The Experts below are selected from a list of 1953 Experts worldwide ranked by ideXlab platform
H Henein - One of the best experts on this subject based on the ideXlab platform.
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strain aging on the yield Strength to Tensile Strength Ratio of uoe pipe
Materials Science and Technology, 2017Co-Authors: J B Wiskel, J Valloton, Douglas G Ivey, H HeneinAbstract:ABSTRACTStrain aging of microalloyed steel pipe can occur at the relatively low temperatures associated with the pipe coating process and/or during long-term storage. A Box–Behnken statistical design was used to determine the significant strain aging variables that affect the longitudinal yield Strength to Tensile Strength (Y/TS) Ratio for three uncoated X70 UOE pipes. The strain aging variables examined include time, temperature, steel composition/microstructure (vis-a-vis the C/Nb Ratio) and position through the pipe wall thickness. Metallographic and electron backscattered diffraction examinations were undertaken to determine the grain size and phase percentages of the as-received pipe steel. Both position in the pipe and the C/Nb Ratio were found to have a statistically significant effect on the yield Strength to Tensile Strength Ratio.
J B Wiskel - One of the best experts on this subject based on the ideXlab platform.
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Transverse Strain Aging Behaviour of Uncoated Thick Walled X70 UOE Microalloyed Steel Pipes
Volume 3: Operations Monitoring and Maintenance; Materials and Joining, 2018Co-Authors: J B Wiskel, Douglas G Ivey, J. Ma, Hani HeneinAbstract:Transverse Tensile samples were extracted from the centreline position of three different compositions of uncoated thick walled microalloyed X70 UOE pipe at a location 180° from the weld. Aging heat treatments of 5, 15, and 25 minutes and temperatures of 175, 215, and 255°C were applied. Tensile tests were conducted on both the original pipe and on pre-strained samples. Microstructural analysis was undertaken using optical microscopy and scanning electron microscopy (SEM). The effects of a combined time and temperature aging parameter, pre-strain, microstructure and Tensile work hardening behaviour on the pipe yield stress and yield to Tensile Strength Ratio, is presented.
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strain aging on the yield Strength to Tensile Strength Ratio of uoe pipe
Materials Science and Technology, 2017Co-Authors: J B Wiskel, J Valloton, Douglas G Ivey, H HeneinAbstract:ABSTRACTStrain aging of microalloyed steel pipe can occur at the relatively low temperatures associated with the pipe coating process and/or during long-term storage. A Box–Behnken statistical design was used to determine the significant strain aging variables that affect the longitudinal yield Strength to Tensile Strength (Y/TS) Ratio for three uncoated X70 UOE pipes. The strain aging variables examined include time, temperature, steel composition/microstructure (vis-a-vis the C/Nb Ratio) and position through the pipe wall thickness. Metallographic and electron backscattered diffraction examinations were undertaken to determine the grain size and phase percentages of the as-received pipe steel. Both position in the pipe and the C/Nb Ratio were found to have a statistically significant effect on the yield Strength to Tensile Strength Ratio.
Hamzeh F. Haghshenas - One of the best experts on this subject based on the ideXlab platform.
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A study on moisture susceptibility of stone matrix warm mix asphalt
Construction and Building Materials, 2017Co-Authors: Mahdieh Khedmati, Ali Khodaii, Hamzeh F. HaghshenasAbstract:Abstract Stone matrix asphalt (SMA) is known to have high resistance to permanent deformation and reflective cracking due to their stone structure but similar to other hot mixes it has a high energy intake during its production. Warm mix asphalt (WMA) has recently gained a lot of popularity worldwide due to environmental concerns. Moisture susceptibility as one of the drawbacks of warm mixes has been investigated by many researchers but the extent and interactive effects of different parameters affecting moisture susceptibility particularly for SMA has not yet been reported. The aim of the present study was to examine the effects of grading, bitumen content, Zycosoil content, Sasobit content and mixing temperature on moisture susceptibility of SMA warm mix asphalt (WSMA), as well as their interactions, using response surface methodology. The results indicated that the influence of Sasobit content and grading was more than the influence of other factors on Tensile Strength Ratio -used as an index of moisture susceptibility- respectively. Also, interaction plots between factors affecting Tensile Strength Ratio were generated that can help to understand the interactive relationship between investigated factors.
