•RAP fraction up to 35% may be used for DBM mixes without rejuvenator.•WMA additive ensure the longevity even in the worst conditions of moisture.•WMA mixes have better long-term performance than HMA ...mixes.•WMA as an anti-ageing product for asphalt mixes.•Cantabro abrasion for dense asphalt mixes indicate bonding.
This paper is an attempt to enhance the long-term performance of Reclaimed Asphalt Pavement (RAP) inclusive dense bituminous macadam (DBM) mixes, in post ageing condition, via inclusions of a Warm Mix Additive. Two sources of Reclaimed Asphalt Pavement (RAP) with two inclusion proportions (35% and 70%) were considered. The effect of inclusions of both the technologies (RAP & WMA) on various properties of DBM mixes such as Marshall Stability, retained Marshall Stability, indirect tensile strength (wet & dry), rutting resistance and Cantabro abrasion loss were studied. Inclusions of WMA was found to significantly improve the aforementioned properties of the DBM mixes regardless of the type of aggregate used. Moreover, the RAP-WMA mixes were found to retain much of its properties even after long-term ageing as compared to RAP-HMA mixes. RAP fraction up to 35% may be used for DBM mixes without much compromising the mechanical and durability properties of the same (as found in the present study). Incorporation of WMA in these mixes would further improve the properties and would ensure the longevity even in the worst conditions of moisture.
•Investigating the effect of hydrated lime and other fillers on mastic stiffening and ageing.•Physical and chemical properties were evaluated to study the effect of hydrated lime.•The evaluation ...testing was aimed to understand the mechanisms of hydrated lime on ageing mitigation.•The results indicate that hydrated lime reduced the ageing indices more as compared to other fillers.•Hydrated lime mastics showed less carbonyl index and asphaltenes content than granite mastics.
The bituminous binder's ageing process is the primary reason behind the decrement in the pavement's in-service life, which can lead to cracking as a result of extreme hardening of the binder. In order to mitigate this problem, several methods have been used, such as polymer modification, functional improvement and modification with nano-particles. Due to its exceptional performance in asphalt mixtures, hydrated lime has also been considered the potential antioxidant in recent studies. However, its impacts have not been well understood. Therefore, this study aims to investigate the effect of hydrated lime and other fillers on mastic stiffening and ageing. In this detailed study on mastics, the effect of hydrated lime on stiffening and ageing mitigation was evaluated by various means involving both physical and chemical properties. The evaluation testing was aimed at understanding the mechanisms of hydrated lime on ageing mitigation. Moreover, special attention was paid to the interactions between hydrated lime and bitumen, which affects bitumen mastics' ageing. The results indicate that hydrated lime reduced the ageing indices more as compared to other fillers. Further, increasing the concentration of hydrated lime resulted in more decrease of ageing indices just opposite to that of granite filler. Also, the bitumen recovered from the hydrated lime mastics showed less carbonyl index and asphaltenes content than granite mastics which prove the ability of hydrated lime to reduce the ageing products. Moreover, it is noticed that the mastics stiffness increased with an increase in the ageing time. The fillers can increase or decrease the ageing of the mastics as the time in the TFOT proceeds.
Asphalt pavements represent the great majority of roads worldwide. However, the bitumen physico-chemical properties change due to ageing processes during both the production and service life of the ...asphalt mixes. In recent years, a completely new trend has been observed in the road engineering industry oriented to extending the service life of roads, bringing direct economic, ecological and social benefits. This work presents the possibility of inhibiting ageing of road bitumen by using polyaniline nanofibers (PANI_NFs) as well as enhancing its rheological properties examined with Linear Amplitude Sweep (LAS) as well as Multiple Stress Creep and Recovery (MSCR) tests. These results show that the application of PANI_NFs maintains the primary penetration value of bitumen short-term and long-term aged road bitumen at 88 % and 52 %, respectively. Moreover, bitumen modification with PANI_NFs reduces the softening temperature increase by 33 % and 24 %, respectively, and the viscosity increase of road asphalt by 50 % and 25 %, respectively. PANI_NFs also stabilised the bitumen surface adhesion force, determined with AFM, consequently confirming the enhanced resistance to ageing processes. In addition, changes in the carbonyl index, sulphoxide index and aromaticity of bitumen demonstrated that PANI_NFs inhibit oxidation and aromatisation reactions of its components. The tests indicated a 4-fold decrease in the degree of bitumen component oxidation after short-term ageing and a 33 % decrease after long-term ageing. FTIR analysis also showed a reduction in the degree of bitumen component aromatisation process of 79 % and 76 % for short-term and long-term ageing, respectively. The LAS and MSCR test results also showed that PANI_NFs had a beneficial impact on the resistance of the bitumen to fatigue and rutting. Overall, the study results suggest that PANI_NFs consitute a promising modifier for bitumen in terms of ageing inhibition and performance characteristics.
