scholarly journals Characterization of TBM Muck for Construction Applications

2021 ◽  
Vol 11 (18) ◽  
pp. 8623
Author(s):  
Ala Abu Taqa ◽  
Mohamed Al-Ansari ◽  
Ramzi Taha ◽  
Ahmed Senouci ◽  
Hassan A. Al-Marwani ◽  
...  
Keyword(s):  
Los Angeles ◽  
Coefficient Of Thermal Expansion ◽  
Morphological Structure ◽  
Tunnel Boring Machine ◽  
Liquid Limit ◽  
Mechanical And Thermal Properties ◽  
Concrete Aggregates ◽  
Los Angeles Abrasion ◽  
Fill Material ◽  
Predominant Component

This paper investigates the potential utilization of the Tunnel Boring Machine (TBM) muck generated from Doha’s Metro Gold Line in different construction applications. The properties of the raw TBM muck were studied, and the results were compared to the specifications of Qatari Construction Standards (QCS 2014) of concrete aggregates, fill material under buildings and road subgrades. Compared to the requirements of concrete aggregates, the results indicated that the gradation of the raw TBM muck does not comply with the QCS 2014 requirements, and hence, sieving and screening may be essential. Moreover, the tests’ results showed that the properties of the muck meet the requirements of the concrete coarse aggregates, except for the water absorption, loss by magnesium sulphate soundness, loss by Los Angeles abrasion and the acid-soluble sulphate. As fill material under buildings or road subgrades, the gradation of the TBM muck complies with the QCS 2014 requirements, while the liquid limit and plasticity index are higher than the QCS 2014 permissible limits. Additionally, the morphological structure and the elemental composition of the raw TBM muck were determined by employing Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX), respectively. Digital images were also taken at larger scale to draw a full picture of the TBM muck morphology. A mixture of rough-rounded to angular-elongated shaped particles with relatively large voids could be observed. The EDX analysis demonstrated the presence of silicon (Si) as the predominant component of the muck, which may alter the Coefficient of Thermal Expansion (CTE) values for mixtures prepared using TBM muck. Hence, further investigations should be performed on the mechanical and thermal properties of mixtures containing TBM muck as aggregates’ replacement, and further work should be directed toward this end.

scholarly journals Research on Thermal Stability and Properties of Ca3ZrSi2O9 as Potential T/EBC Materials

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 583
Author(s):  
Yangyang Pan ◽  
Bo Liang ◽  
Yaran Niu ◽  
Dijuan Han ◽  
Dongdong Liu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Fracture Toughness ◽  
Room Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Mechanical And Thermal Properties ◽  
Self Healing ◽  
Barrier Coating

In this study, a new coating material for thermal barrier coating (TBC) or environment barrier coating (EBC) application, Ca3ZrSi2O9 (CZSO), was synthesized and prepared by atmospheric plasma spray (APS) technology. The evolution of the phases and microstructures of the coatings with different thermal-aged were characterized by XRD, XRF, EDS and SEM, respectively. The thermal stability was measured by TG-DTA and DSC. The mechanical and thermal properties, including Vickers hardness (HV), fracture toughness (KIC), thermal conductivity () and coefficient of thermal expansion (CTE) were focused on. It was found that the as-sprayed CZSO coating contained amorphous phase. Crystalline transformation happened at 900–960 ∘C and no mass changes took place from room temperature (RT) to 1300 ∘C. The phenomena of microcrack self-healing and composition uniformity were observed during thermal aging. The of coating was very low at about 0.57–0.80 Wm−1K−1 in 200–1200 ∘C. The combined properties indicated that the CZSO coating might be a potential T/EBC material.

