▎ 摘　　要

This study presents the results of an experimental study of the influence of graphene oxide (GO) on the static and dynamic mechanical characteristics of cement concrete. Four different dosages of GO, 0.05%, 0.10%, 0.15% and 0.20% by weight of cement and two different grades of concrete, standard concrete (M30) and high strength concrete (M60) were studied. The static properties such as compressive strength and chord modulus of elasticity were determined. The impact hammer technique was used to obtain dynamic characteristics such as fundamental natural frequency, damping ratios, and mode shapes of concrete beams under free-free condition. In addition, fundamental resonant frequencies under different modes of vibration were determined. The dynamic elasticity modulus, dynamic shear modulus and dynamic poisons ratio of all concrete mixes were also determined. Experimental results revealed that the compressive strength of the concrete with the incorporation of GO was remarkably enhanced. The highest increase in compressive strength was found at GO dosage of 0.15%, and the improvement at 7 and 28 days was 58.2% and 47.7% for standard concrete and 51.2% and 24.3% for high strength concrete respectively compared to control concrete. The impact hammer test revealed that the maximum increase in fundamental natural frequency was 8.0% and 6.6%, and the maximum decreased damping ratio was 29.1% and 26.3% for standard concrete and high strength concrete respectively when compared to the control concrete. Ultrasonic pulse velocity results indicated that the homogeneity of the concrete with GO addition was significantly improved. SEM and EDX microstructure investigations found that the addition of GO to concrete promoted the development of improved hydration phases leads to the dense microstructure. The findings of this study demonstrated that GO nanomaterial had a potential future as a reinforcing material in cement concrete for improved microstructure, strength, and free vibration characteristics.