Laboratory study on the performance of recycled concrete aggregates blended with reclaimed asphalt pavement as pavement granular material

Production of recycled concrete aggregates (RCA) from construction and demolition (C&D) waste has become popular all over the world since the availability of land spaces are limited to dispose. Therefore it is important to seek alternative applications for RCA. The use of RCA in base and sub-base layers in granular pavement is a viable solution. In mechanistic pavement design, rutting (permanent deformation) is considered as the major failure mechanisms of the pavement. The rutting is the accumulation of permanent deformation of pavement layers caused by the repetitive vehicle load. In Queensland, Australia, it is accepted to have the maximum of 20% of reclaimed asphalt pavement (RAP) in RCA and therefore, it is important to investigate the effect of RAP on the permanent deformation properties of RCA. In this study, a series of repeated load triaxial (RLT) tests were conducted on RCA blended with different percentage of RAP to investigate the permanent deformation and resilient modulus properties of RCA. The vertical deformation and resilient modulus values were used to determine the response of RCA for the cyclic loading under standard pressure and loading conditions.

Investigation on characteristics and performance of recycled concrete aggregates as granular materials for unbound pavements

This research was a step forward in investigating the characteristics of recycled concrete aggregates to use as an unbound pavement material. The results present the guidelines for successfully application of recycled concrete aggregates in high traffic volume roads. Outcomes of the research create more economical and environmental benefits through reducing the depletion of natural resources and effectively manage the generated concrete waste before disposal as land fill.

Analysis of asphalt concrete permeability data using representative pore size

The permeability of asphalt concrete has been the subject of much study by pavement engineers over the last decade. The work undertaken has tended to focus on high air voids as the primary indicator of permeable asphalt concrete. This paper presents a simple approach for understanding the parameters that affect permeability. Principles explained by Taylor in 1956 in channel theory work for soils are used to derive a new parameter-representative pore size. Representative pore size is related to the air voids in the compacted mix and the D75 of the asphalt mix grading curve. Collected Superpave permeability data from published literature and data collected by the writers at the Queensland Department of Transport and Main Roads is shown to be better correlated with representative pore size than air voids, reducing the scatter considerably. Using the database of collected field and laboratory permeability values an equation is proposed that pavement engineers can use to estimate the permeability of in-place pavements. © 2011 ASCE.

Design and Evaluation of a Retrofittable Electric Snow Melting System for Pavements

Gemstone Team SnowMelt

Design of granular pavements

The use of high-quality quarried crushed rock aggregates is generally required to comply with current specifications for unbound granular materials (UGMs) in pavements. The source of these high-quality materials can be a long distance from the site, resulting in high transportation costs. The use of more local sources of marginal materials or the use of secondary aggregates is not allowed if they do not fully comply with existing specifications. These materials can, however, be assessed for their suitability for use in a pavement by considering performance criteria such as resistance to permanent deformation and degradation instead of relying on compliance with inflexible specifications. The final thickness of the asphalt cover and the pavement depth are governed by conventional pavement design methods, which consider the number of vehicle passes, subgrade strength, and some material property, commonly the California bearing ratio or resilient modulus. A pavement design method that includes as a design criterion an assessment of the resistance to deformation of a UGM in a pavement structure at a particular stress state is proposed. The particular stress state at which the aggregate is to perform in an acceptable way is related to the in situ stress, that is, the stress that the aggregate is anticipated to experience at a particular depth in the pavement. Because the stresses are more severe closer to the pavement surface, the aggregates should be better able to resist these stresses the closer they are laid to the surface in the pavement. This method was applied to two Northern Ireland aggregates of different quality (NI Good and NI Poor). The results showed that the NI Poor aggregate performed at an acceptable level with respect to permanent deformation, provided that a minimum of 70 mm of asphalt cover was provided. It was predicted that the NI Good material would require 60 mm of asphalt cover.

