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Louay N Mohammad - One of the best experts on this subject based on the ideXlab platform.
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The effect of tack coat material, application rate, and pavements surface types on the Interface Shear Strength
2011Co-Authors: Louay N Mohammad, Mostafa A Elseifi, Nachiketa PatelAbstract:This paper presents the effects of tack coat material type, tack coat application rate, and surface type (i.e., HMA vs. PCC) including milled vs. unmilled surfaces on the Interface Shear Strength based on full-scale test application. Five types of tack coat materials were applied at three application rates on four different types of surfaces at the Louisiana Pavement Research Facility (PRF) site. Samples were cored from the constructed test lanes, and the Interface Shear Strength was measured using the Louisiana Interface Shear Strength Tester (LISST). Results of this study showed that the trackless tack coat produced the highest Shear Strength at the three application rates, and SS-1 and CRS-1 resulted in the medium and the lowest Strength, respectively. Within the considered application rate range, it was difficult to determine the optimum residual application rate. This was attributed to the highly oxidized and coarse HMA surface at the selected site that required greater tack coat rates than expected.
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Factors that influence the performance of Interface Shear Strength of pavement interlayers
2010Co-Authors: Louay N Mohammad, Abraham Bae, Mostafa A Elseifi, Nachiketa PatelAbstract:This paper examines the effects of tack coat type, tack coat application rate, and surface type (i.e., hot mix asphalt (HMA) versus Portland cement concrete (PCC)) including milled versus unmilled surfaces on the Interface Shear Strength based on full-scale test application. To achieve this objective, four types of tack coat materials were applied at four three application rates on four different types of surfaces (existing HMA, new HMA, milled HMA, and PCC). To simulate field test conditions, cores were extracted from a full-scale test site that was designed and constructed using conventional tack coat application and paving equipment. Results of this study showed that all tack coat materials showed the highest Shear Strength at an application rate of 0.70 litres per square metre. A direct relationship is observed between the roughness of the existing surface and the developed Shear Strength at the Interface. (a) For the covering entry of this conference, please see ITRD abstract no. E220164.
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effects of pavement surface type and sample preparation method on tack coat Interface Shear Strength
Transportation Research Record, 2010Co-Authors: Louay N Mohammad, Abraham Bae, Mostafa A Elseifi, Joe W Button, Nachiketa PatelAbstract:The objective of this study was to quantify the effects of tack coat type, tack coat application rate, and surface type (i.e., hot-mix asphalt versus portland cement concrete) including milled versus unmilled surfaces on the Interface Shear Strength based on full-scale test application. The variation of Interface Shear Strength between field- and laboratory-prepared samples was also investigated. To achieve this objective, five types of tack coat materials were applied at three application rates on four types of surfaces at the Pavement Research Facility site of the Louisiana Transportation Research Center. Samples were cored from the constructed test lanes, and the Interface Shear Strength was measured using the Louisiana Interface Shear Strength Tester. Results of this study showed that a direct relationship was observed between the roughness of the existing surface and the developed Shear Strength at the Interface. A small amount of water seemed to negatively affect Interface Shear Strength with PG 64-22 used as a tack coat material. However, the effect of surface wetness on Interface Shear Strength was less evident for emulsion-based tack coat materials. Laboratory-prepared samples grossly overestimated the Interface Shear Strength when compared with field-extracted cores. While a decreasing trend was observed in the laboratory, an increasing trend in the measured Interface Shear Strength was observed in the field.
