China Building Materials Academy

A hypothesis on the mechanism of “salt-scaling” of porous building materials is described. The hypothesis is based on theories on frost heaving in soils and observations made on micro ice-lens growth in cement paste specimens. The main principle is that ice crystals close to the surface are able to feed from the remaining liquid phase of the outer salt solution after freezing has begun. Though the text mainly deals with cement based materials, the mechanism described should be valid for any brittle, porous material. A simplified calculation in the form of a traditional calculation of depth of ice-lens growth shows that the hypothesis predicts reasonable values. The correct calculation is only briefly described. Results from a first pre-series test on water absorption during freezing support the hypothesis.

Cold-bent glass has been utilized in a number of landmark projects globally, owing to its cost-effectiveness and low carbon footprint. To investigate the impact of cold bending loads on the long-term performance of insulating laminated glass, this paper proposes a durability testing method for cold-bent glass. This method is based on the hypothesis that the failure of the glass sealing system is caused by the cold bending process. It is novel in its use of full-scale glass panel specimens subjected to the maximum design cold-bend curvature to replicate the worst-case sealing boundary conditions present in actual installations. This method comprises three components: cold bending, cyclic immersion in water, and high–low temperature cycling. The durability is evaluated by assessing the laminating condition and sealing performance of the insulating laminated glass before and after testing. In total, 24 insulating glass samples from an actual engineering project were studied by the proposed methodology. The results indicate the following: (1) the proposed method demonstrates strong operational feasibility, suitable for durability testing and the assessment of cold-bent insulating laminated glass across diverse dimensions; (2) no significant quality or sealing issues were observed in the tested samples during the tests, suggesting that durability is minimally affected when the glass’s cold bending warpage is controlled within certain range; and (3) a discernible trend observed in the full-scale test data is that cold bending results in increased misalignment and decreased argon content. These findings provide a valuable reference for the design and construction of cold-bent glass curtain wall projects.

Abstract Due to the inherent material limitations of Cu/Al substrates—particularly their low melting point (approximately 660°C for Al) and high coefficient of thermal expansion (CTE)—these materials pose significant challenges in sealing processes. To address these challenges, this study focuses on developing a tailored low‐temperature, high‐CTE phosphate sealing glass. The structural influence of Y 2 O 3 substitution for Sb 2 O 3 in phosphate glasses was comprehensively investigated using Fourier‐transform infrared spectroscopy (FTIR), Raman spectroscopy, and nuclear magnetic resonance (NMR). The corresponding thermal properties and chemical durability of the glasses were also evaluated. The aim is to develop glasses with a high CTE (>14 × 10 −6 °C −1 ), low sealing temperature (<600°C), and enhance chemical durability, thereby enabling highly reliable sealing of Cu/Al substrates.