Fabricio Leiva - Academia.edu (original) (raw)
Papers by Fabricio Leiva
Airfield and Highway Pavements 2023
Journal of Testing and Evaluation
CRC Press eBooks, Jul 7, 2022
The objective of this experiment was to evaluate cracking potential of asphalt mixtures containin... more The objective of this experiment was to evaluate cracking potential of asphalt mixtures containing RAP in the laboratory and in the field. A secondary objective of this work was to characterize the mixtures' properties in the laboratory to determine which crack ing tests might most successfully predict cracking resistance in the field. Four mixtures were placed in 100-foot test strips at the NCAT Test Track in the 2015 test cycle. The mixtures varied in terms of binder type (PG grades: 64-28 and 76-22) and recycled material content (20, 25 and 30% RAP). The mixtures were evaluated for cracking potential using five different tests: Illinois flexibility index test (I-FIT), Energy ratio from Florida, Cantabro test, Overlay test (OT)-NCAT modified and dynamic modulus test. 20 million ESALs of traffic have been applied to all sections. Laboratory results did not completely exhibit expected trends in terms of cracking potential. The mixture with the highest content of RAP and highest critical per formance temperature (30% RAP, PG 76-22) was not the worst cracking performer. However, the mixture with the softest binder was the top performer. With regards to field performance, all four sections have shown no significant differences in rutting, ride quality and texture. On the other hand, after 15 million ESALs, there is significant cracking in all sections (from 6% to 19% per lane). All sections followed the expected cracking trend but the section with the highest RAP content. At 15 million ESALs, Energy Ratio and Cantabro test results have shown good correlations with field cracking performance with R 2 values over 0.7.
CRC Press eBooks, Jul 7, 2022
The parameter or coefficient gamma obtained from the E* master curve has been shown to relate to ... more The parameter or coefficient gamma obtained from the E* master curve has been shown to relate to the width of the relaxation spectra and is related to the slope of the master curve. Incorporation of aged binders or binders with hardening modifiers to a mixture leads to an increase in gamma, which corresponds to a flattening of the master curve (lower susceptibility to frequency changes) and widening of the relaxation spectra. For a standard logistic function, the inflection point modulus (-beta/gamma) is controlled by the aggregate structure and volumetric effects. At high temperatures, the aggregate structure begins to dom inate the behavior of the mixture, while volumetric properties and binder stiffness control the behavior at lower temperatures. Incorporation of aged binder or hardening modifiers to a mixture leads to a shift of the inflection point to lower frequencies. In this study, 15 asphalt mixtures containing Recycled Asphalt Shingles (RAS) where tested to evaluate their cracking susceptibility in the laboratory. Besides mixture characterization under dynamic modulus test protocols, the laboratory testing program evaluated recovered binder performance grade and fatigue cracking laboratory performance tests including Bending Beam Fatigue test, Energy Ratio, Overlay Tester and Fracture Energy (Flexibility Index test). The results of this study indicated good relationships between the master curve inflection point with the flexibility index and the dissipated creep strain energy (DCSE, from Energy Ratio testing). These results suggested that as the mixtures become more susceptible to cracking (lower Flexibility Index) and become more brittle (lower DCSE) the inflection point of the master curve decreases (due to stiffening of the binder in the mixture). In addition, when all the mixtures where ranked from top to bottom cracking susceptibility, the master curve inflection point agreed well with all the other cracking test results.
