Anomalous moisture transport in dried cementitious material: A numerical analysis

Moisture transport is an important phenomenon related to the deterioration of concrete; thus, a quantitative evaluation is essential to clarify the deterioration level. However, anomalies have been observed in the moisture transport in cement-based materials, and the mechanism has been debated. To clarify this mechanism, anomalous moisture transport in cement-based materials was investigated using a mesoscale rigid body spring model (RBSM). The influences of relevant phenomena reported in previous studies (e.g., the colloidal nature of calcium silicate hydrate (C-S-H) and microcracks) were introduced. The good agreement of the moisture transport characteristics and mechanical responses with reference experiments demonstrated the capability of the proposed method. Further numerical investigations indicated that anomalies in penetration depth and cumulative water absorption exhibited sigmoidal (S-shaped) curves that were differentiated by the degree of drying. The S-shape was mainly caused by the colloidal nature of C-S-H, whereas microcracking was a secondary phenomenon affecting the S-shaped curve. • Anomalous moisture transport in cement-based material was studied by mesoscale RBSM. • Influence of relevant phenomena on anomalous moisture transport was investigated. • This anomalous behavior originates from the colloidal behavior of C-S-H and microcracks. • Anomalies in moisture transport behave differently at different drying degrees. • Penetration depth and cumulative water absorption exhibit an S-shaped curve.