The paper describes lightweight-foamed concretes (LFC) that were formulated from cement, natural sand, and
foam from a foaming agent with densities of 600 and 700 kg/m3. The identified mineral phases in the cement are
alite, belite, Celite, ferrite, calcite, and gypsum. The obtained foamed concretes have a porosity varying from
29.17 to 37.14 vol%, a thermal conductivity below 0.2 W/m.K, and a mechanical strength greater than 2 MPa. At
28 days setting, the relative quantities of crystalline and amorphous phases were identified by XRD and DTA/TG.
These techniques allowed to show the importance of the carbonation process and hydrated phases formation on
the macroscopic strength increase. The microstructural characterization by image analyses evidences that when
the density decreases, growth of both crystalline and amorphous phases in the bubble walls during setting is a
mean of compensating the role of density in strength.

Foamed concretes, Thermal conductivity, Porosity, Foaming agent, Mechanical strength