The effect of fly ash content and types of aggregates on the properties of pre-fabricated concrete interlocking blocks (PCIBs) Tayfun Uygunog ˘lu a , Ilker Bekir Topcu b , Osman Gencel c,d,⇑ , Witold Brostow d a Civil Engineering Department, Faculty of Engineering, Afyon Kocatepe University, 03200 Afyonkarahisar, Turkey b Civil Engineering Department, Faculty of Engineering and Architecture, Osmangazi University, 26100 Eskisehir, Turkey c Civil Engineering Department, Faculty of Engineering, Bartin University, 74100 Bartin, Turkey d Laboratory of Advanced Polymers and Optimized Materials (LAPOM), Department of Materials Science and Engineering and Center for Advanced Research and Technology (CART), University of North Texas, 1150 Union Circle # 305310, Denton, TX 76203-5017, USA 1 article info Article history: Received 9 July 2011 Received in revised form 27 November 2011 Accepted 4 December 2011 Keywords: Pavement blocks Concrete waste Marble waste Fine aggregate Fly ash Waste management abstract We studied the influence of fly ash content and replacement of crushed sand stone aggregate with concrete wastes and marble wastes in pre-fabricated concrete interlocking blocks (PCIBs). We have compared properties of PCIBs with fly ash produced with three different replacement ratios of aggregate. Compressive strength, tensile splitting strength, density, apparent porosity, water absorption by weight, abrasion resis- tance, alkali-silica reaction and freeze–thaw resistance of PCIBs were determined. When comparing the PCIBs with crushed sand stone, the replacement of crushed sand stone with concrete waste and marble waste results in lower physical and mechanical properties. By contrast, replacement of cement with fly ash (from 10% to 20%) has a significant effect in increasing important properties of PCIBs. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction USA, Belgium, France, Spain, Sweden, Italy, Egypt, Portugal, Brazil and Greece are among the countries with considerable marble reserves. Turkey has even more, 40% of total marble reserves in the world. Seven million tons of marble are produced in Turkey annu- ally. In processing marble such as cutting to size and polishing for decorative purposes, marble dust and aggregate are created as byproducts. More specifically, during the cutting process 20–30% of the marble block turns into dust. Thus, waste materials from mar- ble processing plants represent millions of tons [1]. 1400 tons of waste marble per day are left and stored on depot areas as wastes in Turkey [2]. Saboya et al. [3] reported that the amount of waste from cutting and sawing process in Brazilian decorative stone indus- tries can easily reaches 20–25% of the total volume of the block. Heb- houb et al. [4] reported that a high volume of marble production has generated a considerable amount of waste materials; almost 70% of this mineral gets wasted in the mining, processing and polishing stages with obvious impact on the environment. A huge quantity of construction waste is produced every day, representing a large fraction of the total solid waste stream all over the word. Construction waste is mainly composed of concrete waste. Eguchi et al. [5] reported that construction industry pro- duces about 20% concrete waste of total industrial waste in Japan. Marinkovic et al. [6] reported that about 850 million tons of con- crete waste is generated in the countries of European Union per year, what represent 31% of the total waste generation. In North America, construction waste and demolition makes up about 25– 45% of the waste stream, depending on the region [7]. Fly ash, a by-product of coal power plants, causes environmental pollution while the cost of storage of fly ash is very high. In Turkey, the annual fly ash production is about 18 million tons more than the rest of all industrial waste in the country [8]. In India, approximately 80 million tons of fly ash is generated each year [9]. The current an- nual production of fly ash worldwide is estimated around 600 million tones [10]. Overall, a very high amount of waste is being produced all around the world. The most common method of managing waste is through its disposal in landfills creating in that way huge deposits of waste. In this situation, waste recycling is gaining increasing importance [11]. Also, restricted laws in the form of prohibitions or special taxes for creating waste areas have been brought into practice. It seems that stricter future waste disposal regulations may be applied because the disposal of the waste has 0950-0618/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.conbuildmat.2011.12.020 ⇑ Corresponding author at: Civil Engineering Department, Faculty of Engineering, Bartin University, 74100 Bartin, Turkey. Tel.: +90 378 223 5363; fax: +90 378 223 5258. E-mail address: osmangencel@gmail.com (O. Gencel). 1 http://www.unt.edu/LAPOM/; Tel.: +1 940 565 4358; fax: +1 940 565 4824. Construction and Building Materials 30 (2012) 180–187 Contents lists available at SciVerse ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat