EXPERIMENTAL STUDY OF POTENTIAL DIFFERENCE, PH VALUES, AND WEIGHT LOSS EFFECTS ON SELECTED REINFORCEMENT, CASE STUDY: LAGOS STATE, NIGERIA

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1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 9, Issue 10, October 2018, pp , Article ID: IJMET_09_10_116 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed EXPERIMENTAL STUDY OF POTENTIAL DIFFERENCE, PH VALUES, AND WEIGHT LOSS EFFECTS ON SELECTED REINFORCEMENT, CASE STUDY: LAGOS STATE, NIGERIA Olukanni David, Ige Babatunde Mutiu and Bamigboye Gideon Department of Civil Engineering, Covenant University, Ota, Ogun State, Nigeria Bamidele Durodola Department of Chemistry, Covenant University, Ota, Ogun State, Nigeria ABSTRACT The effects of potential difference, ph values and weight loss of selected reinforcement in Lagos State, Nigeria were studied in this research. The samples of the High yield reinforcement such as Pulkit, LCI and Tiger TMT with 12mm, 16mm and 20mm diameters were considered. The media used for this study are lagoon water (which was taken directly from source in Lagos lagoon), fresh water, sodium chloride and potassium chloride (NaCl and KCL) solutions. Direct immersion method was explored in this study, while the ph value, the electrode potential, and the weight loss of each reinforcement brand was taken at an interval of seven days and the process are repeated for thirty-five days to determine the corrosion rate. It was established that show that Tiger TMT has the least negative electro potential and its ability to resist corrosion is high as compared to LCI and Pulkit. But LCI resist corrosion more in NaCl. Also, Pulkit has the lowest ph value while Tiger TMT has the highest ph value among the three specimens in the four-host environments used in this research. It was concluded that Tiger s TMT ability to corrode is less compared to Pulkit and LCI. Keywords: Potential difference, ph, weight loss, concrete, reinforcement, compressive strength. Cite this Article: Olukanni David, Ige Babatunde Mutiu, Bamigboye Gideon and Bamidele Durodola, Experimental Study of Potential Difference, PH Values, and Weight Loss Effects on Selected Reinforcement, Case Study: Lagos State, Nigeria, International Journal of Mechanical Engineering and Technology, 9(10), 2018, pp editor@iaeme.com

2 Experimental Study of Potential Difference, PH Values, and Weight Loss Effects on Selected Reinforcement, Case Study: Lagos State, Nigeria 1. INTRODUCTION Steel being one of the most important construction materials, because of its good strength properties it has been used for several years both in land and saline environment for structural and engineering purposes [1, 2]. Corrosion is the main problem of structural steel when exposed to various environmental species [3]. The formation of passive film starts immediately as the mixing water ph rises in concrete when cement starts to hydrate and stabilize over the first seven days to prevent the steel from active corrosion [4, 5]. Corrosion process either at the damaging active rate or the negligible passive rate, is an electrochemical process which includes the formation of catholic and anodic half-cell reactions on the macroscopic and microscopic levels [4]. Novak et al., (2001) reported that the current use of high yield steel which reduced the total steel consumptions supersede those with normalized mild steel and conventional hot rolled which has been used for reinforcing concrete structures for a long time. Higher corrosion rate formation in steel is as a result of higher level of residual stress in steel [4]. Andruis et al., [7] studied the degree of reinforcement on adhesion with concrete and the result from the potentiometric measurement showed that the most favourable probability of steel reinforcement corrosion to perform is when the steel reinforcement is exposed to NH 4 NO 3. The occurrence of calcium hydroxide in wet concrete produces an alkaline environment within the concrete of ph 12 to 13, and it was reported that high alkalinity of this nature causes a passive oxide layer to form on steel surface. Occurring of corrosion is prevented by this passive oxide layer [8, 9]. Kayyalir and Yeomous [10] concluded that the disintegration of passive layer as a result of chlorine ingress leads to steel corrosion if there is an accurate balance of oxygen and moisture. Kumar et al., [11] studied reinforcement corrosion in concrete and inhibitor effect on the reinforced concrete service life, the study shows that the strength of concrete was reduce with combination of calcium palmitate and calcium nitrite but service life of concrete increases with inhibition to the corrosion of rebar. Shi et al., [12] reported that pitting is the most insidious type of corrosion as comparatively little weight loss can result in an important reduction in section size and its localized attack can be hard to recognize before severe deterioration occurs. Ashutosh et al., [13] studied the ph and weight loss influence on steel corrosion embedded in reinforced concrete and concluded that increase in temperature increase the corrosion rate. Ghaz [14] used Laplace equation to determine concrete resistivity and corrosion rate with polarization test to analyse effect of high temperature on steel corrosion. Song and Saraswathy [15] & Bamigboye et al. [16] studied reinforced concrete corrosion by electrochemical and non-destructive techniques and found that the risk of reinforcing steel corrosion can be determine by electrical resistivity of concrete. This current research focus on experimental study of potential difference, ph values, and weight loss effects on selected reinforcement in Lagos State, Nigeria. 2. MATERIAL AND EXPERIMENTAL SETUP Pulkit, LCI and Tiger TMT are the high yield reinforcements selected in Lagos Nigeria for this study. Each of three different diameters 12mm, 16mm, and 20mm were mechanically machined using a vice with hacksaw and cut into sizes (36 pieces) of 40mm length each. Each sample cut is then examined carefully to check for rough edges, and then polished with sand paper in other to avoid any element of corrosion which could influence the corrosion monitoring process. The method adopted in this research is referred to as the direct immersion method. The weight loss, the potential difference and ph values for this study were carried out by measuring 5.50 ml each of the test media into a plastic container and the materials were subjected for corrosion test by hanging the sample on a support and suspended into the media (fresh water, lagoon water, 1.0M of NaCl and 1.0M of KCl). The weight loss, potential editor@iaeme.com

