Sulfur concrete for haul road construction at Suncor oil sands mines

2007 ◽  
Vol 44 (5) ◽  
pp. 564-578 ◽  
Author(s):  
Dawit G Abraha ◽  
David C Sego ◽  
Kevin W Biggar ◽  
Robert Donahue
Keyword(s):  
Oil Sands ◽  
Critical Strain ◽  
Resilient Modulus ◽  
Physical And Mechanical Properties ◽  
Mine Wastes ◽  
Element Analysis ◽  
Near Surface ◽  
Truck Tires ◽  
Operational Life ◽  
Haul Road

The feasibility of constructing mine roads at oil sands mines (Fort McMurray, Alberta) using concrete prepared from bitumen extraction and upgrading by-products and mine wastes (sulfur, fly ash, coke, and tailing sand) is evaluated. An extensive laboratory test program, including unconfined compression testing, sonic velocity measurement, and split tensile and freeze–thaw durability tests, was carried out to characterize the physical and mechanical properties of different mix designs of sulfur concrete. A study of the geochemical interaction of sulfur concrete with the near-surface environment included short-term interaction of surface-exposed sulfur concrete during the construction and operational life of the haul road and long-term interaction of sulfur concrete with groundwater following its eventual burial with mine wastes in the mined-out pits. Haul road test sections were designed based on the critical strain and resilient modulus design method. Stress and strain distributions in the selected haul road cross section induced by the truck tires were calculated using finite element analysis. Required pavement layer thicknesses were then determined on the basis of the truck loads, and resilient modulus and strength of the sulfur concrete and subgrade material using the critical strain and resilient modulus design method.Key words: sulfur concrete, mine haul road design, concrete pavement.

Relationship Between Soil Stiffness Gauge Modulus and Other Test Moduli for Granular Soils

2003 ◽  
Vol 1849 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Auckpath Sawangsuriya ◽  
Tuncer B. Edil ◽  
Peter J. Bosscher
Keyword(s):  
Shear Strain ◽  
Strain Amplitude ◽  
Laboratory Tests ◽  
Resilient Modulus ◽  
Granular Soils ◽  
Dynamic Force ◽  
Element Analysis ◽  
Near Surface ◽  
Soil Stiffness ◽  
Shear Strain Amplitude

Recently, there has been a concerted effort to develop methods for direct measurement of soil stiffness, modulus, or both. A new field test device called the soil stiffness gauge (SSG), which is currently marketed as GeoGauge, shows potential to assess near-surface stiffness. A comparison is presented of moduli obtained from the SSG with moduli obtained from other tests on granular soils. The maximum singleamplitude dynamic force produced during the SSG measurement is determined to be 17.3 N. On this basis, an estimate of the shear strain amplitude produced from the SSG is made by finite element analysis. A plot of shear modulus versus shear strain amplitude on a medium sand obtained from different laboratory tests, including the SSG, is presented. The comparison of the SSG modulus with the moduli from other laboratory tests indicates that the SSG outputs a dynamic modulus corresponding to a strain amplitude approximately 20 times higher than the expected range and with a magnitude lower than it should be on the basis of the induced strain. Nevertheless, the SSG modulus is still higher than that from the resilient modulus test typically used for pavement design.

Tread Depth Effects on Tire Rolling Resistance

2001 ◽  
Vol 29 (3) ◽  
pp. 134-154 ◽  
Author(s):  
J. R. Luchini ◽  
M. M. Motil ◽  
W. V. Mars
Keyword(s):  
Finite Element Analysis ◽  
Common Knowledge ◽  
Rolling Resistance ◽  
Test Method ◽  
Tire Model ◽  
Element Analysis ◽  
Truck Tires ◽  
The Finite Element Analysis ◽  
Equilibrium Test ◽  
Depth Effects

Abstract This paper discusses the measurement and modeling of tire rolling resistance for a group of radial medium truck tires. The tires were subjected to tread depth modifications by “buffing” the tread surface. The experimental work used the equilibrium test method of SAE J-1269. The finite element analysis (FEA) tire model for tire rolling resistance has been previously presented. The results of the testing showed changes in rolling resistance as a function of tread depth that were inconsistent between tires. Several observations were also inconsistent with published information and common knowledge. Several mechanisms were proposed to explain the results. Additional experiments and models were used to evaluate the mechanisms. Mechanisms that were examined included tire age, surface texture, and tire shape. An explanation based on buffed tread radius, and the resulting changes in footprint stresses, is proposed that explains the observed experimental changes in rolling resistance with tread depth.

scholarly journals Evaluation on the Bond Capacity of the Fire-Protected FRP Bonded to Concrete Under High Temperature

