Mechanical, thermal and acoustic properties of cellular alkali activated fly ash concrete

This article characterizes a cellular system prepared from alkali activated Class C fly ash mixed with a preformed foam. The resulting mixture was cast at three densities between 1000 and 1400 kg/m3 and all tests were conducted under ambient drying conditions resulting in densities between 940 and 1310 kg/m3. A phase analysis of the components in the cell wall was performed using X-ray diffraction. The compressive strength ranged from 3 to 9 MPa, while the corresponding modulus of elasticity was between 850 and 1700 MPa. The thermal constants were measured using the Transient Plane Heat Source (TPS) technique per ISO 22007-2. Sound absorption and noise reduction coefficients were evaluated using the impedance tube method per ASTM C384-04. The results show that at an oven dry density near 1000 kg/m3, this alkali activated system is a viable alternative for thermal and sound insulation with properties comparable to those of current commercially available options.