Research Direction 1: Research on green and low-carbon recycled concrete based on ground material recycling
Facing the strategic needs of carbon emission reduction and solid waste recycling in the field of civil engineering, this research direction focuses on the preparation of high-performance recycled cementitious materials and concrete using local characteristic ground materials (such as volcanic ash materials, tunnel slag, waste concrete sleepers, etc.). The multi-scale physicochemical properties and activity excitation mechanisms of volcanic ash materials, waste concrete powders and aggregates were systematically analyzed, and the reconstruction law and rehydration kinetics of aluminosilicate phases in multi-source solid wastes under the coupling effect of thermal activation and chemical excitation were revealed. In-depth study of the interface compatibility, ion competitive adsorption and synergistic hydration effect of recycled components and local ground materials in multiple systems, and establish the design theory and performance control method of recycled concrete mix based on the "gene" characteristics of ground materials, so as to realize the high-value utilization of all components from tunnel slag, waste sleepers to new low-carbon cementitious materials, and provide green building material solutions for regional infrastructure construction.

        Research Direction 2: Research on the deterioration mechanism and durability design of engineering materials in extreme environments
In view of the bottlenecks of engineering materials in extreme environments such as extreme cold, dry heat, strong radiation, and high salt spray, such as easy cracking, fast performance degradation, and difficult maintenance, this research direction is committed to revealing the multi-field coupling damage mechanism and long-term performance evolution law of materials in extreme environments. By establishing a multi-field coupling test platform for temperature-humidity-load-chemical attack, the phase transition behavior, microstructural damage accumulation and internal correlation with macroscopic performance degradation of cementitious materials were analyzed from the atomic/molecular scale, and the mechanism of chemical-mechanical-thermal coupling failure of materials in extreme environments was clarified. On this basis, based on the concept of material genome, this paper designs and develops maintenance-free engineering materials with adaptive microstructure regulation ability, low shrinkage and high crack resistance, and proposes a quantitative design method for material durability for extreme environments, which provides key material support for the construction of major projects in special environments such as the western plateau and the deep sea.

        Research direction 3: Research on rapid in-situ toughening and life extension technology of existing concrete structures
In order to meet the needs of emergency repair and durability improvement after the damage of concrete structures in service, this research direction focuses on the development of toughening and reinforcement materials and construction technologies that can achieve rapid in-situ recovery. Based on the principles of interface chemistry and molecular design, polymer-cementitious composite repair materials with high permeability and adjustable curing rate were developed to reveal the chemical bonding and mechanical interlocking mechanisms with existing concrete substrates at the micro-nano scale, so as to realize the deep reconstruction and enhancement of the old and new interfaces. The volume stability and microstructure evolution of rapid repair materials in the early hydration stage are systematically studied, and the correlation model of "material formula-construction process-interface performance-structural life extension" is established, and the rapid in-situ toughening and reinforcement technology scheme suitable for different damage degrees and different environmental conditions is proposed, which provides theoretical and technical support for the extension of the service life of existing concrete infrastructure.

        Research Direction 4: Research on biomimetic high-strength, tough, crack-resistant composites based on AI-based design
Aiming at the common problems of insufficient toughness and easy cracking of traditional cement-based materials, this research direction breaks through the inherent limitation of the inverted relationship of "strength-toughness", and draws on the multi-scale structural design principle of biomineralized materials (such as shell nacre "brick-mud" structure) to develop biomimetic composites with mortar-brick characteristics. By introducing machine learning algorithms, a quantitative structure-effect relationship prediction model of material components, microstructures, and macroscopic properties is established, and the geometric configuration, interface transition zone characteristics and organic-inorganic hybrid interface combination mode of bionic units are intelligently optimized. Integrating 3D printing fine molding technology, the controllable fabrication of bionic hierarchical structures is realized, and the multiple toughening mechanisms of crack deflection, bridging and energy dissipation are systematically studied, and finally a new composite material with high strength, high toughness and excellent crack resistance is developed, providing a material basis for the long-life safety of major engineering structures.