Evaluation of Reclaimed Asphalt Pavement Aggregate in Road Bases and Subbases (original) (raw)
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IMPROVEMENT OF THE MECHANICAL CHARACTERISTICS OF RECLAIMED ASPHALT PAVEMENT IN IRAQ
The technique of Recycling Asphalt Pavement (RAP) for road construction is widely used so that RAP has been called the most recycled material in the world. RAP is most commonly used as an aggregate substitute in asphalt mix also it is used as granular sub-base or base aggregate and embankment or fill material. Unfortunately, the mechanical properties of RAP materials do not meet the requirements of State Organization for Roads and Bridges (SORB, 2003) in Iraq for sub-base and base aggregate materials, such as gradation, California Bearing Ratio (CBR), and other strength coefficients. The objective of this study was to investigate and examine different RAP/virgin aggregate blending techniques to improve the mechanical characteristics of local RAP materials in Iraq. A detailed laboratory testing program was conducted to achieve these objectives. It was found that the blending of up to 40% RAP materials with different local virgin sub-base materials improves the RAP mechanical characteristics to meet SCRB (2003) requirements for road sub-base materials and provides economical, environmental, and sustainable road construction technique in Iraq. A computerized design and management analysis which was carried out on life cycle costs of flexible pavement with unbounded sub-base layer of blended virgin aggregate materials with RAP showed savings of up to 39% of total pavement cost depending on design in comparison with conventional flexible pavement in Iraq.
Performance Evaluation of Reclaimed Asphalt Pavement (RAP) Aggregates in Rigid Pavement: A Review
www.jetir.org(ISSN-2349-5162), 2019
The objective of this study is to understand the importance of using RAP for the construction of bituminous pavements. From this study and from previous research papers it can be concluded that using RAP is advantageous as RAP mixes can yield results equal or even higher than virgin mixes. If calculated and implemented appropriately RAP mixes have a constructive effect on various parameters like Marshall Stability, moisture resistance and density. This paper presents the importance of using RAP mixes.
IAEME PUBLICATION, 2019
Removed and / or reprocessed pavement materials containing asphalt and aggregate are termed as Reclaimed Asphalt Pavement (RAP).These materials are generated when asphalt pavements are removed for reconstruction and/or resurfacing of bituminous roads. When scraped or removed RAP properly screened and crushed, it consists of high quality well graded aggregate coated by asphalt cement. Recycling of asphalt pavement makes both environmental and economic profits. Presently use of recycled asphalt pavement has grown worldwide, reducing use of virgin materials thus becoming Technique of Sustainable Development. The objective of this review is to understand the scenario of using RAP in road construction basically in reference to India; learning from developed countries and other nations where use of RAP is in Advance stage.
Characterization of Reclaimed Asphalt Pavement (RAP) for Use in Bituminous Road Construction
Procedia - Social and Behavioral Sciences, 2013
A good road network is a critical infrastructure requirement for rapid economic growth. It provides connectivity to remote areas; provides accessibility to markets, schools, and hospitals; and opens up backward regions to trade and investment. Roads play an important role in intermodal transport development, through links with airports, railway stations, and ports. Road network in India aggregates to about 4.2 million kilometers. This extensive road network, the second largest in the world only after US, caters to about 65 per cent of the freight traffic and 87 per cent of the passenger traffic. National Highways (NH) constitute about 70,934 kilometers which is only 2 percent of the total network. However, it caters to nearly 40% of the total road traffic. State Highways (SH) and Major District Roads (MDR) together constitute the secondary system of road transportation which contributes significantly to the development of the rural economy and industrial growth of the country. The conventional method of providing bituminous surfacing on flexible pavements require significant amount of energy for production of bituminous binder from crude petroleum, drying aggregates and subsequently production of bituminous mix at hot mix plant (HMP).Hot mix recycling is the process in which reclaimed asphalt pavement materials are combined with new materials, sometimes along with a recycling agent, to produce hot mix asphalt mixtures. When properly designed, recycled mixtures can have better or similar performance to those of new conventional hot mix asphalt mixtures. Recycling or Rejuvenating agents have been defined as organic materials with chemical and physical characteristics selected to restore properties of aged asphalt to desired specifications. In selecting the recycling agent, the viscosity characteristics of the combined aged asphalt binder and the recycling agent are the determining factors. These agents are also known as softening agents, reclaiming agents, modifiers, fluxing oils, extender oils, and aromatic oils. The choice of Recycling Agent (RA) grade will depend on the amount and hardness of the asphalt in the aged pavement. In general, the lower viscosity RA types can be used to restore aged asphalts of high viscosity and vice versa. Laboratory studies have been carried out on asphalt mixes with RAP material and rejuvenating agent and their performance has been compared with virgin asphalt mixes. Various performance tests such as Retained Stability, Indirect Tensile Strength (ITS), Creep test, beam fatigue test, resilient modulus and wheel tracking test has been carried out to compare the performance properties. This paper presents the results of all such performance tests carried out on asphalt mixes with RAP and virgin mixes. The laboratory results indicate that the asphalt mixes with RAP and rejuvenating agent provide better performance compared to virgin mixes. The paper also recommends that the Accelerated Pavement Testing Facility (APTF) should be put to use to evaluate the actual field performance of recycled pavements in a faster and effective manner.
