Glutamic Acid Carbon Quantum Dots Modifying Mechanical Properties, Dynamic Characteristics, and Chloride Binding of Cement Composites

Abstract

Carbon quantum dots were synthesized using glutamic acid as the carbon source, and their effects on the mechanical properties and durability of concrete were systematically investigated. Different dosages of CQDs were incorporated into concrete mixtures, followed by a comprehensive evaluation of their performance. Mechanical properties were assessed via compressive strength, splitting tensile strength, flexural strength, and dynamic mechanical tests, whereas durability was examined through water absorption and chloride ion penetration tests. Furthermore, FESEM and EDS were employed for microstructural analysis to clarify the corresponding changes in the concrete matrix. The experimental results indicate that the incorporation of CQDs significantly enhances the overall performance of concrete. Specifically, the compressive strength of CQDs-modified concrete approaches 52 MPa, the flexural strength reaches 2.89 N/mm² (a 20.89% increase), the dynamic elastic modulus attains 50.54 GPa (a 19.05% increase), and the Poisson’s ratio is 0.18. With respect to durability, refinement of the concrete pore structure and reduction in chloride ion penetration contribute to a remarkable improvement in durability. This study offers a new pathway for the development of advanced construction materials and makes a significant contribution to the application of novel nanomaterials in the field of civil engineering.