Comparison of frost resistance for the fiber reinforced geopolymer and cementitious composites

Abstract

The design of the structural composites is significant for civil engineering applications which exposures cyclic freeze and thawing action. Accordingly, it is important to design the infrastructures with the appropriate frost-resistant composite material. Besides a wide range of applications of cement-based composites, geopolymer composites are also of interest under frost action. The current paper deals with the frost resistance of different structural composites with and without fiber reinforcement. A comparison of frost resistance was made between geopolymer and cementitious composites at different curing ages. As frost durability is mainly related to air void parameters, characterization was made for both matrix types in the presence of fiber reinforcement. After applying freeze–thaw cycles, mechanical, water absorption parameters and weight loss were performed for a complete comparison. The results revealed that although inclusion of fiber slightly reduced the compressive strength, reductions after freezing and thawing tests were similar between plain and fiber reinforced cement mortars. On the other hand, frost damage surpassed the geopolymerization as higher rate of cyclic frost action lowered the mechanical properties at 28 days compared to 7-day-old specimens. The flexural strength of each mixture was reduced after freeze and thaw cycles, however, it was limited for the fiber reinforced cement mortars. Plain specimens were more prone to cyclic freeze and thaw curing compared to fiber inclusion irrespective of composite type. Geopolymer composites were prone to frost damage as water immersion of geopolymer mortars and excessive sodium content seems to be harmful to geopolymers, especially at earlier ages.