CEMENT & CONCRETE COMPOSITES(2021 - 2022)
Numerical simulation and experiment on the coupled effects of macro-cell corrosion and multi-ion equilibrium with pseudo structural concrete
Wang, Z; Maekawa, K; Takeda, H; Gong, FY
CEMENT & CONCRETE COMPOSITES, Elsevier Ltd., Vol.123, 2021, OCT.
(https://doi.org/10.1016/j.cemconcomp.2021.104181)
Abstract
Corrosion of reinforcing bars in structural concrete is a critical deterioration issue. Corrosion could attribute to the electro-chemical reactions which are closely related to the electrical field and chemical substances. Generally, two types of corrosion are classified including the micro-cell and macro-cell corrosion depending on whether the anodic and cathodic polarization take place at the same location or not. This paper presented a numerical evaluation of macro-cell corrosion of structural concrete with integrating the electrical field and multiion kinetics in electrolyte. Space-averaged simulation method was adopted which allowed the analytical domain to be structural members, structures or even structure clusters instead of specific concrete-reinforcement interface. Experimental validation was also conducted with pseudo concrete materials to verify the reliability of numerical simulation where satisfied correlation was found.
Numerical method for predicting flow and segregation behaviors of fresh concrete
Xu, ZS; Li, ZG
CEMENT & CONCRETE COMPOSITES, Elsevier Ltd., Vol.123, 2021, OCT.
(https://doi.org/10.1016/j.cemconcomp.2021.104150)
Abstract
Current meshless particle methods are able to simulate the flow of fresh concrete, but fail to predict the segregation since fresh concrete is regarded as homogeneous fluid. This study aims to develop a numerical approach to predict the segregation of coarse aggregate (CA) in fresh concrete together with the flow behavior. A double-phase & multi-particle (DPMP) model was proposed to describe fresh concrete, which treats fresh concrete as a double-phase fluid composed of matrix mortar and the CA particles that had random shapes, size distribution, and different density from matrix mortar. Each CA particle was formed by the element particles, of which number was dependent on the size and shape of described CA particle. Three types of inter-particle interaction, including CA-CA particles, CA-mortar particles, and two mortar particles, were investigated, respectively. Then, based on the complete implicit MPS (I-MPS) method and the DPMP model, the L-box flow of two series of high fluidity concrete were simulated. The ability of the proposed numerical approach to simultaneously simulate the flow and segregation behaviors of fresh concrete was confirmed. Moreover, this numerical method can analyze the changes of localized rheological parameters of segregated concrete.