Foamed concrete, a lightweight material with excellent thermal insulation and low density, is increasingly popular in construction. This study uses the discrete element method (DEM) to simulate the compressive behavior of foamed concrete, analyzing the effects of particle radius, porosity, and void distribution. The results highlight the important role of geometric and material parameters. Smaller particle radii improve packing density and strength, while a uniform void distribution maximizes compressive strength by minimizing stress concentration. This information provides a basis for optimizing the design of foamed concrete for better mechanical performance and wider applications in sustainable construction.

This paper examines the parameter ν, a shape factor of the particle size distribution (PSD) in granular materials, and its broad applications in geotechnical engineering. Defined as the slope of the PSD in a log-log plot, ν provides a funda-mental measure of distribution shape, capturing the evolution of granular materials under varying conditions. While initially developed to quantify particle break-age, ν has proven to be a versatile tool with applications extending to the modeling of PSD evolution, micromechanical analysis, and the influence of environ-mental factors such as moisture. The paper explores the theoretical foundation of ν, its connections to fractal theory, and its role in describing granular transformations under mechanical and hydraulic influences. Additionally, the relationship between ν and other PSD-based breakage parameters, such as those proposed by Marsal, Hardin, and Einav, is examined, highlighting its advantages as a unifying descriptor of grain size evolution. By synthesizing these perspectives, this study underscores the value of ν as a robust and adaptable parameter for advancing the understanding of granular mechanics and geotechnical engineering.

Stress corrosion cracking (SCC) of prestressing steel threatens prestressed concrete structures with sudden, brittle failure and minimal visible warning. While mechanical stress, localized corrosion, and hydrogen uptake are recognized drivers, the mechanisms connecting sulfide exposure in cementitious materials to hydrogen uptake and crack initiation at the steel–concrete interface remain poorly understood. This review synthesizes the coupled electrochemical, mechanical, metallurgical, and environmental processes governing SCC, with particular emphasis on the interactions of sulfide species with chloride ingress, carbonation, pitting, and hydrogen-assisted cracking under sustained tensile stress. Evidence indicates that sulfides weaken passive-film protectiveness and facilitate hydrogen entry, while localized corrosion and acidification create favorable conditions for crack initiation and propagation. Because SCC susceptibility emerges from the combined effects of environmental exposure, steel microstructure, and mechanical loading, isolated environmental parameters cannot adequately predict risk. Accelerated laboratory tests offer comparative insight but have limited representativeness of the complex conditions of prestressed concrete. A critical gap persists: no quantitative relationship has yet been established between cement sulfide content, sulfide availability at the steel surface, hydrogen uptake, and actual SCC susceptibility. Bridging this gap requires service-representative experiments on stressed prestressing steel embedded in mortar or concrete to develop reliable durability criteria and move beyond precautionary regulatory limits.