scholarly journals Analytical and Experimental Investigations on Mechanical Properties of Weak Plane Bedding in Mudstone

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Yijin Zeng ◽  
Hailong Jiang ◽  
Shidong Ding ◽  
Junhai Chen ◽  
Yi Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Triaxial Test ◽  
Evaluation Method ◽  
Wellbore Stability ◽  
The Other ◽  
Experimental Investigations ◽  
Plane Failure ◽  
The Core ◽  
Weak Plane

Wellbore instabilities frequently occur in mudstone formation with weak plane bedding because of strong anisotropies. The mechanics parameters of weak plane bedding are of vital significance to the wellbore stability analysis for mudstone formations. The conventional method for determining the mechanics parameters is to fit lots of triaxial test data due to the blindness of coring. In this paper, an evaluation method of the mechanics parameters of weak plane bedding is proposed to improve the accuracy of weak plane bedding mechanical properties. The mechanics parameters of weak plane bedding are obtained by combing the single-weak plane failure criterion with the compressive strength of rock obtained by the triaxial test of cores with different coring angles. It is seen that the new evaluation method is simple and convenient. On the other hand, a validation method of the mechanics parameters of weak plane bedding is proposed to ensure their accuracy. The compressive strength obtained from the core with the special coring angle is compared with the theoretical compressive strength for verifying the accuracy of weak plane bedding mechanical properties. It is observed that the proposed evaluation and validation methods can be used to measure the value of weak plane bedding mechanical properties precisely. The proposed methods are general and can be used for measuring the mechanical properties of fracture weak-plane and joint weak-plane.

scholarly journals Investigation of the Effect of Freeze-thaw Cycles on the Mechanical Properties of Hardened Self-compacting Concrete

2020 ◽  
Author(s):  
Tuncay Kap
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Statistical Analysis ◽  
Fresh Concrete ◽  
The Other ◽  
Unit Weight ◽  
Self Compacting Concrete ◽  
Freeze Thaw ◽  
The Core ◽  
Average Compressive Strength

This study investigated the effects of freeze-thaw cycles on the mechanical properties of hardened self-compacting concrete for varying column heights. A column (100×20×300 cm) was fabricated by C30 self-compacting concrete in the laboratory and 10 cube samples (10x10x10 cm) were taken from fresh concrete as the references. After a period of 28 days, 160 core specimens (Ø67 mm in diameter) were taken from different column heights. Unit weight, water absorption, compressive strength, and freeze-thaw tests were performed on these 170 (10 reference cubic and 160 core) samples. The mechanical properties of the core specimens before freeze-thaw and after 8-56 freeze-thaw cycles were reported for varying column heights. The average compressive strength value of the reference cubic samples was determined as 40.28 MPa, while the compressive strengths of the core specimens before freeze-thaw were ranged from 40.25 MPa to 49.62 MPa, impying an increase in compressive strength values up to 23.18% compared to the reference cubic samples. Compressive strengths of the specimens subjected to 8 and 56 freeze-thaw cycles varied between 38.71‒48.07 MPa and 31.72‒39.11 MPa, respectively. Statistical analysis revealed that the compressive strength of the concrete exposed to 56 freeze-thaw cycles was significantly different from that of the other specimens.

The Effect of Steel Slag Coarse Aggregate on the Mechanical and Durability Performances of Concrete

2020 ◽  
Vol 833 ◽  
pp. 228-232
Author(s):  
Md. Jihad Miah ◽  
Mohammad Shamim Miah ◽  
Anisa Sultana ◽  
Taukir Ahmed Shamim ◽  
Md Ashraful Alom
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Water Absorption ◽  
Coarse Aggregate ◽  
Steel Slag ◽  
Experimental Investigations ◽  
Clay Brick ◽  
Crushing Strength ◽  
Burnt Clay ◽  
Good Agreement

