Utilization of Electrolytic Manganese Dioxide (E.M.D.) waste in concrete exposed to salt crystallization N. Chousidis a,b,⇑ , I. Ioannou b , G. Batis a a School of Chemical Engineering, National Technical University of Athens, Athens, Greece b Department of Civil and Environmental Engineering, University of Cyprus, Nicosia, Cyprus highlights  Durable composite concretes with EMDW addition may be produced.  EMDW induces a positive effect on the pitting corrosion of reinforcement steel.  5% w/w EMDW addition slightly improves the elastic modulus of concrete in NaCl.  Composite EMDW concretes exhibit lower porosity values than OPC concrete.  The sorptivity of EMDW concrete is lower than that of OPC concrete at late ages. article info Article history: Received 14 June 2017 Received in revised form 4 October 2017 Accepted 5 October 2017 Keywords: Electrolytic Manganese Dioxide Waste additive Reinforcement corrosion Compressive strength Sorptivity Porosity Modulus of elasticity Thermal analysis Concrete abstract In the present study, the physico-mechanical properties and corrosion resistance of reinforced concrete containing Electrolytic Manganese Dioxide (E.M.D.) waste were investigated. Concrete samples prepared in the lab with and without the use of EMD waste were exposed to sulfate and chloride salt solutions. In particular, the test samples were placed in 5% w/w Na 2 SO 4 solution, while chloride penetration resistance was studied in 3.5% w/w NaCl solution. The concrete mixtures were prepared with 0%, 5% and 10% w/w replacement of Ordinary Portland Cement (OPC) with the aforementioned waste additive. For testing, specimens of varying shapes and dimensions were cast; cylindrical reinforced cement mortar specimens were also prepared. Tests for estimating the physico-mechanical properties (compressive strength, mod- ulus of elasticity, porosity and sorptivity), mass loss of steel and thermal response of concrete (DTA/TG) were performed; the carbonation depth of mortars exposed to atmospheric conditions was also estimated. The experimental results generally suggest that the EMD waste additive does not affect negatively the properties of concrete partially immersed in chloride salt solution; in addition, the anticor- rosive effect of EMD waste on steel rebars embedded in cement mortars was also observed. On the other hand, the composite concretes immersed in sulfate salt solution exhibited inferior values for all measured properties. Ó 2017 Elsevier Ltd. All rights reserved. 1. Introduction The chemical reaction between Portland cement and water, which is widely known as cement hydration, plays a decisive role in the performance and durability of hardened concrete [1,2]. The use of additives as cement replacement, which is currently gaining popularity in an effort to reduce the carbon footprint of concrete production, affects the aforementioned chemical reaction. At the same time, the chemical composition of concrete constituents and the presence of heavy, toxic or trace chemical elements within the waste additives may cause deterioration to the end-product and contamination of the immediate surroundings [3]. Traditional additives used in cement manufacturing, such as fly ash, natural pozzolans, slags, silica fume etc., generally improve the physico-mechanical performance of concrete, but may consist of heavy metals or harmful elements [4–6]. The leaching of these metals from concrete elements [7] contaminates the underground water and soil. Besides the traditional concrete additives, other industrial haz- ardous materials are also utilized in concrete design. A generally unknown material used in concrete production is the gamma Electrolytic Manganese Dioxide (c-MnO 2 ). The aforementioned https://doi.org/10.1016/j.conbuildmat.2017.10.036 0950-0618/Ó 2017 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Department of Civil and Environmental Engineering, University of Cyprus, Nicosia, Cyprus E-mail address: chousidis.nikolaos@ucy.ac.cy (N. Chousidis). Construction and Building Materials 158 (2018) 708–718 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat