scholarly journals LABORATORY TESTS ON THE STRENGTHENING OF WET-MIX SHOTCRETE LINING WITH THE USE OF NANOMATERIALS

2021 ◽  
Vol 36 (1) ◽  
pp. 49-59
Author(s):  
Hamid Kalhori ◽  
Raheb Bagherpour ◽  
Mohammad Amir Akhlaghi ◽  
Sayed Mohsen Mirdamadi ◽  
Mehdi Nasiri Sarvi
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Laboratory Tests ◽  
Size Range ◽  
Maximum Increase ◽  
Nano Clay ◽  
Cement Based Materials ◽  
Cast Concrete ◽  
Shotcrete Lining ◽  
Micro Silica

Adding nanomaterials to concrete extends the size range of constituent particles well into nano-scale dimensions, which could help the compacting of particles in cement-based materials. Regarding the differences between shotcrete and cast concrete, in this study, the properties of shotcrete with nano and micro-silica and nano-clay were experimentally studied. The micro and nanomaterials have been added at different percentages (6%, 9%, and 12%) to a shotcrete paste. The comparison was based on the uniaxial compressive strength, flexural strength, tensile strength, and porosity tests of different specimens. The results indicated that the maximum increase in compressive, flexural, and tensile strengths of shotcrete was related to 12% nano-SiO2, while for 12% nano-clay, all of these strengths were decreased at 28 days. The optimum percentage for shotcrete substitution by nano-clay was established to be 6%. Also, the application of the nanomaterials led to a decrease in the water absorption and porosity of shotcrete. Eventually, the results revealed that the improvement of mechanical properties by the introduction of the nanomaterials in shotcrete could be satisfactory.

Effect of Zr on the microstructures and mechanical properties of as-extruded Mg–2.3Zn–0.18Y–xZr alloys

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744001 ◽  
Author(s):  
Yufan Wang ◽  
Yingbo Zhang ◽  
Wei Gao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Aging Treatment ◽  
Grain Refining ◽  
Maximum Increase ◽  
Microstructures And Mechanical Properties ◽  
Average Size ◽  
Precipitate Strengthening ◽  
Zr Alloys

The microstructures and mechanical properties of as-extruded Mg–2.3Zn–0.18Y–[Formula: see text]Zr ([Formula: see text] = 0.03, 0.06 and 0.13 at.%) alloys and aged Mg–2.3Zn–0.18Y–0.13Zr alloy were studied. The results revealed that the microstructures of as-extruded Mg–2.3Zn–0.18Y–[Formula: see text]Zr alloys are typical bimodal structures. The coarse [Formula: see text]-Mg grains are surrounded by fine dynamically recrystallized [Formula: see text]-Mg grains. The average size of [Formula: see text]-Mg grains decreases with increasing Zr content. Moreover, the addition of Zr (at.%) can improve the mechanical properties of alloy. The as-extruded Mg–2.3Zn–0.18Y–0.13Zr alloy has the best mechanical properties with ultimate tensile strength (UTS) and yield strength (YS) of 346 MPa and 292 MPa, respectively, and an elongation of 26.7%, which can be attributed to the grain refining effect and precipitate strengthening. The UTS and elongation of Mg–2.3Zn–0.18Y–0.13Zr alloy changed slightly after aging treatment, but the YS increases remarkably, with the maximum increase of 30 MPa. The fracture surfaces of all alloys consist of many tearing ridges and dimples.

scholarly journals Preparation and properties of (epoxy resin)/(nylon 6,6 oligomer) blends

2009 ◽  
Vol 3 (2) ◽  
pp. 111-115
Author(s):  
Jason Bragg ◽  
◽  
Alberto Alvarez-Castillo ◽  
Monica Trejo-Duran ◽  
Victor Castano ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Epoxy Resin ◽  
Considerable Increase ◽  
Flexural Modulus ◽  
Strength Testing ◽  
Curing Agent ◽  
Maximum Increase ◽  
Maximum Value ◽  
Nylon 6,6

A series of polymer alloys based on different compositions of Nylon 6,6 oligomers (NYL66Oґs) and epoxy resin have been prepared. The oligomer was extracted from the waste residues of the industrial production of nylon 6,6 and was dissolved in the epoxy resin. The mixture was crosslinked at 333 K using dodecenylsuccinic anhydre (DDSA) as a curing agent. The tensile strength and flexural modulus were found to increase with the addition of NYLO66O up to a maximum value of 2 wt % oligomer content. Both, the tensile and impact strength show a maximum increase due to the addition of 35 wt % NYLO66O. The compressive strength testing revealed a considerable increase, up to 87 %, over that of the neat epoxy with the addition of 1 wt % NYLO66O. An interesting relationship between the mechanical properties and the developed morphology of the blends has been found.

