Age-dependent lattice discrete particle model for quasi-static simulations

For decades, concrete plays an important role worldwide as a structural material. Construction planning and reliability assessment require a thorough insight of the effects that determine concrete lifetime evolution. This study shows the experimental characterization as well as the results of subsequent aging simulations utilizing and coupling a Hygro-thermo-chemical (HTC) model and the Lattice Discrete Particle Model (LDPM) with aging effects for concretes at various early ages. The HTC component of the computational framework allows taking into account any form of environmental curing conditions as well as known material constituents and predicts the level of concrete maturity. Mechanical response and damage are captured by the well-established LDPM, which is formulated in the framework of discrete meso-scale constitutive models. The chemo-mechanical coupling is accomplished by a set of aging functions that link the meso-scale material properties to an effective aging degree, accounting for cement hydration, silica fume reaction, polymerization, and temperature effects. After introducing the formulations the framework is applied to experimental data of 3 standard low and higher strength concretes. Investigated tests include two types of unconfined compression, Brazilian splitting, three-point-bending, and wedge splitting. Following the model calibration the framework is validated by purely predictive simulations of structural level experimental data obtained at different ages for the same concretes