Modified Asphalt

Recycled asphalt products are increasingly being used in asphalt concrete pavements to improve pavement sustainability. Asphalt recycling, while it is undoubtedly an environmentally sustainable practice, includes asphalt binder that is already oxidised. Aged binder is highly brittle and becomes a driving factor for cracking related distresses. As a result, use of recycled materials can have a significant negative impact on pavement performance, specifically when used in increased amounts and cold climatic conditions. In order to improve the performance of asphalt concrete mixtures with recycled materials, rheological properties are changed by adding rejuvenators. In asphalt industry, rejuvenators are either used at an initial virgin state of the binder to reduce mix ageing or blended at a later stage in recycled materials to improve the properties of aged mix. The current study focuses on evaluating the performance of asphalt mixes prepared by blending rejuvenators in already aged binders. Virgin PG 64-22 binder was aged using RTFO and PAV and further mixed with three different kinds of rejuvenators namely Hydrolene 90T,Kendex@ME, and Hydrogreen S at 3%, 6% and 9% by weight of the total binder. To study the behaviour of rejuvenated asphalt binder samples over a long period of time, mixed asphalt samples were then aged for 5, 10, 15, 20, 40 and 60 h in the PAV. Frequency sweep tests were conducted to characterise binder rheology, and parameters such as Glower-Rowe, crossover frequency, and Superpave rutting parameter were calculated. A comparative analysis was carried out to determine the impact of increased ageing and rejuvenator addition in varying amounts on the performance of asphalt mixes. A significant correlation was found out between the types of rejuvenator used in different dosages and the level of ageing in the asphalt binder.Keywords:Long-term ageing;asphalt rheology;cracking potential;rejuvenato

INVESTIGATION OF ENGINEERING PROPERTIES OF STONE MASTIC ASPHALT COATINGS UNDER DIFFERENT LOADS

ABSTRACTPermanent way selection is achieved according to the repeated load and environmental factors in theroad superstructure, and stone mastic asphalt (SMA) coatings are one of the selected coating types onroads with heavy vehicle traffic. Determining the behavior of roads under load is a complexconstruction. Generally, tests are applied on the performance of the road with laboratory and fieldexperiments. Since the test method usually requires many experiments and costs, it is important tosupport the behavior of road pavements under different conditions with numerical analyzes as well.In particular, the stress-strain relations in the layer transitions of the road pavement are betterunderstood by numerical analysis. In this study, the engineering properties of SMA coatings indifferent axle load applications were investigated, and the stress-strain relations in different layerswere evaluated. As a result, less stress-deformations were observed in the transitions to the lowerlayers.Keywords: SMA, numerical analysis, road pavement, stress-strai

Investigation of Asphalt Pavement to Improve Environmental Noise and Water Sustainability

Controlling environmental noise and reducing excessive noise is necessary to protect human health and provide auditory comfort. People are frequently exposed to traffic noise in their daily life and traffic noise is a considerable problem on the city scale. This study investigates the sound absorption coefficient in asphalt pavements so as to reduce traffic and environmental noise. The important parameters affecting the sound absorption coefficient in asphalt pavement, such as the use of porous asphalt pavements, clogging pores, the mixture content change, the thickness change, and getting wet, were identified. It is stated that the sound absorption coefficient in the asphalt layer can be increased with the use of a porous asphalt layer, and by changing the thickness and mixture content. In addition, with the effects of global warming, water supply problems are observable in cities. In this context, the use of rainwater is of vital importance. Permeability of the asphalt layer and storage of rainwater in the lower layer are recommended. The accumulation of rainwater with the aid of drainage in porous asphalt pavements has been investigated and the use of rainwater within the scope of recycling is explored. Within the scope of the research, the construction of porous asphalt pavements is suggested in a system that can store water, reuse rainwater with a new system proposal, and reduce environmental noise by increasing sound absorption performance. Accordingly, it will be possible to reduce the environmental noise level and to use rainwater within the scope of recycling. According to varying thicknesses, porous asphalt pavements were modeled using the finite element method, and the Von Mises stress and vertical deformation results of different thicknesses were compared

