Graphene-oxide-reinforced cement composites mechanical and microstructural characteristics at elevated temperatures

• Published in: Nanotechnology reviews (Berlin) 2022-12, Vol.11 (1), p.3174-3194
• Main Authors: Han, Seungyeon, Hossain, Mohammad Shakhawat, Ha, Taeho, Yun, Kyong Ku
• Format: Article
• Language: English
• Subjects: Cement; cement nanocomposites; Cement reinforcements; Chemical composition; Composite materials; Compressive strength; Computed tomography; Crack initiation; Fracture mechanics; Graphene; graphene oxide; Heat resistance; High temperature; Hydration; Mechanical properties; Microcracks; Microstructure; Modulus of elasticity; Mortars (material); Nanomaterials; Pore size; Reinforced cements; Scanning electron microscopy; Thermal resistance; Thermodynamic properties; Thermogravimetry; Water-cement ratio; X-ray diffraction; X-ray spectroscopy
• ISSN: 2191-9097; 2191-9089; 2191-9097
• DOI: 10.1515/ntrev-2022-0495

The focus of this research was to investigate the effects of graphene oxide (GO) on the microscopic composition, structure, pore size, and mechanical properties of GO-reinforced cement composites. Furthermore, the research explored the thermal behavior of GO-reinforced cement mortar at different elevated temperatures (250, 500, 750, and 1,000°C). This study considered three sets of GO-reinforced cement composites with 0.1, 0.2, and 0.3 wt% of GO (by weight of cement); the water–cement ratio in all the mixtures was 0.5. To characterize the chemical composition, microstructure, and hydration degree resulting from GO addition, X-ray diffraction, thermogravimetry, derivative thermogravimetry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and micro-computed tomography (Micro-CT) were used. The experimental results revealed that GO addition changed the microstructural composition and pore diameter distribution of the cement composite. The optimal amount of GO required for improving the mechanical properties of the cement composite under both unheated and heated conditions was identified to be 0.1 wt%. GO improves the cement matrices’ ability to bind with GO nanosheets, leading to compressive strength retention and decreased micro-cracking (computed by material and defected volume changes by Micro-CT analysis). This is primarily due to the hydration products. However, the optimal amount of GO can result in nanomaterial agglomeration, thus lowering the thermal resistance of the cement composite. Overall, the study identified GO as a nano-additive with the potential to improve the strength and toughness of the cement composites. Moreover, the effect of elastic modulus was also evaluated. As a result, the GO microstructure analysis revealed that it has a porous structure with a visible crack pattern.