Pavimentos

FOUNDATIONS OF CIVIL AND ENVIRONMENTAL ENGINEERING

No. 10

2007

Wojciech GRABOWSKI*, Jarosław WILANOWICZ, Mieczysław SŁOWIK, Tomasz SOBÓL
Poznan University of Technology, Institute of Civil Egeneering 5, Piotrowo st., 60-965 Poznań

THE ASSESSMENT OF THE STIFFENING PROPERTIES OF MINERAL FILLERS OBTAINED FROM A DUST EXTRACTOR INSTALLED IN AN ASPHALT PLANT
Received: 15 May 2007Accepted: 20 November 2007

The object of the studies presented in this paper were the samples of mineral fillers obtained from a dust extractor of asphalt plant as well as mastics containing these fillers. The work consists of two parts. In the first part a comparative analysis of the structural and functional properties of the limestone, basaltic and melaphyre fillers was carried out. To this end, thegrain-size distribution, specific surface area, Rigden voids as well as bulk volume concentration and activity index of fillers were determined. In the second part, quantitative and qualitative estimations of the stiffening properties of these fillers in mastics were performed. A search for the quantitative relationship between the filler’s structural features and the selected rheologicalproperties of mastics was conducted in order to assess a practicability of dusts obtained from a dust extractor of asphalt plant to use in asphalt pavement layers.

Key words: baghouse filler, mastic, structural feature, stiffening property

1. INTRODUCTION
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Mineral fillers used in Hot Mix Asphalt (HMA) can be considered as [7]: basis filler (limestone dust produced by industrial method),Corresponding author. Tel.: 0-61-6652-487; fax: 0-61-6652-478. E-mail address: wojciech.grabowski@put.poznan.pl (W. Grabowski)
© Publishing House of Poznan University of Technology, Poznań 2007 ISSN 1642-9303

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Wojciech Grabowski, Jarosław Wilanowicz, Mieczysław Słowik, Tomasz Soból

mineral fines founded in aggregate after passing through a hot air stream in dryer mixer, • baghousefines from a dust extractor installed in an asphalt plant. The first two types of fillers are almost always a major component of HMA, used in the construction of asphalt pavement layers. Usability of the third type of filler is restricted by rules [2]. The Polish standard PN-S-96025:2000 admits usability of baghouse fines instead of a quantity of basis filler in asphalt pavement layers provided thatthese baghouse fines have a positive decision of road laboratory or Technical Approval [1]. Since the European standard PN-EN 13043:2004 became legally valid some of its statements concerning dusts and fillers are contradictory to the requirements of the PN-S-96025:2000 standard. Mineral fines (called filler aggregate in the standard PN-EN) are treated as traditional limestone fillers (calledadded filler in the standard PN-EN). In addition, in PN-EN a new concept was introduced a mixed filler, i.e. “filled aggregate of mineral origin, mixed with calcium hydroxide”, for example mineral dusts mixed with hydrated lime. On the basis of the above mentioned information it can be said that, according to PN-EN standard, a limestone filler lost its significance for the benefit of other mineralfillers i.e. filling aggregate [1]. In many countries baghouse fillers are admitted as suitable for use in HMA as mineral fillers [7, 8]. In France and the US the fines from a dust extractor installed in an asphalt plant are the basic source of mineral filler and are utilized in HMA as a whole. In Belgium both baghouse and limestone fillers have been used, and the application of baghouse fillers isnot limited if the results of the laboratory tests are positive. However, in England limestone filler is added to HMA as a supplement of a filling fraction of an aggregate in quantities resulting from a required graining of mixture [7]. The properties of limestone fillers are objects of many research works, standards and guidelines [5, 9], while features of baghouse fillers are still known to a...