Sürdürülebilir Kalkınma Amaçları
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- MakaleAçık Erişim2024Scopus SJRQ2Effects of Recycled Asphalt Material and Natural Pozzolan as Additives of Hot-Mix Asphalt: A Field Study
Yilmaz, Bahadır; Şentürk, Mehmet Akif
Using existing resources more efficiently and effectively becomes important currently. The question of how to make the best use of resources arises in the choice between constructing new roads and improving deteriorated existing roads. It is also important to reduce the amount of consumption and cost of materials. This has emerged the need to use waste materials by recycling and reusing. In this study, a new hot-mix asphalt (HMA) mixture was developed using recycled asphalt pavement (RAP), which was obtained by excavating the surface of a road at the end of its service life, together with a waste material namely natural pozzolan (NP). The final obtained mixture was used as a wear layer on an active highway. Core specimens were extracted from the paved layer for one year and subjected to dynamic and mechanical laboratory tests. Adding NP improved the resistance of the HMA mixture under heavy seasonal effects and traffic loads. In addition, NP increased the tensile strength, making the HMA mixture more resistant to deformation than control and RAP HMA mixtures. Dynamic creep test results showed that the control asphalt mixture had the most deformation and that the RAP mixture with NP had the least. According to the laboratory results, NP addition increased the stability value of the control mixture by 40%. Especially in cold seasons, the role of NP was more evident. In the performance tests that were applied on core samples taken from the field, ITS values for September increased by 98%, and the deformation values obtained as a result of the dynamic creep test decreased by 12%. In summary, adding NP to RAP HMA improves the performance of the pavement and the cost-effectiveness of the environmentally friendly use of RAP in HMA.
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İncele - MakaleYalnız künye2011Scopus SJRQ1A new energy saving for the determination of mixing temperature in hot mix asphalts
Yener, Engin; Hinislioglu, Sinan
The equi-viscous temperature range of asphalt has long been used in establishing the mixing temperature for mix designs and field production of hot mix asphalt (HMA). However, this method considers only binder viscosity to determine the mixing temperatures of the aggregate and asphalt. It is well known that depending on the gradation of aggregate and the type of plant and the mixing time. The appropriate mixing temperature for the proper coating may be lower than that of the viscosity based method. The excessive temperature causes the possible performance problems related to the hardening of the asphalt binder and increases the energy consumption, the gas emissions and fumes. In this study, a new method for the determination of asphalt-aggregate mixing temperature which considers the mixture properties was introduced to asphalt industry. The mixing temperatures of different nine mixtures were determined by both conventional and the proposed method. The effects of the nominal maximum aggregate size (NMAS), crushed coarse aggregate ratio (CCAR), the type of gradation, and the grade of binder on the mixing temperature were evaluated with an experimental study. Results show that decreasing NMAS, CCAR and increasing the grade of binder decreased the mixing temperature which is needed for proper coating. In addition, results showed that as going away from restricted zone of the Superpave gradation, the needed temperature to coat the aggregates decreased. The proposed method resulted in lower temperatures comparing to the conventional method on an average of 13°C. This means a possible energy saving of 14.3 x 10 9 kcal or 1362000 kg of crude oil in a year in Turkey. As a result, the new method is recommended due to not only the saving in energy but also decreasing the gas emissions and fume, and possible performance benefits.
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