Evaluation of CeSZ Thermal Barrier Coatings for Diesels

2000 ◽  
Author(s):  
P.J. Huang ◽  
J.J. Swab ◽  
P.J. Patel ◽  
W.S. Chu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Barrier Coatings ◽  
Coefficient Of Thermal Expansion ◽  
Fuel Efficiency ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Mechanical And Thermal Properties ◽  
Barrier Coatings ◽  
Spray Process

Abstract The development of thermal barrier coatings (TBCs) for diesel engines has been driven by the potential improvements in engine power and fuel efficiency that TBCs represent. TBCs have been employed for many years to reduce corrosion of valves and pistons because of their high temperature durability and thermal insulative properties. There are research programs to improve TBCs wear resistance to allow for its use in tribologically intensive areas of the engine. This paper will present results from tribological tests of ceria stabilized zirconia (CeSZ). The CeSZ was applied by atmospheric plasma spray process. Various mechanical and thermal properties were measured including wear, coefficient of thermal expansion, thermal conductivity, and microhardness. The results show the potential use of CeSZ in wear sensitive applications in diesel applications. Keywords: Thermal Barrier Coating, Diesel Engine, Wear, Thermal Conductivity, and Thermal Expansion

scholarly journals Assessing the moisture susceptibility of aggregates with Los Angeles abrasion test

2017 ◽  
Author(s):  
Adelia Dwidarma Nataadmadja ◽  
Oki Setyandito ◽  
Eduardi Prahara ◽  
Ida Riyanti
Keyword(s):  
Los Angeles ◽  
Moisture Susceptibility ◽  
Abrasion Test ◽  
Los Angeles Abrasion

NOISE LEVEL MEASUREMENT TEST TO PREDICT THE ABRASION RESISTANCE OF ROCK AGGREGATES

2013 ◽  
Vol 12 (04) ◽  
pp. 1350021 ◽  
Author(s):  
S. KAHRAMAN ◽  
M. S. DELIBALTA ◽  
R. COMAKLI
Keyword(s):  
Regression Analysis ◽  
Los Angeles ◽  
Multiple Regression Analysis ◽  
Multiple Regression ◽  
Noise Level ◽  
Regression Equation ◽  
Abrasion Loss ◽  
Los Angeles Abrasion ◽  
Indirect Tests ◽  
Simple Regression

Compared to the indirect tests, the determination of the Los Angeles abrasion loss is time consuming and expensive, and requires a large amount of samples. For this reason, the prediction of Los Angeles abrasion loss from some indirect tests is useful for preliminary studies. In this study, Los Angeles abrasion, noise level (NL) measurement, density, and porosity tests were carried out on 27 different rock types such as igneous, metamorphic, and sedimentary. The test results were evaluated using the simple and multiple regression analysis. A good relation was found between the Los Angeles abrasion loss and the NL. In order to check the possibility of obtaining more significant relations, multiple regression analysis was performed by including density and porosity values. However, the regression analysis showed that the correlation coefficients of the multiple regression equations were slightly higher than that of the simple regression equation. Since the simple regression equation is practical and statistically significant, it is suggested for estimation purpose. In conclusion, it can be said that Los Angeles abrasion loss of aggregates can be reliably estimated from NL measurement.

scholarly journals EVALUATING THE SAWABILITY OF ROCKS BY CHAIN-SAW MACHINES USING THE PROMETHEE TECHNIQUE

2021 ◽  
Vol 36 (1) ◽  
pp. 25-36
Author(s):  
Reza Mikaeil ◽  
Akbar Esmaeilzadeh ◽  
Sara Aghaei ◽  
Sina Shaffiee Haghshenas ◽  
Amir Jafarpour ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Los Angeles ◽  
Production Rate ◽  
Physical And Mechanical Properties ◽  
Dimension Stone ◽  
Quartz Content ◽  
Los Angeles Abrasion ◽  
Production Values ◽  
Schmidt Hardness ◽  
Dimension Stone Quarry

One of the most significant factors in the estimation of dimension stone quarry cost is the production rate of rock cutting machines. Evaluating the production rate of chain-saw machines is a very significant and practical issue. In this research, it has been attempted to evaluate and select the suitable working-face for a quarry by examining the maximum production rate in the Dehbid and Shayan marble quarries. For this purpose, fi eld studies were carried out which included measuring operational characteristics of the chain-saw cutting machine, the production rate and sampling for laboratory tests from seven active case studies. Subsequently, the physical and mechanical properties of rocks including: Uniaxial Compressive Strength (UCS), Brazilian Tensile Strength (BTS), Los Angeles abrasion, quartz content, water absorption percentage, porosity, Schmidt hardness and grain size for all sample measurements were studied after transferring the samples to a rock-mechanics laboratory. Finally, the sawability of the quarried working-faces was evaluated using the PROMETHEE multi-criteria decision-making (MCDM) model according to the physical and mechanical properties. The results of the study indicated that the number 1 and 5 working-faces from the Dehbid and Shayan quarries are the most suitable working-faces in terms of production rate with the maximum recorded production values (4.95 and 3.1 m2 /h), and with net fl ow rates (2.67 and -0.36) respectively.