Influence of additives on the charactaristics of stone matrix asphalt

The increase in traffic growth and maintenance expenditures demands the urgent need for building better, long-lasting, and more efficient roads preventing or minimizing bituminous pavement distresses. Many of the principal distresses in pavements initiate or increase in severity due to the presence of water. In Kerala highways, where traditional dense graded mixtures are used for the surface courses, major distress is due to moisture induced damages. The Stone Matrix Asphalt (SMA) mixtures provide a durable surface course. Proven field performance of test track at Delhi recommends Stone Matrix Asphalt as a right choice to sustain severe climatic and heavy traffic conditions. But the concept of SMA in India is not so popularized and its application is very limited mainly due to the lack of proper specifications. This research is an attempt to study the influence of additives on the characteristics of SMA mixtures and to propose an ideal surface course for the pavements. The additives used for this investigation are coir, sisal, banana fibres (natural fibres), waste plastics (waste material) and polypropylene (polymer). A preliminary investigation is conducted to characterize the materials used in this study. Marshall test is conducted for optimizing the SMA mixtures (Control mixture-without additives and Stabilized mixtures with additives). Indirect tensile strength tests, compression strength tests, triaxial strength tests and drain down sensitivity tests are conducted to study the engineering properties of stabilized mixtures. The comparison of the performance of all stabilized mixtures with the control mixture and among themselves are carried out. A statistical analysis (SPSS package Ver.16) is performed to establish the findings of this study

Estimated lifetimes of road pavements in Sweden using time-to-event analysis

Maintenance planning of road pavement requires reliable estimates of roads’ lifetimes. In determining the lifetime of a road, this study combines maintenance activities and road condition measurements. The scope of the paper is to estimate lifetimes of road pavements in Sweden with time to event analysis. The model used includes effects of pavement type, road type, bearing capacity, road width, speed limit, stone size and climate zone, where the model is stratified according to traffic load. Among the nine analyzed pavement types, stone mastic had the longest expected lifetime, 32 percent longer than asphalt concrete. Among road types, ordinary roads with cable barriers had 30 percent shorter lifetime than ordinary roads. Increased speed lowered the lifetime, while increased stone size (up to 20 mm) and increased road width lengthened the lifetime. The results are of importance for life cycle cost analysis and road management.

Performance evaluation of low environmental impact asphalt concretes using the mechanistic empirical design method based on laboratory fatigue and permanent deformation models

The "sustainability" concept relates to the prolonging of human economic systems with as little detrimental impact on ecological systems as possible. Construction that exhibits good environmental stewardship and practices that conserve resources in a manner that allow growth and development to be sustained for the long-term without degrading the environment are indispensable in a developed society. Past, current and future advancements in asphalt as an environmentally sustainable paving material are especially important because the quantities of asphalt used annually in Europe as well as in the U.S. are large. The asphalt industry is still developing technological improvements that will reduce the environmental impact without affecting the final mechanical performance. Warm mix asphalt (WMA) is a type of asphalt mix requiring lower production temperatures compared to hot mix asphalt (HMA), while aiming to maintain the desired post construction properties of traditional HMA. Lowering the production temperature reduce the fuel usage and the production of emissions therefore and that improve conditions for workers and supports the sustainable development. Even the crumb-rubber modifier (CRM), with shredded automobile tires and used in the United States since the mid 1980s, has proven to be an environmentally friendly alternative to conventional asphalt pavement. Furthermore, the use of waste tires is not only relevant in an environmental aspect but also for the engineering properties of asphalt [Pennisi E., 1992]. This research project is aimed to demonstrate the dual value of these Asphalt Mixes in regards to the environmental and mechanical performance and to suggest a low environmental impact design procedure. In fact, the use of eco-friendly materials is the first phase towards an eco-compatible design but it cannot be the only step. The eco-compatible approach should be extended also to the design method and material characterization because only with these phases is it possible to exploit the maximum potential properties of the used materials. Appropriate asphalt concrete characterization is essential and vital for realistic performance prediction of asphalt concrete pavements. Volumetric (Mix design) and mechanical (Permanent deformation and Fatigue performance) properties are important factors to consider. Moreover, an advanced and efficient design method is necessary in order to correctly use the material. A design method such as a Mechanistic-Empirical approach, consisting of a structural model capable of predicting the state of stresses and strains within the pavement structure under the different traffic and environmental conditions, was the application of choice. In particular this study focus on the CalME and its Incremental-Recursive (I-R) procedure, based on damage models for fatigue and permanent shear strain related to the surface cracking and to the rutting respectively. It works in increments of time and, using the output from one increment, recursively, as input to the next increment, predicts the pavement conditions in terms of layer moduli, fatigue cracking, rutting and roughness. This software procedure was adopted in order to verify the mechanical properties of the study mixes and the reciprocal relationship between surface layer and pavement structure in terms of fatigue and permanent deformation with defined traffic and environmental conditions. The asphalt mixes studied were used in a pavement structure as surface layer of 60 mm thickness. The performance of the pavement was compared to the performance of the same pavement structure where different kinds of asphalt concrete were used as surface layer. In comparison to a conventional asphalt concrete, three eco-friendly materials, two warm mix asphalt and a rubberized asphalt concrete, were analyzed. The First Two Chapters summarize the necessary steps aimed to satisfy the sustainable pavement design procedure. In Chapter I the problem of asphalt pavement eco-compatible design was introduced. The low environmental impact materials such as the Warm Mix Asphalt and the Rubberized Asphalt Concrete were described in detail. In addition the value of a rational asphalt pavement design method was discussed. Chapter II underlines the importance of a deep laboratory characterization based on appropriate materials selection and performance evaluation. In Chapter III, CalME is introduced trough a specific explanation of the different equipped design approaches and specifically explaining the I-R procedure. In Chapter IV, the experimental program is presented with a explanation of test laboratory devices adopted. The Fatigue and Rutting performances of the study mixes are shown respectively in Chapter V and VI. Through these laboratory test data the CalME I-R models parameters for Master Curve, fatigue damage and permanent shear strain were evaluated. Lastly, in Chapter VII, the results of the asphalt pavement structures simulations with different surface layers were reported. For each pavement structure, the total surface cracking, the total rutting, the fatigue damage and the rutting depth in each bound layer were analyzed.

