Determination of the Influence of Hydraulic Additives on the Foaming Process and Stability of the Produced Geopolymer Foams

Abstract

The research described in this article was aimed at determining the influence of hydraulic additives on the foaming process and the stability of the produced geopolymer foams. These foams can be used as insulation materials to replace the currently commonly used insulations such as expanded polystyrene or polyurethane foams. Geopolymers have low thermal conductivity, excellent fire- and heat-resistant properties, and have fairly good mechanical properties. Research on foamed materials shows that they have the highest class of fire resistance; therefore, they are most often used as insulation products in construction. Geopolymer foams were made of aluminosilicate materials (fly ash) and foaming agents (H2O2 and Al powder), and the stabilizers were gypsum and portland cement. Additionally, surfactants were also used. It was found that better foaming effects were obtained for H2O2—it is a better foaming agent for geopolymers than Al powder. When using a hydraulic additive—a stabilizer in the form of cement—lower densities and better insulation parameters were obtained than when using gypsum. Portland cement is a better stabilizer than gypsum (calcium sulfates), although the effect may change due to the addition of surfactants, for example.

The Effect of Different Modifying Methods on Physical, Mechanical and Thermal Performance of Cellular Geopolymers as Thermal Insulation Materials for Building Structures

“…On the other hand, the GPC mix has the highest average density and thermal conductivity coefficient as well. This relationship has also been confirmed in a work [34].…”

Porous Maize Stalk Cellulose Fiber-Reinforced Geopolymer Composites for Heat Insulation at the Bottom Side of a Local Electric Stove

“…However, the decomposition of aluminum powder and silica fume generates hydrogen gas. The potential problems arise when the porous structure produced by foaming agents is stable only for a short time and then falls for a while (before the bonding process-geopolymerization) [17]. Moreover, the repeatability of the results obtained on an industrial scale is still regarded as a challenge of using geopolymer materials as insulators in buildings and other applications [18].…”

Experimental Evaluation of the Mechanical Strengths and the Thermal Conductivity of GGBFS and Silica Fume Based Alkali-Activated Concrete

“…Several researchers are done with the application of the same principle for determining the conductivity of geopolymeric concrete. For instance, Lach et al [70] have studied the thermal conductivity by varying the hydraulic additives; Kozub et al [71] have found that the addition of glass wool waste can reduce the thermal conductivity coefficient and the amount of 5% by weight of glass wool waste causes a reduction of −6.6% in relation to the reference sample.…”