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Soo-yeon Seo ◽  
Jong-wook Lim ◽  
Su-hyun Jeong
Keyword(s):  
High Temperature ◽  
Critical Temperature ◽  
Temperature Variation ◽  
Fire Resistance ◽  
Fire Protection ◽  
Element Analysis ◽  
External Temperature ◽  
Near Surface ◽  
Board Type ◽  
The Face

AbstractTo figure out the change in the reinforcing effect of FRP system used for the retrofit of RC beam when it is exposed to high temperature, it is required to evaluate not only the behavior of the entire beam, but also the bond performance at anchorage zone through a bond test according to the increase of external temperature. Moreover, the study to find various fire-protection methods is necessary to prevent the epoxy from reaching the critical temperature during an exposure to high temperature. In this manner, the fire-resistance performances of externally bonded (EB) FRP and near-surface-mounted (NSM) FRP to concrete block were evaluated by high-temperature exposure tests after performing a fire-protection on the surface in this paper. Board-type insulation with mortar was considered for the fire-protection of FRP system. After the fire-protection of the FRPs bonded to concrete blocks, an increasing exposure temperature was applied to the specimens with keeping a constant shear bond stress between concrete and the FRP. Based on the result, the temperature when the bond strength of the FRP disappears was evaluated. In addition, a finite element analysis was performed to find a proper method for predicting the temperature variation of the epoxy which is fire-protected with board-type insulation during the increase of external temperature. As a result of the test, despite the same fire-protection, NSM specimens were able to resist 1.54–2.08 times higher temperature than EB specimens. In the design of fire-protection of FRP system with the board-type insulation, it is necessary to consider the transfer from sides as well as the face with FRP. If there is no insulation of FP boards on the sides, the epoxy easily reaches its critical temperature by the heat penetrated to the sides, and increasing the thickness of the FP board alone for the face with FRP does not increase the fire-resistance capacity. As a result of the FE analysis, the temperature variation at epoxy can be predicted using the analytical approach with the proper thermal properties of FP mortar and board.

The Site Tilt and Lander Transfer Function from the Short-Period Seismometer of InSight on Mars

2021 ◽  
Author(s):  
Alexander E. Stott ◽  
Constantinos Charalambous ◽  
Tristram J. Warren ◽  
William T. Pike ◽  
Robert Myhill ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Dust Devils ◽  
Total Change ◽  
Noise Sources ◽  
Element Analysis ◽  
Near Surface ◽  
Seismic Experiment ◽  
Short Period ◽  
Sensitivity Changes

ABSTRACT The National Aeronautics and Space Administration InSight mission has deployed the seismic experiment, SEIS, on the surface of Mars, and has recorded a variety of signals including marsquakes and dust devils. This work presents results on the tilt and local noise sources, which provide context to aid interpretation of the observed signals and allow an examination of the near-surface properties. Our analysis uses data recorded by the short-period sensors on the deck, throughout deployment and in the final configuration. We use thermal decorrelation to provide an estimate of the sol-to-sol tilt. This tilt is examined across deployment and over a Martian year. After each modification to the site, the tilt is seen to stabilize over 3–20 sols depending on the action, and the total change in tilt is <0.035°. Long-term tilt over a Martian year is limited to <0.007°. We also investigate the attenuation of lander-induced vibrations between the lander and SEIS. Robotic arm motions provide a known lander source in the 5–9 Hz bandwidth, yielding an amplitude attenuation of lander signals between 100 and 1000 times. The attenuation of wind sensitivity from the deck to ground presents a similar value in the 1.5–9 Hz range, thus favoring a noise dominated by lander vibrations induced by the wind. Wind sensitivities outside this bandwidth exhibit different sensitivity changes, indicating a change in the coupling. The results are interpreted through a finite-element analysis of the regolith with a depth-dependent Young’s modulus. We argue that discrepancies between this model and the observations are due to local compaction beneath the lander legs and/or anelasticity. An estimate for the effective Young’s modulus is obtained as 62–81 MPa, corroborating previous estimates for the top layer duricrust.

scholarly journals MULTI-WAVE ULTRASONIC CONTROL OF CONCRETE

2017 ◽  
Vol 16 (4) ◽  
pp. 289-297
Author(s):  
D. Yu. Snezgkov ◽  
S. N. Leonovich
Keyword(s):  
Rayleigh Wave ◽  
Pulse Propagation ◽  
Ultrasonic Method ◽  
Physical And Mechanical Properties ◽  
Pulse Velocity ◽  
Energy Localization ◽  
Near Surface ◽  
In Situ Conditions ◽  
Selection Of

