Performance Evaluation of Recycled Asphalt Pavement Materials and Cold Recycling Mixtures Designed with Vibratory Compaction Method

Abstract

In this paper, the basic composition and performance evaluation of the recycled asphalt pavement (RAP) materials were firstly analyzed, and two methods were proposed to evaluate strength characteristics of RAP materials, including a triaxial method for the residual strength and the mortar cementing method for the strength of RAP lump. Then, the cold recycling technology was applied on RAP materials with emulsified asphalt by using vibratory compaction and heavy-duty compaction methods (Proctor compaction method), and the results showed that the maximum dry density obtained by heavy-duty compaction was closer to the actual situation. Finally, the effects of wetting water, emulsified asphalt dosage and curing conditions on the performance of the specimens were investigated. It was found that when the emulsified asphalt was mixed uniformly, whether or not to add the wetting water have almost no effect on the strength of the molded specimens. When the matrix asphalt content of the emulsified asphalt was 30%~60%, the water could be directly added to the cold recycling mixture. The intensity of accelerated curing for two days at 40 • C was approximately equal to that of natural curing for three days, while that of accelerated curing for three days at 40 • C was approximately equal to that of natural curing for seven days, which provided a basis for the short-term laboratory test. emulsion content, aggregate properties, coating and adhesion tests. Strength testing mainly refer to the indirect tensile strength test, in addition to resistance, moisture-induced damage sensitivity test and rutting test [7]. A. Widayanti et al. used SEM imaging technology to observe the morphology and surface texture of the RAP materials [8]. Also, Y. N. Li et al. evaluated the effects of emulsified asphalt and cement on the porosity, indirect tensile strength, tensile strength ratio, dynamic stability and mechanical properties of RAP materials [9]. X. Zhang made an in-depth research on the RAP materials treatment process from four aspects: Method of recycling RAP materials, selection of crushing equipment, old material screening process, storing and testing [10]. F. Ye et al. researched the layered aging regulation of asphalt stratification on the surface of RAP materials [11]. T. Ma et al. researched the effects of aging properties in asphalt on the performance of 48 RAP materials by measuring the low temperature performance of mortar with bending beam 49 rheometer (BBR) [12].However, there has not been a uniform conclusion on the research of RAP materials compaction methods abroad. Some of the compaction methods are mainly selected according to different design methods of recycling asphalt mixtures. Generally, the Marshall compaction method is used to mold specimens for the Marshall design method. The kneading method is used for Hveem method. The gyratory compaction method is used for Superpave design method, which is more popular in the U.S. and Sweden [13][14][15].H. Y. Wei et al. used the method of vibration compaction specimens and de...

Study on Cold Recycled Asphalt Mixtures with Emulsified/Foamed Asphalt in the Laboratory and On-Site

“…In previous studies [62][63][64], the aged asphalt binder in the RAP was considered to be inactive and a part of the RAP particles. No extra heating was used to melt the aged asphalt in the mixing of CRM, and RAP was employed as "black aggregates" [18].…”

Experimental Study of Low Temperature Performance of Porous Asphalt Mixture

“…From Equation (2), it is noted that when the porosity is controlled within 25%, thus the limit requirement on maximum bending strain is satisfied. Finally, the possible use of recycled asphalt pavement to enhance the sustainability of highway infrastructure has attracted vast research interest in recent years [59][60][61]. Recycled asphalt mixtures, which are prepared by blending reclaimed asphalt pavement, virgin bitumen, and mineral additives, offer various advantages including resources recycling, cost saving, and reduced environmental impact [62].…”