Experimental Determination of how the Static Modulus of Elasticity is Influenced by the Value of the Upper Loading Stress

2018 ◽  
Vol 272 ◽  
pp. 64-69
Author(s):  
Dalibor Kocáb ◽  
Petr Misák ◽  
Petr Daněk ◽  
Barbara Kucharczyková ◽  
Romana Halamová

There is a large number of factors that have a strong influence on the elastic modulus of concrete. These are technological influences as well as issues connected with the testing methods for its determination, one of which is the choice of the upper loading stress of cyclic loading during testing the static modulus of elasticity of concrete in compression. The upper loading stress should be equal to 1/3 of the specimen’s compressive strength, however, its choice is often made incorrectly. This paper describes an experiment focused on discovering the impact that deviating from the 1/3 upper loading stress has on the measured value of the static modulus of elasticity.

2018 ◽  
Vol 195 ◽  
pp. 01005 ◽  
Author(s):  
M. Mirza Abdillah Pratama ◽  
B. Sri Umniati ◽  
Bunga Arumsari Mutiara Wulandari ◽  
Ay Lie Han ◽  
Buntara Sthenly Gan ◽  
...  

The elastic modulus of materials plays a role in determining the stiffness of a structural element and its level of serviceability. Previous research indicates that the concrete modulus of elasticity could be improved by combining 2 (two) concrete mixes using a gradual compacting method. In this study, the effect of different concrete strength combinations to the resulting modulus of elasticity is examined. Three types of concrete mixes with a strength of 30 MPa, 40 MPa and 50 MPa are prepared. The graded concrete is moulded in cylindrical concrete casts (150 mm x 300 mm) with the following casting configurations: 30-40 MPa, 30-50 MPa, and 40-50 MPa. The static modulus of elasticity test is performed at an age of 28 days using compressometers in accordance with ASTM C469. The test results show that the modulus of elasticity of the graded concrete is proportionally influenced by the stiffness of the higher and the lower concrete material. Additionally, the resulting compressive strength of the graded concrete is determined by the lower concrete strength.


2011 ◽  
Vol 57 (3) ◽  
pp. 249-260 ◽  
Author(s):  
Eethar Thanon Dawood ◽  
Mahyuddin Ramli

Abstract This study investigates the use of steel fibers and hybrid composite with a total fibers content of 2% on the high strength flowing concrete and determines the density, compressive strength, static modulus of elasticity, flexural strength and toughness indices for the mixes. The results show that the inclusion of more than 0.5% of palm fibers in hybrid fibers mixes reduces the compressive strength. The hybrid fibers can be considered as a promising concept and the replacement of a portion of steel fibers with palm fibers can significantly reduce the density, enhance the flexural strength and toughness. The results also indicates that the use of hybrid fibers (1.5 steel fibers + 0.5% palm fibers) in specimens increases significantly the toughness indices and thus the use of hybrid fibers combinations in reinforced concrete would enhance their flexural toughness & rigidity and enhance their overall performances


2018 ◽  
Vol 272 ◽  
pp. 214-219
Author(s):  
Petr Misák ◽  
Tomáš Vymazal ◽  
Dalibor Kocáb ◽  
Barbara Kucharczyková

In recent years, the static modulus of elasticity is one of the most discussed property of hardened concrete. The aim of this article is to show results of 6 performed experiments focused on test results precision. The measurements were made according to the standards ISO 6784 and ISO 1920-10. More than 20 participants (laboratories) from Europe took part in these experiments. Test results were compared using the statistical methods for interlaboratory comparison. Repeatability and reproducibility, which provide more detailed information about range of expected values of elastic modulus, are the most discussed characteristics in the article.


2018 ◽  
Vol 760 ◽  
pp. 266-271
Author(s):  
Dalibor Kocáb ◽  
Libor Topolář ◽  
Vlastimil Bílek Jr. ◽  
Barbara Kucharczyková ◽  
Michaela Hoduláková ◽  
...  

This paper describes an experiment focused on monitoring the development of the modulus of elasticity and the compressive strength of composites that are based on alkali‑activated slag (AAS) during the first 28 days of ageing. The test specimens were tested at the age of 3 and 28 days using two non-destructive methods (ultrasonic pulse and resonance methods) to determine the value of the dynamic modulus of elasticity. Subsequently, the same specimens were used to determine the static modulus of elasticity using compressive stress test, during which the behaviour of the composite was monitored by equipment for recording the acoustic emission in the material. The result of the experiment is the evaluation of the behaviour of the AAS composite in regard to the development of its modulus of elasticity and compressive strength, as well as in regard to the acoustic emission method during loading.


2021 ◽  
Vol 25 (01) ◽  
pp. 100-108
Author(s):  
Samer S. Abdulhussein ◽  
◽  
Ashraf A. Alfeehan ◽  

Currently, the industry of construction requires finding efficient materials to increase the durability and strength as well as decreasing the concrete structure’s total weight. Therefore, an effort was made in this study for examining the impact of adding waste materials such as the iron lathing waste fibers. Iron lathe wastes have been deformed into twisted strips with a width of (4mm) and sieving size of (4.75-10) mm. The experimental investigation has been achieved with the use of four mixes related to light-weight concretes, involving different volumetric ratios of the iron lathing waste fibers as (0%, 1 %, 1.5 %, and 2 %). With the increase in the volume fraction of the lathing waste fibers from 0% to 2%, the results showed that there were a significant increase and improvement in compressive strength, splitting tensile strength, flexural tensile strength, static modulus of elasticity, and dynamic modulus of elasticity by 12%, 67.5%, 134%, 27%, and 26% respectively. This indicates that the iron waste fibers have an important impact in enhancing the mechanical properties of the hardened concrete through the structural change in the concrete matrix.


2019 ◽  
Vol 292 ◽  
pp. 45-49
Author(s):  
Petr Misák ◽  
Dalibor Kocáb ◽  
Martin Alexa ◽  
Barbara Kucharczyková ◽  
Petr Daněk ◽  
...  

The paper deals with results of the experiment when ordinary and lightweight concrete was subjected to cyclic loading. Each test specimen was loaded with the force equivalent to one third of the expected compressive strength value similarly to the static modulus of elasticity test with the difference that the total number of loading cycles was nearly 4500. Dynamic modulus of elasticity and compressive strength was measured before and after cyclic loading. The result of this experiment is statistical analysis of the test results and assessment of the influence of multiple cyclic loading.


2014 ◽  
Vol 1054 ◽  
pp. 243-247 ◽  
Author(s):  
Ondřej Holčapek ◽  
Jiří Litoš ◽  
Jan Zatloukal

This paper aims at determination of mechanical properties of 28 years old concrete with various nondestructive and destructive testing methods. All investigated parameters were determined on drilled cores with diameter 79.8 mm gained from existing bridge. On these samples Schmidt rebound testing and destructive force loading test were performed. Static (from loading test) and dynamic (measured by ultrasonic device) modulus of elasticity was also measured. The evaluation of destructive and nondestructive testing was according to the Czech Standards. Testing of old concrete from real structures is important especially prior to the reconstruction, strengthening or repair of the structure, when the structural engineer needs to know the characteristics. The compressive strength measured destructively on cylinders achieved average value 28 MPa, while the Schmidt rebound hammer test showed strength 44 MPa. The average value of static modulus of elasticity was 26 GPa.


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