The existing non-destructive testing system of structure concrete is actually orientated on the usage of longitudinal acoustical waves. This is due to simplicity of technical realization for measuring velocity (time) of acoustical pulse propagation in bulk concrete. But a reverse side of simple measuring procedure is a loss of additional information on concrete which is contained in the accepted acoustical signal. Therefore usage of an ultrasonic concrete testing method is limited by assessment of its strength. Joint usage of several wave types, so-called multi-wave testing, allows to refine metrology parameters of the ultrasonic method and to gain more information while determining physical and mechanical properties of concrete in laboratory and in situ conditions. The paper considers testing of elongated concrete elements and structures by an ultrasonic pulsing method on the basis of longitudinal subsurface and Rayleigh waves. It has been proposed to use methodology for time selection of wave components according to amplitude parameter and it has been applied for standard acoustical transformers with considerable reverberation time and not possessing spatial selectivity Basic principle of the proposed methodology is visual (according to oscillogram of the received signal) determination of characteristic time moments which are used for calculation of differential value of a propagation velocity in the Rayleigh wave impulse. The paper presents results pertaining to simulation of acoustical pulse propagation on the basis of 0.15 m and data of concrete ultrasonic in situ testing on measuring bases from 0.25 to 1.75 m. Advantage of large baseline for sonic test is a possibility for execution of a hundred percent inspection for surface of large-sized elements and structures, and so there is no need to make a selective inspection in some control areas as it is stipulated by provided by existing regulations. Responsivity of the Rayleigh wave parameters to near surface concrete defects permits quickly and efficiently to detect crack areas in a reinforced structure. Energy localization of a surface wave in a layer having width λ/2–λ provides a possibility to ignore reinforcement availability under appropriate selection of oscillation frequency. In addition to this, large measuring baseline makes it possible to lower effect of concrete structural inhomogeneity on statistical stability for pulse velocity assessment that ultimately reveals a possibility to register an appearance of concrete acoustical elasticity effect under in situ conditions.

Evaluating Measured Tire Contact Stresses to Predict Pavement Response and Performance

2000 ◽  
Vol 1716 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Reynaldo Roque ◽  
Leslie Ann Myers ◽  
Bjorn Birgisson
Keyword(s):  
Contact Stress ◽  
Contact Stresses ◽  
Embedded Sensors ◽  
Stress Distributions ◽  
Near Surface ◽  
Weak Bases ◽  
Truck Tires ◽  
Pavement Response ◽  
Pavement Structures ◽  
And Performance

Recent research has indicated that measured contact stress distributions under radial truck tires are highly complex. These stress distributions help to explain near-surface distresses that have become more prevalent since the inception of radial tires, indicating that realistic contact stresses must be considered when pavement response and performance are evaluated. However, because of the complexities involved in measuring contact stresses under tires, obtaining these measurements directly on real pavements is not possible. Consequently, contact stress measurements have been made on systems having rigid foundations with embedded sensors. Therefore, determining whether tire contact stresses measured on a rigid foundation are significantly different from contact stresses under the same tire on an actual pavement is critical. Finite element analyses conducted indicated that both vertical and lateral tire contact stresses measured on rigid foundations accurately represent the contact stresses for the same tire on typical asphalt pavement structures. Some minor differences were observed for thin (50-mm surface) pavements on weak bases, but the correspondence in terms of both distribution and magnitude was still very good. The conclusion was that contact stresses measured by devices with rigid foundations appear to be suitable for predicting response and performance of highway pavements.

Influence of ion treatment modes on the physical and mechanical properties of zirconia ceramics

2020 ◽  
Vol 10 ◽  
pp. 5-18
Author(s):  
S. А. Ghyngаzоv ◽  
◽  
V. А. Коstеnко ◽  
A. K. Khassenov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Current Density ◽  
Ion Beam ◽  
Physical And Mechanical Properties ◽  
Oxygen Stoichiometry ◽  
Continuous Mode ◽  
Zirconia Ceramics ◽  
Surface Layers ◽  
Near Surface ◽  
Ion Treatment

