Physico-mechanical properties and micromorphological characteristics of graphene oxide reinforced geopolymer foam concrete

Geopolymer foam concrete (GFC) has recently attracted extensive interest owing to its potential application in non-bearing structures and backfilling. However, the simultaneous realization of high strength, good durability, and maintained lightweight in GFC is still challenging. Fortunately, the potential of carbon nanomaterials to improve the mechanical properties of concrete has emerged in recent years. Herein, graphene oxide (GO) was introduced in the preparation of GFC, and the effects of different GO contents on GFC's bulk density, compressive strength, water absorption, freeze-thaw resistance, thermal conductivity, and porosity were studied. The results showed that adding GO improved GFC's compressive strength, freeze-thaw resistance, and thermal conductivity. The highest compressive strength of GFC with GO was 2.958 MPa, increasing by 58.37% compared to without GO. On the other hand, the mass loss rate and compressive strength loss rate decreased by 51.2% and 41.1% respectively, when the content of GO reached 0.06% in GFC. Moreover, the addition of GO slightly reduced the water absorption and porosity of GFC. In addition, through an optical microscope, MIP, XRD, SEM, and EDS analysis, it is inferred that the mechanisms of GO on reinforcing GFC are mainly: (1) providing nucleation sites and promoting the process of geopolymerization; (2) strong network connection and mechanical interlocking structure formed in GO reinforced GFC; (3) refining and filling pore structure. With the improvement of physico-mechanical properties, the GO reinforced GFC should be promising to open up an avenue that moves GFC further to our world.