The presented initiative is an attempt to combine both, numerical simulation and experimental techniques, to further understand the phenomena which characterize the pull-out of a reinforcement bar from the surrounding concrete ‘matrix’. Based on the Finite-Element Method, non-linear constituitive relations are introduced to reflect the sliding of the reinforcement bar inside the concrete and to...

cracked and un-cracked brazilian disc specimens subjected to diametral compression were used for conducting fracture toughness and tensile strength experiments on a polymer concrete (pc) material. the value of mode i fracture toughness (kic) was determined from the center- cracked brazilian disc and the indirect tensile strength (σt) was obtained from the un-cracked brazilian disc specimen. the...

A fracture theory for a heterogeneous aggregate material which exhibits a gradual strainsoftening due to microcracking and contains aggregate pieces that are not necessarily small compared to struttural dimensions is developed. Only Mode I is considered. The fracture is modeled as a blunt smeared crack band, which is justified by the random nature of the microstructure. Simple triaxial stress-s...

The fracture front in concrete, as well as rock, is blunted by a zone of microcracking, and in ductile metals by a zone of yielding. This blunting causes deviations from the structural size effect known from linear elastic fracture mechanics (LEFM). The size effect is studied first for concrete or rock structures, using dimensional analysis and illustrative examples. Fracture is considered to b...

This study numerically predicts the failure scenario of a cracked concrete gravity dam through a push-over nonlinear analysis. The mixed-mode Linear Elastic Fracture Mechanics (LEFM) was employed using the extended finite element method (XFEM). The dam base was considered to be fully fixed without any foundation effects. The hydrostatic pressure on the dam's upstream face was increased incremen...

Concrete is a heterogeneity material consisting of mortar and aggregate in meso scale. Evaluation of fracture process in this scale is useful to clarify the material characteristics of concrete. However, analytical approach in this scale has not been carried out enough yet. And in meso scale, mortar-aggregate interface is the weakest part in concrete so that it is considered that its material p...

The main objective of this study is to evaluate the workability of fresh portland cement concrete while it is still in the mixing truck by determining fundamental rheological parameters (plastic viscosity and yield stress). Nine concrete mixtures with different values of yield stress and plastic viscosity were tested in a concrete truck. The measurements made with the truck were based on the ty...

The pyroclastic aggregate concrete of Trajan's Markets (110 CE), now Museo Fori Imperiali in Rome, has absorbed energy from seismic ground shaking and long-term foundation settlement for nearly two millenia while remaining largely intact at the structural scale. The scientific basis of this exceptional service record is explored through computed tomography of fracture surfaces and synchroton X-...

Plain concrete structures such as dams or retaining walls, as well as rock structures such as tunnels, caverns, excavations, and rock slopes, have commonly been designed by elastic-perfectly plastic analysis in which the tensile yield strength of the material is taken as zero. The paper analyzes the safety of this "notension" design in the light of the finiteness of the tensile strength of conc...