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effects of temperature on Interface Shear Strength of emulsified tack coats and its relationship to rheological properties
Transportation Research Record, 2010Co-Authors: Louay N Mohammad, Mostafa A Elseifi, Joe W Button, Nachiketa PatelAbstract:The objective of this study was to investigate tack coat Interface Shear bond characteristics at various temperatures and to relate tack coat characteristics in the field to the rheological test results in the laboratory. Interface Shear Strength (ISS) of two emulsified asphalt tack coats (CRS-1 and trackless) was evaluated at temperatures ranging from -10°C to 60°C. Two emulsified tack coats were applied on full-scale pavement test sections at application rates of 0.14, 0.28, and 0.70 L/m2. Cores were then extracted from the full-scale test sites to be tested in the laboratory while simulating different field conditions. Tests were conducted with a newly developed direct Shear device. The binder grade for the residue of CRS-1 emulsion was PG 58-28. The high temperature grade for the residue of the trackless emulsion was PG 82. Trackless material was brittle at a low temperature, and its low temperature PG grade could not be determined. Within the evaluated temperature range, the ISS of the tacked interfa...
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Effect of Tack Coat Materials and Application Rate on the Interface Shear Strength
2009Co-Authors: Louay N Mohammad, Abraham Bae, Mostafa A ElseifiAbstract:This paper evaluates Interface Shear Strength of emulsified tack coats under a wide range of testing conditions commonly encountered in field applications. Three types of emulsified tack coats, CRS-1, SS-1h, and Trackless, were considered at three application rates, 0.14, 0.28, and 0.70 l/m2. Laboratory direct Shear tests were performed at 25oC under two confinement pressures, 0- and 138-kPa. To simulate these test conditions, cores were extracted from a full-scale test site. Results of this analysis showed that the trackless tack coat produced the highest Shear Strength at the three application rates, and SS-1 and CRS-1 resulted in the medium and the lowest Strength, respectively. While higher application rates may increase Interface Shear Strength, excessive tack coat may migrate into the hot mix asphalt (HMA) mat during compaction causing a decrease in the air void content in the mix.
Wai Keong Wong - One of the best experts on this subject based on the ideXlab platform.
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sand geotextile Interface Shear Strength by torsional ring Shear tests
Geotextiles and Geomembranes, 1998Co-Authors: S H Chew, Wai Keong WongAbstract:Abstract The torsional ring Shear apparatus was developed to evaluate the residual Shear Strength of soft soils. It has the advantage of allowing large displacement to take place while Shearing. In using geotextiles for geotechnical engineering applications, the soil–geotextile Interface Shear Strength is an important design parameter. Hence this paper describes the evaluation of the soil–geotextile Interface Shear Strength using the torsional ring Shear test. Dry medium sand and nonwoven polypropylene geotextile were used. The test program consisted of three series of tests for parametric study as well as the fourth series that compares the results from the direct Shear and ring Shear test. This test program was the first in a series aimed at studying the feasibility of measuring the soil–geotextile Interface Shear Strength using the ring Shear apparatus. The test results show that the peak friction angle and residual friction angle of the sand–geotextile Interface is not significantly affected by the nominal mass of geotextile. The results also show that the sand–geotextile Interface peak and residual friction angles are not greatly influenced by the rate of Shear. However, the results show that the tests should not be conducted at a strain rate higher than 10 deg/min, beyond which erratic readings were observed. The results also show that the friction angle of the sand–geotextile Interface decreases as the overburden pressure increases. Finally tests were conducted using the ring Shear and direct Shear operating at similar conditions. The results show that measurements of sand–geotextile Interface friction angle measured by both equipments is almost identical at small Shear displacement of less than 3 mm. Beyond the 3 mm small Shear displacement, the direct Shear test indicates higher friction angle than the ring Shear test. The direct Shear test is unable to measure Interface Shear Strength at a displacements larger than about 15 mm, whereas the ring Shear test can measure residual Interface Shear Strength at displacement of more than 200 mm.
