Evaluation of ﬁne limestone quarry by-products, for the production of building elements – An experimental approach Michael Galetakis ⇑ , George Alevizos, Konstantinos Leventakis Department of Mineral Resources Engineering, Technical University of Crete, University Campus, Akrotiri, 73100 Chania, Greece article info Article history: Received 2 September 2010 Received in revised form 6 May 2011 Accepted 27 May 2011 Available online 25 June 2011 Keywords: Quarry dust characterization Quarry dust utilization Compaction moulding Building elements abstract Aggregates, produced via quarrying operations, are used extensively in the construction industry and are considered vital for the development of any economy. However quarrying has severe environmental impacts such as the emission of dust dispersed in air, water and soil. The utilization of the accumulated dust during aggregates production is thus crucial for the quarrying and construction industry. A charac- terisation methodology, based on selected quality characteristics of quarry dust, has been developed and limestone dust collected from a concrete and asphalt mixture production plant, in Crete, has been char- acterized as a case study. Next the development of a simple method for the production of building ele- ments in order to massively recycle quarry dust was investigated at laboratory scale: the production of building blocks by means of compaction moulding. The optimal mix design, as well as the compaction pressure and water content were determined during the experimental procedure. The produced speci- mens were cured and tested in order to evaluate their major mechanical and physical properties. Results indicated that the production of building elements with market-acceptable quality characteristics is feasible. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Environmental management has become a major issue for all quarrying companies, which try to assess the potential impact of their operation, to improve their environmental performance and to meet the standards speciﬁed by laws and regulations that are in force. Regardless of the type, size, and location of a quarrying operation, dynamic companies that have the capability and resources to innovate are reducing environmental costs, while at the same time improve their environmental performance. On the contrary, older ongoing operations often exhibit poor environmen- tal performance, which is closely related with low production efﬁciency, outdated technology, limited capital, and poor human resources management. Aggregate materials, extracted mainly via quarrying operations, are used extensively for all construction applications and are essential for the development of any modern economy. In Greece, the majority of aggregates are extracted from limestone deposits. More than 300 small to medium size quarries produce about 100 million tones of crushed limestone aggregates annually [1,2]. The main uses of the extracted aggregates are related to concrete pro- duction and to road pavement construction (sub-base and cap). During the extraction, hauling and crushing processes for the production of aggregates, large quantities of limestone ﬁnes, here- on referred to as quarry dust, are generated. Particularly at the stage of crushing and screening, ﬁne airborne material such as silt and crusher dust can be generated and emitted into the surround- ing atmosphere. Silt is a material between 2 and 60 lm reduced to this size by natural processes and it is found in aggregates won from natural deposits. Crusher dust is a ﬁne material formed mainly during the process of rock crushing and sieving. In coarse aggregates used in concrete, this ﬁne material is present in the form of surface coating which interferes with the bond between aggregate and cement paste [3]. Since Greek Concrete Regulation limits the content of ﬁne material contained in coarse crushed aggregates for structural concrete to 1% and in crushed stone sand to 15%, it is necessary to remove the excess dust by implementing a suitable dedusting process. This quarry dust, that is usually removed from the aggregates by bag ﬁlters, suction or air cyclones, amounts up to 10% of the total aggregate production [4]. In Greece the quantity of the collected quarry dust, because of the origin of the aggregates, is estimated to 10 Mt annually [2] and conse- quently the stockpiling and disposal of this ﬁne by-product is one of the most important problems facing the quarry industry today in Greece (Fig. 1). Although many different ways for the utilization of limestone dust have been proposed (agricultural uses, industrial waste neutralization, ﬁller for paper and plastics’ industry, etc.) due to 0950-0618/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.conbuildmat.2011.05.011 ⇑ Corresponding author. Tel.: +30 2821037616; fax: +30 2821069554. E-mail address: galetaki@mred.tuc.gr (M. Galetakis). Construction and Building Materials 26 (2012) 122–130 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat