Effect Of Reclaimed Asphalt Pavement On Ontario Hot Mix Asphalt Performance
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Effect Of Reclaimed Asphalt Pavement On Ontario Hot Mix Asphalt Performance
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Author : Xiomara A. Sanchez-Castillo
language : en
Publisher:
Release Date : 2014
Effect Of Reclaimed Asphalt Pavement On Ontario Hot Mix Asphalt Performance written by Xiomara A. Sanchez-Castillo and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
The use of Reclaimed Asphalt Pavement (RAP), sometimes called Recycled Asphalt Pavement, in Hot Mix Asphalt (HMA) provides many benefits and has been successfully used in Ontario for several years. The production and usage of this material results in numerous environmental and economic advantages. Using RAP in HMA has various proven benefits including: reuse of high quality materials, saves on dwindling non-renewable aggregate resources, diverts large volumes of materials from overloaded landfills, reduces road building costs and contributes significantly to provincial and municipal recycling obligations. However, the usage of this material is still very conservative. Several challenges can be faced when introducing RAP in HMA, particularly in higher amounts. The characteristics of the RAP, particularly the aged (stiffer) asphalt cement (AC) in the recycled material, can affect the performance of the mix. The primary concern with increasing RAP percentages in HMA mixes are its effects on endurance against fatigue and thermal cracking. The common question in many agencies within the pavement industry is whether RAP acts as a “black rock” or the aged AC in RAP blends with the new AC in the mix. Accordingly, this research evaluated the impact that RAP in varying percentages has on a conventional Ontario mix, Superpave (SP) 12.5mm, and provided some new guidelines on the usage of RAP. Using virgin aggregates and RAP collected from a local contractor, twelve mixtures were modelled in the laboratory, with 0%, 20%, and 40% RAP contents and AC with different Performance Grade (PG). The research also examined how the addition of RAP to HMA alters the performance of the mix, and how HMA can be tested to determine the RAP content. This research intended to answer the following questions: First, can the RAP percentage be determined from the recycled hot mix asphalt characteristics or performance? And second, can the blended binder PG be deduced from performance testing of recycled hot mix? This research demonstrated that is possible to design Superpave mixes incorporating 20% RAP and 40% RAP without compromising the specified consensus properties and volumetric characteristics. Based on the results, it was determined that the performance of the recycled hot mixes regarding low temperature cracking, rutting and stiffness, which is related to the fatigue susceptibility of the mix, was simultaneously influenced by the RAP content and the virgin asphalt PG. The effect of the RAP addition was more dramatic for the mixes with virgin binder PG 52-xx than for the mixes with PG 58-xx. A method to determine the presence and quantity of RAP was formulated, and also an estimation of the performance grade of the resulting blended binder without extraction and recovery of the asphalt was possible.
Evaluating The Performance Of The Asphalt Mixes Containing Reclaimed Asphalt Pavement By Considering The Effect Of Silo Storage Time
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Author : Hawraa Kadhim
language : en
Publisher:
Release Date : 2020
Evaluating The Performance Of The Asphalt Mixes Containing Reclaimed Asphalt Pavement By Considering The Effect Of Silo Storage Time written by Hawraa Kadhim and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with Asphalt pavements categories.
The use of reclaimed asphalt pavement (RAP) in hot mix asphalt (HMA) has been increasing in the last few decades because of its cost benefits and because of a compelling need to preserve the environment and natural resources. It is commonly assumed that HMA containing RAP (HMA-RAP) has an improved resistance to permanent deformation (rutting) and decreased resistance to the fatigue cracking. This is due to the fact that asphalt binder contained in the RAP has been oxidized over the years and is typically stiffer than virgin asphalt binder. However, during the production stage of the HMA-RAP, the blending between aged and virgin asphalt binders would be incomplete or partial, which would lead to heterogeneous distribution of the aged and virgin asphalt binders within the asphalt mix with RAP. Therefore, the purpose of this article is to evaluate the effect of silo storage on the blending mechanism between virgin and RAP asphalt binders and the impact that this would have on performance of the mix. Two plant-produced asphalt mixes (HL-3 and HL-8), typically used in the province of Ontario for surface and base courses in flexible pavements, were considered in this study. The mixes were designed with 15 and 30 % RAP, respectively, and the samples were collected immediately after the production (0 h) or at different silo storage times (1, 4, 8, and 12 h). The temperatures of the collected materials were closely monitored and recorded. The findings of this research indicated that silo-stored samples exhibited some improvement in their rutting and fatigue resistance. The examination of the dynamic modulus master curves indicated that the rheology of the mixes evolved with silo storage and that blending between the aged and the virgin binders has been improved.
Effect Of Recycled Asphalt Pavement On Mechanistic Performance Of Hot Mix Asphalt
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Author : Adjamoussi David Adje
language : en
Publisher:
Release Date : 2012
Effect Of Recycled Asphalt Pavement On Mechanistic Performance Of Hot Mix Asphalt written by Adjamoussi David Adje and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Pavements, Asphalt categories.
