Cement-based materials are widely used in construction worldwide, but they are vulnerable to environmental stressors and thermal fluctuations, leading to the formation of internal cracks that compromise structural integrity and durability. Traditional repair methods such as surface coatings, grouting, and groove filling are often costly and labor-intensive. In response, self-repairing technologies for cement-based materials have emerged as an innovative and promising solution, offering the potential to significantly extend the lifespan of structures and reduce maintenance costs. A particularly novel approach is the development of microcapsule-based self-repairing concrete. In this system, repair agents are encapsulated within microcapsules and combined with curing agents in the concrete matrix. When cracks form, the microcapsules rupture, releasing the repair agents to autonomously heal the damage. This self-repairing mechanism is characterized by its high efficiency, durability, environmental sustainability, and versatility, making it a promising alternative to traditional repair methods. Recent research has focused on the development of microcapsules with various core materials, such as TDI (toluene diisocyanate), IPDI (isophorone diisocyanate), or epoxy resin, as well as composite shell materials including paraffin wax, PE (polyethylene) wax, nano-SiO₂, and nano-CaCO₃. A novel advancement in this area involves the enhancement of microcapsules through the incorporation of magnetic nanomaterials into the shell, providing new possibilities for self-repairing systems that address cracks in cement-based materials.

This study examines the mechanical performance, deformability properties and rheological properties of a newly developed waterborne epoxy resin (WER)-modified emulsified asphalt (WE/A) binder for micro-surfacing. Two types of WER, semi-flexible and rigid, were used to modify the binder. Furthermore, the modification mechanism was investigated using the fluorescent microscope test and the scanning electron microscope (SEM). In addition, the pavement performance at micro-surfacing was studied using the wet wheel wear resistance test, the pendulum friction test and the slurry rutting test. The results indicated that with a small content (<15%) of WER in WE/A, WER existed as a continuous structure (cellular membrane wrapped around asphalt bubbles), thereby enhancing its high temperature properties and mechanical properties. Meanwhile, it also improved the cohesion properties of the transition interface between the aggregate and asphalt (enhanced by at least 30.0%) and the rutting resistance (improved by about 55.3–63.8%). In addition, WER could also improve the peeling resistance and water damage resistance of the micro-surfacing.

In the realm of bridge structural engineering, it is customary to meticulously contemplate the material’s strength and rigidity attributes during the dimensioning phase. In recent years, there has been a burgeoning interest in employing Ultrahigh-Performance Concrete (abbreviated as UHPC) for the construction of bridge decks and wet joints. However, the large self-shrinkage of UHPC can easily lead to shrinkage cracking and affect its service life. This study delves into the utilization of a blend of basalt coarse aggregate and high-modulus aggregate (HMA) in the formulation of Ultrahigh-Performance Concrete (UHPC) with the objectives of achieving exceptional strength (>180 MPa), superior modulus of elasticity (>56 GPa), and synergistic effect of using prewetted internal curing aggregate (ICA), metallurgical ore sand (MOS), and calcium–magnesium composite-based expansion agent (EA) to reduce the shrinkage of UHPC. Furthermore, the mechanical properties, shrinkage, hydration process, and microstructure of UHPC prepared with EA and ICA were studied. The results show that UHPC prepared with both 3% EA and 20% ICA had the optimal volume stability (the shrinkage was only 273 με at 180 d). In contrast, the 180 d shrinkage of UHPC with 3% EA and 20% ICA separately was 287 με and 373 με, respectively. In addition, the incorporation of EA and ICA can effectively improve the flexural strength of UHPC, although it affects the compressive strength and modulus of elasticity of UHPC (small decrease).

To realize the efficient utilization of biochar and construction solid waste in building materials production, a novel core–shell aggregate concept is proposed, in which artificial aggregates are prepared by encapsulating coarse-particle bamboo biochar (C-BB) with concrete slurry waste (CSW), calcium carbide slag (CCS), and fine-particle bamboo biochar (F-BB). The results showed that the best engineering properties of the artificial aggregates were achieved when the F-BB content was about 6%, with crushing strength, water absorption, and bulk density values of 4.7 MPa, 14.3%, and 796 kg/m³, respectively. In addition, the artificial aggregates have promising potential for CO₂ uptake under a CO₂ curing system and can achieve 5.72% (by mass) uptake when the F-BB content is 6%. This performance is attributed to the formation of well-developed CO₂ transport channels in the shell matrix by the F-BB particles. In summary, the novel core–shell aggregate not only has better engineering properties than commercial lightweight aggregates but also offers significant potential for CO₂ sequestration, opening new opportunities for the efficient application of biochar in construction materials with both engineering and environmental benefits.