Peyman Aghazadeh Dokandari (Ağazade) | Dokuz Eylül University (original) (raw)

Papers by Peyman Aghazadeh Dokandari (Ağazade)

Pamukkale University Journal of Engineering Sciences, 2014

Son yıllarda araştırmacılar, bitümlü sıcak karışım asfaltın yerini alacak benzer veya tercihen da... more Son yıllarda araştırmacılar, bitümlü sıcak karışım asfaltın yerini alacak benzer veya tercihen daha yüksek performanslı, üretim maliyetlerini azaltan, doğal kaynakları koruyan, çevreye daha az zararlı ve uygulamada daha verimli bitümlü karışımlar elde etme yolunda çalışmalar yürütmektedirler. Ilık karışım asfalt sistemlerinin kullanımı ile asfalt numunelerinin karıştırma ve sıkıştırma derecelerinde fark edilebilir düşüş gözlenmektedir. Uygulama sıcaklıklarındaki belirgin düşüşlerin, asfalt kaplamalarda meydana gelebilecek yaşlanmadan kaynaklanan bozulmaları azaltacağı öngörülmektedir. Bu çalışmada, organik ılık karışım asfalt katkı maddesinin bitümlü karışımların yaşlanma özellikleri üzerine etkileri araştırılmıştır. Çeşitli oranlarda organik ılık karışım asfalt katkı maddesi içeren bitüm ile hazırlanan asfalt karışımları ve kontrol karışımları; kısa dönem ve uzun dönem yaşlanmaya tabi tutulduktan sonra yaşlanma oranları ve yaşlanma indeksleri, indirekt çekme mukavemeti deneyleri ile belirlenmiştir. Deney sonuçları, bitümlü sıcak karışımlara kıyasla organik katkı içeren ılık karışım asfalt numunelerinin yaşlanmaya karşı daha dirençli olduğunu göstermektedir.

Proceedings of the International Conference on Road and Rail Infrastructure CETRA, Feb 28, 2017

Demand for sustainable pavements increases day by day in asphalt paving industry. Efficient utili... more Demand for sustainable pavements increases day by day in asphalt paving industry. Efficient utilization of raw materials along with the economic issues is the main reason to increase the amount of Reclaimed Asphalt Pavement (RAP) in bituminous mixtures. Since RAP is essentially aged material, it is considered not to behave like a fresh pavement. Hence, many researchers have tried to seek for innovative technologies in order to enhance RAP characteristics to utilize it over again. The objective of this study is to investigate the influence of Waste Engine Oil (WEO) on properties of RAP and therefore to determine the optimum amount of RAP in order to achieve desired characteristics of mixture. In this study the mixtures including various contents of RAP, modified with optimum WEO content, were prepared together with control mixtures. Mixture characteristics such as air void contents and Marshall Stability and Flow values were determined to be checked with specification requirements. Indirect Tensile Strength (ITS) values were accordingly measured for mixtures containing high possible amounts of RAP modified with WEO and control specimens. Based on the developed evaluation indices (as the ratio of ITS results of RAP containing specimens modified with WEO to ITS results of control specimens) comparisons were made. The results showed that the use of WEO, as a rejuvenator for mixtures containing RAP, enhanced the amount of RAP used in bituminous mixtures.

International Journal of Civil Engineering, Mar 13, 2017

Periodica Polytechnica-civil Engineering, 2015

In recent decades, the utilization of the warm mix technologies in pavement constructions is incr... more In recent decades, the utilization of the warm mix technologies in pavement constructions is increasing rapidly with rise in public environmental awareness. The durability of a pavement highly depend on the behavior of the pavement against aging induced failures. Therefore this study encompasses the evaluation of short-and long-term aging characteristics of four kinds of Warm Mix Asphalt (WMA) additives. Additives distinctly assessed in this study, consist of two non-foaming (organic and chemical) and two foaming(synthetic and natural zeolite) additives. In order to appraise the proportion of hardening of mixtures containing different kinds of additives, indirect tensile strength (ITS) values of both short-and long-term aged specimens were determined. Based on relative aging indices derived from the ratio of ITS values of aged and unaged specimens, comparisons were made between the additives assessing the impact of their utilization on aging characteristics of WMA.

