###### Abstract  
This research evaluates the behavior corrosion of galvanized steel (GS) and AISI 1018 carbon steel (CS) embedded in conventional concrete (CC) made with 100% CPC 30R and two binary sustainable concrete (BSC1 and BSC2) made with sugar cane bagasse ash (SCBA) and silica fume (SF), respectively, after 300 days of exposure to 3.5 wt.% MgSO4 solution as aggressive medium. Electrochemical techniques were applied to monitor corrosion potential (\(E_{\mathrm{corr}}\)) according to ASTM C-876-15 and linear polarization resistance (LPR) according to ASTM G59 for determining corrosion current density (\(i_{\mathrm{corr}}\)). \(E_{\mathrm{corr}}\) and \(i_{\mathrm{corr}}\) results indicate after more than 300 days of exposure to the sulfate environment (3.5 wt.% MgSO4 solution), that the CS specimens embedded in BSC1 and BSC2 presented greater protection against corrosion in 3.5 wt.% MgSO4 than the specimens embedded in CC. It was also shown that this protection against sulfates is significantly increased when using GS reinforcements. The results indicate a higher resistance to corrosion by exposure to 3.5 wt.% magnesium sulfate two times greater for BSC1 and BSC2 specimens reinforced with GS than the specimens embedding CS. In summary, the combination of binary sustainable concrete with galvanized steel improves durability and lifetime in service, in addition to reducing the environmental impact of the civil engineering structures. caption; binary sustainable concrete; galvanized steel; AISI 1018 steel; sugar cane bagasse ash; silica fume; sulfates +
Footnote †: journal: Applied Sci. the anthropogenic and 2-3% (4-5 GJ/ton) of energy consumption. CO\({}_{2}\) is emitted from the calcination process of limestone, the combustion of fuels in the furnace and from the generation of energy for electricity [1; 2; 3]. Although there is an impact on the environment generated by the manufacture of OPC, Hydraulic concrete is the most widely used construction material worldwide [4; 5; 6]. This is due to the great versatility it presents in its physical, mechanical and durability properties [7; 8; 9; 10; 11]. However, the problem of corrosion in reinforced concrete structures is a multimillion-dollar problem in India among other countries [12]. It is also of great interest because it is considered the main factor causing premature structure damage. Over time, significant damage might occur, compromising the structural integrity of civil works such as bridges, buildings, etc. [13; 14; 15; 16]. Corrosion of steel in concrete consists of an electrochemical redox reaction in which the oxidation of iron takes place at the anode while oxygen reduction reaction takes place at the cathode. Corrosion of steel happens due to several factors that affect the passive layer formed by the steel in a high pH environment, compromising its stability. The main factors that promote this passivity breakdown are carbonation and the ingress of aggressive ions [17; 18]. Chloride and sulfate ions are detrimental for reinforced concrete, deteriorating its structural integrity, reducing its lifetime and increasing the cost of maintenance of civil infrastructures [19; 20; 21; 22]. These ions are considered the main cause of the corrosion initiation stage of reinforcing steel. They are present in the environment from sulphated soils or contaminated by agrochemicals, wastewater, de-icing salts and marine environment, among others [23; 24; 25]. Furthermore, they can also be found in elements of the concrete mix (aggregates, cement, water, additives) [26; 27; 28; 29; 30]. During the oxidation of the steel embedded in concrete, an increased internal pressure is promoted due to the increased volume of the corrosion products from steel. This generates internal stresses or forces on the surrounding concrete, causing cracking or fragmentation [31; 32]. Several investigations have been carried out from various approaches in order to mitigate corrosion of steel in concrete.