Evaluation of MSA mortar pore structure characteristics in water-saturated curing environment based on Talbot gradation theory

Abstract

To investigate the impact of aggregate gradation on the pore structure of manufactured sand aggregate (MSA) mortar and its fractal characteristics under water-saturated curing conditions. The static pore structure characteristics of the pore structure of MSA mortar with 10 aggregate gradations were explored. The analysis is based on the Talbot gradation theory, the NMR technique, and fractal theory. The surface area and roughness of aggregate particles contribute to a reduction in the porosity of MSA mortar. The aggregate gradation is quantified using the Talbot index. The correlation characteristics and intrinsic relationships between Talbot index and different pore structure parameters, such as total porosity, pore gradation, pore fractal dimension and permeability of MSA mortar, are analyzed. Two pore division methods are employed to explore the interrelationships among pore types, fractal dimensions and Talbot index. Additionally, A correlation model between Talbot index and permeability is developed to investigate the intrinsic correlation of parameter variations from a microscopic perspective. It is found that aggregate gradation is optimal with a Talbot index of 0.4, leading to the highest number of micropores and the lowest number of larger pores, thereby enhancing resistance to seepage and dissolution. Furthermore, The contribution of pore size, content and type to permeability varies with different aggregate gradations. Overall, this study serves as a valuable guide for the design and durability evaluation of mortar concrete projects in water-saturated curing environments.