scholarly journals The effect of temperature on the mechanical properties and workability of rock salt

2019 ◽  
Vol 2 (1) ◽  
pp. 384-393
Author(s):  
Piotr Małkowski ◽  
Łukasz Bednarek ◽  
Krzysztof Kotwica ◽  
Grzegorz Stopka
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Shear Strength ◽  
Temperature Increase ◽  
Laboratory Tests ◽  
Effect Of Temperature ◽  
Transverse Strain ◽  
Salt Rock ◽  
The Road ◽  
Salt Mining

Abstract Underground salt mining accounts for about 16 percent of the total salt production worldwide. When excavating salt rock, the cutters of the road header come into contact with the rock. This produces friction and, consequently, a rise in temperature. Generally, as temperature increases, salt gradually loses its plasticity. The extent of these alterations depends on the presence of other minerals in the rock. This paper presents the results of laboratory tests on regularly shaped samples of salt. An analysis was performed of the results of compressive, tensile and induced-shear strength, and of Young's modulus, Poisson's ratio, cuttability index and side chipping angle. The testing was conducted on samples with a temperature of about 20°C and samples heated to 50°C and 80°C. The tests showed that as temperature increased, so did compressive and tensile strength, and longitudinal and transverse strain of salt. The temperature increase caused, however, a decrease in shear strength. The cuttability index and the side chipping angle also decreased when the heated samples were being cut. The percentage changes in the parameters within the 60-degree temperature range were as high as several dozen percent.

scholarly journals A review of the effect and optimization of use of nano-TiO2 in cementitious composites

2022 ◽  
Author(s):  
Mahmud Sami Döndüren ◽  
◽  
Mohammed Gamal Al-Hagri ◽  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Setting Time ◽  
Cementitious Materials ◽  
Partial Replacement ◽  
Cementitious Composites ◽  
Nano Materials ◽  
Microstructural Properties ◽  
Nano Tio2 ◽  
Cement Based Materials

There are some problems and weaknesses related to cement-based materials, such as their very low tensile strength, low chemical resistance and the huge contribution of cement production to industrial CO2 emissions. One possible method to reduce the impacts of such problems is the partial replacement of cement in cementitious materials with nano materials. This work provides a detailed review of incorporation of one of the most widely used nano materials, namely nano-titanium dioxide, and its effect on the properties of cementitious composites. Different properties have been considered in the current study, such as fresh properties, mechanical properties (compressive strength, split tensile strength and flexural strength), durability (permeability, ultrasonic pulse velocity (UPV), electrical resistivity, carbonation resistance, freeze and thaw resistance and sulfate attack resistance) and microstructural properties. This paper also investigates the optimum content of nano-TiO2 in cement-based materials. Moreover, the cost effectiveness of use on nano-titania in cementitious composites has been discussed. Nano titania reduces the workability and setting time of cement-based materials. It can be very effective in improving the mechanical properties, durability and microstructural properties of cementitious composites.

scholarly journals The physical and mechanical properties of magnesium oxychloride cement-based materials

2015 ◽  
Vol 14 (4) ◽  
pp. 089-098 ◽  
Author(s):  
Szymon Malinowski ◽  
Justyna Jaroszyńska-Wolińska
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Compressive Strength ◽  
Physical And Mechanical Properties ◽  
Polypropylene Fibers ◽  
Experimental Part ◽  
Cement Based Materials ◽  
Magnesium Oxychloride ◽  
Magnesium Oxychloride Cement ◽  
Micro Silica

The aim of this paper was the examination of the physical-mechanical properties of Sorel cement-based material. In the experimental part the effect of polypropylene fibers (PP) and micro-silica on properties of composite materials were studied. The results show that addition of these modifiers increases compressive strength, waterproofing and resistance against corrosion. Increase of compressive strength was observed from both addition of PP and micro-silica. PP resulted in an increase in compressive strength of 0,72 MPa, whereas addition of micro-silica caused an increase of 17,5 % compared to pure Sorel’s cement. Improvement of water-tightness was observed in both additions of PP and micro-silica. Weight loss of samples with PP addition to the concrete after a 7-day bath in an aggressive solution of 5% HCl was less than about 20%.