The article considers the influence of the treatment modes by N2+ and Ar+ ions beams on the physical and mechanical properties of zirconia ceramics. Surface modification of zirconia ceramics was performed using two modes of ion treatment — pulsed and continuous. The pulse mode of treatment by N2+ ions was realized at an accelerating voltage of 250 – 300 kV, current density j = 150 – 200 A/cm2, and energy density W = (3.5 and 5) ± 5 % J/cm2. The continuous mode of treatment by Ar+ ions was realized at an accelerating voltage of 30 kV and an ion current density of 300 and 500 μA/cm2. The fluence of the Ar+ ion beam varied from 1016 to 1018 cm–2. It is established that the pulsed mode of ion treatment leads to the melting and recrystallization of the surface of ceramics. It is shown that this treatment leads to a violation of the oxygen stoichiometry in ceramics and, as a result, there is an appearance of electrical conductivity in the near-surface layers, the layers of zirconia ceramics become conductive. It was established that the continuous mode of ion treatment does not lead to the melting and recrystallization of the ceramics surface, but is accompanied by its slight etching. It is shown that under the action of continuous ion treatment, microhardness increases (by 14 %). Hardening of the surface layers of ceramics is observed at a depth that exceeds the average projected range of Ar+ ion by 103 times.

scholarly journals Validation of MAX-DOAS retrievals of aerosol extinction, SO<sub>2</sub>, and NO<sub>2</sub> through comparison with lidar, sun photometer, active DOAS, and aircraft measurements in the Athabasca oil sands region

2020 ◽  
Vol 13 (3) ◽  
pp. 1129-1155 ◽  
Author(s):  
Zoë Y. W. Davis ◽  
Udo Frieß ◽  
Kevin B. Strawbridge ◽  
Monika Aggarwaal ◽  
Sabour Baray ◽  
...  
Keyword(s):  
Oil Sands ◽  
Aerosol Extinction ◽  
Vertical Profiles ◽  
Aircraft Measurements ◽  
Mining Operations ◽  
Athabasca Oil Sands ◽  
Near Surface ◽  
Athabasca Oil Sands Region ◽  
Mixing Ratios ◽  
Sun Photometer

Abstract. Vertical profiles of aerosols, NO2, and SO2 were retrieved from Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements at a field site in northern Alberta, Canada, during August and September 2013. The site is approximately 16 km north of two mining operations that are major sources of industrial pollution in the Athabasca oil sands region. Pollution conditions during the study ranged from atmospheric background conditions to heavily polluted with elevated plumes, according to the meteorology. This study aimed to evaluate the performance of the aerosol and trace gas retrievals through comparison with data from a suite of other instruments. Comparisons of aerosol optical depths (AODs) from MAX-DOAS aerosol retrievals, lidar vertical profiles of aerosol extinction, and the AERONET sun photometer indicate good performance by the MAX-DOAS retrievals. These comparisons and modelling of the lidar S ratio highlight the need for accurate knowledge of the temporal variation in the S ratio when comparing MAX-DOAS and lidar data. Comparisons of MAX-DOAS NO2 and SO2 retrievals to Pandora spectral sun photometer vertical column densities (VCDs) and active DOAS mixing ratios indicate good performance of the retrievals, except when vertical profiles of pollutants within the boundary layer varied rapidly, temporally, and spatially. Near-surface retrievals tended to overestimate active DOAS mixing ratios. The MAX-DOAS observed elevated pollution plumes not observed by the active DOAS, highlighting one of the instrument's main advantages. Aircraft measurements of SO2 were used to validate retrieved vertical profiles of SO2. Advantages of the MAX-DOAS instrument include increasing sensitivity towards the surface and the ability to simultaneously retrieve vertical profiles of aerosols and trace gases without requiring additional parameters, such as the S ratio. This complex dataset provided a rare opportunity to evaluate the performance of the MAX-DOAS retrievals under varying atmospheric conditions.

An assessment of the Sachs method for measuring residual stresses in cold worked fastener holes

1998 ◽  
Vol 33 (4) ◽  
pp. 263-274 ◽  
Author(s):  
D J Smith ◽  
C G C Poussard ◽  
M J Pavier
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Cold Working ◽  
Element Model ◽  
Fe Model ◽  
Working Process ◽  
Element Analysis ◽  
Near Surface ◽  
Cold Worked ◽  
Good Agreement

Measurements of residual stresses in 6 mm thick aluminium alloy 2024 plates containing 4 per cent cold worked fastener are made using the Sachs method. The measurements are made on discs extracted from the plates. The measured tangential residual stress distribution adjacent to the hole edge are found to be affected by the disc diameter. The measured residual stresses are also in good agreement with averaged through-thickness predictions of residual stresses from an axisymmetric finite element (FE) model of the cold working process. A finite element analysis is also conducted to simulate disc extraction and then the Sachs method. The measured FE residual stresses from the Sachs simulation are found to be in good agreement with the averaged through-thickness predicted residual stresses. The Sachs simulation was not able to reproduce the detailed near-surface residual stresses found from the finite element model of the cold working process.

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