International Journal of Civil Engineering, Feb 16, 2021

Utilization of RAP in asphalt pavements may lead to severe quality problems, mostly due to asphal... more Utilization of RAP in asphalt pavements may lead to severe quality problems, mostly due to asphalt aging phenomenon. Within the scope of this study, the use of rejuvenators to improve the properties of RAP is investigated. Two different types of waste oils together with a commercial rejuvenator are used. The rejuvenated bitumen samples are evaluated from both rheological and microstructural aspects. In addition, mixture testing also employed to investigate the effectiveness of used rejuvenators. Experimental studies on bitumen samples included conventional and Dynamic Shear Rheometer (DSR) testing and Atomic Force Microscopy (AFM) imagings. The results unveiled that, the utilization of rejuvenators can significantly improve the quality of recycled asphalt and threatened the aged bitumen quality. Missing bee-structures of aged bitumen samples evolve in a different type of surface topography while the mixtures performance evolves in terms of workability. The rejuvenation process provides viscous behavior to aged bitumen. The Rejuvenation Index (RI) which is a dimensionless value, simply evolves this fact. While the RI of the non-rejuvenated aged bitumen is taken as 1 (one) as per RI definition, the neat bitumen RI is calculated as 0.79, the RI of waste oils are calculated as 0.74 and 0.79 while the commercial sample RI is calculated as 0.60. Among the rejuvenators, waste oils showed similar results with almost same volume of peri-and para-phase since the commercial rejuvenator behaved more similar to neat bitumen. The rejuvenated samples workability performance improves using rejuvenating additives. Binder and mixture testing demonstrated high consistency and conformity with each other in terms of performance and aging characteristics. The results proved that, waste oils can be used as rejuvenating agents within RAP. Rejuvenators can significantly restore the properties of aged RAP bitumen and increase the amount of RAP in bituminous mixtures.

Demand for sustainable pavements increases day by day in asphalt paving industry. Warm Mix Asphal... more Demand for sustainable pavements increases day by day in asphalt paving industry. Warm Mix Asphalt (WMA) technology has begun to be an interesting topic for researchers owing to sustainability and environmental issues. Within the scope of this study, the effect of an organic WMA additive was evaluated in terms of mixture characteristics and performance. The fundamental and rheological properties of bitumen samples involving organic WMA additive were determined by conventional bitumen tests and dynamic shear rheometer (DSR). Mixtures modified with organic WMA additives were produced according to Marshall mix design method and the optimum bitumen content of the samples were determined. Following the determination of optimum bitumen content, the effect of the organic WMA additive was investigated in terms of indirect tensile stiffness modulus, fatigue and creep behaviour. Hamburg wheel tracking device was also applied to evaluate the permanent deformation characteristics of WMA mixtures in comparison to Hot Mix Asphalt (HMA) mixtures. The results appraised the effect of the organic WMA additive on rheological and performance characteristics of bituminous mixtures.

Materials Research Express

Asphalt pavements are amongst the most recycled materials in the contemporary world depending on ... more Asphalt pavements are amongst the most recycled materials in the contemporary world depending on the environmental and financial advantages. The introduction of Recycled Asphalt Pavement (RAP) on newly produced asphalt pavement is possible by the utilization of rejuvenating agents, which should contain oily fractions. For this purpose, within the scope of this study, three types of agents with optimum amounts (by weight of bitumen) were utilized 5.4% Waste Engine Oil (WEO), 5.1% Waste Vegetable Oil (WVO), and 6.8% Commercial Rejuvenating Agent (CRA). The highest applicable RAP content in mixtures depends on the rejuvenator type determined by Marshall Mix Design tests (air voids, flow, and stability). Rejuvenation facilitated the use of 50 to 60% of additional RAP material in the mixtures depending on the rejuvenator type. Indirect Tensile Strength (ITS) test results declared that RAP mixtures, when subjected to the rejuvenation process, resulted in relatively less brittleness and en...

Proceedings of the 2nd World Congress on Civil, Structural, and Environmental Engineering, 2017

The present asphalt pavement industry faces two major issues. These two major issues are the incr... more The present asphalt pavement industry faces two major issues. These two major issues are the increasing demand for ecofriendly asphalt mixtures and the costs of raw materials. The use of reclaimed asphalt pavement will be an essential attempt to reduce the costs of aggregates and bitumen in the final mixture. On the other hand, the main challenge for implementing RAP (Reclaimed Asphalt Pavement) is to overcome quality issues. RAP doesn't perform like a fresh pavement since it is an aged material and needs to be improved. This puts forward the requirement for extra practices like using of rejuvenating agents. Since bitumen loses its oily constituents when it ages, the use of oil-containing additives can be effective. In this study, two kinds of waste oils were used to rejuvenate aged asphalt mixture. Optimum contents of Waste Engine Oil (WEO) and Waste Vegetable Oil (WVO) additives were determined in order to implement various RAP contents. The effects of these two oily based rejuvenators on utilization of RAP in bituminous mixtures were investigated. The results represented that the use of WEO and WVO as rejuvenators for mixtures containing RAP enhances the amount of RAP used in bituminous mixtures.