This work performs experimental investigations on concrete made with difference replacement percentage of first-class burnt clay brick aggregate (0, 10, 20, 30, 40, 50, 60, 80, and 100%) by steel slag (SS) aggregate. The aim is to evaluate the mechanical properties as well as durability performances, additionally, water absorption porosity test is performed to investigate the influence of steel slag aggregate on the durability of tested concrete. The experimental results have shown that the compressive strength was improved significantly due to the replacement of brick aggregate by steel slag aggregate. The crushing strength of concrete made with 100% steel slag aggregate has gained up to 70% more than the control concrete (100% brick aggregate). However, the porosity of concrete was reduced with the adding percentage of brick aggregate by steel slag aggregate which is consistent with the compressive strength results. Further, a quite good agreement between compressive strength and porosity was observed as well.

scholarly journals Effects of the Variety and Content of Natural Pozzolan Coarse Aggregate on the Thermo-Mechanical Properties of Concrete

2021 ◽  
Vol 12 (4) ◽  
pp. 5405-5415
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
The Other ◽  
Natural Pozzolan ◽  
Coarse Aggregates ◽  
Natural Aggregate ◽  
Middle Atlas

The present study investigated the effects of the variety and content of three natural pozzolan coarse aggregates on concrete. Natural pozzolan aggregates have been obtained from three volcanoes (Boutagrouine, Timahdite, and Jbel Hebri) located in the Middle Atlas region in Morocco. The three pozzolans studied were characterized, and then a comparison was made by replacing the natural aggregate with the pozzolan aggregate in the concrete in different percentages, namely 25, 50, and 100 % in volume. The results showed that the variety and content of pozzolan aggregate have a significant impact on the properties of concrete, primarily caused by the characterization of pozzolan aggregate. The density of concrete decreases with the addition of pozzolan aggregate, which decreases depending on the type of pozzolan aggregate used. The highest compressive strength was measured in the concrete specimens prepared with aggregate BP while the lowest compressive strength was noted in the concrete specimens prepared with aggregate RP. On the other hand, the substitution of NA at 100% by BP, GP, and RP aggregates leads to a decrease in the thermal conductivity of about 67%, 62%, and 55% respectively.

scholarly journals Polymerization characteristics of colored compomers cured with different LED units

2019 ◽  
Vol 17 (1) ◽  
pp. 228080001982780 ◽  
Author(s):  
Meltem Bakkal ◽  
Berza Yılmaz ◽  
Ali Durmus ◽  
Zehra Durmus ◽  
Serife Ozalp
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Dental Restoration ◽  
The Other ◽  
Microstructural Properties ◽  
Complex Interactions ◽  
Light Curing ◽  
Degree Of Curing ◽  
Light Absorbance ◽  
Scanning Electron

Aim: Incomplete polymerization of a resin material used for dental restoration affects the properties of the restoration. We evaluated the structural and mechanical properties of three different colored compomers cured with three different LED units to observe the characteristic changes occurring in different matches. Methods: Polytetrafluoroethylene molds (5 mm in diameter and 2 mm in thickness) were used to prepare disk-shaped sample specimens. Nine sample groups (each of five specimens) were prepared, three each of different compomer resin colors (gold, berry, and silver). Samples were cured using three different LED units (Optima, VALO, and Demi Ultra), according to the manufacturers’ instructions. Microstructural properties of samples were characterized by determining the degree of curing using Fourier-transform infrared spectroscopy and by analyzing sample morphology under a scanning electron microscope. The Vickers hardness, compressive strength, and elastic modulus of the samples were measured to investigate their mechanical properties. Results: The degrees of curing decreased in the order of silver > berry > gold for all curing units. Conversely, gold compomers exhibited poorer mechanical values than the berry and silver counterparts. The Optima 10 unit yielded slightly higher degrees of curing than the other devices, followed by Demi Ultra and VALO light-curing units, respectively. Conclusion: The resin color affected the structural and mechanical properties of the compomers, possibly as a result of the complex interactions and relationships between the irradiation light and resin material, such as light absorbance and reflectance; thus, depending on the color as well as the curing protocol.

scholarly journals Influence of Filler Loading on the Mechanical Properties of Flowable Resin Composites