Investigation of using waste engine oil blended with reclaimed asphalt materials to improve pavement recyclability

With the increasing importance of conserving natural resources and moving toward sustainable practices, the aging transportation infrastructure can benefit from these ideas by improving their existing recycling practices. When an asphalt pavement needs to be replaced, the existing pavement is removed and ground up. This ground material, known as reclaimed asphalt pavement (RAP), is then added into new asphalt roads. However, since RAP was exposed to years of ultraviolet degradation and environmental weathering, the material has aged and cannot be used as a direct substitute for aggregate and binder in new asphalt pavements. One material that holds potential for restoring the aged asphalt binder to a usable state is waste engine oil. This research aims to study the feasibility of using waste engine oil as a recycling agent to improve the recyclability of pavements containing RAP. Testing was conducted in three phases, asphalt binder testing, advanced asphalt binder testing, and laboratory mixture testing. Asphalt binder testing consisted of dynamic shear rheometer and rotational viscometer testing on both unaged and aged binders containing waste engine oil and reclaimed asphalt binder (RAB). Fourier Transform Infrared Spectroscopy (FTIR) testing was carried out to on the asphalt binders blended with RAB and waste engine oil compare the structural indices indicative of aging. Lastly, sample asphalt samples containing waste engine oil and RAP were subjected to rutting testing and tensile strength ratio testing. These tests lend evidence to support the claim that waste engine oil can be used as a rejuvenating agent to chemically restore asphalt pavements containing RAP. Waste engine oil can reduce the stiffness and improve the low temperature properties of asphalt binders blended with RAB. Waste engine oil can also soften asphalt pavements without having a detrimental effect on the moisture susceptibility.