Periodica Polytechnica Civil Engineering, 2016

Warm mix asphalt (WMA) technology provides not only the production of asphalt pavement at a lower... more Warm mix asphalt (WMA) technology provides not only the production of asphalt pavement at a lower temperature than the temperature maintained in Hot Mix Asphalt (HMA) but also encourages the utilization of Recycled Asphalt Pavement (RAP) and therefore saves energy and nonrenewable resources as well as reduces emissions and fuel consumption. This paper describes the feasibility of utilizing four different WMA additives (organic, chemical, synthetic zeolite and natural zeolite) with different rates of RAP. Following the determination of optimum RAP content corresponding to each WMA additive, Marshall analysis, indirect tensile stiffness modulus and fatigue behavior of HMA and WMA involving RAP were analyzed and compared with control specimens. Hamburg wheel tracking device was also utilized to evaluate the permanent deformation characteristics of mixtures containing optimum RAP content.

Social Science Research Network, 2022

International Journal of Civil Engineering, 2021

Warm Mix Asphalt (WMA) is a technology that allows lowering the production and paving temperature... more Warm Mix Asphalt (WMA) is a technology that allows lowering the production and paving temperature compared to Hot Mix Asphalt (HMA). The reduction of temperature enables various benefits over asphalt mixtures such as decreasing greenhouse gas emissions, lowering energy consumption, fuel cost saving, improved workability and easy compaction. Besides, WMA technology gives an option to use Recycled Asphalt Pavement (RAP) that provides a very economic method and eco-friendly pavements. The objective of this study was to evaluate the utilization of organic and chemical WMA additives with different percentages of RAP. Following the determination of optimum RAP contents corresponding to each WMA additive Hamburg Wheel Tracking Test is performed to obtain the permanent deformation characteristics of mixtures containing optimum RAP contents.

Utilization of warm mix asphalt (WMA) in pavement construction is a relatively new technology, th... more Utilization of warm mix asphalt (WMA) in pavement construction is a relatively new technology, therefore there is nearly no chance to practically evaluate the long-term characteristics of the existing WMA pavements. Due to lower application temperatures, it can intuitively be expected that a WMA pavement would be less subjected to aging-induced failures. This study attempts to evaluate the effects of a chemical WMA additive on aging characteristics of bituminous mixtures. The chemical additive tested within the scope of this study is a combination of both organic additive and a kind of cationic surfactant developed by Akzo Nobel. Short- and long-term aging conditions were simulated on mixtures containing various contents of chemical WMA additive as well as on control specimens. To estimate the proportions of hardening, aging indices were determined based on indirect tensile strength (ITS) results. The aging indices unveiled that the specimens containing chemical WMA additive demonst...

International Journal of Civil Engineering, 2017

In recent years, environmental protection is increasingly becoming a major issue in transportatio... more In recent years, environmental protection is increasingly becoming a major issue in transportation including asphalt production. Despite the fact that hot mix asphalt (HMA) is widely used around the world, some recent studies suggest that using warm mix asphalt (WMA) technology reduces the production and placement temperature of asphalt mixes. Currently, a common way of producing WMA is through the utilization of additives. This paper firstly characterizes the effect of WMA additives (organic, chemical, water-containing additives) on base bitumen properties. Following the determination of optimum bitumen content of the mixtures with different WMA additives through Marshall test, Hamburg wheel-tracking device is used to measure the permanent deformation characteristics of WMA mixtures. Based on the findings of this study, the utilization of WMA additives helps in the reduction in viscosity values which in return decreases mixing and compaction temperature leading to the reduction in ...

Construction and Building Materials, 2014

The utilization of zeolites decreases the optimum bitumen content. Zeolites improve the repetitiv... more The utilization of zeolites decreases the optimum bitumen content. Zeolites improve the repetitive loading strength of bituminous mixtures. Zeolites improves permanent deformation ability and increases rigidity. Natural zeolite is an acceptable alternative to commercial synthetic zeolite.

Periodica Polytechnica Civil Engineering, 2015