Few studies have examined the statistical uncertainty which has been found by experimentation in mechanical interaction between discrete fibers and a cement-based matrix. This review work includes not only existing test results showing considerable fluctuation particularly in post-peak behavior, but also statistical and probabilistic approaches to account for that fluctuation. Our emphasis is on time-dependent behaviors such as pull-out creep and loading rate effects because of their remarkable scatter, which might hinder further research progress (e.g., difficulty separating true mechanical response from statistical variation). Potential sources of statistical fluctuation are identified using non-destructive measurements: X-ray computed tomography and acoustic emission techniques. Along with the observational evidence, fracture mechanics is effective at reinforcing the physical importance of probabilistic approaches such as a Markov chain. The necessity of a probabilistic perspective of cumulative damage processes is addressed because the viewpoint provides a common theoretical basis between time-dependent and stress-dependent pull-out processes.

3D printing concrete technology has gained significant attention for its mold-free construction and precision molding capabilities, yet its application in underwater environments remains underexplored. This study evaluates the feasibility of underwater self-protecting 3D printing concrete (USP-3DPC) and investigates the effect of varying underwater protective agent (UPA) ratios on key performance metrics, including underwater anti-dispersion, extrudability, and buildability. Compressive strength, splitting tensile strength, and porosity characteristics of USP-3DPC were also analyzed. The results indicate that incorporating UPA enhances underwater anti-dispersion, with an optimal ratio of 6% providing the best balance of extrudability and buildability. Although USP-3DPC specimens exhibit lower compressive and splitting tensile strengths than air-printed 3DPC, both demonstrate similar mechanical anisotropy. Analyses of porosity using mercury intrusion porosimetry reveal distinct differences in pore structure evolution and strength development between specimens printed in air and underwater environments. Strength comparisons at different curing ages confirm that USP-3DPC retains substantial mechanical integrity, supporting its potential for underwater construction applications.

Minimizing the use of ordinary portland cement (OPC) in concrete not only enhances cost-performance balance but also significantly reduces carbon emissions. In this research, we develop the technology of sectioned compaction self-assembly (S-CSA), which enables a nearly 50% reduction in OPC content without compromising strength. Through the sectioned operation, the processing system can be based on a relatively small press.

This paper aims to address limitations of assembled foundations through a systematic approach involving the careful design and validation of precast foundations for transmission towers. Specifically, we introduce a novel method known as the Segmented Prestressed Assembled Foundation (SPAF), and demonstrate its application through a detailed design process based on an actual engineering project. Subsequent to the design phase, finite element models of both the proposed SPAF and conventional foundations are developed to facilitate a comprehensive comparison of their respective load-bearing performances. Furthermore, we conduct a full-scale test of the SPAF to verify the safety and efficacy of the newly proposed foundation design scheme. The results of our study indicate that the SPAF exhibits sufficient load-bearing performance comparable to that of a conventional cast-in-place foundation. Moreover, the inter-component connection method employed enhances the integrity of the SPAF, ensuring adequate joint strength and safety. Additionally, the SPAF offers significant advantages in terms of structural design and construction methods.

Pavement–vehicle interaction affects vehicle fuel consumption, and reducing fuel consumption lowers CO₂ emissions. Therefore, replacing asphalt pavements, which result in greater vehicle fuel consumption, with concrete or composite pavements when repairing pavement may reduce CO₂ emissions for vehicle driving. This paper proposes a calculation method for CO₂ emissions considering fuel consumption reduction by pavement–vehicle interaction and evaluate the difference in environmental impact among pavement types. We consider the reduction in CO₂ emissions from cars as an environmental contribution by concrete or composite pavement, and we propose an evaluation method to introduce the reduction into the calculation of CO₂ emissions throughout the life cycle of the pavement. We also introduce the effect of environmental temperature on CO₂ emission reductions into the evaluation method. The results show that concrete and composite pavements have higher CO₂ emissions than asphalt pavements throughout the life cycle of the pavement. Nevertheless, the reduction in CO₂ emissions owing to the lesser fuel consumption by cars in concrete and composite pavements is significant, and CO₂ emissions of concrete and composite pavements, including the effect of reduced fuel consumption, may be less than CO₂ emissions of asphalt pavements, especially in cold areas.