•Polyaniline nanofibers effectively inhibit the bitumen ageing process.•Polyaniline nanofibers inhibit the oxidation reactions of bitumen hydrocarbons.•Polyaniline nanofibers inhibit the aromatisation process of bitumen components.•Polyaniline nanofibers enhance the rutting and fatigue resistance of bitumen.
The ageing of bitumen is an inevitable phenomenon which is still challenging to be characterised. This paper aims at evaluating the ageing degrees of bitumen comprehensively. There were six types of ...bitumen being aged to five levels for comparing purposes and multiple rheological tests by a DSR as well as chemical test for the SARA (saturates, aromatics, resins and asphaltenes) properties of bitumen were carried out. The critical temperatures, G-R parameter and nonrecoverable-compliance-based ageing indices were proposed to evaluate the ageing degrees of bitumen in terms of low-, intermediate- and high-temperature performance of bitumen, respectively. Also, a novel ageing evaluation index based on the integration of modulus of master curves was employed and modified, which can evaluate the ageing degrees of bitumen accurately in terms of the whole range of temperature. Finally, the chemical ageing index were analysed and was confirmed to have strong linear relationship with rheological indices of bitumen.
Ageing has long been recognised as a major distress mechanism for asphalt concrete and, by extension, asphalt pavements. Ageing causes the material to stiffen and embrittle, which leads to a high ...potential for cracking. Although a significant amount of effort has been placed on understanding the ageing process of asphalt binder, less effort has been put forth to develop laboratory ageing procedures for producing aged mixture specimens for performance testing. An optimal laboratory conditioning procedure to simulate long-term ageing for performance testing and prediction is required in order to integrate the effects of long-term ageing in pavement prediction models and other mechanistic design and analysis methods. In this study, oven ageing and pressure ageing vessel ageing are applied to both loose mix and compacted specimens in order to evaluate and select an ageing method to simulate long-term ageing for performance testing and prediction. The selected method must be able to maintain specimen integrity in order to be used for performance testing and prediction. Efficiency, practicality, and versatility also are considered in evaluating the ageing methods. The results demonstrate that loose mix ageing in an oven is the most promising ageing method to produce mixture specimens for performance testing in terms of efficiency, specimen integrity, versatility, and cost.
Active ageing is a dominant but disputed discourse in the field of ageing. Since it is usually associated with the third age, this article will focus on the active ageing of older adults who need ...care and services, who are known as the fourth agers. Our data consists of interviews collected from 16 older adults. We analysed the data through content analysis that was guided by the Active Ageing Index (AAI) that is a measuring tool concerning active ageing. According to our results, active ageing during the fourth age can be understood through the lens of small actions and precarity. Although some actions had to be given up or modified, participants were active in various ways, and help from other people and from services was essential. Based on our results, there is a need for further discussion about theorisation and defining active ageing for fourth agers.
•It is important to consider the Active Ageing Index from the perspective of fourth age.•Small and supported action should be acknowledged concerning active ageing.•The importance to theorize the active ageing from the perspective of fourth age and precarity.
Although the active ageing concept generally has positive connotations, with expected benefits at the micro, meso and macro levels, the application of this concept in terms of policy making presents ...challenges and risks to be avoided (for instance, a predominantly productivist interpretation and a top-down imposition with limited possibilities for bottom-up exchanges; or a disregard for the risk of excluding older people with more disadvantaged backgrounds). Two crucial strategies to minimise risks are the implementation of policies by considering and respecting territorial diversity, and the involvement of all the relevant stakeholders in a participatory consultative and co-decisional approach. This paper entwines both strategies together by focusing on Italian in-country differences in terms of active ageing, and employing the Active Ageing Index for policy-making purposes. This activity is part of a governmental national pilot project aimed at promoting multilevel co-managed co-ordination of active ageing policies across Italy. The analysis identified five groups of regions that differ from the classical, geographic and socio-economic division between the North, Centre and South. Additional in-group analyses were conducted to investigate within-cluster differences. This study will inform a large multilevel stakeholder network for evidence-based policies and their monitoring at both the national and regional levels, in line with the perspective of mainstreaming ageing.
A critique of the Active Ageing Index São José, José Manuel de; Timonen, Virpi; Amado, Carla Alexandra Filipe ...