Improving Durability Of Asphalt Mixes Produced With Reclaimed Asphalt Pavement Rap By Enhancing Binder Blending
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Author : Hawraa Kadhim
language : en
Publisher:
Release Date : 2019
Improving Durability Of Asphalt Mixes Produced With Reclaimed Asphalt Pavement Rap By Enhancing Binder Blending written by Hawraa Kadhim and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with Asphalt concrete categories.
Reclaimed Asphalt Pavement (RAP) has been favoured over virgin materials in the light of the unstable cost of virgin asphalt binders, shortage of quality aggregates, and compelling need to preserve the environment and natural resources. Mixes containing up to 20% RAP are commonly considered to have similar behaviour to virgin mixes. However, during the production process of HMA with RAP, the blending between aged and virgin binders would be partial, which would create heterogeneity in distribution of the aged recycled binder and the soft virgin binder in the HMA-RAP mixes. Hence, it is important to control the blending process between old and new binders to obtain more homogenous mix. Therefore, the main objectives of this research are to examine the kinematics of blending of aged and virgin binders by considering the time-temperature effect during mixing and silo-storage, and assess the thermo-mechanical behaviour of Hot Mix Asphalt (HMA) containing RAP at different blending states. The asphalt mixes used in this research were produced and collected at two plants (Plant 1) and (Plant 2) located in Ontario, Canada. Two Marshall mixes were produced and collected from Plant 1 including a surface course HL-3 containing 15 percent RAP and a base course HL-8 containing 30 percent RAP. These mixes were labelled as 1HL-3 and 1HL-8 respectively. In addition, two Marshall mixes were produced and collected from Plant 2 including a surface course HL-3 containing 20 percent RAP and a base course HL-8 containing 40 percent RAP. These mixes were labelled as 2HL-3 and 2HL-8 respectively. To investigate the impact of storage time on the blending progress and achieving a cohesive final binder, the mix samples were collected as a function of storage time in the silo. The first sampling was done immediately after production (t = 0-hour), and then at several time intervals of silo-storage; i.e., at 1, 4, 8, and 12 hours. In case of Plant 2, the samples were additionally collected after 24-hour of storage time. All samples were then kept in a storage room at 7ʻC until the day of compaction to minimize any further blending between aged and virgin binder. To understand the blending phenomena and its effect on the performance of the pavement, a multi-scale investigation is carried out. The blending was examined in terms of micro-mechanical and rheological properties. The microstructure of the blending zones were examined under The Environmental Scanning Electron Microscope (ESEM). In addition the effect of the silo-storage time on the rheology of the binders was investigated. The results indicate that increasing the interaction time and temperature between the aged and virgin binder significantly results in a better blending. The performance of RAP-HMA with respect to the silo-storage time was examined using Dynamic Modules Test, Thermal Stress Restrained Specimen Test (TSRST), Rutting Test, and Flexural Beam Fatigue Test. The experimental data indicates that samples collected after 12-hour of silo storage exhibited a reduction in the stiffness due to better blending of aged and virgin binder. In addition, the 12-hour samples showed enhancement in their fracture temperature, rutting depth, and fatigue life, accompanied with a better blending between their aged and virgin binder. On the other hand, the samples that collected after 24-hour silo-storage had a higher stiffness in comparison with the 8 and 12-hour samples. Moreover, the AASHTOWare Pavement Mechanistic-Empirical Design was utilized to examine the effect of the 12-hour silo-storage time on the long term performance of the pavements. Four pavement structures have been designed for this purpose. These pavements have the same structure of their granular A, granular B, and the subgrade. Yet, the first layer (surface course and base course) is a silo-storage time-dependent. The long-term field performance prediction indicates a slight improvement with the 12-hour pavements (Plant1 12hrs and Plant2 12hrs). However, it should be noted that AASHTOWare Pavement Mechanistic-Empirical Design does not appear to properly capture the effect of blending in the pavement performance. The collected experimental evidences unveils correlations between time-temperature effects and mixture performance. Based on these findings, the research provides practical recommendations to the professionals of the Canadian asphalt industry for a better use of RAP. Ultimately, this research recommends a 12-hour silo-storage time for the RAP-HMA for better performance and durability of the mixes.
Evaluating The Effects Of Recycling Agents On Asphalt Mixtures With High Ras And Rap Binder Ratios
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Author : Amy Epps Martin
language : en
Publisher:
Release Date : 2020
Evaluating The Effects Of Recycling Agents On Asphalt Mixtures With High Ras And Rap Binder Ratios written by Amy Epps Martin and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with Asphalt categories.
