Comparison of size effect for different types of strength tests

1982 ◽  
Vol 15 (4) ◽  
pp. 243-254 ◽  
Author(s):  
Y. Tsur-Lavie ◽  
S. A. Denekamp

Author(s):  
T. R. Welberry ◽  
M. Honal

AbstractWe show in this paper that by applying size-effect distortions to a perfect Penrose tiling, on the basis that rhomb-edges which connect different types of vertices assume different lengths, we can obtain a diffraction pattern which shows remarkable similarity to the zero-level (





2021 ◽  
Vol 880 ◽  
pp. 161-167
Author(s):  
Joaquin Humberto Aquino Rocha ◽  
Fernando Palacios Galarza

Waterproof additives and bonding agent mixtures are commonly employed in the setting up of render mortars. This practice often shows beneficial results, enhancing the properties of the common mortars. Yet, the use of these additives does not seem to have a direct effect on the mechanical properties of the mortars. This study thus aims to evaluate the influence of the use of waterproof and adhesion additives on the mechanical properties of render mortars. Based on their chemical composition, three different types of mortar admixtures were evaluated, using fourfold additive-mortar weight ratios: 0%, 1.5%, 3%, and 5%. Compressive and flexural strength tests were conducted after 28 days. The results showed a negative impact on the mechanical properties of the mortars. The lowest flexural and compression strength values reported are 1.52 and 4.57 (MPa), respectively. However, all compressive and flexural strength values lied within the limit range recommended by the “Mortars applied on walls and ceilings” construction code (i.e., ABNT NBR 13281). It is compulsory to continue the experimental tests to determine render mortars mechanical properties with higher waterproof additive-mortar weight ratios since higher ratios might produce mortars with non-allowed mechanical properties.



2014 ◽  
Vol 1000 ◽  
pp. 28-34 ◽  
Author(s):  
Michael Tupý ◽  
Daniela Štefková ◽  
Konstantinos Sotiriadis ◽  
Lukáš Krmíček ◽  
Ladislav Carbol ◽  
...  

The paper deals with testing of CO2 diffusivity through poly (vinyl butyral) (PVB) layers and their efficiency to serve as barriers against cement mortar carbonation. Two different types of PVB were tested; PVB sheet made from original extruded PVB polymer and PVB sheet made from PVB dispersion obtained from recycled windshields. The first part of the work was focused on testing CO2 diffusion when polymer sheets were exposed to a CO2 atmosphere (10% v/v CO2) with 0% RH. The excellent barrier capability against CO2 permeability of both types of polymer layers was observed. In the second part, mortar specimens were exposed for 23 days to two different carbonation regimes (laboratory conditions and chamber with CO2 atmosphere (1% v/v CO2) and 60% RH), having been coated or not with recycled PVB dispersion. Compressive strength tests, carbonation depth measurements and acoustic measurements (impact-echo method) were performed. The results showed the alternation of the compressive strength values depending on whether PVB coating was used or not. Both phenolphthalein test and impact-echo method confirmed the protective effect of PVB layer against mortar carbonation.



2014 ◽  
Vol 1013 ◽  
pp. 1-6
Author(s):  
Eduard Kozlov ◽  
Natal'ya Popova ◽  
Marina Fedorischeva ◽  
Nina Koneva

In the paper we consider the size effect of the closed structural formations as the function of accumulation of scalar density dislocations and their components under plastic deformation. The focus is on the role of interfaces of different types. The sizes are determined and the various parameters of the structure defining the micro-and mesolevel are identified at the development of the mechanisms of plastic deformation. The role of statistically stored dislocations (SSD) and geometrically necessary dislocations (GND) in the formation of the defect structure of the material is examined. It has been established that the smaller the size of the closed structure, the greater the GND part and the smaller the SSD component. The work is based on the TEM research of the structure of deformed materials.



2015 ◽  
Vol 17 (3) ◽  
pp. 8-12 ◽  
Author(s):  
Magdalena Janus ◽  
Kamila Bubacz ◽  
Justyna Zatorska ◽  
Ewelina Kusiak-Nejman ◽  
Adam Czyżewski ◽  
...  

Abstract In presented studies the photocatalytic decomposition of NOx on gypsum plates modified by TiO2-N,Cphotocatalysts were presented. The gypsum plates were obtained by addition of 10 or 20 wt.% of different types of titanium dioxide, such as: pure TiO2 and carbon and nitrogen co-modified TiO2 (TiO2-N,C) to gypsum. TiO2-N,C photocatalysts were obtained by heating up the starting TiO2 (Grupa Azoty Zakłady Chemiczne Police S.A) in the atmosphere of ammonia and carbon at the temperature: 100, 300 i 600ºC. Photocatalyst were characterized by FTIR/DRS, UVVis/DR, BET and XRD methods. Moreover the compressive strength tests of modified gypsum were also done. Photocatalytic activity of gypsum plates was done during NOx decomposition. The highest photocatalytic activity has gypsum with 20 wt.% addition of TiO2-N,C obtained at 300ºC.



2021 ◽  
Vol 338 ◽  
pp. 01017
Author(s):  
Rafael Miozga ◽  
Marta Kurek

The paper reported the results of a study concerned with the principle of operation of the 3D printing technology using the method of selective sintering of metallic powders, and taking into account their advantages and drawbacks. The principle of the operation of 3D printing technology applying the DMLS (Direct Metal Laser Sintering) method is presented. On the basis of the performed tests, the anisotropy of the printed materials is demonstrated. The reasons responsible for this phenomenon are identified. The paper presents the results of the strength tests which indicate that the crack during the test occur in the building direction of the layers during printing. The results were compiled for two different types of specimens and two different testing machines.



2016 ◽  
Vol 36 (9) ◽  
Author(s):  
吴未 WU Wei ◽  
许丽萍 XU Liping ◽  
张敏 ZHANG Min ◽  
欧名豪 OU Minghao ◽  
符海月 FU Haiyue


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