PERFORMANCE EVALUATION OF LLDPE/CaCO3 MODIFIERS WITH AND WITHOUT TITANATE COUPLING AGENT ON ASPHALT BINDER AND MIXTURE

The complexity and challenge created by asphalt material motivates researchers and engineers to investigate the behavior of this material to develop a better understanding, and improve the performance of asphalt pavement. Over decades, a wide range of modification at macro, meso, micro and nano scales have been conducted to improve the performance of asphalt pavement. This study was initiated to utilize the newly developed asphalt modifier pellets. These pellets consisted of different combinations of calcium carbonate (CaCO3), linear low-density polyethylene (LLDPE) and titanate coupling agent (CA) to improve the asphalt binder as well as pavement performance across a wide range of temperature and loading pace. These materials were used due to their unique characteristics and promising findings from various industries, especially as modifiers in pavement material. The challenge is to make sure the CaCO3 disperses very well in the mixture. The rheological properties of neat asphalt binder PG58-28 and modified asphalt binder (PG58-28/LLDPE, PG58-28/CaCO3, PG58-28/CaCO3/LLDPE, and PG58-28/CaCO3/LLDPE/CA), were determined using rotational viscometer (RV) test, dynamic shear rheometer (DSR) test and bending beam rheometer test. In the DSR test, the specimens were evaluated using frequency sweep and multiple shear creep recovery (MSCR). The asphalt mixtures (aggregate/PG58-28, aggregate/ PG58-28/LLDPE, aggregate/PG58-28/CaCO3, aggregate/PG58-28/LLDPE/CaCO3 and aggregate/PG58-28/LLDPE/CaCO3/CA) were evaluated using the four point beam fatigue test, the dynamic modulus (E*) test, and tensile strength test (to determines tensile strength ratio, TSR). The RV test results show that all modified asphalt binders have a higher viscosity compared to the neat asphalt binder (PG58-28). Based on the Jnr results (using MSCR test), all the modified asphalt binders have a better resistance to rutting compared to the neat asphalt binder. A higher modifier contents have resulted in a better recovery percentage of asphalt binder (higher resistance to rutting), except the specimens prepared using PECC’s modified asphalt binder (PG58-28/CaCO3/LLDPE). The BBR test results show that all the modified asphalt binders have shown comparable performance in term of resistance to low temperature cracking, except the specimen prepared using the LLDPE modifier. Overall, 5 wt% LLDPE modified asphalt binder was found to be the best asphalt binder in terms of resistance to rutting. Meanwhile, 3 wt% PECC-1CA’s modified asphalt binder can be considered as the best (in terms of resistance to thermal cracking) with the lowest mean critical cracking temperature. The appearance of CaCO3 was found useful merely in improving the resistance to fatigue cracking of asphalt mixture. However, application of LLDPE has undermined the fatigue life of asphalt mixtures. Adding LLDPE and coupling agent throughout this study does not sufficiently help in terms of elastic behavior which essential to enhance the resistance to fatigue cracking. In contrast, application of LLDPE has increased the indirect tensile strength values and TSR of asphalt mixtures, indicates a better resistance to moisture damage. The usage of the coupling agent does not change the behavior of the asphalt mixture, which could be due to imbalance effects resulted by combination of LLDPE and CaCO3 in asphalt binder. Further investigations without incorporating CaCO3 should be conducted further. To investigate the feasibility of using LLDPE and coupling agent as modifiers in asphalt pavements, more research should be conducted on different percentages of LLDPE (less than 3 wt%), and at the higher and w wider range of coupling agent content, from 3 wt% to 7 wt% based on the polymer mass.

Study of the effect of four warm mix asphalt additives on bitumen modified with 15% crumb rubber

Due to a growing concern over global warming, the bituminous mixture industry is making a constant effort to diminish its emissions by reducing manufacturing and installation temperatures without compromising the mechanical properties of the bituminous mixtures. The use of mixtures with tyre rubber has demonstrated that these mixtures can be economical and ecological and that they improve the behaviour of the pavements. However, bituminous mixtures with a high rubber content present one major drawback: they require higher mixing and installation temperatures due to the elevated viscosity caused by the high rubber content and thus they produce larger amounts of greenhouse gas emissions than conventional bituminous mixtures. This article presents a study of the effect of four viscosity-reducing additives (Sasobit®, Asphaltan A®, Asphaltan B® and Licomont BS 100®) on a bitumen modified with 15% rubber. The results of this study indicate that these additives successfully reduce viscosity, increase the softening temperature and reduce penetration. However, they do not have a clear effect on the test for elastic recovery and ductility at 25 °C.