3 Olukanni David, Ige Babatunde Mutiu, Bamigboye Gideon and Bamidele Durodola difference and the ph were monitored at every 7 days (one week) interval for the period of 35 days of exposure. The potential difference of each sample in each of the test media was taken by immersing a zinc rod directly into the test media and a Digital multimeter was used to determine the potential difference as shown in Plate 1. Also, the ph value of each sample was taken while the sample was still inside the test media with ph digital multi-parameter and then recorded for the interval of days adopted for the study as shown in Plate 2. Immediately the Potential difference and the ph value were taken, the test samples were then taken out of the solution, the rusts accumulated on the steel bar surfaces was removed by washing in water and totally dried with ethanol, after which the mass losses were measured using a very sensitive digital analytical balance. This experimental cycle was repeated for 35 days, for each sample, weight losses were measured for 5 times. Plate 1 Potential Difference of sample is being taking using the Digital Multimeter Plate 2 ph of sample is being taking with the ph digital multi-parameter 3. RESULTS AND DISCUSSIONS 3.1. Electro Potential Results for Various Environments Fresh water Figures 1-3 shows the variation in the electrode potentials (Pd) of the three brands of reinforcements for the three diameters (12mm, 16mm and 20mm) used in this study when immersed in fresh water. It was observed from the first day of immersion that the Pd for Tiger TMT for both the 12mm and 20mm diameter has the least negative values i.e. (-519) and (- 385), respectively. Comparing the other days of exposure up to the last day of exposure, Tiger TMT of both 12mm and 20mm diameters still show negative Pd. 16mm diameter LCI has the editor@iaeme.com

4 Experimental Study of Potential Difference, PH Values, and Weight Loss Effects on Selected Reinforcement, Case Study: Lagos State, Nigeria least negative Pd value from the day one of exposure all through to the final day of exposure. This shows that Tiger TMT generates more current with negative Pd, because of the chemical reaction that take place between the medium and the sample, and less tendency to form metal ions and hence resist corrosion. Pulkit has more negative Pd than others and hence produce lesser resistance to corrosion compared to others. Figure 1 Plot of electrode potential against exposure time of LCI, Tiger TMT and Pulkit of 12mm diameter reinforcement in fresh water Figure 2 Plot of electrode potential against exposure time of LCI, Tiger TMT and Pulkit of 16mm diameter reinforcement in fresh water Figure 3 Plot of electrode potential against exposure time of LCI, Tiger TMT and Pulkit of 20mm diameter reinforcement in fresh water editor@iaeme.com