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1477 ◽  
Author(s):  
Ioana-Codruţa Mirică ◽  
Gabriel Furtos ◽  
Bogdan Bâldea ◽  
Ondine Lucaciu ◽  
Aranka Ilea ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Flexural Modulus ◽  
Filler Loading ◽  
The Other ◽  
Inorganic Filler ◽  
Resin Composites ◽  
Homogeneous Type ◽  
Sem Images

The aim of this study was to evaluate the correlation between the percent of inorganic filler by weight (wt. %) and by volume (vol. %) of 11 flowable resin composites (FRCs) and their mechanical properties. To establish the correlation, the quantity of inorganic filler was determined by combustion and shape/size analyzed by SEM images. The compressive strength (CS), flexural strength (FS), and flexural modulus (FM) were determined. The CS values were between 182.87-310.38 MPa, the FS values ranged between 59.59 and 96.95 MPa, and the FM values were between 2.34 and 6.23 GPa. The percentage of inorganic filler registered values situated between 52.25 and 69.64 wt. % and 35.35 and 53.50 vol. %. There was a very good correlation between CS, FS, and FM vs. the inorganic filler by wt. % and vol. %. (R2 = 0.8899–0.9483). The highest regression was obtained for the FM values vs. vol. %. SEM images of the tested FRCs showed hybrid inorganic filler for Filtek Supreme XT (A3) and StarFlow (A2) and a homogeneous type of inorganic filler for the other investigated materials. All of the FS values were above 50 MPa, the ISO 4049/2019 limit for FRCs.

An Experimental Study on Evaluation of Mechanical Properties in High Performance Concrete Using Admixture

2013 ◽  
Vol 372 ◽  
pp. 231-234
Author(s):  
Jeong Eun Kim ◽  
Wan Shin Park ◽  
Nam Yong Eom ◽  
Sun Woong Kim ◽  
Do Gyeum Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Silica Fume ◽  
Modulus Of Elasticity ◽  
High Performance ◽  
High Performance Concrete ◽  
Splitting Tensile Strength ◽  
Experimental Investigations ◽  
Binder Ratio

In this study, some experimental investigations on the development of mechanical properties with age of high performance concrete (HPC) incorporated with blast furnace slag with fly ash or silica fume have been reported. Four different blended HPC were prepared in 0.40 water-binder ratio. At every four mixtures, the compressive strength, splitting tensile strength and modulus of elasticity at 7 and 28 days have been observed for HPC developments. Consequently, only replacement of silica fume significantly increases the mechanical properties in terms of compressive strength, splitting tensile strength and modulus of elasticity.

Mechanical Properties of Antarctic Sea Ice

1988 ◽  
Vol 110 (4) ◽  
pp. 403-408 ◽  
Author(s):  
N. Urabe ◽  
M. Inoue
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Compressive Strength ◽  
Ice Sheet ◽  
The Other ◽  
Square Root ◽  
Thickness Direction ◽  
Air Content ◽  
Brine Volume

Ice samples were extracted from a land-fast ice sheet of 90 cm thickness at Lutzow-Holm Bay in the Antarctica. The ice samples were then shipped to a cold room in Tokyo, and unconfined uniaxial compression tests and fracture toughness tests were performed for a wide range of loading rate under temperature varying from −5°C to −30°C. During the tests limited in number, acoustic emission measurements were also carried out. On the other hand, distributions of salinity, density, air content, fabric structure and grain size were examined along the thickness direction of the ice sheet. The ice sheet consisted of fine-grained granular ice at the top surface layer and columnar grains below it. The grain size was less than 1 mm for the granular ice and the columnar ice grain size increased linearly with the depth from about 1 mm just beneath the transition zone to about 13 mm at the bottom surface. The density and the air content also varied showing its maximum or minimum value, respectively, at the mid-thickness position along the thickness direction of the ice sheet. Thus, correlations between the mechanical properties and the physical features were studied. The fracture toughness (KIC) of the columnar grained ice showed a strong dependence on the grain size (diameter of the columnar ice). Namely, the KIC decreased in proportion to the inverse square root of the grain size. The compressive strength showed a linear relationship with the density, which was a function of not only the brine volume, but also the air content. Accordingly, the compressive strength was recognized to decrease with an increase in the sum of the square root of brine volume and the square root of air content. The other ice samples were also extracted from one of icebergs in Lutzow-Holm Bay. And the compressive strength and the fracture toughness were measured and reported in this paper.