Directed by E. Ray Brown Compactability of HMA mixtures is often used to describe how easy or dif... more Directed by E. Ray Brown Compactability of HMA mixtures is often used to describe how easy or difficult a mixture is to compact on a roadway. Several asphalt researchers have proposed laboratory measured parameters of mixtures and/or their components as indicators of HMA compactability and/or resistance to permanent deformation. However, most of these measured characteristics have not been validated with actual field performance. The first part of this study includes a comparison between the laboratory compactability parameters Compaction Energy Index (CEI), number of gyrations to reach 92% of G mm (N@92%G mm), Slope, Locking Point and Bailey Method ratios. The data used for this stage came from Superpave mixtures placed on the NCAT Test Track in the vi first two cycles (quality control samples). It was found that CEI, N@92%G mm , Slope, Locking Point can be used to represent the applied energy to reach a level of compaction in the SGC. The second part of this study includes the determination of a field compactability indicator based on rolling operation (Accumulated Compaction Pressure-ACP) and correlation between this indicator and laboratory parameters. When all the combined data were used to correlate ACP and lab compactability parameters, the values of simple linear correlation (R-value) were always near zero. The results showed that t/NMAS and temperature significantly affected the applied compactive effort to reach the postconstruction density level. The third part of this project includes compaction of specimens using the SGC at to meet the 8% air voids at thicknesses equal to those in the field. A multiple regression analysis showed that eighty two percent of the variability in the ACP can be explained by four predictors: PCSI, FAc ratio, lift temperature and number of gyrations to reach the post construction density level at lift thickness (N@field-density). The last part of this study involved density testing during the rolling operation. The purpose of this part was to determine the field compaction energy required to produce the same level of density as samples compacted in the laboratory and correlate that energy with laboratory compaction parameters. A multiple regression analysis provided a model with ACP@92%G mm as the response, while ninety two percent of the variability in the response can be explained by the interaction temperature*thickness, % passing No 200 sieve, actual PG grade, slope, locking point/Slope ratio, FAc ratio and
United States. Federal Highway Administration. Office of Preconstruction, Construction, and Pavements, Dec 1, 2020
Federal Highway Administration2020PDFBriefHand, Adam J. T.Aschenbrener, T.Tran, Nam H.Leiva, Fabr... more Federal Highway Administration2020PDFBriefHand, Adam J. T.Aschenbrener, T.Tran, Nam H.Leiva, FabricioUniversity of Nevada, RenoUnited States. Federal Highway Administration. Office of Preconstruction, Construction, and PavementsUnited States. Federal Highway Administration. Office of Preconstruction, Construction, and PavementsUnited StatesIn place densityAsphalt pavementsDurabilityDemonstration projectsFHWA-HIF-21-022This Technical Brief summarizes techniques used to overcome obstacles to achieving increased density on individual State projects associated with the FHWA Enhancing Durability of Asphalt Pavements Through Increased In-Place Density Demonstration Project.112
United States. Federal Highway Administration. Office of Preconstruction, Construction, and Pavements, Dec 1, 2020
Federal Highway Administration2020PDFBriefAschenbrener, T.Tran, Nam H.Leiva, FabricioHand, Adam J... more Federal Highway Administration2020PDFBriefAschenbrener, T.Tran, Nam H.Leiva, FabricioHand, Adam J. T.United States. Federal Highway Administration. Office of Preconstruction, Construction, and PavementsUniversity of Nevada, RenoUnited States. Federal Highway Administration. Office of Preconstruction, Construction, and PavementsUnited StatesIn place densityDurabilityAsphalt pavementsDemonstration projectsTechniques and toolsIncreased densityFHWA-HIF-21-021This Technical Brief summarizes contractor and agency changes made leading to increased density on projects associated with the FHWA Enhancing Durability of Asphalt Pavements Through Increased In-Place Density Demonstration Project.112
Trabajo final de graduación de 26 páginas en formato pdfLa multi-dimensión de la administración d... more Trabajo final de graduación de 26 páginas en formato pdfLa multi-dimensión de la administración de obras viales hace que esta tarea sea compleja y costosa. La agencia encargada de dicha administración (el MOPT o cualquier municipio) cuenta con sistemas que apoyan la gestión de elementos (sistemas de gestión de pavimentos y sistema de gestión de puentes) y actividades particulares relacionadas con la construcción y mantenimiento de obras viales (caminos y carreteras). Esta práctica no siempre es la óptima desde la perspectiva del objetivo global de la agencia. El presente estudio propone crear una herramienta de planificación integral de la red, que permita alcanzar el objetivo global de la agencia, a través de evaluaciones técnicas y económicas. A dicha herramienta se le ha denominado Sistema de Gestión Vial (SGV) o Sistema de Gestión de Pavimentos (SGP). Este sistema plantea una perspectiva alternativa con respecto a la manera de entender la red y a la forma de actuar sobre ella. U...