UTILIZATION OF RECLAIMED ASPHALT PAVEMENT (RAP) IN JORDAN ROADWAYS
Using Reclaimed Asphalt Pavement (RAP) in asphalt mixes has become a common practice in many countries as experience indicated that the recycling of asphalt pavements is very advantageous from different perspectives. Some of the advantages of utilizing RAP include conservation of asphalt and aggregate resources, conservation of energy, and reduction in life-cycle cost. In this study, the suitability of asphalt mixes using RAP was investigated. Two hot asphalt mixes were prepared following gradations recommended by Ministry of Public Works & Housing (MPWH/ Jordan). Marshall mix design procedure was used to determine the optimum asphalt content. The first mix composed of 100% fresh aggregate and virgin asphalt and the second mix composed of 30% RAP and 70% fresh aggregates and virgin asphalt. Marshal stability, loss of Marshall Stability, water sensitivity, indirect tensile strength, dynamic creep, and fatigue tests were performed on samples of the two mixes. Comparing the results of the conducted tests indicated that the use of RAP in hot mix asphalt was advantageous in all properties measured except for the fatigue test where shorter fatigue life was observed.
Today's sustainability-driven systems require a product or process to be environmentally beneficial as well as cost-effective. This study used life-cycle cost analysis (LCCA) and life-cycle assessment (LCA) to consider the economic and environmental feasibility of using a high content of reclaimed asphalt pavement (RAP) in asphalt mixtures. The LCCA conducted in the study incorporated agency cost as well as the costs incurred by the user in the construction work zone. Initial construction as well as future maintenance and rehabilitation activities were considered in the analysis. The hybrid LCA took into account the material, construction, and maintenance and rehabilitation phases of the pavement life cycle. The results showed savings in terms of costs and energy use and reduction in greenhouse gas emissions with an increase in RAP content. On the basis of the LCCA and LCA performed under various performance scenarios, break-even performance levels were identified for mixtures with up to 50% RAP content. Break-even performance levels underscored the importance of achieving field performance for recycled mixtures equivalent to that for control virgin mixtures.
Journal of Civil & Environmental Engineering, 2014
More than 15 million tons of aggregates are imported each year to Qatar from neighbouring countries. Large quantities of waste materials (around 20 million tons/year) from excavation waste, demolition rubble and reclaimed asphalt pavement (RAP) are being generated. The main objective of this paper is to present the results on the use of combined excavation waste (EW) and RAP aggregates in the construction of road bases and sub-bases. Physical and chemical properties were determined. Different combinations of both materials were subjected to compaction and California Bearing Ratio (CBR) testing in accordance with Qatar Construction Specifications. Results indicated that, for the materials tested, it is not feasible to use excavation waste, RAP aggregates or a combination of the two materials in road bases and sub-bases. The materials failed to meet some Qatari standards such as Los Angeles abrasion, liquid limit, plasticity index and CBR specified for road construction.
Evaluation of reclaimed asphalt pavement as base/subbase material in Egypt
Transportation Geotechnics, 2020
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Performance Assessment of Reclaimed Asphalt Pavement (RAP) in Road Surface Mixtures
Recycling
Considerable amounts of Reclaimed Asphalt Pavement (RAP) are produced every year, as the road network requires maintenance to ensure the safety and comfort of its users. RAP is a 100% recyclable material and a useful fit to be re-introduced into another cycle without downgrading its functionality. Despite the current knowledge about the benefits associated with RAP use, it is not yet largely applied in several countries. This paper aims to validate, on the basis of both short- and long-term mechanical behaviours, the application of a bituminous mixture with a high RAP incorporation rate (75%) in road pavement wearing courses. A crude tall oil rejuvenator was used. Both short- and long-term oven ageing procedures were employed to simulate the ageing that occurs during mixture production and in-service life, respectively. The tests for validating the RAP mixture as an alternative solution comprised stiffness, resistance to fatigue, permanent deformation, and determination of the water...
Beni-Suef University Journal of Basic and Applied Sciences
Background The depletion of natural resources has led to the need of looking out for alternatives of primary construction materials. The use of reclaimed asphalt pavement (RAP) has become a common practice as it reduces economic burden and saves natural resources and energy. This study is based on partial replacement of fresh natural aggregate with reclaimed aggregate. The project is divided into two phases; first one discusses the mechanical viability of replacing 10%, 20%, 30%, 40%, 50% and 60% of fresh aggregates with reclaimed aggregates. The second phase involves the study conducted on a 9.8 KM dense bituminous macadam (DBM) layer, constructed using the most optimum mix from the first phase of study. Finally, a cost analysis of the pavement was conducted to assess its economic viability. Results In the light of MORTH guidelines, laboratory results showed improvement in the Marshall parameters till 30% replacement of fresh aggregates. Eventually, the DBM layer was constructed us...