Search

Ilık Karışım Asfalt (WMA) karışımına nemin sızması, kaplamanın yapısal bütünlüğünü potansiyel olarak tehlikeye atan birincil faktörlerden biridir. Bu makale, ılık karışım katkı maddesinin WMA'da soyulma önleyici bir madde olarak etkinliğini değerlendirmektedir. Bu çalışmada, laboratuvarda saha ortam koşullarını simüle etmek için, asfalt karışım numuneleri önce uzun süreli yaşlanma ve nem hasarına (eşzamanlı olarak) maruz bırakılmıştır. Daha sonra sıkıştırılabilirlik, işlenebilirlik, çekme ve kesme dayanımları dahil olmak üzere WMA ve Sıcak Karışım Asfalt (HMA) performansının farklı yönleri incelendi ve karşılaştırıldı. Test edilen numunelerin kırık yüzeyindeki yapışmanın neden olduğu bozulma yüzdesini kesin olarak ölçmek için bir 3D görüntü analizi yapıldı. Test sonuçları, WMA numunelerinin HMA'ya kıyasla yalnızca daha fazla işlenebilir ve sıkıştırılabilir olduğunu değil, aynı zamanda şiddetli nem koşullandırmasına maruz kaldıktan sonra bile HMA'ya göre nem hasarına karşı üstün direnç sergilediğini gösterdi. Bu eğilim, test türünden bağımsız olarak, HMA'ya kıyasla WMA'nın daha yüksek mukavemeti ve daha düşük yapışma bozulmasına dayalı olarak da gözlendi. Çekme ve kayma gerilmeleri sonuçları, asfalt karışımlarda kübik agrega kullanımının karışım performansını iyileştirebileceğini göstermiştir. Ayrıca, 3D görüntü analizi sonuçları, modifiye WMA'yı hazırlamak için kullanılan kübik agregaların, WMA katkı maddesinin etkinliği ile ilişkilendirilebilecek daha düşük yapışma bozulması sergilediğini gösterdi., Infiltration of moisture into the Warm Mix Asphalt (WMA) mixture is one of the primary factors that potentially compromises pavement structural integrity. This paper evaluates the effectiveness of a warm mix additive as an antistripping agent in WMA. In this study, to simulate field environmental conditions in the laboratory, asphalt mixture specimens were first exposed to long-term aging and moisture damage (simultaneously). Different aspects of WMA and Hot Mix Asphalt (HMA) performance including compactability, workability, tensile and shear strengths were then studied and compared. A 3D image analysis was performed to precisely quantify the percentage of failure contributed by adhesion on the fractured surface of the tested specimens. The test results showed that WMA samples were not only more workable and compactable compared to HMA but also exhibited superior resistance toward moisture damage over HMA even after experiencing severe moisture conditioning. Such trend was also observed based on higher strength and lower adhesion failure of WMA compared to HMA, regardless of test type. The tensile and shear stresses results indicated that utilization of cubical aggregates in asphalt mixtures can improve mixture performance. Moreover, the 3D image analysis results showed that the cubical aggregates utilized to prepare modified WMA exhibited lower adhesion failure which could be correlated to the effectiveness of the WMA additive.

Numerous factors may disrupt pavement construction including human errors and unforeseen changes in the environmental conditions. These incidents can shorten pavement life span. New technologies recently came to the aid of contractors and road agencies to detect and possibly mitigate undesirable impacts of unpredictable incidents during the asphalt paving process as well as monitoring pavement performance during pavements service life. In this study, several technologies including layer thickness assessment (using both MIT-scan device coupled with metal plates and conventional topographical technique), infrared thermal camera, intelligent roller compactors, and density gauge devices were utilized to develop a coherent construction system and improve the durability of asphalt pavements in Antwerp, Belgium. The data collected in situ were compared with the characterized cores in the laboratory. It was clear that several factors can influence the outcome of the employed devices. For instance, surface temperatures obtained from an infrared camera fluctuated when the camera tilted from the perpendicular axis. Such discrepancies may be associated with the changes in the distance and environmental condition that affect the refraction of the infrared spectra. It was also found that an elaborated data collection format is essential to clearly understand the correlations between the results of the employed technologies.

Pavement performance prediction is a mounting task due to the many varied influencing factors particularly aging which varies with time, weather, production, type of pavement and etc. This paper presents a conventional mathematical model named Superpave model, Artificial Neural Network (ANN), and Supporting Vector Machine (SVM) techniques to predict the effects of extended aging on asphalt mixture performance measured in terms of rutting properties determined from the dynamic creep test. The accuracy of each method was compared to select the most reliable technique that can be used to forecast the rutting behavior of asphalt mixtures subjected to different aging conditions. The results indicated that the Superpave model was only reliable at lower temperatures, while ANN and SVM techniques showed the capability of precise prediction under all conditions. The overall results showed that the ANN was the most promising technique that can be adopted to satisfactorily forecast the effects of aging on rutting properties of all mixtures. The developed model can be embraced by the pavement management sector for more precise estimation of the pavement life cycle subjected to different aging conditions which can be used to design efficient pavement maintenance and rehabilitation plans.

Hot mix asphalt (HMA) is a common material that has been largely used in the road construction industries. The main constituents of HMA are asphalt binder, mineral aggregate, and filler. The asphalt binder bounds aggregate and filler particles together and also waterproofs the mixture. The aggregate acts as a stone skeleton to impart strength and toughness to the structure, while the filler fills pores in the mixture which can improve adhesion and cohesion as well as moisture resistance. The HMA behavior depends on individual component properties and their combined reaction in the mixture. Asphalt binder properties change due to different factors. Over the years, asphalt pavement materials age, causing binder embrittlement which adversely affects pavement service life. Response Surface Method (RSM) is a set of techniques that are used to develop a series of experiment designs, determining relationships between experimental factors and responses, and using these relationships to determine the optimum conditions. Incorporating RSM in pavement technologies can beneficially help researchers to develop a better experimental matrix and give them the opportunity to analyze the changes in pavement performance in a faster, more effective, and reliable way.