Numerical modeling of bearing wall manufacturing in the restoration of historic buildings: Wall layer analysis

Tarihi yapıların restorasyonunda binanın özgün formunun korunması esas olmaktadır ve tarihi kimliğinin gelecek kuşaklara sağlıklı bir şekilde aktarılması gerekmektedir. Bu kapsamda, tarihi yapılardaki özgün bina formlarının korunması ve iç mekân hacimlerinin bozulmaması büyük önem arz etmektedir. Ayrıca tarihi yapıların restorasyonunda gelişen standartlar ve yeni deprem yönetmeliğinin kriterleri de göz önünde tutulması elzemdir. Bu sebeple, tarihi yapı restorasyonlarındaki gereksinimlerin karşılanabilmesi için modern tekniklerin de geliştirildiği görülmektedir. Tarihi yapılardaki restorasyon çalışmalarında doğru müdahale kararının belirlenmesi, farklı disiplindeki uzmanların bir arada çalışması ile gerçekleştirilebilmektedir. Çok sayıdaki uzman görüşü doğrultusunda hazırlanan güçlendirme projeleri her binanın özel ihtiyacına ve gerekliliğine göre hazırlanmaktadır. Belirtilen sebeplerden dolayı tarihi yapılardaki güçlendirme projeleri çeşitlilik arz etmektedir. Bu kapsamda, tarihi yapıların restorasyonunda kullanılabilecek farklı detayların ve çözüm önerilerinin analiz edilmesine ihtiyaç duyulmaktadır. Bu çalışmada, tarihi yapılardaki duvar güçlendirilmesinde kullanılan yöntemler incelenmiş, duvar katman kalınlığının ve güçlendirme katmanı kalınlığının etkisi numerik olarak analiz edilmiştir. Değişen duvar katmanı kalınlığının gerilme dayanımı etkisi detaylandırılmıştır. Farklı taşıyıcı duvar kalınlıklarına göre yük altındaki gerilme-deformasyon ilişkileri eğri uyarlama yöntemi ile incelenmiştir. Sonuç olarak duvar kalınlığının arttırılmasının basınç gerilmesi ve deformasyonlardaki değişimlere önemli katkı sunduğu görülmüştür. Hazırlanan numerik modeller, restorasyon projelerinin hazırlanması sırasında farklı disiplindeki uzmanlara yardımcı olabilecektir.In the restoration of historical buildings, it is essential to preserve the original form of the building and its historical identity should be transferred to future generations in a healthy way. In this context, it is important to preserve the original building forms in historical buildings and not spoill the interior volumes. In addition, it is essential to consider the standards developed in the restoration of historical buildings and the criteria of the new earthquake regulation. For this reason, it is seen that modern techniques have been developed to meet the requirements in historical building restorations. For this reason, it is seen that modern techniques have been developed in ordetohe requirements in historical building restorations. Determining the right intervention decision in restoration works in historical buildings can be realized by the joint work of experts from different disciplines. Strengthening projects, prepared in line with the opinions of many experts, are prepared according to the specific needs and requirements of each building. Due to the reasons stated, retrofitting projects in historical buildings are diverse. Within this scope, there is a need to analyze different details and solution proposals that can be used in the restoration of historical buildings. In this study, the methods used in wall reinforcement in historical buildings were examined and the effect of wall layer thickness and reinforcement layer thickness was analyzed numerically. The tensile strength effect of varying wall layer thickness is detailed. Stress-strain relations under load according to different load-bearing wall thicknesses were investigated by curve fitting method. As a result, it was seen that increasing the wall thickness contributed significantly to the changes in compressive stress and deformations. Stress-strain relations under load according to different load-bearing wall thicknesses were investigated by curve fitting method