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A mathematical model for predicting stripping potential of Hot Mix Asphalt
Construction and Building Materials, 2015Co-Authors: Hamzeh F. Haghshenas, Ali Khodaii, Mahdieh Khedmati, Serkan TapkınAbstract:Abstract Stripping – the most important mode of Hot Mix Asphalt (HMA) failure – is a problematic issue in the pavement performance and its maintenance. Identification and quantification of the pertinent parameters influencing on stripping process is a prerequisite for dealing with it effectively. Previous studies on stripping potential of HMA have focused on this issue based on empirical/semi-empirical models. In the present work Response Surface Methodology (RSM) was used for the study and optimization of pertinent factors, namely bitumen content employed, grading and lime content, in the stripping process of HMA. Tensile Strength Ratio (TSR) was chosen as the response for the evaluation of stripping potential of HMA using a Central Composite Design (CCD). The statistical analyses showed that second order polynomial models can successfully describe the relationship between the response and factors and the maximum Tensile Strength Ratio (TSR) is achieved at 5.73% bitumen content, 1.84% lime content and 65.30% of the materials passing sieve size 4.75 mm.
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Hydrated lime effect on moisture susceptibility of warm mix asphalt
Construction and Building Materials, 2012Co-Authors: Ali Khodaii, H. Kazemi Tehrani, Hamzeh F. HaghshenasAbstract:Abstract Beneficial effects of using hydrated lime to reduce moisture susceptibility of Hot Mix Asphalts are well recognized and widely used in industry. In present study, the effect of varying percentages of hydrated lime (from 0% to 2%) on the moisture susceptibility of warm mix asphalt was evaluated. Based on the obtained results it was shown that increasing hydrated lime content reduces the moisture susceptibility of dense graded warm mix asphalt. However, 80% of Tensile Strength Ratio was reached without utilization of hydrated lime in some prepared samples with gap grading, using polymer modified bitumen.
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effect of grading and lime content on hma stripping using statistical methodology
Construction and Building Materials, 2012Co-Authors: Ali Khodaii, Hamzeh F. Haghshenas, Kazemi H TehraniAbstract:Abstract Response surface methodology was employed to evaluate the effect of lime content and grading on the dry and saturated indirect Tensile Strength as well as Tensile Strength Ratio of hot mix asphalt. The statistical significance of linear, quadratic and interactive terms of these factors were examined and second order polynomial models were successfully fitted to the experiment data. It was shown that maximum Tensile Strength Ratio was achieved at 1% lime content and with grading containing most coarse aggregate. It was further concluded that decreasing the aggregate size and increase in mastic asphalt would increase the stripping potential of hot mixes asphalt.
Ali Khodaii - One of the best experts on this subject based on the ideXlab platform.
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A study on moisture susceptibility of stone matrix warm mix asphalt
Construction and Building Materials, 2017Co-Authors: Mahdieh Khedmati, Ali Khodaii, Hamzeh F. HaghshenasAbstract:Abstract Stone matrix asphalt (SMA) is known to have high resistance to permanent deformation and reflective cracking due to their stone structure but similar to other hot mixes it has a high energy intake during its production. Warm mix asphalt (WMA) has recently gained a lot of popularity worldwide due to environmental concerns. Moisture susceptibility as one of the drawbacks of warm mixes has been investigated by many researchers but the extent and interactive effects of different parameters affecting moisture susceptibility particularly for SMA has not yet been reported. The aim of the present study was to examine the effects of grading, bitumen content, Zycosoil content, Sasobit content and mixing temperature on moisture susceptibility of SMA warm mix asphalt (WSMA), as well as their interactions, using response surface methodology. The results indicated that the influence of Sasobit content and grading was more than the influence of other factors on Tensile Strength Ratio -used as an index of moisture susceptibility- respectively. Also, interaction plots between factors affecting Tensile Strength Ratio were generated that can help to understand the interactive relationship between investigated factors.
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Identification of dominant parameters for stripping potential in warm mix asphalt using response surface methodology
Materials and Structures, 2015Co-Authors: Ali Khodaii, Ehsan S. Mousavi, Mahdieh Khedmati, A. IranitalabAbstract:In this study, response surface methodology was utilized for creating a continuous response function and optimization of effective variables to improve the Tensile Strength Ratio, as an indicator of stripping potential, using factorial experiment with center composite design. The polynomial regression model equations were proposed based on the regression coefficients calculated for the indirect Tensile Strength in dry and saturated condition as well as Tensile Strength Ratio. Statistical analyses indicated that all first and second orders plus interactive terms were statistically significant with 90 % confidence level except for interactive terms of bitumen–Sasobit content in Tensile Strength Ratio, and grading-Sasobit content in dry indirect Tensile Strength. Furthermore, it was found that all first, second and interactive terms were statistically significant for saturated indirect Tensile Strength.
