Research paper Investigation of concrete produced using recycled aluminium dross for hot weather concreting conditions Gireesh Mailar a, *, Sujay Raghavendra N b , Sreedhara B.M b , Manu D.S c , Parameshwar Hiremath c , Jayakesh K. c a Department of Civil Engineering, Karavali Institute ofTechnology, Neermarga, Mangalore 575029, India b Department of Applied Mechanics and Hydraulics, National Institute of Technology Karnataka, Surathkal, Mangalore 575025, India c Department of Civil Engineering, National Institute of Technology Karnataka, Surathkal, Mangalore 575025, India Received 9 May 2016; received in revised form 24 June 2016; accepted 25 June 2016 Available online Abstract Aluminium dross is a by-product obtained from the aluminium smelting process. Currently, this dross is processed in rotary kilns to recover the residual aluminium, and the resultant salt cake is sent to landfills. The present study investigates the utilization of recycled aluminium dross in producing concrete, which is suitable for hot weather concreting condition. The primary objectives of the experimental study are to examine the feasibility of using concrete blended with recycled aluminium dross under hot weather concreting situations and then to evaluate the strength and durability aspects of the produced concrete. From the experimental results it is observed that the initial setting time of the recycled aluminium dross concrete extended by about 30 minutes at 20% replacement level. This property of recycled aluminium dross concrete renders it to be suitable for hot weather concreting conditions. Based on the results obtained, the replacement of cement with 20% of Al dross yields superior mechanical and durability characteristics. © 2016Tomsk Polytechnic University. Production and hosting by Elsevier B.V.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Keywords: Hot weather concrete; Recycled aluminium dross; Durability of concrete 1. Introduction The hot weather is considered to be any combination of high air temperature, low relative humidity and increased wind velocity [1]. Concrete applications may be considered as hot weather concrete at temperatures above 40 °C depending on the site specific application as per IS:7861 (Part 1)-1975 [2]. The actual temperature of the concrete mix as conveyed to the site is effected by the temperature of the ingredient materials used in the mix, the temperature of the equipment used to batch and transport the concrete, the cementitious content of the mixture, and finally by the ambient temperature and conditions at the project site. Ideal conditions for placing concrete occur when temperature ranges between 68 °F and 72 °F (20 °C and 22 °C), the relative humidity is 50 percent or higher and the near surface wind velocity is low [3]. As a general rule of thumb, an increase of 20 °F will reduce the setting time of a concrete mixture by as much as 50 percent [4]. Some of the effects of hot weather concreting include accelerated setting time of concrete; increased tendency for plastic shrinkage; potential strength reduction due to high water demand and high curing tempera- tures; and stiffening of the mix prematurely, preventing it from being well compacted and finished properly. Nowadays, there is an intense need to come out with novel technologies to convert various wastes into serviceable feedstock cost-effectively. Currently, various kinds of pozzolanic materials are blended along with cement during the production of concrete for modifying the strength and durability properties of conven- tional concrete. Indeed, the use of pozzolanic materials existed before the discovery of contemporary ordinary Portland cement (OPC) nearly about 2000 years ago itself [5]. Most of the poz- zolanic materials are nothing but the by-products procured from industries, for instance, coal fly ash, blast furnace slag, rice husk ash, silica fume, etc. Intrinsically, there has been not much research done with respect to manufacturing, engineered and optimized pozzolanic materials, which are purposely explored for usage along with Portland cement. * Corresponding author. Department of Civil Engineering, Karavali Institute of Technology, Neermarga, Mangalore 575029, India. E-mail address: gireeshmailar@zoho.com (G. Mailar). http://dx.doi.org/10.1016/j.reffit.2016.06.006 2405-6537/© 2016Tomsk Polytechnic University. Production and hosting by Elsevier B.V.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer review under responsibility of Tomsk Polytechnic University. ARTICLE IN PRESS Please cite this article in press as: Gireesh Mailar, et al., Investigation of concrete produced using recycled aluminium dross for hot weather concreting conditions, Resource-Efficient Technologies (2016), doi: 10.1016/j.reffit.2016.06.006 Available online at www.sciencedirect.com Resource-Efficient Technologies ■■ (2016) ■■–■■ www.elsevier.com/locate/reffit HOSTED BY ScienceDirect