"More than 90 percent of highways and roads in the United States are built using hot-mix asphalt (HMA) or warm-mix asphalt (WMA) mixtures, and these mixtures now recycle more than 99 percent of some 76.2 million tons of reclaimed asphalt pavement (RAP) and about 1 million tons of recycled asphalt shingles (RAS) each year. Cost savings in 2017 totaled approximately $2.2 billion with these recycled materials replacing virgin materials. The TRB National Cooperative Highway Research Program's NCHRP Research Report 927: Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios presents an evaluation of how commercially available recycling agents affect the performance of asphalt mixtures incorporating RAP and RAS at high recycled binder ratios."--
Improved Mix Design Evaluation And Materials Management Practices For Hot Mix Asphalt With High Reclaimed Asphalt Pavement Content
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Author : Randy Clark West
language : en
Publisher: Transportation Research Board
Release Date : 2013
Improved Mix Design Evaluation And Materials Management Practices For Hot Mix Asphalt With High Reclaimed Asphalt Pavement Content written by Randy Clark West and has been published by Transportation Research Board this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Pavements, Asphalt categories.
TRB's National Cooperative Highway Research Program (NCHRP) Report 752: Improved Mix Design, Evaluation, and Materials Management Practices for Hot Mix Asphalt with High Reclaimed Asphalt Pavement Content describes proposed revisions to the American Association of State Highway and Transportation Officials (AASHTO) R 35, Superpave Volumetric Design for Hot Mix Asphalt, and AASHTO M 323, Superpave Volumetric Mix Design, to accommodate the design of asphalt mixtures with high reclaimed asphalt pavement contents.
Effect Of Warm Mix Asphalt On Recycled Asphalt Pavement In Hot Mix Asphalt
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Author : Thomas Bennert
language : en
Publisher:
Release Date : 2015
Effect Of Warm Mix Asphalt On Recycled Asphalt Pavement In Hot Mix Asphalt written by Thomas Bennert and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Asphalt emulsion mixtures categories.
Study Of Hot Mix Recycling Of Asphalt Pavements
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Author : Frank Meyer
language : en
Publisher:
Release Date : 1983
Study Of Hot Mix Recycling Of Asphalt Pavements written by Frank Meyer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1983 with Asphalt categories.
Interest in hot mix recycling has recently been stimulated by:rising cost of asphalt cement and fuels; depletion and risingcosts of readily available conventional aggregate resources; theneed to reduce energy consumption; reduction in available fundsfor transportation facilities due to inflation; and, environmental problems due to mining of aggregate materials. Since hot mix recycling can offer advantages in all these areas, the overall objective of this project is to encourage the use ofthis cost and energy efficient strategy in the rehabilitation andmaintenance of pavements in the national road system.
100 Recycled Hot Mix Asphalt And The Use Of Rejuvenators
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Author : Martins Zaumanis
language : en
Publisher:
Release Date : 2014
100 Recycled Hot Mix Asphalt And The Use Of Rejuvenators written by Martins Zaumanis and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
Abstract: The desire to find more sustainable paving practices as well as the dramatically rising binder costs driven by the growing global demand for paved roads, has led to increased interest of the use of reclaimed asphalt pavement (RAP) in very high amounts. So far the major industry trend has been to develop procedures, invest in technologies and build confidence in mixtures with up to 40 % RAP content. However, a few innovators have refined 100 % recycling technologies over the past four decades to a level where routine production of 100 % recycled hot mix asphalt is in clear sight. Rejuvenators are an integral part of 100 % recycled asphalt production and they can also allow to significantly increase the RAP content for conventionally produced asphalt mixtures. An evaluation of the feasibility of production of 100 % recycled hot-mix asphalt was made and the use of rejuvenators is presented in this study. 100 % recycling is discussed by evaluating ten readily available production technologies along with proposing mix design procedures and identifying best RAP management strategies. A total of eleven different products were evaluated for restoring the RAP binder grade with a definite conclusion that achieving target grade (PG or empirical specification) is possible. In addition a rheological, micromechanical and chemical characterization was performed with select rejuvenators and binders from Strategic Highway Research Program (SHRP) library. To further assess the rejuvenators and feasibility of 100 % RAP recycling a series of 100 % mixture tests were performed that indicated significant improvement in low temperature and fatigue cracking resistance while providing a rut resistant mixture. With the use of some rejuvenators a performance equal to that of reference virgin mix was achieved. Based on these findings of rejuvenator effectiveness a methodology for choice of rejuvenator type and dose was proposed. Finally, a cradle-to-gate analysis of environmental effects was performed which indicated 35 % CO2eq savings per ton of produced 100 % RAP asphalt mixture compared to virgin mix while cost analysis showed at least 50 % savings in material related expenses. A short video summarizing the research is available at http://youtu.be/y-rYvdGiEbY.
Impact Of High Rap Content On Structural And Performance Properties Of Asphalt Mixtures
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Author : Imad L. Al-Qadi
language : en
Publisher:
Release Date : 2012
Impact Of High Rap Content On Structural And Performance Properties Of Asphalt Mixtures written by Imad L. Al-Qadi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Pavements, Asphalt categories.