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A mathematical model for predicting stripping potential of Hot Mix Asphalt
Construction and Building Materials, 2015Co-Authors: Hamzeh F. Haghshenas, Ali Khodaii, Mahdieh Khedmati, Serkan TapkınAbstract:Abstract Stripping – the most important mode of Hot Mix Asphalt (HMA) failure – is a problematic issue in the pavement performance and its maintenance. Identification and quantification of the pertinent parameters influencing on stripping process is a prerequisite for dealing with it effectively. Previous studies on stripping potential of HMA have focused on this issue based on empirical/semi-empirical models. In the present work Response Surface Methodology (RSM) was used for the study and optimization of pertinent factors, namely bitumen content employed, grading and lime content, in the stripping process of HMA. Tensile Strength Ratio (TSR) was chosen as the response for the evaluation of stripping potential of HMA using a Central Composite Design (CCD). The statistical analyses showed that second order polynomial models can successfully describe the relationship between the response and factors and the maximum Tensile Strength Ratio (TSR) is achieved at 5.73% bitumen content, 1.84% lime content and 65.30% of the materials passing sieve size 4.75 mm.
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Hydrated lime effect on moisture susceptibility of warm mix asphalt
Construction and Building Materials, 2012Co-Authors: Ali Khodaii, H. Kazemi Tehrani, Hamzeh F. HaghshenasAbstract:Abstract Beneficial effects of using hydrated lime to reduce moisture susceptibility of Hot Mix Asphalts are well recognized and widely used in industry. In present study, the effect of varying percentages of hydrated lime (from 0% to 2%) on the moisture susceptibility of warm mix asphalt was evaluated. Based on the obtained results it was shown that increasing hydrated lime content reduces the moisture susceptibility of dense graded warm mix asphalt. However, 80% of Tensile Strength Ratio was reached without utilization of hydrated lime in some prepared samples with gap grading, using polymer modified bitumen.
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effect of grading and lime content on hma stripping using statistical methodology
Construction and Building Materials, 2012Co-Authors: Ali Khodaii, Hamzeh F. Haghshenas, Kazemi H TehraniAbstract:Abstract Response surface methodology was employed to evaluate the effect of lime content and grading on the dry and saturated indirect Tensile Strength as well as Tensile Strength Ratio of hot mix asphalt. The statistical significance of linear, quadratic and interactive terms of these factors were examined and second order polynomial models were successfully fitted to the experiment data. It was shown that maximum Tensile Strength Ratio was achieved at 1% lime content and with grading containing most coarse aggregate. It was further concluded that decreasing the aggregate size and increase in mastic asphalt would increase the stripping potential of hot mixes asphalt.
Srinivas F Chitragar - One of the best experts on this subject based on the ideXlab platform.
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laboratory performance of recycled asphalt mixes containing wax and chemical based warm mix additives using semi circular bending and Tensile Strength Ratio tests
Construction and Building Materials, 2018Co-Authors: Dharamveer Singh, Prabin Kumar Ashish, Srinivas F ChitragarAbstract:Abstract Durability and sustainability are two major requirements of the asphaltic pavement structure. Durability aspect may involve performance parameters such as fracture property, moisture sensitivity etc., whereas, sustainability aspect may involve utilization of Recycled Asphalt Pavement (RAP) and Warm Mix Additive (WMA) in the conventional asphaltic mixture. Though improvement in high temperature performance may be expected with the addition of RAP due to its stiffer nature, it may degrade intermediate temperature performance. Additionally, RAP utilization may also increase the mixing and compaction temperature during the construction phase. Therefore, researchers have recommended using different WMA additives to decrease production temperature of mixes containing RAP. Though the use of WMA additives with RAP may decrease mixing and compaction temperature, their effects on various performance parameters of the asphaltic mixture must be evaluated. Sufficient research works have been reported on the performance of RAP and WMA mixes at high temperature, however, so far, limited work is available on understanding effects of RAP and WMA additives on fatigue and moisture sensitivity of asphalt mixture. Therefore, the present research work aimed at evaluating intermediate temperature fracture properties and moisture sensitivity of asphaltic mixture containing RAP and WMA. Five different RAP contents (0%, 10%, 20%, 30%, and 40%), two different types of WMA additives (2% wax based “Sasobit” and 0.5% chemical based “Evotherm”) and one without WMA additive (Control mixture) were considered. Fracture properties of different asphaltic mixture combinations were evaluated using Semi Circular Bending (SCB) test. Improvement in fracture property of Control mixture was observed with increase in RAP content, however, the addition of wax based and chemical based WMA additives showed an overall reduction in fractured resistance. Further, the asphaltic mixture containing wax based WMA additive showed better fracture performance compared to the corresponding mixture containing chemical based WMA additive. Similarly, moisture sensitivity of asphaltic mixtures was evaluated using Tensile Strength Ratio (TSR) approach. Addition of both WMA additives resulted in lowered Indirect Tensile Strength (ITS) under dry as well as wet condition. Though the addition of WMA additive showed a negative impact on moisture sensitivity, all mixture considered in the present research work passed the minimum TSR requirement. Therefore, wax and chemical based WMA additive may deem acceptable from moisture sensitivity point of view.
