Work

Experimental study on pore structure and capillary absorption characteristics of concrete under cyclic sulfate attack

Year: 2026

Type: article

Abstract: Understanding the erosion of concrete pore structure by sulfate solutions is critical for preventing sulfate-induced damage. This study quantitatively analyzes the evolution of pore structure and capillary absorption characteristics during concrete capillary absorption after cyclic sulfate attack at ambient temperature, employing experimental methods including nuclear magnetic resonance (NMR) and uniaxial compression, alongside conducting mechanical compression tests. The findings demonstrate: (1) The evolution of pore structure under sulfate attack can be divided into three stages: initial stage (0-10 cycles) dominated by erosion product filling leading to porosity reduction; intermediate stage (10-30 cycles) where crack propagation causes a sharp drop in mechanical uniaxial compressive strength ( UCS ); late stage (30-40 cycles) with crack development stabilizing. (2) Concrete capillary absorption intensifies with increasing erosion cycles. Accumulated products reduce average pore size, converting partial pores into effective capillary pores; the dominant pore sizes in mesopores/micropores approach the optimal range (0.1-5 μm); microcrack proliferation increases total capillary pores, collectively enhancing concrete absorption capacity. Quantitative analysis based on the Washburn equation revealed a dramatic increase in the equivalent hydraulic radius, signaling a fundamental shift in the water transport mechanism from capillary absorption to crack-dominated flow. (3) Micropores serve as the core driving force for capillary absorption; mesopores relay water transport; macropores rely on micro-mesopore networks to distribute water; open pores maintain dynamic absorption-diffusion equilibrium. (4) As erosion intensifies, capillary absorption rate in edge zones significantly surpasses that in core regions; furthermore, enhanced overall absorption capacity synchronously amplifies this effect. • This paper comprehensively characterizes the coupling relationship between pore structure evolution and water absorption behavior during cyclic sulfate attack, focusing on revealing dynamic response patterns of water transport mechanisms throughout erosion progression, aiming to provide experimental foundations for refining sulfate attack theory and developing long-term protection technologies for concrete.

Source: Case Studies in Construction Materials

DOI: 10.1016/j.cscm.2026.e05827

Authors: Junqiao Yu, Jian Lin, Yun Wu, Yongheng Li, Xiaoqiang Xi

Institutions: Anhui Jianzhu University, China University of Mining and Technology

Language: English

Topic: Concrete Corrosion and Durability

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,660

Funders: National Natural Science Foundation of China, Natural Science Foundation of Anhui Province