Asfalt üretim sıcaklığının düşürülmesinde kullanılan kimyasal katkıların etkilerinin araştırılması
Investigation of the effects of chemical additives used in lowering asphalt production temperature
Yazar: SÜLEYMAN NURULLAH ADAHİ ŞAHİN
Danışman: PROF. DR. METİN İPEK
Sakarya Uygulamalı Bilimler Üniversitesi / Lisansüstü Eğitim Enstitüsü / İnşaat Mühendisliği Ana Bilim Dalı
Derece: Yüksek Lisans, 2020
Konu: Ulaşım = Transportation ; İnşaat Mühendisliği = Civil Engineering

Özet:
Dünyanın değişken ve devinim içinde olan yapısı, birçok konuda olduğu gibi İnşaat Mühendisliği alanında da kendisini göstermektedir. Asfalt sıcaklıklarının dünya üzerinde yaygınlığı gittikçe artan küresel ısınma ve çevre sağlığına etkisi neticesinde, bu eksiklikleri gidermek açısından, Ilık Karışım Asfalt (IKA) teknolojileri gayet büyük bir önem kazanmıştır. Bu sayede, Bitümlü Sıcak Karışıma (BSK) kıyasla, ısı kaynaklı tüketim ve çevreye olan zararları oldukça minimize edebilmektedir. Bu durum enerji ihtiyacı açısından önemli oranda verimlilik sağlamaktadır
Bu çalışma kapsamında, Karayolları Teknik Şartnamesi (KTŞ)'ne göre tasarım, performans ve değerlendirmeleri yapılarak IKA katkılarının uygulanabilirliği, gerekli bitüm deneyleri ve Marshall Stabilite Testi neticesinde ortaya konulmuştur. Bunun yanında tercih edilen katkılarla modifiye edilen bitümler, Dönel Viskozimetre Cihazı ile IKA için istenen ve uygun görülen sıcaklıklarda viskozite ölçümüne tabi tutulmuştur. Bu ölçümlere destek olması açısından Yumuşama Noktasına ve Penetrasyonuna bakılmıştır. Elde edilen sonuçlar, kullanılan IKA katkılarının bitüm viskozitesini, referans bitüme göre düşürdüğünü, böylelikle karışım sıcaklığını da büyük oranda düşürdüğünü göstermiştir. Marshall Stabilite sonuçları, KTŞ'de belirtilen sınırlar içerisinde kalarak, tercih edilebilme olasılığını yukarı çekmiştir. IKA'nın avantajları ve elde edilen sonuçlar, bu teknolojinin hem uygun olmayan hava koşullarında hem de daha geniş bir coğrafyada kullanılabilme potansiyelini ortaya koymuştur.
Enerji tasarffu açısından incelenen bu yöntemle, Sakarya Büyükşehir Belediyesi Asfalt Şantiyesi bünyesinde kullanılan plent üzerinden katkı maliyetleri ve tasarruf miktarı hesaplanmıştır. Bu hesaplamalar neticesinde, asfalt betonu üretiminin IKA yöntemiyle gerçekleşebileceği, enerjiden tasarruf edilebileceği ve gerekli performansı sağlayabileceği gösterilmiştir.
Anahtar Kelimeler: Ilık KArışım Asfalt (IKA), Bitümlü Sıcak Karışım (BSK), Modifiye Bitüm, Viskozite, Penetrasyon, Yumuşama Noktası

Abstract:
The variable and dynamic structure of the world is manifested in the field of Civil Engineering as in many other subjects. As a result of the increasing global warming and environmental health effects of asphalt temperatures, Warm Mix Asphalt (WMA) technologies have gained great importance in terms of eliminating these deficiencies. In this way, compared to Hot Mix Asphalt (HMA), heat-induced consumption and environmental damage can be minimized considerably. This provides significant efficiency in terms of energy needs.
Warm Mix Asphalt (WMA) is basically to reduce the high temperatures in the production of conventional methods using additives used. Thus, it is aimed to provide great advantage by facilitating the applicability, workability and laying of asphalt. At the same time, as a return to low temperatures, it provides the ability to work comfortably. There are many additives and types of additives produced or designed with this objective. WMA technology is an energy-efficient asphalt binder with environmental advantages. Since WMA reduces the bitumen temperature by an average of 20-55°C, it reduces fuel consumption by an average of 11-35%.
In warm mix asphalt techniques applied at temperatures above 100°C, the amount of water remaining in the mixture is very low. Various techniques are used to lower the viscosity of the binder to ensure complete coating of the aggregate at low temperature and compressibility of the mixture. These techniques are created using additives. The additives can be presented in three types. The first is organic additives, the second is foam additives and finally chemical additives.
Within the scope of this study, the design, performance and evaluations were made according to the Highways Technical Specification (HTS) and the applicability of WMA additives was demonstrated as a result of necessary bitumen tests and Marshall Stability Test. Warm Mix Asphalt additive types PAWMA entering the foamy mixture group, SASOBIT entering the organic additive group and MGB entering the chemical additive group were selected. The other additives tested were PDL6020 and LOMOT Warm Mix Asphalt additives. Also, the modified bitumen with the preferred additives were subjected to viscosity measurement at the desired and suitable temperatures for WMA with the Rotational Viscometer. To support these measurements, Softening Point and Penetration were examined.