TechBrief, Dec 1, 2020
Federal Highway Administration2020PDFTech ReportAschenbrener, T.Tran, Nam H.Leiva, FabricioHand, ... more Federal Highway Administration2020PDFTech ReportAschenbrener, T.Tran, Nam H.Leiva, FabricioHand, Adam J. T.University of Nevada, RenoUnited States. Federal Highway Administration. Office of Preconstruction, Construction, and PavementsUnited States. Federal Highway Administration. Office of Preconstruction, Construction, and PavementsUnited StatesIn place densityAsphalt pavementsDurabilityDemonstration projectsSpecificationsFHWA-HIF-21-020This Technical Brief introduces the FHWA Enhancing Durability of Asphalt Pavements Through Increased In-Place Density Demonstration Project and a series of Technical Briefs Associated with the outcomes of it. Specifically, key overall observations and related specification examples are presented in this Technical Brief.112
Transportation Research Record: Journal of the Transportation Research Board, 2022
State highway agencies (SHAs) are looking for guidance on how they can make changes to their Supe... more State highway agencies (SHAs) are looking for guidance on how they can make changes to their Superpave volumetric mix design procedures to obtain higher design binder contents to improve the cracking resistance and durability of asphalt mixtures. To assist SHAs, this paper was prepared to: (a) synthesize most common adjustments made by SHAs to their Superpave volumetric mix design procedures to obtain higher design binder contents; and (b) verify the effectiveness of these adjustments through laboratory experiments. Based on a survey of SHAs, the three most common adjustments to the Superpave mix design system to obtain higher design binder contents include: lowered design gyrations (Ndesign), increased minimum requirements for voids in mineral aggregate (VMA), and lowered design air voids (including air voids regression). These adjustments were verified in a laboratory testing program which included a virgin fine-graded mixture and a 20% reclaimed asphalt pavement (RAP) coarse-grad...
Airfield and Highway Pavements 2023
Journal of Testing and Evaluation
CRC Press eBooks, Jul 7, 2022
The objective of this experiment was to evaluate cracking potential of asphalt mixtures containin... more The objective of this experiment was to evaluate cracking potential of asphalt mixtures containing RAP in the laboratory and in the field. A secondary objective of this work was to characterize the mixtures' properties in the laboratory to determine which crack ing tests might most successfully predict cracking resistance in the field. Four mixtures were placed in 100-foot test strips at the NCAT Test Track in the 2015 test cycle. The mixtures varied in terms of binder type (PG grades: 64-28 and 76-22) and recycled material content (20, 25 and 30% RAP). The mixtures were evaluated for cracking potential using five different tests: Illinois flexibility index test (I-FIT), Energy ratio from Florida, Cantabro test, Overlay test (OT)-NCAT modified and dynamic modulus test. 20 million ESALs of traffic have been applied to all sections. Laboratory results did not completely exhibit expected trends in terms of cracking potential. The mixture with the highest content of RAP and highest critical per formance temperature (30% RAP, PG 76-22) was not the worst cracking performer. However, the mixture with the softest binder was the top performer. With regards to field performance, all four sections have shown no significant differences in rutting, ride quality and texture. On the other hand, after 15 million ESALs, there is significant cracking in all sections (from 6% to 19% per lane). All sections followed the expected cracking trend but the section with the highest RAP content. At 15 million ESALs, Energy Ratio and Cantabro test results have shown good correlations with field cracking performance with R 2 values over 0.7.
