Mechanical Fracture Parameters of Fine-Grain Concretes with Zeolite: Effect of Composition and Origin of Cements

2014 ◽  
Vol 1000 ◽  
pp. 330-333
Author(s):  
Hana Šimonová ◽  
Pavel Schmid ◽  
Zbyněk Keršner ◽  
Pavla Rovnaníková
Keyword(s):  
Czech Republic ◽  
Portland Cement ◽  
Natural Zeolite ◽  
Mineralogical Composition ◽  
Fracture Parameter ◽  
Mechanical Fracture ◽  
Fine Grain ◽  
Chemical And Mineralogical Composition ◽  
Parameter Values ◽  
Different Origin

This paper introduces results of fracture experiments on fine-grain concrete specimens prepared from CEM 42.5 R Portland cement of different origin (five Czech Republic localities: Mokrá, Hranice, Radotín, Prachovice, Čížkovice), with natural zeolite admixture. Although the specimens were produced using the same type of cement, this paper shows that even small differences in chemical and mineralogical composition (caused by different origin) can result in changes of mechanical fracture parameter values.

Evaluation of Concrete Fatigue Measurement Using Standard and Non-Linear Regression Model

2011 ◽  
Vol 121-126 ◽  
pp. 2726-2729 ◽  
Author(s):  
Stanislav Seitl ◽  
Hana Šimonová ◽  
Zbyněk Keršner ◽  
Alfonso Fernández Canteli
Keyword(s):  
Fatigue Loading ◽  
Weibull Model ◽  
Fracture Parameter ◽  
Power Dependence ◽  
Dynamic Tests ◽  
Standard Description ◽  
Mechanical Fracture ◽  
Fatigue Measurement ◽  
Parameter Values ◽  
Specific Fracture

The paper deals with the problem of estimating the S-N curve for the cement based composites under fatigue loading. Selected approximation curves for mechanical-fracture parameter values derived from specific fracture energy in time are used to determine the most accurate fatigue parameter values corresponding to the age of specimens when dynamic tests were performed. For standard description of S-N curve the power dependence and Weibull model developed by Castillo et al. are used to discuss the problem under study and the suitability of using models as an input data for finite element modeling

Effect of Cement Replacement by Zeolite on the Basic Mechanical Fracture Properties of Concrete: A Parametric Study

2014 ◽  
Vol 969 ◽  
pp. 140-143 ◽  
Author(s):  
Pavla Rovnaníková ◽  
Pavel Schmid ◽  
Zbyněk Keršner
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Fracture Energy ◽  
Parametric Study ◽  
Elasticity Modulus ◽  
Volume Density ◽  
Fracture Parameter ◽  
Mechanical Fracture ◽  
Fracture Properties ◽  
Parameter Values

This paper introduces the results of fracture experiments on concrete specimens of different composition modified by zeolite (7.5 to 30 % by weight of cement dosage). It presents the determination and comparison of basic mechanical/fracture parameter values such as volume density, compressive strength, elasticity modulus, effective fracture toughness and fracture energy.

Effect of Spontaneous Drying on Mechanical Parameters of Alkali-Activated Slag Mortar

2014 ◽  
Vol 969 ◽  
pp. 144-147
Author(s):  
Pavel Rovnaník ◽  
Libor Topolář ◽  
Pavel Schmid ◽  
Zbyněk Keršner
Keyword(s):  
Drying Shrinkage ◽  
Industrial Applications ◽  
Fracture Parameter ◽  
Lower Strength ◽  
Mechanical Fracture ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
High Level ◽  
Parameter Values ◽  
Alkali Activated

Alkali-activated slag is a material which has great potential for use in industrial applications. The main drawback of this material is the high level of autogenous and especially drying shrinkage that affects it, causing the deterioration of its mechanical properties. Mechanical and mechanical fracture parameter values show that an alkali-activated slag composite which is saturated with water is more brittle and exhibits lower strength in comparison with the same material after being surface-dried. These results are essential for the adjustment of testing conditions in order to obtain accurate and reproducible results.

Complex Evaluation of Fatigue Tests Results of Plain C30/37 and C45/55 Class Concrete Specimens

2013 ◽  
Vol 592-593 ◽  
pp. 801-804 ◽  
Author(s):  
Hana Šimonová ◽  
Barbara Kucharczyková ◽  
Ivana Havlíková ◽  
Stanislav Seitl ◽  
Zbyněk Keršner
Keyword(s):  
Fatigue Tests ◽  
Fatigue Properties ◽  
Fracture Parameter ◽  
Dynamic Tests ◽  
Mechanical Fracture ◽  
Time Dynamic ◽  
Complex Evaluation ◽  
Nominal Size ◽  
Power Law Equation ◽  
Parameter Values

The aim of this paper is to summarize basic fatigue parameter values obtained for plain C30/37 and C45/55 class concrete specimens during dynamic tests. Selected approximation curves for relative mechanical-fracture parameter values over time − compressive cube strength, modulus of elasticity, effective fracture toughness and specific fracture energy − were used to determine the most accurate fatigue parameter values corresponding to the age of specimens at the time dynamic tests were performed. Three models are used for standard description of theS−Ncurve: the Weibull and Gumbel models developed by Castillo et al. as well as the power law equation. Fatigue properties were obtained from three point bending tests conducted on beam specimens (100×100×400 mm nominal size) with a central edge notch (depth 10 mm).