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Sand–geotextile Interface Shear Strength by torsional ring Shear tests
Geotextiles and Geomembranes, 1998Co-Authors: Siew-ann Tan, S H Chew, Wai Keong WongAbstract:Abstract The torsional ring Shear apparatus was developed to evaluate the residual Shear Strength of soft soils. It has the advantage of allowing large displacement to take place while Shearing. In using geotextiles for geotechnical engineering applications, the soil–geotextile Interface Shear Strength is an important design parameter. Hence this paper describes the evaluation of the soil–geotextile Interface Shear Strength using the torsional ring Shear test. Dry medium sand and nonwoven polypropylene geotextile were used. The test program consisted of three series of tests for parametric study as well as the fourth series that compares the results from the direct Shear and ring Shear test. This test program was the first in a series aimed at studying the feasibility of measuring the soil–geotextile Interface Shear Strength using the ring Shear apparatus. The test results show that the peak friction angle and residual friction angle of the sand–geotextile Interface is not significantly affected by the nominal mass of geotextile. The results also show that the sand–geotextile Interface peak and residual friction angles are not greatly influenced by the rate of Shear. However, the results show that the tests should not be conducted at a strain rate higher than 10 deg/min, beyond which erratic readings were observed. The results also show that the friction angle of the sand–geotextile Interface decreases as the overburden pressure increases. Finally tests were conducted using the ring Shear and direct Shear operating at similar conditions. The results show that measurements of sand–geotextile Interface friction angle measured by both equipments is almost identical at small Shear displacement of less than 3 mm. Beyond the 3 mm small Shear displacement, the direct Shear test indicates higher friction angle than the ring Shear test. The direct Shear test is unable to measure Interface Shear Strength at a displacements larger than about 15 mm, whereas the ring Shear test can measure residual Interface Shear Strength at displacement of more than 200 mm.
Nachiketa Patel - One of the best experts on this subject based on the ideXlab platform.
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The effect of tack coat material, application rate, and pavements surface types on the Interface Shear Strength
2011Co-Authors: Louay N Mohammad, Mostafa A Elseifi, Nachiketa PatelAbstract:This paper presents the effects of tack coat material type, tack coat application rate, and surface type (i.e., HMA vs. PCC) including milled vs. unmilled surfaces on the Interface Shear Strength based on full-scale test application. Five types of tack coat materials were applied at three application rates on four different types of surfaces at the Louisiana Pavement Research Facility (PRF) site. Samples were cored from the constructed test lanes, and the Interface Shear Strength was measured using the Louisiana Interface Shear Strength Tester (LISST). Results of this study showed that the trackless tack coat produced the highest Shear Strength at the three application rates, and SS-1 and CRS-1 resulted in the medium and the lowest Strength, respectively. Within the considered application rate range, it was difficult to determine the optimum residual application rate. This was attributed to the highly oxidized and coarse HMA surface at the selected site that required greater tack coat rates than expected.
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Factors that influence the performance of Interface Shear Strength of pavement interlayers
2010Co-Authors: Louay N Mohammad, Abraham Bae, Mostafa A Elseifi, Nachiketa PatelAbstract:This paper examines the effects of tack coat type, tack coat application rate, and surface type (i.e., hot mix asphalt (HMA) versus Portland cement concrete (PCC)) including milled versus unmilled surfaces on the Interface Shear Strength based on full-scale test application. To achieve this objective, four types of tack coat materials were applied at four three application rates on four different types of surfaces (existing HMA, new HMA, milled HMA, and PCC). To simulate field test conditions, cores were extracted from a full-scale test site that was designed and constructed using conventional tack coat application and paving equipment. Results of this study showed that all tack coat materials showed the highest Shear Strength at an application rate of 0.70 litres per square metre. A direct relationship is observed between the roughness of the existing surface and the developed Shear Strength at the Interface. (a) For the covering entry of this conference, please see ITRD abstract no. E220164.