Asphalt rubber mixtures with warm mix asphalt additives

En los últimos años, debido a la creciente preocupación por el calentamiento global y el cambio climático, uno de los retos más importantes a los que se enfrenta nuestra sociedad es el uso eficiente y económico de energía así como la necesidad correspondiente de reducir los gases de efecto invernadero (GEI). Las tecnologías de mezclas semicalientes se han convertido en un nuevo e importante tema de investigación en el campo de los materiales para pavimentos ya que ofrece una solución potencial para la reducción del consumo energético y las emisiones de GEI durante la producción y puesta en obra de las mezclas bituminosas. Por otro lado, los pavimentos que contienen polvo de caucho procedente de neumático fuera de uso, al hacer uso productos de desecho, ahorran energía y recursos naturales. Estos pavimentos ofrecen una resistencia mejorada a la formación de roderas, a la fatiga y a la fisuración térmica, reducen los costes de mantenimiento y el ruido del tráfico así como prolongan la vida útil del pavimento. Sin embargo, estas mezclas presentan un importante inconveniente: la temperatura de fabricación se debe aumentar en comparación con las mezclas asfálticas convencionales, ya que la incorporación de caucho aumenta la viscosidad del ligante y, por lo tanto, se producen mayores cantidades de emisiones de GEI. En la presente Tesis, la tecnología de mezclas semicalientes con aditivos orgánicos (Sasobit, Asphaltan A, Asphaltan B, Licomont) se incorporó a la de betunes de alta viscosidad modificados con caucho (15% y 20% de caucho) con la finalidad de dar una solución a los inconvenientes de mezclas con caucho gracias a la utilización de aditivos reductores de la viscosidad. Para este fin, se estudió si sería posible obtener una producción más sostenible de mezclas con betunes de alto contenido en caucho sin afectar significativamente su nivel de rendimiento mecánico. La metodología aplicada para evaluar y comparar las características de las mezclas consistió en la realización de una serie de ensayos de laboratorio para betunes y mezclas con caucho y con aditivos de mezclas semicalientes y de un análisis del ciclo de vida híbrido de la producción de mezclas semicalientes teniendo en cuenta la papel del aditivo en la cadena de suministro con el fin de cuantificar con precisión los beneficios de esta tecnología. Los resultados del estudio indicaron que la incorporación de los aditivos permite reducir la viscosidad de los ligantes y, en consecuencia, las temperaturas de producción y de compactación de las mezclas. Por otro lado, aunque la adición de caucho mejoró significativamente el comportamiento mecánico de los ligantes a baja temperatura reduciendo la susceptibilidad al fenómeno de fisuración térmica, la adición de las ceras aumentó ligeramente la rigidez. Los resultados del estudio reológico mostraron que la adición de porcentajes crecientes de caucho mejoraban la resistencia del pavimento con respecto a la resistencia a la deformación permanente a altas temperaturas y a la fisuración térmica a bajas temperaturas. Además, se observó que los aditivos mejoran la resistencia a roderas y la elasticidad del pavimento al aumentar el módulo complejo a altas temperaturas y al disminuir del ángulo de fase. Por otra parte, el estudio reológico confirmó que los aditivos estudiados aumentan ligeramente la rigidez a bajas temperaturas. Los ensayos de fluencia llevados a cabo con el reómetro demostraron una vez más la mejora en la elasticidad y en la resistencia a la deformación permanente dada por la adición de las ceras. El estudio de mezclas con caucho y aditivos de mezclas semicalientes llevado a cabo demostró que las temperaturas de producción/compactación se pueden disminuir, que las mezclas no experimentarían escurrimiento, que los aditivos no cambian significativamente la resistencia conservada y que cumplen la sensibilidad al agua exigida. Además, los aditivos aumentaron el módulo de rigidez en algunos casos y mejoraron significativamente la resistencia a la deformación permanente. Asimismo, a excepción de uno de los aditivos, las mezclas con ceras tenían la misma o mayor resistencia a la fatiga en comparación con la mezcla control. Los resultados del análisis de ciclo de vida híbrido mostraron que la tecnología de mezclas semicalientes es capaz de ahorrar significativamente energía y reducir las emisiones de GEI, hasta un 18% y 20% respectivamente, en comparación con las mezclas de control. Sin embargo, en algunos de los casos estudiados, debido a la presencia de la cera, la temperatura de fabricación debe reducirse en un promedio de 8 ºC antes de que los beneficios de la reducción de emisiones y el consumo de combustible puedan ser obtenidos. Los principales sectores contribuyentes a los impactos ambientales generados en la fabricación de mezclas semicalientes fueron el sector de los combustibles, el de la minería y el de la construcción. Due to growing concerns over global warming and climate change in recent years, one of the most important challenges facing our society is the efficient and economic use of energy, and with it, the corresponding need to reduce greenhouse gas (GHG) emissions. The Warm Mix Asphalt (WMA) technology has become an important new research topic in the field of pavement materials as it offers a potential solution for the reduction of energy consumption and GHG emissions during the production and placement of asphalt mixtures. On the other hand, pavements containing crumb-rubber modified (CRM) binders save energy and natural resources by making use of waste products. These pavements offer an improved resistance to rutting, fatigue and thermal cracking; reduce traffic noise and maintenance costs and prolong pavement life. These mixtures, however, present one major drawback: the manufacturing temperature is higher compared to conventional asphalt mixtures as the rubber lends greater viscosity to the binder and, therefore, larger amounts of GHG emissions are produced. In this dissertation the WMA technology with organic additives (Sasobit, Asphaltan A, Asphaltan B and Licomont) was applied to CRM binders (15% and 20% of rubber) in order to offer a solution to the drawbacks of asphalt rubber (AR) mixtures thanks to the use of fluidifying additives. For this purpose, this study sought to determine if a more sustainable production of AR mixtures could be obtained without significantly affecting their level of mechanical performance. The methodology applied in order to evaluate and compare the performance of the mixtures consisted of carrying out several laboratory tests for the CRM binders and AR mixtures with WMA additives (AR-WMA mixtures) and a hybrid input-output-based life cycle assessment (hLCA) of the production of WMA. The results of the study indicated that the incorporation of the organic additives were able to reduce the viscosity of the binders and, consequently, the production and compaction temperatures. On the other hand, although the addition of rubber significantly improved the mechanical behaviour of the binders at low temperatures reducing the susceptibility to thermal cracking phenomena, the addition of the waxes slightly increased the stiffness. Master curves showed that the addition of increasing percentages of rubber improved the resistance of the pavement regarding both resistance to permanent deformation at high temperatures and thermal cracking at low temperatures. In addition, the waxes improved the rutting resistance and the elasticity as they increased the complex modulus at high temperatures and decreased the phase angle. Moreover, master curves also attest that the WMA additives studied increase the stiffness at low temperatures. The creep tests carried out proved once again the improvement in the elasticity and in the resistance to permanent deformation given by the addition of the waxes. The AR-WMA mixtures studied have shown that the production/compaction temperatures can be decreased, that the mixtures would not experience binder drainage, that the additives did not significantly change the retained resistance and fulfilled the water sensitivity required. Furthermore, the additives increased the stiffness modulus in some cases and significantly improved the permanent deformation resistance. Except for one of the additives, the waxes had the same or higher fatigue resistance compared to the control mixture. The results of the hLCA demonstrated that the WMA technology is able to significantly save energy and reduce GHG emissions, up to 18% and 20%, respectively, compared to the control mixtures. However, in some of the case studies, due to the presence of wax, the manufacturing temperature at the asphalt plant must be reduced by an average of 8ºC before the benefits of reduced emissions and fuel usage can be obtained. The results regarding the overall impacts generated using a detailed production layer decomposition indicated that fuel, mining and construction sectors are the main contributors to the environmental impacts of manufacturing WMA mixtures.

