Coupled Heat and Moisture Transport in Concrete at Elevated Temperatures—Effects of Capillary Pressure and Adsorbed Water

Influence of moisture on fire resistance of side-plated RC beams

“…the first step of the analysis). In the second step, the coupled heat and mass transfer in the beam is observed by implementing the model of Davie et al [1]. Additionally, the recommendations of Dwaikat and Kodur [2] are implemented in this step considering the thermal and mechanical damage dependent calculations of concrete permeability and predictions of concrete spalling.…”

“…In general, two fundamental groups of such models can be distinguished. The first group of these models are the models where "mechanical" (stress induced) damage effects are neglected in the heat and mass transfer inside the concrete element (e.g., [1]) and are, therefore, applicable for concrete structures with zero mechanical loading and where thermal dilatations of the concrete element are not (significantly) restrained, so that no (significant) stress is induced in the element during fire. In a general case of a mechanically loaded concrete structure in fire, however, the alternative fully coupled thermo-hygro-mechanical models must be applied (e.g.…”

Multi-Physics Modeling of Fire-Induced Damage in High-Performance Concrete

“…Accounting for the presence of fluid flowing through the matrix, the thermal equilibrium over volume V with boundary surface S in the absence of heat generation is (8) where ρ w and c w , and ρ s and c s are the density and heat capacity of the fluid and solid, respectively, v w is the fluid velocity, and q s is the conductive heat flux through S. Fluid flow in the matrix is modeled using Forchheimer's Law; which states that high flow velocities reduce the effective permeability of the medium. For low velocities, it closely approximates the more well-known Darcy's Law.…”

“…The coupled thermo-poro-mechanical constitutive behavior of homogenous concrete has been computationally modeled [5][6][7][8]. The framework has been used to predict the time and location of thermal spall during heating [9,10].…”

Spalling of concrete due to fire exposure: A coupled fracture mechanics and pore pressure approach

“…Each of these phases is described by a mass balance equation which are combined with an equation of energy assuming thermodynamic equilibrium [19][20][21]. The resulting system of 4 coupled differential equations depicted in equation (1) numerically by the Finite Element Method (FEM) [22].…”