Pilot Study of the Effect of Admixtures in Fine-Grained Cement-Based Composites on Volume Changes and Fracture Parameters

2014 ◽  
Vol 969 ◽  
pp. 294-297
Author(s):  
Vlastimil Bílek Jr. ◽  
Libor Topolář ◽  
Hana Šimonová ◽  
Barbara Kucharczyková ◽  
Ivana Havlíková ◽  
...  
Keyword(s):  
Mouth Opening ◽  
Partial Replacement ◽  
Crack Mouth Opening Displacement ◽  
Fracture Parameter ◽  
Volume Changes ◽  
Opening Displacement ◽  
Mechanical Fracture ◽  
Fine Grained ◽  
Stable Crack Propagation ◽  
Parameter Values

The partial replacement of cement in concrete by an alternative admixture is a current topic in materials engineering. In order to examine the effect of replacing 20 % of the weight of Portland cement in fine-grained concrete using selected admixtures on volume changes and mechanical fracture parameter values, a set of specimens was fabricated from these quasi-brittle materials. Granulated blast-furnace slag, high-temperature fly ash, metakaolin and specially selected combinations of them were used as admixtures. Three-point bending fracture tests were conducted on these specimens and load versus crack mouth opening displacement (PCMOD) diagrams were recorded during the testing. In this paper, the outputs of the double-K fracture model were used for the prediction of beginning of stable crack propagation in fine-grained cement-based composites with admixtures.

scholarly journals Mineralogical Composition and Physical–Mechanical Properties of Dasht-E-Taatrang Zar Sand Deposits (Afghanistan)

2020 ◽  
Vol 5 (1) ◽  
pp. 2
Author(s):  
Hemayatullah Ahmadi ◽  
Atal Yousufi ◽  
Amir Mohammad Mosazai
Keyword(s):  
Mechanical Properties ◽  
Construction Material ◽  
Mineralogical Composition ◽  
Xrd Analysis ◽  
Sample Collection ◽  
Extensive Field ◽  
Chemical And Mineralogical Composition ◽  
New City ◽  
Two Phases ◽  
Field Works

Sand is a common construction material used for various purposes, e.g., concrete, mortar, render, screed, and asphalt. The usage depends on its fineness, and its fineness is controlled by its mineralogical composition and physical-mechanical properties. This research aims to determine the chemical and mineralogical composition and the physical-mechanical properties of the Dasht-e-Taatrang Zar sand deposits within the Qarabagh and Bagram districts of Kabul and Parwan provinces in Afghanistan. To achieve the objectives of this research, a review of the existing literature has been combined with new extensive field works for macroscopic studies and sample collection, and laboratory analyses. In total, 23 samples during two phases of field works were collected and subjected to lab works for XRF, Schlich, and XRD analysis to determine the chemical and mineralogical composition; moreover, sieve and Atterberg analysis, specific gravity, soundness, and alkali-silica reaction tests were performed for characterization of the physical-mechanical properties of the studied samples. The results of the tests show that the Taatrang Zar sand deposits are considered as a suitable construction material, and due to their simple accessibility, the deposits have high potential as a construction material supplier for the Kabul new city project (Dehsabz) in Kabul and adjacent Parwan and Kapisa provinces.

Basic Physical and Mechanical Properties of Composites Based on Three Different Cements

2016 ◽  
Vol 677 ◽  
pp. 186-190 ◽  
Author(s):  
Monika Čáchová ◽  
Eva Vejmelková ◽  
Kateřina Šestáková ◽  
Pavel Reiterman ◽  
Martin Keppert ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Open Porosity ◽  
Mercury Porosimetry ◽  
Physical And Mechanical Properties ◽  
Mineralogical Composition ◽  
Physical Parameters ◽  
Vacuum Saturation ◽  
Saturation Method ◽  
Properties Of Composites

This article is focused on cement based composites. Two cements differing in mineralogical composition are utilised as main binder in composites mixtures. Results of measured physical parameters of studied materials are presented. For the sake of comparison, a reference material with Portland cement was also prepared. Basic physical properties (measured by water vacuum saturation method and by helium pycnometry), characterizations of pore system (determined by mercury porosimetry) and mechanical properties are the matter of this study. Composites show various open porosity; the results of open porosity of materials containing special cements show higher values, in comparison with composite based on Portland cement. This fact of course influences other material characteristics - mainly mechanical properties.

scholarly journals WHAT THE BRICKS TELL US FROM A TEMPLE AT BURKHAN KHALDUN MOUNTAINS: CHRONOLOGICAL INSIGHTS FROM pIRIR LUMINESCENCE

2017 ◽  
pp. 4-12
Author(s):  
Saran S ◽  
Tengis S ◽  
Tsogtbaatar B
Keyword(s):  
Mineralogical Composition ◽  
World Heritage Site ◽  
Sacred Landscape ◽  
Great Opportunity ◽  
Fine Grain ◽  
Infrared Luminescence ◽  
Heritage Site ◽  
Unesco World Heritage Site ◽  
Time Period ◽  
History Of

The Burkhan Khaldun Mountains (Mongolia) and its surrounding sacred landscape are associated with Genghis Khan’s birth and burial place as described in “The Secret History of the Mongols”. It was listed as a UNESCO World Heritage Site on 4 July 2015 under the title «Great Burkhan Khaldun Mountain and its surrounding sacred landscape.”This study offered a great opportunity to apply the recently developed post-IR infrared luminescence (pIRIR) approach to feldspar using coarse and polymineral fine grain techniques and determine the manufacturing date of a brick sample associated with the ruins of the Buddhist temple at the Burkhan Khaldun Mountains. Furthermore, the mineralogical composition of different blue-grey colored bricks from various temple buildings such as the Buddhist temples in Karakorum, Dugan in Erdene Zuu and Avargyn Balgas were studied. The original place and date of manufacturing of the bricks was revealed using the pIRIR180 and pIRIR240 from coarse and fine grains from a heated feldspar sample and were 1280±40 AD and 1230±50 AD, correspondingly, which falls into the time period of extensive constructions in Karakorum.

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