Sustainability of Reinforced Concrete Beams with/without BF Influenced by Cracking Capacity and Chloride Diffusion

Abstract

Concrete’s production causes pronounced environmental impacts. It is confirmed that adding basalt fiber (BF) into concrete can improve the mechanical properties and reduce the chloride diffusion coefficient of concrete. Moreover, research on the environmental impact of BF and its application in concrete has gradually emerged in recent years. However, there is little research on the chloride diffusivity of concrete structures with BF under the coupling interaction of external loads and chloride action. Therefore, at first, six beams were cast to obtain the depth-dependent chloride diffusivity of concrete under the coupling interaction of chloride penetration and 50% and 80% of the cracking capacity. Then, a functional unit (FU) combining durability, cracking capacity and volume was proposed to evaluate the sustainability of the concrete structure. In addition, three extra FUs (volume, considering volume and cracking capacity simultaneously and considering volume, cracking capacity and durability simultaneously) were also proposed and compared with the first FU. Results indicate that, regardless of the applied load level, the average chloride diffusion coefficient of a reinforced concrete (RC) beam with BF is larger than that of an ordinary RC beam. Moreover, the sorting of life cycle assessment (LCA) results will vary significantly with the different preset functional units. When taking the cracking capacity into consideration, adding BF into concrete is a suitable solution to improve the sustainability of RC beams.

Chloride Binding Capacity and Its Effect on the Microstructure of Mortar Made with Marine Sand

“…Therefore, the chloride binding capacity is of great significance for the promotion of MS applications. The chloride binding capacity of concrete can be divided into two aspects [13][14][15][16]: a physical one, in which the chloride ions can be adsorbed by C-S-H gel because of its high specific surface values, and a chemical one, which denotes the reaction between chloride ions and C 3 A or AFm phase. However, chemical binding occupies the dominant position, and the contribution of chemical binding accounts for 70% of the total bound chloride capacity, whilst the contribution of physical adsorption remains stable between 25% and 28% [14].…”