CRC Press eBooks, Jul 7, 2022
The parameter or coefficient gamma obtained from the E* master curve has been shown to relate to ... more The parameter or coefficient gamma obtained from the E* master curve has been shown to relate to the width of the relaxation spectra and is related to the slope of the master curve. Incorporation of aged binders or binders with hardening modifiers to a mixture leads to an increase in gamma, which corresponds to a flattening of the master curve (lower susceptibility to frequency changes) and widening of the relaxation spectra. For a standard logistic function, the inflection point modulus (-beta/gamma) is controlled by the aggregate structure and volumetric effects. At high temperatures, the aggregate structure begins to dom inate the behavior of the mixture, while volumetric properties and binder stiffness control the behavior at lower temperatures. Incorporation of aged binder or hardening modifiers to a mixture leads to a shift of the inflection point to lower frequencies. In this study, 15 asphalt mixtures containing Recycled Asphalt Shingles (RAS) where tested to evaluate their cracking susceptibility in the laboratory. Besides mixture characterization under dynamic modulus test protocols, the laboratory testing program evaluated recovered binder performance grade and fatigue cracking laboratory performance tests including Bending Beam Fatigue test, Energy Ratio, Overlay Tester and Fracture Energy (Flexibility Index test). The results of this study indicated good relationships between the master curve inflection point with the flexibility index and the dissipated creep strain energy (DCSE, from Energy Ratio testing). These results suggested that as the mixtures become more susceptible to cracking (lower Flexibility Index) and become more brittle (lower DCSE) the inflection point of the master curve decreases (due to stiffening of the binder in the mixture). In addition, when all the mixtures where ranked from top to bottom cracking susceptibility, the master curve inflection point agreed well with all the other cracking test results.
Directed by E. Ray Brown Compactability of HMA mixtures is often used to describe how easy or dif... more Directed by E. Ray Brown Compactability of HMA mixtures is often used to describe how easy or difficult a mixture is to compact on a roadway. Several asphalt researchers have proposed laboratory measured parameters of mixtures and/or their components as indicators of HMA compactability and/or resistance to permanent deformation. However, most of these measured characteristics have not been validated with actual field performance. The first part of this study includes a comparison between the laboratory compactability parameters Compaction Energy Index (CEI), number of gyrations to reach 92% of G mm (N@92%G mm), Slope, Locking Point and Bailey Method ratios. The data used for this stage came from Superpave mixtures placed on the NCAT Test Track in the vi first two cycles (quality control samples). It was found that CEI, N@92%G mm , Slope, Locking Point can be used to represent the applied energy to reach a level of compaction in the SGC. The second part of this study includes the determination of a field compactability indicator based on rolling operation (Accumulated Compaction Pressure-ACP) and correlation between this indicator and laboratory parameters. When all the combined data were used to correlate ACP and lab compactability parameters, the values of simple linear correlation (R-value) were always near zero. The results showed that t/NMAS and temperature significantly affected the applied compactive effort to reach the postconstruction density level. The third part of this project includes compaction of specimens using the SGC at to meet the 8% air voids at thicknesses equal to those in the field. A multiple regression analysis showed that eighty two percent of the variability in the ACP can be explained by four predictors: PCSI, FAc ratio, lift temperature and number of gyrations to reach the post construction density level at lift thickness (N@field-density). The last part of this study involved density testing during the rolling operation. The purpose of this part was to determine the field compaction energy required to produce the same level of density as samples compacted in the laboratory and correlate that energy with laboratory compaction parameters. A multiple regression analysis provided a model with ACP@92%G mm as the response, while ninety two percent of the variability in the response can be explained by the interaction temperature*thickness, % passing No 200 sieve, actual PG grade, slope, locking point/Slope ratio, FAc ratio and
United States. Federal Highway Administration. Office of Preconstruction, Construction, and Pavements, Dec 1, 2020