scholarly journals The Impact of Secondary Phyllosilicate Minerals on the Engineering Properties of Various Igneous Aggregates from Greece

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 329 ◽  
Author(s):  
Petros Petrounias ◽  
Panagiota Giannakopoulou ◽  
Aikaterini Rogkala ◽  
Paraskevi Lampropoulou ◽  
Eleni Koutsopoulou ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Los Angeles ◽  
Moisture Content ◽  
Total Porosity ◽  
Physicomechanical Properties ◽  
Engineering Properties ◽  
Petrographic Analysis ◽  
Rock Samples ◽  
Los Angeles Abrasion ◽  
The Impact

This paper investigates the effect of alteration on the physicomechanical properties of igneous rocks used as aggregates, from various areas from Greece. The studied lithologies include serpentinized dunites, serpentinized harzburgites, serpentinized lherzolites, metamorphic gabbros, diabases, dacites and andesites. Quantitative petrographic analysis shows that the tested samples display various percentages of secondary phyllosilicate minerals. Mineral quantification of the studied rock samples was performed by using the Rietveld method on X-ray diffraction patterns. The samples were also tested to assign moisture content (w (%)), total porosity (nt (%)), uniaxial compressive strength (UCS (MPa)) and Los Angeles abrasion test (LA (%)). The influence of secondary phyllosilicate minerals on the physicomechanical behavior of the tested samples was determined using regression analysis and their derived equations. Regression analysis shows a positive relationship between the percentage of the phyllosilicate minerals of the rocks and the moisture content as well as with the total porosity values. In mafic and ultramafic rock samples, the relationships between the secondary phyllosilicate minerals and their physicomechanical properties have shown that the total amount of the secondary phyllosilicate minerals results negatively on their physicomechanical properties. On the other hand, the low percentage of phyllosilicate minerals in volcanic rocks can’t be able to define their engineering properties.

scholarly journals The effect of coarse aggregate hardness on the fracture toughness and compressive strength of concrete

2019 ◽  
Vol 258 ◽  
pp. 04011
Author(s):  
Atur P. N. Siregar ◽  
Emma L. Pasaribu ◽  
I Wayan Suarnita
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Los Angeles ◽  
Coarse Aggregate ◽  
Concrete Aggregate ◽  
Beam Size ◽  
Intensity Factors ◽  
Coarse Aggregates ◽  
Los Angeles Abrasion ◽  
Compressive Strength Of Concrete

Coarse aggregate is the dominant constituent in concrete. Aggregate hardness is a variable needed to investigate in determining its effect on the critical stress intensity factors (KIC), dissipated fracture energy (Gf) and compressive strength (fc’) of the concrete. The hardness of coarse aggregate based on Los Angeles abrasion values of 16.7%., 22.6%, and 23.1% was used incorporated with Portland Composite Cement (PCC), and superplasticizer to create specimens. Cubes of 150x150x150 mm were employed to determine the fc’, and four beam sizes: 50x100x350 mm, 50x150x500 mm, 50x300x950 mm and 50x450x1250 mm were engaged to determine KIC and Gf. The fc’ and Gf of specimens manufactured by three different hardness of coarse aggregates were 45, 43, 40 MPa and 89.4, 54.0, 56.3 N/m respectively. KIC of specimens was 138.9, 119.4 and 114.1 MPa.mm1/2 for beam size of 50x100x350 mm; 148.2, 115.8 and 108.8 MPa.mm1/2 for beam size of 50x150x500 mm; 230.9, 183.1 and 157.9 MPa.mm1/2 for beam size of 50x300x950 mm; and 293.2, 248.1 and 244.3 MPa.mm1/2 for beam size of 50x450x1250 mm. Experimental results showed that decreasing hardness of coarse aggregate was found to have significant effect on the fracture toughness rather than on the compressive strength of concrete.

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