Journal of aging studies,
2017, 2017-Jan, 2017-01-00, 20170101, Volume:
40
Journal Article
Peer reviewed
Abstract Active ageing and successful ageing are ubiquitous concepts in contemporary societies. In the European Union, active ageing is monitored and promoted chiefly by the Active Ageing Index, a ...policy tool in use since 2012. We acknowledge that the AAI may contribute to sensitizing people, including policymakers, to the multidimensionality and complexity of the process of “ageing well”. However, we note that despite being widely used and promoted, the Active Ageing Index remains under-scrutinized. In this article, we undertake a comprehensive critical analysis of the Active Ageing Index. This critical analysis is supported by the Theory of Model Ageing, the Capability Approach and, to a lesser extent, by relevant literature on composite indices. We conclude that the Active Ageing Index was developed with the paradoxical aim of deriving “the solution” from “the problem”. It is an under-theorized and narrowly conceptualized index that contributes to the process of Model Ageing, as its conceptual foundation, and its domains and indicators, convey a certain model of active ageing. This model is expert-based and ingrained with a priori assumptions about the potential of older people, the domains of life and activities they value and how strongly they value them. Finally, the Active Ageing Index measures current achievements, not capabilities (i.e. the opportunity set of achievable “doings” and “beings”), resulting in a valuable but incomplete tool for policymaking purposes. We hope that this critical analysis will initiate a debate on the Active Ageing Index that, in our view, is overdue.
Organo-modified nanoclay has got considerable attention in recent years to improve the performance of asphalt binders. However, various aspects such as rutting performance using Multiple Stress Creep ...Recovery (MSCR) test, fatigue performance using Linear Amplitude Sweep (LAS) test and ageing resistivity potential using advanced rheological parameter are still unexplored for better rheological characterisation. The present study deals with rutting, ageing resistivity potential and fatigue performance of asphalt binder (AC-10) modified with organo-modified nanoclay (CL-30B). Different percentages (0, 2, 4 and 6% by weight of binder) of CL-30B were mixed with AC-10 using a high-shear mixer. Different rheological studies, such as Brookfield viscosity, Superpave performance grading, time-temperature sweep, MSCR and LAS tests, were conducted on CL-30B-modified asphalt binders. Effects of CL-30B on performance were observed to be predominant in intermediate to high-temperature range as obtained from the master curve. The ageing resistivity of asphalt binder increased with the addition of CL-30B. The Superpave rutting parameter (G*/Sinδ) increased and non-recoverable creep compliance (J
nr
) estimated from MSCR decreased with inclusion of CL-30B, indicating a better rutting performance of asphalt binders. The number of cycles to fatigue estimated from the LAS test showed improvement in fatigue performance of asphalt binder with addition of CL-30B. The high-temperature performance grade of CL-30B-modified binder was found to be higher compared to virgin binder. The relationship between J
nr
and G*/Sinδ, and recovery (R) and storage modulus (G′) parameters are presented in this paper. In addition, ranking of asphalt binder based on various parameters (i.e. G*/Sinδ, AI, J
nr
, R, N
f
) is discussed in this paper.
Ageing of asphalt mixtures occurs by intrinsic variables (properties and quantity of the binder and air voids) and extrinsic variables (environmental factors) during production and service life. This ...topic has been studied extensively in the existing literature, but the potential of alternate filler on the ageing resistance of asphalt mixes and the influence of the interaction between filler and asphalt binder has not been thoroughly examined. The underlying objective of this study was to evaluate the ageing resistance potential of four waste fillers, Jarosite (JS), Hydrated Lime mud (HL), Fly Ash (FA) and Sugarcane Ash (SA), compared to conventional fillers, Stone Dust (SD) on the recycled mix. The recycled mixes were prepared with 50% Reclaimed Asphalt Pavement (RAP) material, locally available natural aggregate, VG-10 grade asphalt binder and studied fillers. The performance properties, including cracking resistance, moisture susceptibility, resilient modulus, rutting, and fatigue resistance of unaged and long-term aged recycled asphalt mix, were evaluated in this study. The results indicated that the ageing resistance of recycled mixtures was highly affected by filler type. HL possesses the highest ageing resistance potential, followed by JS, FA, SA, and SD. The results demonstrated that JS and HL filler significantly improved moisture, rutting, and crack resistance in unaged and long-term aged recycled mix, which are critical factors in extending the durability of pavement. JS and HL filler showed lower fatigue life of recycled mix while tested at higher strain levels due to their higher stiffness. In contrast, FA and SA fillers resulted in a mixed value of properties of the recycled mix compared to SD filler. SA filler showed the lowest cracking resistance (Indirect tensile strength value 1420 kPa for unaged mix and 1573 kPa for aged mix) and moisture resistance (Tensile strength ratio value 78% for unaged mix and 75% for aged mix) among all fillers. The recycled asphalt mix containing SA was found to be highly susceptible to moisture damage, cracking and ageing. The overall conclusions of this study ascertain that the ageing resistance potential of HL was highest among the studied waste fillers for all the studied properties due to its fineness, higher porosity, presence of calcite and increased asphalt film thickness of the mix.
•Ageing resistance potential of lime mud was highest due to its fineness and the presence of calcite.•Jarosite and hydrated lime mud filler significantly improved moisture, rutting, and crack resistance.•Lime possesses the highest ageing resistance potential among waste fillers, followed by jarosite, fly ash, and sugarcane ash.•Sugarcane ash filler showed the lowest cracking resistance and moisture resistance.
PDF
