scholarly journals IMPACT OF RECYCLED ASPHALT PAVEMENT ON PROPERTIES OF FOAMED BITUMINOUS MIXTURES

2018 ◽  
Vol 13 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Siksha Swaroopa KAR ◽  
Aravind Krishna SWAMY ◽  
Devesh TIWARI ◽  
Pramod Kumar JAIN

In recent years, the use of foamed bitumen technology along with Reclaimed Asphalt Pavement is gaining popularity across the world. The mechanical response of foamed bitumen mixtures containing reclaimed asphalt pavement is significantly influenced by constituent material properties and aggregate gradation. This article presents results from a study where foamed bitumen mixtures conforming to Indian specifications were evaluated. For this purpose, foamed bitumen mixtures using a different percentage of reclaimed asphalt pavement and bitumens were prepared. Initially, the foaming characteristics of virgin bitumens were evaluated to optimize for optimum water content and foaming temperature. In the second stage, mixture design was conducted to optimize for foamed bitumen content in foamed bitumen mixtures containing a different percentage of reclaimed asphalt pavement. Finally, these foamed bitumen mixtures were evaluated for their mechanical properties. The results from this laboratory study indicated properties of foamed bitumen and foamed mixtures are significantly influenced by properties of bitumen, the quantity of bitumen, and reclaimed asphalt pavement. Among the different mixtures, a mixture containing 50% reclaimed asphalt pavement exhibited best results in resilient modulus and resistance to moisture damage tests. A mixture containing 80% reclaimed asphalt pavement also shows acceptable strength and resistance to water susceptibility. Thus, it is possible to design high-quality bituminous mixes using higher reclaimed asphalt pavement percentages, which meet the required volumetric and desired performance criteria.

2007 ◽  
Vol 34 (5) ◽  
pp. 581-588 ◽  
Author(s):  
J S Chen ◽  
P Y Chu ◽  
Y Y Lin ◽  
K Y Lin

Abstract: The purpose of this study was to recommend a testing procedure to detect the content of reclaimed asphalt pavement (RAP) used in hot-mix asphalt mixtures. Asphalt was extracted from RAP for use in blending with new binder and aggregate. The recovered binders were blended with virgin asphalt (AC-10) at 10 different concentrations. A concept called relative energy loss was proposed to determine the engineering properties of recycled asphalt concrete (RAC). The relative energy loss was found to be directly related to the resistance of RAC to moisture-induced damage. A noticeable increase in relative energy loss with as much as 50% RAP was observed. At 20% RAP, there was not enough RAP to change binder or mixture properties. The predicted performance of mixtures containing up to 40% RAP by weight was shown to be similar to that of virgin material mixtures. A model was developed to estimate the RAP content in terms of penetration, viscosity, and relative energy loss. Key words: reclaimed asphalt pavement, relative energy loss, moisture sensitivity.


2020 ◽  
Vol 12 (20) ◽  
pp. 8343
Author(s):  
Ana E. Hidalgo ◽  
Fernando Moreno-Navarro ◽  
Raúl Tauste ◽  
M. Carmen Rubio-Gámez

The main characteristics of bituminous mixtures manufactured with a considerable amount of reclaimed asphalt pavement (RAP), compared to conventional mixtures, are a reduction in workability, an increase in stiffness, and a loss of ductility, due to the presence of the aged bitumen contained in the RAP particles. To minimize these impacts, softer binders or rejuvenators are commonly used in the design of these mixtures in order to restore part of the ductility lost and to reduce the stiffness. In spite of previous investigations demonstrating that the mortar plays an essential role in the workability, long-term performance, and durability of bituminous mixtures (where cracking, cohesion, and adhesion problems all start at this scale), not many studies have assessed the impacts caused by the presence of RAP. In response to this, the present paper analyzes the workability, fatigue performance, and water sensitivity of bituminous mortars containing different amounts of RAP (from 0% to 100%) and rejuvenators. Mortar specimens were compacted using a gyratory compactor and studied via dynamic mechanical analysis under three point bending configuration. The results demonstrated that the presence of RAP reduces the workability and ductility of asphalt mortars. However, it also causes an increase in their stiffness, which induces a more elastic response and causes an increase in their resistance to fatigue, which could compensate for the loss of ductility. This aspect, together with the low water sensitivity shown, when using Portland cement as an active filler, would make it possible to produce asphalt materials with high RAP contents with a similar long-term mechanical performance as traditional ones. In addition, the use of rejuvenators was demonstrated to effectively correct the negative workability and ductility impacts caused by using RAP, without affecting the fatigue resistance and material adhesion/cohesion.


2018 ◽  
Vol 8 (12) ◽  
pp. 2668 ◽  
Author(s):  
Zhen Yang ◽  
Guoyi Zhuang ◽  
Xiaoshu Wei ◽  
Jintao Wei ◽  
Huayang Yu ◽  
...  

Recycled asphalt mixtures (RAM), which are prepared by blending reclaimed asphalt pavement (RAP), virgin bitumen and mineral additives, provide a variety of advantages, including resource recycling, reductions in costs, and reduced negative environmental impacts. However, multiple agencies have expressed concerns about the utilization ratio of RAP; thus, a comprehensive understanding of the blending degree of virgin and RAP binders in RAM would be significantly helpful for promoting the application of RAP. This study aims to quantitatively analyze the blending degree of virgin and RAP binders in RAM with high RAP contents. Carboxyl-terminated butadiene acrylonitrile (CTBN) was utilized as a tracer to mark the virgin bitumen; in addition, Fourier transform infrared (FTIR) spectroscopy was used to develop the structural index of CTBN (ICTBN). By establishing the standard curve between ICTBN and the CTBN content, the blending degree of virgin and RAP binders at different locations within RAM can be determined quantitatively. The study results indicate that the RAP binder was completely blended with the virgin bitumen in the outer RAP layer. However, the blending degree decreased with an increase in the RAP depth, and the blending degree in the inner RAP layer was only approximately half that which was found in the case of complete blending.


2019 ◽  
Vol 276 ◽  
pp. 03001
Author(s):  
I Nyoman Arya Thanaya ◽  
I Nyoman Karnata Mataram ◽  
Bayu Setiawan

The availability of natural aggregate is getting limited, therefore it is required new alternative materials to substitute natural aggregates. Within this experiment reclaimed asphalt pavement (RAP) was used as masonry block with waste cooking oil as the binder. The objective of this experiment was to analyze the RAP asphalt content and aggregate gradation; and the samples characteristics particularly the compressive strength of masonry block minimum of 25 kg/cm2 that meet the Indonesian national standard SNI-03-0348-1989. The asphalt content of the RAP was initially extracted and tested for its aggregate gradation and specific gravity. The RAP was added 20% sand and a certain amount of waste cooking oil and evenly mixed. After that the mixture was compacted in a mould with a Marshall hummer, with compaction cycles for 15, 25, and 35 times where each cycle consists of 3 even blows. The size of the compacted samples were 20x10x8cm. After the samples were taken out from the mould, they were heated in an oven for 12 and 24 hours at 160°C and 200°C. It was found that the minimum waste cooking oil content required 4%. The best compressive strength was found on samples compacted at 15 compaction cycles and heated at 200°C for 24 hours. The un-soaked compressive strength was 80.5 kg/cm2 and 68.67 kg/cm2 for the soaked samples. In general the compressive strength well met the minimum 25 kg/cm2. Other best characteristics was found on samples heated at 160°C for 12 hours, with lowest water absorption of 5.64% and porosity of 4.53%. The Initial Rate of Suction (IRS) was 0,25~0,45 kg/m2.minute.


2010 ◽  
Vol 37 (11) ◽  
pp. 1414-1422 ◽  
Author(s):  
Feipeng Xiao ◽  
Serji Amirkhanian ◽  
Bradley Putman ◽  
Junan Shen

An improved understanding of the rheological and engineering properties of a rubberized asphalt concrete (RAC) pavement that contains reclaimed asphalt pavement (RAP) is important to stimulating the use of these recycled and by-product materials in asphalt mixtures. The uses of RAP and rubberized asphalt in the past have proven to be economical, environmentally sound, and effective in hot mix asphalt (HMA) mixtures across the US and the world. The objective of this research was to investigate the binder and mixture performance characteristics of these modified asphalt mixtures through a series of laboratory tests to evaluate properties such as the fatigue factor G*sinδ, rutting resistance, resilient modulus, and fatigue life. The results of the experiments indicated that the use of RAP and crumb rubber in HMA can effectively improve the engineering properties of these mixes.


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