The penetration value is inversely proportional to consistency. The higher the penetration, the softer the bitumen. As viscosity increases, bitumen hardens. Since the bitumen with very softening point has a high viscosity, the hot mixing temperatures are also high. Viscosity is a measure of the viscosity of the asphalt and the resistance to flow. The viscosity value increases as the viscosity increases, i.e. as the asphalt approaches the semi-solid state. The purpose of the viscosity test is to determine the flow properties of asphalt concrete within the temperature limits during which they are heated during application.
Samples were prepared by mixing with IKA LABORTECHNIK for 30 minutes at 180 ° C. Dosage decisions are based on brochures and instructions from the contributor manufacturers. In the light of these dosages, Viscosity values of bitumen were obtained by subjecting bitumen only at certain temperatures, except for Softening Point and Penetration test applied to bitumen. The aim will be to determine whether the heat gain can be applied following the specified criteria, as well as to examine the effect of asphalt concrete on the workability of the asphalt concrete as a result of improved fluidity.
Warm Mix Asphalt additives have been shown to affect bitumen penetration at different rates. PDW6020, LOMOT and MGB additives increased the penetration while PAWMA and SASOBIT additives decreased the penetration. Bitumen with a high softening point will show less deformation at the same air temperature. According to these results, while PDL6020 and LOMOT showed a slight increase in softening point, SASOBIT additive significantly increased softening point. While the MGB additive reduced the softening point, the PAWMA additive did not affect the softening point.
As can be seen from the viscosity tests, it was measured for three selected temperature values: 110°C, 135°C and 150°C. In these temperatures, 50/70 reference bitumen, PDL6020 with 3%, SASOBIT, LOMOT and MGB, PAWMA with 0,3% were used. When the effect of additives for each temperature was examined, it was observed that all additives decreased the viscosity at 110°C. LOMOT contributed the least decrease, while MGB and SASOBIT contributed the highest decrease. When the viscosity values were examined at 135°C, it was observed that all additives except LOMOT decreased the viscosity. SASOBIT and MGB achieved the highest decrease as well as 110°C. Finally, when the viscosity values at 150°C are examined, it is seen that LOMOT additive increases the viscosity again. All other additives, while lowering the Viscosity, showed the highest decrease in SASOBIT and MGB as in 110°C and 135°C.
According to HTS, aggregate properties are specified according to the type of coating. In this study, aggregates taken from Sakarya Metropolitan Municipality Asphalt Site were preferred. The aggregates obtained here are supplied according to both Binder and Wear TYPE 1 as coating types.
Bitumen rates, all materials and conditions SBB Asphalt will be used by the construction site, this institution will be used as a result of the rates. Performance analysis will be performed on both the Binder and Wear Layer considering only stability and yield values. Bitumen rate was determined for 4.2% Binder Layer and 4.8% Abrasion Layer.
As a result of the experiments, it was observed that the stability values of all samples were higher than the specification standards. However, the yield values of the reference sample were outside the standard. Also, yield and stability values of the samples produced by using additive showed a strength higher than expected. MGB contribution in stability yielded a good result, while Pawma gave the best results in yield values. When all parameters are examined, it is observed that the best result for the Binder Layer is MGB contribution. It can be said that it will provide great advantage both in low temperature and in the field because it provides the best strengths required.
When all parameters are examined, it is observed that the best result for the Abrasion Layer is given by the sample prepared with Sasobit additive. It can be said that the MGB contribution, which is tested, can be considered except for the yield value. It can be stated that it will provide great advantage both in low temperature and in the field as it provides the best resistance.
Although it cannot be said in terms of Wear Layer, MGB seems to be in a very good condition as it reduces the required temperature drop due to viscosity and saves 112 TL per hour for Binder Layer. MGB is a preferable additive due to both ease of production, environmental impact and cost.
The values obtained as a result of the viscosity tests show that PAWMA, SASOBIT and MGB additives are suitable for low temperature asphalt production. It was observed that the mixture temperatures of WMA Wear and Binder Layer prepared with these additives decreased 20 - 30°C. This reduction in the mixture temperature not only saves fuel but also means a reduction in harmful gas emissions from the plant.
The results show that the WMA additives used reduce the viscosity of bitumen relative to the reference bitumen, thereby reducing the mixing temperature to a great extent. The advantages and results of WMA have demonstrated the potential for this technology to be used both in unfavorable weather conditions and in a wider geography.
With this method, which is examined in terms of energy saving, contribution costs and savings amount are calculated on the plant used in the Asphalt Construction Site of Sakarya Metropolitan Municipality. As a result of these calculations, it was shown that asphalt concrete production can be realized by WMA method, it can save energy and provide the required performance.
At this time when the whole world stands against environmental conditions, global warming and climate deterioration, testing and even applying WMA and similar technologies is of great importance and importance for our country because of its economic and environmental friendliness.
Keywords: Warm Mix Asphalt (WMA), Hot Mix Asphalt (HMA), Modified Bitumen, Viscosity, Penetration, Softening Point