scholarly journals Experiments on Fiber Concrete Foundation Slabs in Interaction with the Subsoil

2020 ◽  
Vol 12 (9) ◽  
pp. 3939 ◽  
Author(s):  
Radim Cajka ◽  
Zuzana Marcalikova ◽  
Marie Kozielova ◽  
Pavlina Mateckova ◽  
Oldrich Sucharda
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Laboratory Tests ◽  
Three Dimensional ◽  
Concrete Slabs ◽  
Two Dimensional ◽  
Load Step ◽  
Loading Test ◽  
Displacement Sensors ◽  
Fiber Concrete

This article focuses on researching the interactions of fiber concrete slabs with subsoil. The experimental series includes four slabs made of fiber concrete with different dosages of fibers, from 0 to 75 kg/m3. The slabs were exposed to a loading test on a specialized loading frame. The laboratory tests for detailed descriptions of the fiber concrete’s mechanical properties were also an integral part of the experiments, including tests of the compressive strength, the modulus of elasticity, and split and bending tensile strength. Each slab’s deformation in a particular load step was evaluated in two-dimensional (2D) sections based on data measured with displacement sensors and in three-dimensional (3D) charts with the use of interpolation.

scholarly journals Mechanical Properties of Cement-Based Materials with Recycled Plastic: A Review

2020 ◽  
Vol 12 (21) ◽  
pp. 9060
Author(s):  
Jun Kil Park ◽  
Min Ook Kim
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Physical And Mechanical Properties ◽  
Recycled Aggregates ◽  
Split Tensile Strength ◽  
Plastic Recycling ◽  
Cement Based Materials ◽  
High Pollution ◽  
Recycled Plastics

This study summarizes existing studies on plastic recycling to determine whether ocean plastics with high pollution degrees could be used for cement-based materials. In particular, the methods to recycle plastic waste, the effects of recycled plastic on the physical and mechanical properties of cement-based materials, and their effective usage were investigated. Workability, density, compressive strength, split tensile strength, and flexural strength of cement-based materials with recycled plastics were reviewed and divided into recycled aggregates and fibers. Based on the previous investigation, the direction of research necessary to recycle marine plastics is suggested. As the amount of recycled plastic aggregate increased, the mechanical strength of cement-based materials decreased. The recycled plastic aggregate lowered the density and increased porosity of the cement-based material. Meanwhile, recycled plastic fibers reduced the compressive strength but improved the tensile strength; to effectively improve tensile strength, a volume content of less than 1.5% should be added to prevent balling fibers. Furthermore, an appropriate aspect ratio should be determined based on the type of plastic to be used.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

Effect of silver nitrate on some mechanical properties of heat polymerizing acrylic resins

2019 ◽  
Vol 14 (1) ◽  
pp. 110
Author(s):  
Assiss. Prof. Dr. Sabiha Mahdi Mahdi ◽  
Dr. Firas Abd K. Abd K.
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Silver Nitrate ◽  
Surface Hardness ◽  
Mechanical Tests ◽  
Hardness Tester ◽  
Acrylic Resins ◽  
The Difference

Aim: The aimed study was to evaluate the influence of silver nitrate on surfacehardness and tensile strength of acrylic resins.Materials and methods: A total of 60 specimens were made from heat polymerizingresins. Two mechanical tests were utilized (surface hardness and tensile strength)and 4 experimental groups according to the concentration of silver nitrate used.The specimens without the use of silver nitrate were considered as control. Fortensile strength, all specimens were subjected to force till fracture. For surfacehardness, the specimens were tested via a durometer hardness tester. Allspecimens data were analyzed via ANOVA and Tukey tests.Results: The addition of silver nitrate to acrylic resins reduced significantly thetensile strength. Statistically, highly significant differences were found among allgroups (P≤0.001). Also, the difference between control and experimental groupswas highly significant (P≤0.001). For surface hardness, the silver nitrate improvedthe surface hardness of acrylics. Highly significant differences were statisticallyobserved between control and 900 ppm group (P≤0.001); and among all groups(P≤0.001)with exception that no significant differences between control and150ppm; and between 150ppm and 900ppm groups(P>0.05).Conclusion: The addition of silver nitrate to acrylics reduced significantly the tensilestrength and improved slightly the surface hardness.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

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