Experimental-computational determination of mechanical fracture parameters of concrete for probabilistic life-cycle assessment

2014 ◽  
pp. 801-807 ◽  
Author(s):  
L Řoutil ◽  
D Lehký ◽  
H Šimonová ◽  
B Kucharczyková ◽  
Z Keršner ◽  
...  
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Mechanical Fracture ◽  
Fracture Parameters

Fracture Resistance of AAAS Composites with Ceramic Precursor

2021 ◽  
Vol 322 ◽  
pp. 54-59
Author(s):  
Iva Rozsypalová ◽  
Petr Daněk ◽  
Pavla Rovnaníková ◽  
Zbyněk Keršner
Keyword(s):  
Mouth Opening ◽  
Crack Model ◽  
Arithmetic Means ◽  
Mechanical Fracture ◽  
Three Point Bending ◽  
Static Modulus ◽  
Fracture Parameters ◽  
Ceramic Precursors ◽  
Static Modulus Of Elasticity

The paper deals with selected alkali-activated aluminosilicate (AAAS) composites based on ceramic precursors in terms of their characterization by mechanical fracture parameters. Composites made of brick dust as a precursor and an alkaline activator with a silicate modulus of Ms = 0.8, 1.0, 1.2, 1.4 and 1.6 were investigated. The filler employed with one set of composites was quartz sand, while for the other set it was crushed brick. The test specimens had nominal dimensions of 40 × 40 × 160 mm and were provided with notches at midspan of up to 1/3 of the height of the specimens after 28 days. 6 samples from each composite were tested. The specimens were subjected to three-point bending tests in which force vs. displacement (deflection at midspan) diagrams (F–d diagrams) and force vs. crack mouth opening (F–CMOD) diagrams were recorded. After the correction of these diagrams, static modulus of elasticity, effective fracture toughness, effective toughness and specific fracture energy values were determined using the Effective Crack Model and the Work-of-Fracture method. After the fracture experiments, informative compressive strength values were determined from one of the parts. All of the evaluations included the determination of arithmetic means and standard deviations. The silicate modulus values and type of filler of the AAAS composites significantly influenced their mechanical fracture parameters.

Detailed Determination of Mechanical Fracture Parameters of Concrete after Fire Experiments

2018 ◽  
Vol 272 ◽  
pp. 220-225 ◽  
Author(s):  
Hana Šimonová ◽  
Tomáš Trčka ◽  
Michal Bejček ◽  
Iva Rozsypalová ◽  
Petr Daněk ◽  
...  
Keyword(s):  
Statistical Dependence ◽  
Crack Model ◽  
Mechanical Fracture ◽  
Three Point Bending ◽  
Fracture Parameters ◽  
Fracture Tests ◽  
Detailed Determination ◽  
Bending Fracture ◽  
Fire Experiments

The aim of this paper is to describe the procedure of determining the mechanical fracture parameters of selected concrete specimens taken from panels after the fire experiments. The records (in form load vs displacement diagrams) of three-point bending fracture tests of these specimens with initial stress concentrators was first advanced corrected and subsequently evaluated using the Effective Crack Model and the work-of-fracture method. The increasing temperatures during the fire experiments ranging between 550 to 1000 °C led to a decrease of modulus of elasticity and fracture toughness values and to the increase of fracture energy value. The 2D laser profile scanner was used to estimate the degree of complexity of fracture surfaces; its statistical dependence on the mechanical fracture parameters proved to be moderate – the absolute value of the correlation coefficient was about 0.5°[–].

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