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effects of pavement surface type and sample preparation method on tack coat Interface Shear Strength
Transportation Research Record, 2010Co-Authors: Louay N Mohammad, Abraham Bae, Mostafa A Elseifi, Joe W Button, Nachiketa PatelAbstract:The objective of this study was to quantify the effects of tack coat type, tack coat application rate, and surface type (i.e., hot-mix asphalt versus portland cement concrete) including milled versus unmilled surfaces on the Interface Shear Strength based on full-scale test application. The variation of Interface Shear Strength between field- and laboratory-prepared samples was also investigated. To achieve this objective, five types of tack coat materials were applied at three application rates on four types of surfaces at the Pavement Research Facility site of the Louisiana Transportation Research Center. Samples were cored from the constructed test lanes, and the Interface Shear Strength was measured using the Louisiana Interface Shear Strength Tester. Results of this study showed that a direct relationship was observed between the roughness of the existing surface and the developed Shear Strength at the Interface. A small amount of water seemed to negatively affect Interface Shear Strength with PG 64-22 used as a tack coat material. However, the effect of surface wetness on Interface Shear Strength was less evident for emulsion-based tack coat materials. Laboratory-prepared samples grossly overestimated the Interface Shear Strength when compared with field-extracted cores. While a decreasing trend was observed in the laboratory, an increasing trend in the measured Interface Shear Strength was observed in the field.
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effects of temperature on Interface Shear Strength of emulsified tack coats and its relationship to rheological properties
Transportation Research Record, 2010Co-Authors: Louay N Mohammad, Mostafa A Elseifi, Joe W Button, Nachiketa PatelAbstract:The objective of this study was to investigate tack coat Interface Shear bond characteristics at various temperatures and to relate tack coat characteristics in the field to the rheological test results in the laboratory. Interface Shear Strength (ISS) of two emulsified asphalt tack coats (CRS-1 and trackless) was evaluated at temperatures ranging from -10°C to 60°C. Two emulsified tack coats were applied on full-scale pavement test sections at application rates of 0.14, 0.28, and 0.70 L/m2. Cores were then extracted from the full-scale test sites to be tested in the laboratory while simulating different field conditions. Tests were conducted with a newly developed direct Shear device. The binder grade for the residue of CRS-1 emulsion was PG 58-28. The high temperature grade for the residue of the trackless emulsion was PG 82. Trackless material was brittle at a low temperature, and its low temperature PG grade could not be determined. Within the evaluated temperature range, the ISS of the tacked interfa...
Yoichi Sugioka - One of the best experts on this subject based on the ideXlab platform.
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comparison of bone implant Interface Shear Strength of hydroxyapatite coated and alumina coated metal implants
Journal of Biomedical Materials Research, 1995Co-Authors: Tatsurou Inadome, Koichiro Hayashi, H. Tsumura, Yasuharu Nakashima, Yoichi SugiokaAbstract:We performed a transcortical push-out test to determine the effect of surface roughness of hydroxyapatite (HA)-coated implants on bone-implant Shear Strength in a canine model. Hydroxyapatite- and alumina-coated SUS316L with the same surface roughness (roughness average: Ra = 5 μm) and HA-coated Ti-6Al-4V (Ra = 8.4 μm), sintered HA (Ra = 0.9 μm), and dense alumina (Ra = 1.3 μm) were inserted into the dog's femur. The Interface Shear Strength of the dense alumina was significantly lower than that of other implants at both 4 and 12 weeks after implantation. At 4 weeks after implantation, the Interface Shear Strength of the alumina-coated SUS316L was significantly lower than that of other implants (P < .05) except the dense alumina, but at 12 weeks, there was no significant difference between the implant types except the dense alumina. This indicates that the surface roughness of the HA coating affects the enhancement of the bone-implant Interface Shear Strength at the early period after implantation, and that a surface roughness of several micrometers does not influence the bond Strength between bone and HA. A scanning electron microscopic study indicated that in almost all cases at 12 weeks, the failure site after push-out testing was the coating-substrate Interface, not the coating-bone Interface. Therefore, protection of the coating-substrate Interface from direct Shear loading is needed. © 1995 John Wiley & Sons, Inc.