Investigation on performance characteristics of dense graded hot mix asphalt with RAP and Crumb Rubber

The use of recycled materials in asphalt mixtures such as reclaimed asphalt pavements (RAP) have become widely accepted as a replacement for virgin asphalt binder or virgin aggregates. In this study, the RAP content was 30%, and CR additives were blended with the soft unmodified binder by using dry processes. The objective of this study was to investigate and evaluate the engineering properties of dry method application of crumb rubber influences on reclaimed asphalt pavement (RAP) mixtures. To evaluate the effect of rubber-bitumen interaction on the mixture’s mechanical properties, a laboratory investigation has been conducted on a range of dense graded and 30% RAP by dry process crumb rubber modified (CRM) asphalt mixtures containing 0% (control), 1% crumb rubber by the total aggregate mass. The experimental program in this research include the binder extraction for estimating the amount of aged binder in the both fine and coarse RAP material. Before extracting the binder the RAP sieve analysis, have been done to provide the Black grading curve. In continue after the binder extraction the material sieved again to providing the white curve. The comparison of Black and White curve indicated that there is a remarkable difference between the aggregate grading even for the fine RAP. The experimental program was continued by fabricating 12 specimens in different 4 types of mixtures. For the first group no RAP, no rejuvenator and no crumb rubber were used. For the second group 30% of virgin aggregates substituted by RAP material and the third group was similar to the second group just with 0.01% rejuvenator. the forth group was the group, which in that the specimens contain RAP, rejuvenator and crumb rubber. Finally the specimens were tested for Indirect tensile strength. The results indicated that the addition of crumb rubber increased the optimum amount of binder in the mixture with 30% RAP.