Federal Highway Administration2020PDFBriefHand, Adam J. T.Aschenbrener, T.Tran, Nam H.Leiva, Fabr... more Federal Highway Administration2020PDFBriefHand, Adam J. T.Aschenbrener, T.Tran, Nam H.Leiva, FabricioUniversity of Nevada, RenoUnited States. Federal Highway Administration. Office of Preconstruction, Construction, and PavementsUnited States. Federal Highway Administration. Office of Preconstruction, Construction, and PavementsUnited StatesIn place densityAsphalt pavementsDurabilityDemonstration projectsFHWA-HIF-21-022This Technical Brief summarizes techniques used to overcome obstacles to achieving increased density on individual State projects associated with the FHWA Enhancing Durability of Asphalt Pavements Through Increased In-Place Density Demonstration Project.112
United States. Federal Highway Administration. Office of Preconstruction, Construction, and Pavements, Dec 1, 2020
Federal Highway Administration2020PDFBriefAschenbrener, T.Tran, Nam H.Leiva, FabricioHand, Adam J... more Federal Highway Administration2020PDFBriefAschenbrener, T.Tran, Nam H.Leiva, FabricioHand, Adam J. T.United States. Federal Highway Administration. Office of Preconstruction, Construction, and PavementsUniversity of Nevada, RenoUnited States. Federal Highway Administration. Office of Preconstruction, Construction, and PavementsUnited StatesIn place densityDurabilityAsphalt pavementsDemonstration projectsTechniques and toolsIncreased densityFHWA-HIF-21-021This Technical Brief summarizes contractor and agency changes made leading to increased density on projects associated with the FHWA Enhancing Durability of Asphalt Pavements Through Increased In-Place Density Demonstration Project.112
Trabajo final de graduación de 26 páginas en formato pdfLa multi-dimensión de la administración d... more Trabajo final de graduación de 26 páginas en formato pdfLa multi-dimensión de la administración de obras viales hace que esta tarea sea compleja y costosa. La agencia encargada de dicha administración (el MOPT o cualquier municipio) cuenta con sistemas que apoyan la gestión de elementos (sistemas de gestión de pavimentos y sistema de gestión de puentes) y actividades particulares relacionadas con la construcción y mantenimiento de obras viales (caminos y carreteras). Esta práctica no siempre es la óptima desde la perspectiva del objetivo global de la agencia. El presente estudio propone crear una herramienta de planificación integral de la red, que permita alcanzar el objetivo global de la agencia, a través de evaluaciones técnicas y económicas. A dicha herramienta se le ha denominado Sistema de Gestión Vial (SGV) o Sistema de Gestión de Pavimentos (SGP). Este sistema plantea una perspectiva alternativa con respecto a la manera de entender la red y a la forma de actuar sobre ella. U...
TechBrief, Dec 1, 2020
Federal Highway Administration2020PDFTech ReportAschenbrener, T.Tran, Nam H.Leiva, FabricioHand, ... more Federal Highway Administration2020PDFTech ReportAschenbrener, T.Tran, Nam H.Leiva, FabricioHand, Adam J. T.University of Nevada, RenoUnited States. Federal Highway Administration. Office of Preconstruction, Construction, and PavementsUnited States. Federal Highway Administration. Office of Preconstruction, Construction, and PavementsUnited StatesIn place densityAsphalt pavementsDurabilityDemonstration projectsSpecificationsFHWA-HIF-21-020This Technical Brief introduces the FHWA Enhancing Durability of Asphalt Pavements Through Increased In-Place Density Demonstration Project and a series of Technical Briefs Associated with the outcomes of it. Specifically, key overall observations and related specification examples are presented in this Technical Brief.112
Transportation Research Record: Journal of the Transportation Research Board, 2022
State highway agencies (SHAs) are looking for guidance on how they can make changes to their Supe... more State highway agencies (SHAs) are looking for guidance on how they can make changes to their Superpave volumetric mix design procedures to obtain higher design binder contents to improve the cracking resistance and durability of asphalt mixtures. To assist SHAs, this paper was prepared to: (a) synthesize most common adjustments made by SHAs to their Superpave volumetric mix design procedures to obtain higher design binder contents; and (b) verify the effectiveness of these adjustments through laboratory experiments. Based on a survey of SHAs, the three most common adjustments to the Superpave mix design system to obtain higher design binder contents include: lowered design gyrations (Ndesign), increased minimum requirements for voids in mineral aggregate (VMA), and lowered design air voids (including air voids regression). These adjustments were verified in a laboratory testing program which included a virgin fine-graded mixture and a 20% reclaimed asphalt pavement (RAP) coarse-grad...