Technological and environmental performance of temperature-reduced mastic asphalt mixtures

Hofko, Bernhard; Dimitrov, M; Schwab, Oliver; Weiss, Fabian; Rechberger, Helmut; Grothe, Hinrich

doi:10.1080/14680629.2016.1141703

Cited by 15 publications

(7 citation statements)

References 23 publications

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“…The main advantages of warm-mix asphalt (WMA) mixtures are lower energy consumption during mixing and compaction and therefore, lower greenhouse gas emissions (Kim, Lee, & Amirkhanian, 2010;Lee, Amirkhanian, Park, & Kim, 2009). They are seen as a more energy efficient, sustainable way for road construction (Hofko, Dimitrov, et al, 2016). In addition, WMA are also used in unfavourable weather situations (mainly low temperatures) to achieve a longer compaction phase at the construction site.…”

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confidence: 99%

Effect of short-term ageing temperature on bitumen properties

Hofko

Falchetto

Grenfell

et al. 2017

Road Materials and Pavement Design

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108

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Properties of asphalt mixtures after ageing are fundamental parameters in determining longterm performance (e.g. durability) of these materials. With increasing popularity of reduced temperature mixtures, such as warm-mix asphalt, WMA, the question remains how a reduction in short-term ageing affects the properties after long-term ageing of bituminous materials. This paper aims to improve our understanding of the effect of asphalt manufacturing temperature on ageing and the resulting mechanical properties of bituminous binder by studying the effect of short-and long-term ageing of different bitumen samples as a function of short-term ageing temperatures. For this purpose, round robin experiments were conducted within the RILEM technical committee (TC) 252 chemo-mechanical characterisation of bituminous materials by 10 laboratories from 5 countries using four binders of the same grade (70/100 pen) from different crude sources. The short-term ageing was carried out using the standard procedure for rolling thin film oven test (RTFOT), but varying the temperatures. Long-term ageing was carried out using the standard procedure for pressure aging vessel (PAV) in addition to RTFOT. For the mechanical characterisation, rheological data were determined by using the dynamic shear rheometer (DSR) and conventional tests, with needle penetration and softening point using the ring and ball method. The results show that although different short-term ageing temperatures showed a significant difference in the mechanical properties of the binders, these differences vanished after long-term ageing with PAV.Keywords: bitumen; DSR; long-term ageing; short-term ageing; asphalt; RTFOT; PAV IntroductionAs an organic material, bitumen undergoes changes in its mechanical characteristics, chemical composition and microstructure due to environmental effects over its lifetime (Glotova, Gorshkov, Kats, Shapiro, & Yureva, 1980;Lee, Tia, Ruth, & Page, 1997;Mills-Beale et al., 2012;Yao, Dai, & You, 2015). Loss of volatile components at elevated temperatures and oxidation are two main factors for these changes. In terms of mechanical properties, bitumen tends to become stiffer, more elastic and brittle over time. Road Materials and Pavement Design109 SARA (saturates, aromatics, resins and asphaltenes) fractions can be observed with an increasing amount of asphaltenes and decreasing amount of aromatics over time Lu & Isacsson, 2002). These changes are generally summarised under the term "ageing". Bitumen ageing can be split up into short-term and long-term ageing. In the case of hot mix asphalt, short-term ageing occurs during asphalt mix production, transport and compaction at the construction site, all of which happens within hours. It is characterised by relatively high temperatures ( > 130°C) and thus, high oxidation rates. Long-term ageing occurs in asphalt pavements in the field as a result of exposure to traffic and climatic conditions during its service life. Compared to short-term ageing, long-term ageing is a slow oxidation process tha...

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confidence: 99%

Effect of short-term ageing temperature on bitumen properties

Hofko

Falchetto

Grenfell

et al. 2017

Road Materials and Pavement Design

Self Cite

108

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“…Data are collected from laboratory investigations, scientific literature, life cycle databases and expert interviews. For a more detailed overview of scenario input data and assumptions, refer to Hofko et al (2016). Embodied energy does obviously not cause energy costs, but increases throughout the life cycle as a consequence of included process energy which in return imposes additional energy costs.…”

Section: Methodology Of Environmental and Economic Evaluationmentioning

confidence: 99%

“…Compared to scenario 0, the mixing temperature can be decreased by 30K in scenario 1 and by 50K in scenario 2. No adverse effects of temperature reduction on the mechanical properties of the asphalts are observed and the mechanical behavior of the construction material in the three scenarios can be assumed identical (Hofko et al 2016). As a consequence of modified composition and temperature reduction, energy demand, emission behavior and costs for materials and process energy differ between the scenarios.…”

Section: Characteristics Of Mastic Asphalt and Modificationsmentioning

confidence: 99%

“…A balance of PM10 emissions during material provision ("ecological backpack"), asphalt production, transport, construction, maintenance and demolition is presented in Table 2. Hofko et al (2016). Process emissions from scenario calculations based on ecoinvent v3.1 data.…”

Section: Environmental Performancementioning

confidence: 99%

“…Prior to the evaluation, central technical characteristics of MA are outlined and options for modifications in material composition are introduced. The MA case study is based on investigations, data and results of Hofko et al (2016). The emphasis of this research paper is on the procedure for combined environmental and economic evaluation of infrastructures.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Environmental Performance and Life Cycle Costs of Construction Materials: The Case of Alternative Mastic Asphalt Mixes

Schwab¹,

Rechberger²,

Hofko³

2016

Sustainable Construction Materials and Technologies (SCMT)

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A procedure for environmental and economic evaluation of construction materials is presented. The selection of appropriate construction materials depends on their technical suitability in particular engineered infrastructures, but also on environmental and economic considerations. The latter can be evaluated in a freely available software, combining principles of Material Flow Analysis (MFA), Life Cycle Energy Analysis (LCEA) and Life Cycle Costing (LCC). With the proposed procedure, different construction options can be compared and an optimal option can be selected. The evaluation procedure is illustrated in a case of mastic asphalt (MA) road surface layers. The production temperature of MA can be reduced my material modifications (application of additives and varying aggregate geometries). Temperature reduction induces changes in material demand, energy demand and costs on various stages of the life cycle. A reference MA is compared to two modified, temperature-reduced mixes with similar mechanical characteristics. The results indicate that the application of a binder additive is controversial and that the complete or partial substitution of crushed aggregates by round aggregates is promising. In either case, reduction of mixing temperature results in reduction of particulate emissions and decreased energy demand. The presented evaluation procedure helps to identify cost-effective, energy-saving and low-emission MA options.

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