Optimizing foam concrete performance using mixed foaming method: impact of mixing speed, mixing duration, and foam dosage

Foamed concrete has gained significant attention, especially in the field of thermal insulation and acoustic insulation. However, all production methods are based on the pre-foaming method, while the mixed foaming method is an infrequent approach that should be considered and could be challenging. For this reason, this paper attempt to highlight this method and valuate it on par with the pre-foaming method in the production of foamed concrete, both in terms of structure and performance. These performances are directly dependent on the pore structure of this material (pore size, porosity rate, and pore distribution). Therefore, a process has been developed for sample preparation to achieve a final product with a well-controlled size and distribution of porosity, meeting the desired performance criteria. This process involves varying the following parameters: mixing speed (from 400 to 1000 rpm), mixing time (from 2 to 12 minutes), and the dosage of foaming agent (from 0.05 to 0.2%). The effect of mixing speed, mixing duration and the dosage of the foaming agent on the generated foam rate, density, structure at the millimeter scale, structure at the micrometer scale, and thermal conductivity was demonstrated. The obtained results show that with a generated foam rate extending to 79%, a density reaching 428 kg/m³, and a thermal conductivity achieving 0.181 w/k.m, the mixed foaming method becomes an important and competitive approach to the pre-foaming method in the production of foamed concrete.