Age-Dependent Lattice Discrete Particle Model for Quasi-Static Simulations

Abstract

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.

Comprehensive data collection for the development of anchorage lifetime prediction models

“…For that purpose, tests at several ages, for all tested concrete mixes, were conducted. Data, which features concretes of different composition, tested in a time range between 1 day and 440 days were generated . The nominal ages tested corresponding to the test types can be found in Table .…”

“…The obtained experimental data serve as calibration data of concrete creep and shrinkage models, which can be applied for modeling fastening systems under sustained loads, and quantifying the concrete creep contribution as well as the effect on the bond stresses along time, as discussed in the studies of Wan et al , Wendner et al and Boumakis et al .…”

Design for lifecycle robustness of fastening systems

“…This cannot be done without the contribution of industrial stakeholders, who collect large experimental databases and perform cooperative research with academia, where advanced multi-physics and multi-scale models of concrete, steel, and mortar are being developed. Additionally, the mechanical long-term performance of all involved materials are studied in detail [24][25][26][27]. They enable the identification of key parameters affecting the time evolution of important characteristics, such as connection ductility, load capacity, deformation capacity, durability, or creep response.…”

Random and Gradient Based Fields in Discrete Particle Models of Heterogeneous Materials

“…An extended version of LDPM is currently being developed and simulates various coupled deterioration mechanisms, such as Alkali-Silica reaction (ASR) [12], [15]. A further development is the age-dependent LDPM framework in which the local material properties are derived by chemo-mechanical coupling with a chemo-hygro-thermal model [16], [17] which also drives the creep and shrinkage analysis in a rate type form [18].…”