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comparison of bone implant Interface Shear Strength of solid hydroxyapatite and hydroxyapatite coated titanium implants
Journal of Biomedical Materials Research, 1993Co-Authors: Kazuo Hayashi, Tatsurou Inadome, Tatsuoki Mashima, Yoichi SugiokaAbstract:The Interface Shear Strength of uncoated Ti-6Al-4V, dense sintered hydroxyapatite (HA), and HA-coated Ti-6Al-4V were compared. Interface Shear Strength was determined using a transcortical push-out model in dogs 4 and 12 weeks after implantation. The Interface Shear Strength of dense sintered HA and HA-coated Ti-6Al-4V was significantly higher than that of uncoated Ti-6Al-4V (P < .001). There was no significant difference between the Interface Shear Strength of dense sintered HA and HA-coated Ti-6Al-4V. After the push-out test for HA-coated implants, the regions fractured at the bone-coating Interface and at the coating-titanium Interface coexisted at 4 weeks after implantation. At 12 weeks, the fracture site was, in all cases, the HA coating-titanium Interface, and, in a few samples, fractures inside the coating layer also were visible. © 1993 John Wiley & Sons, Inc.
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Comparison of bone–implant Interface Shear Strength of solid hydroxyapatite and hydroxyapatite‐coated titanium implants
Journal of biomedical materials research, 1993Co-Authors: Kazuo Hayashi, Tatsurou Inadome, Tatsuoki Mashima, Yoichi SugiokaAbstract:The Interface Shear Strength of uncoated Ti-6Al-4V, dense sintered hydroxyapatite (HA), and HA-coated Ti-6Al-4V were compared. Interface Shear Strength was determined using a transcortical push-out model in dogs 4 and 12 weeks after implantation. The Interface Shear Strength of dense sintered HA and HA-coated Ti-6Al-4V was significantly higher than that of uncoated Ti-6Al-4V (P < .001). There was no significant difference between the Interface Shear Strength of dense sintered HA and HA-coated Ti-6Al-4V. After the push-out test for HA-coated implants, the regions fractured at the bone-coating Interface and at the coating-titanium Interface coexisted at 4 weeks after implantation. At 12 weeks, the fracture site was, in all cases, the HA coating-titanium Interface, and, in a few samples, fractures inside the coating layer also were visible. © 1993 John Wiley & Sons, Inc.
Neil Dixon - One of the best experts on this subject based on the ideXlab platform.
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Deterministic and reliability-based design: veneer cover soil stability
Geosynthetics International, 2019Co-Authors: A.h.i. Sia, Neil DixonAbstract:A design chart is a graphical tool that provides solutions to different scenarios of a system. In this paper, two types of design chart are developed based on deterministic and reliability-based analyses for determining the Interface Shear Strength required for stability of a cover system to achieve a target safety factor of 1.5 and failure probability of 1 × 10−2. The deterministic design chart assists in the selection of different types of geosynthetic for lining materials based on the required Interface Shear Strength for stability, and the reliability-based design chart enhances decision-making by taking into account the uncertainties in the design parameters, such as the variability of Interface Shear Strength parameters. Additionally, the latter chart can also be used to determine the optimum slope angle for a containment facility that will satisfy both the target factor of safety and acceptable failure probability. Examples are provided to illustrate the use of the design charts in estimating the m...
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stability performance and Interface Shear Strength of geocomposite drain soil systems
AIP Conference Proceedings, 2018Co-Authors: Maidiana Othman, Matthew W Frost, Neil DixonAbstract:Landfill covers are designed as impermeable caps on top of waste containment facilities after the completion of landfill operations. Geocomposite drain (GD) materials consist of a geonet or geospacer (as a drainage core) sandwiched between non-woven geotextiles that act as separators and filters. GD provides a drainage function as part of the cover system. The stability performance of landfill cover system is largely controlled by the Interface Shear Strength mobilized between the elements of the cover. If a GD is used, the Interface Shear Strength properties between the upper surface of the GD and the overlying soil may govern stability of the system. It is not uncommon for fine grained materials to be used as cover soils. In these cases, understanding soil softening issues at the soil Interface with the non-woven geotextile is important. Such softening can be caused by capillary break behaviour and build-up of water pressures from the toe of the drain upwards into the cover soil. The interaction processes to allow water flow into a GD core through the soil-geotextile Interface is very complex. This paper reports the main behaviour of in-situ Interface Shear Strength of soil-GD using field measurements on the trial landfill cover at Bletchley, UK. The soil softening at the Interface due to soaked behaviour show a reduction in Interface Shear Strength and this aspect should be emphasized in design specifications and construction control. The results also help to increase confidence in the understanding of the implications for design of cover systems.