scholarly journals Peculiarities of hydration of Portland cement with synthetic nano-silica

2017 ◽  
Vol 12 (2) ◽  
pp. 101-106 ◽  
Author(s):  
Galyna Kotsay
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Portland Cement ◽  
Cement Hydration ◽  
Physical And Mechanical Properties ◽  
The Other ◽  
Nano Materials ◽  
Nano Silica ◽  
Other Hand ◽  
Materials Used

Abstract Application of nano-materials in cement products significantly, improves their properties. Of course, the effectiveness of the materials depends on their quantity and the way they are introduced into the system. So far, amongst nano-materials used in construction, the most preferred was nano-silica. This research investigated the effect of synthetic precipitated nano-silica on the cement hydration as well as, on the physical and mechanical properties of pastes and mortars. Obtained results showed that admixture of nano-silica enhanced flexural and compressive strength of cement after 2 and 28 days, however, only when admixture made up 0.5% and 1.0%. On the other hand, the use of nano-silica in the amount 2% had some limitations, due to its ability to agglomerate, which resulted in deterioration of the rheological and mechanical properties.

scholarly journals Concrete Properties using Treated Recycled EPS

2021 ◽  
Vol 877 (1) ◽  
pp. 012028
Author(s):  
Hasan Jasim Mohammed ◽  
Yasir Gaib Hussein
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Silica Fume ◽  
Coarse Aggregate ◽  
Splitting Tensile Strength ◽  
The Other ◽  
Modulus Of Rupture ◽  
Normal Concrete ◽  
Concrete Properties

Abstract The study explores the mechanical properties of treated recycled extended polystyrene (TEPS) concrete, treated by two methods, one by heating, and the other by immersed recycled EPS in cement neat. By substituting 0 %, 15 %, 25 %, and 35 % of the coarse aggregate volume with treated recycled EPS, (for both method). Treated recycled TEPS concrete ratios are experimentally prepared, while the cement is substituted thru 10 % silica fume (SF). Tests were carried out, like compressive strength, splitting tensile strength, modulus of rupture, and density. The outcomes display the decreasing of the compressive strength, tensile strength and modulus of rupture of TEPS concretes with rise TEPS percentage around 26 %, 17 % and 32 %, respectively (35% TEPS) related to standard concrete. They also show that TEPS concrete density decrease about 30 % of normal concrete. The TEPS is suitable in concrete and meets provisions.

scholarly journals Effect of SiC Powder Additive on Mechanical Properties of Al-Pb Alloy Produced by Mechanical Alloying

2018 ◽  
Vol 21 (3) ◽  
pp. 389-392
Author(s):  
Suhair G. Hussein ◽  
Adnan N. Abood ◽  
Nabeel Kadim Abdel Sahib
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
The Other ◽  
Heavy Duty ◽  
Hydraulic Pump ◽  
Phase Component ◽  
Milling Machines ◽  
Percentage Weight

One of the major usages for Al–Pb alloy are bearing alloys because of its lubricant behavior of Pb phase component. Applications of these alloys are in heavy duty, such as boring mills, presses, lathes, milling machines and hydraulic pump bushings. In present work, SiC powder was selected as additive for improving the mechanical properties of Al-Pb alloy that produced by mechanical alloying method. The percentage weight of SiC powder are (2.5, 5,10, 15 %) which mixing together with Al- Pb alloy for two hours in ball milling device, then compacted and sintering to obtain the improved alloy, and examine the mechanical properties (compressive strength and microhardness) of produced alloy. Results show that the additive of SiC powder on the Al-Pb alloy lead to improve the microhardness which increased with increased the percentage of additive, in the other hand, the compressive strength had a reverse effective with increased the percentage of SiC powder.

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