development of eco-friendly construction materials and promote the utilization of agricultural waste in the construction industry.