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Stability performance and Interface Shear Strength of geocomposite drain/soil systems
2018Co-Authors: Maidiana Othman, Matthew W Frost, Neil DixonAbstract:Landfill covers are designed as impermeable caps on top of waste containment facilities after the completion of landfill operations. Geocomposite drain (GD) materials consist of a geonet or geospacer (as a drainage core) sandwiched between non-woven geotextiles that act as separators and filters. GD provides a drainage function as part of the cover system. The stability performance of landfill cover system is largely controlled by the Interface Shear Strength mobilized between the elements of the cover. If a GD is used, the Interface Shear Strength properties between the upper surface of the GD and the overlying soil may govern stability of the system. It is not uncommon for fine grained materials to be used as cover soils. In these cases, understanding soil softening issues at the soil Interface with the non-woven geotextile is important. Such softening can be caused by capillary break behaviour and build-up of water pressures from the toe of the drain upwards into the cover soil. The interaction processes to allow water flow into a GD core through the soil-geotextile Interface is very complex. This paper reports the main behaviour of in-situ Interface Shear Strength of soil-GD using field measurements on the trial landfill cover at Bletchley, UK. The soil softening at the Interface due to soaked behaviour show a reduction in Interface Shear Strength and this aspect should be emphasized in design specifications and construction control. The results also help to increase confidence in the understanding of the implications for design of cover systems.
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Distribution and variability of Interface Shear Strength and derived parameters
Geotextiles and Geomembranes, 2007Co-Authors: A.h.i. Sia, Neil DixonAbstract:Abstract Knowledge of distribution type and quantification of variability are fundamental for evaluation of characteristic values for use in design as well as inputs for reliability analyses. The paper formally examines the assumption of normality to represent peak and large displacement Interface Shear Strengths and the derived Coulomb Strength parameters. Additionally, the variability and uncertainty for three generic Interfaces are computed and compared using information obtained from global databases, inter-laboratory and repeatability testing programmes. Using subjective and objective statistical test methods, normal distribution is found suitable to represent Interface Shear Strengths and their derived Strength parameters especially when variability is small. When variability of the Interface Shear Strength is high, a normal distribution with truncated tails at possible minimum and maximum values is recommended to avoid sampling of negative or extreme values. The variability of Interface Shear Strengths computed using global databases are 3–5 times, and can reached up to 8 times higher for the derived parameters compare to repeatability datasets. It is concluded that variability and uncertainty computed using global and inter-laboratory datasets yield overly conservative outcomes when adopted in design.
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Interface Shear Strength variability and its use in reliability based landfill stability analysis
Geosynthetics International, 2006Co-Authors: Neil Dixon, D R V Jones, Gary John FowmesAbstract:Failure of modern landfills by slippage of lining materials and waste bodies is not uncommon. The majority of failures are controlled by slippage at Interfaces between lining components. Information on variability of Interface Shear Strength is required both to carry out limit equilibrium stability analysis using characteristic Shear Strengths and to analyse the probability of failure. Current practice is to carry out a limited number of site-specific tests, and this provides insufficient information on the variability of Interface Strength for design. A summary of measured Strengths and an assessment of variability are presented for seven generic Interfaces common in landfill lining systems. This combines values from the international literature, from an internal database, and from the results of repeatability testing programmes. The implications of variable Shear Strength are examined though failure probability analysis for two common design cases – veneer and waste body slippage – and this adds to the ...