5 Olukanni David, Ige Babatunde Mutiu, Bamigboye Gideon and Bamidele Durodola Sodium Chloride (NaCl) 1.0 molar Figures 4-6 show the variation in the electrode potentials (Pd) of the three (3) brands of reinforcement for the three (3) diameters used when immersed in 1.0 mole of Sodium chloride. From the first day of immersion to the last day, Tiger TMT for both the 12mm and 20mm diameter has the least negative value of Pd, while LCI produces the least negative value in 16mm diameter. As presented earlier, the more negative the Pd, the more the ability of the sample to corrode. Pulkit has the most negative Pd, therefore has the least ability to resist corrosion. Figure 4 Plot of electrode potential against exposure time of LCI, Tiger TMT and Pulkit of 12mm diameter reinforcement in 1M NaCl Figure 5 Plot of electrode potential against exposure time of LCI, Tiger TMT and Pulkit of 12mm diameter reinforcement in 1 NaCl Figure 6 Plot of electrode potential against exposure time of LCI, Tiger TMT and Pulkit of 20mm diameter reinforcement in 1M NaCl editor@iaeme.com

6 Experimental Study of Potential Difference, PH Values, and Weight Loss Effects on Selected Reinforcement, Case Study: Lagos State, Nigeria Potassium Chloride (KCl) Figures 7-9 show the variation in the electrode potentials (Pd) of the three (3) brands of reinforcement for the three (3) diameters used in this research when immersed in Potassium chloride (KCl). It was observed from the first day of immersion that Pulkit has more negative Pd value. This shows that its ability to resist corrosion is less compare to the other brands. LCI in the same medium has lower negative Pd value from the first day of immersion except for the 12mm diameter where Tiger has lowest negative Pd, though LCI follow closely and this is due to the fact that reaction between the medium and the sample generates more current and its tendency to produce metal ion is low. So LCI has the upper hand, followed by Tiger. Figure 7 Plot of electrode potential against exposure time of LCI, Tiger TMT and Pulkit of 12mm diameter reinforcement in 1M KCl Figure 8 Plot of electrode potential against exposure time of LCI, Tiger TMT and Pulkit of 16mm diameter reinforcement in 1M KCl editor@iaeme.com

7 Olukanni David, Ige Babatunde Mutiu, Bamigboye Gideon and Bamidele Durodola Figure 9 Plot of electrode potential against exposure time of LCI, Tiger TMT and Pulkit of 16mm diameter reinforcement in 1M KCl Lagoon Figures shows the variation in the electrode potentials (Pd) of the three (3) brands of reinforcements for the three (3) diameters used in this research when immersed in Lagoon. Except for the first day and day fourteen (14) of immersion, Pulkit has less negative Pd in 12 mm diameter, while Tiger TMT has less negative Pd both in 16mm and 20mm diameter. The lesser their negative Pds the less they are prone to corrosion. In this case, Tiger TMT has the potential to resist corrosion in 16 and 20mm diameter, while Pulkit 12mm diameter is good for Lagoon environment Figure 10 Plot of electrode potential against exposure time of LCI, Tiger TMT and Pulkit of 12mm diameter reinforcement in 1M Lagoon Figure 11 Plot of electrode potential against exposure time of LCI, Tiger TMT and Pulkit of 16mm diameter reinforcement in 1M Lagoon editor@iaeme.com

8 Experimental Study of Potential Difference, PH Values, and Weight Loss Effects on Selected Reinforcement, Case Study: Lagos State, Nigeria Figure 12 Plot of electrode potential against exposure time of LCI, Tiger TMT and Pulkit of 20mm diameter reinforcement in 1M Lagoon Figures 1 12 are the graphical representation of the results obtained for electrode potential against exposure time of selected reinforcements when immersed in the various environment. Just as explained earlier on, the plots of Figures 1 6 and 10 and 12 which show that Tiger TMT has the least negative electro potential. Therefore, Tiger (TMT) ability to resist corrosion is high as compared to others. Also, considering Figures 7-8. It was observed that LCI has the least negative Pd which means LCI resist corrosion more in NaCl solution ph for Various Environments Fresh water Figure show the variation in the ph values of the three (3) brands of reinforcement for the three (3) diameters used when immersed in Fresh water. It was observed that Tiger TMT has the highest ph value, which means that it displays higher resistance to corrosion, followed by LCI. Pulkit has the lowest ph value i.e. the chloride content of the host environment has reacted extensively to the sample and makes it more acidic and tend to corrode easily than others. The lesser the ph value the more the solution is acidic and the more the sample is liable to corrode. Figure 13 Plot of ph against exposure time of LCI, Tiger TMT and Pulkit of 12mm diameter reinforcement in fresh water editor@iaeme.com

9 Olukanni David, Ige Babatunde Mutiu, Bamigboye Gideon and Bamidele Durodola Figure 14 Plot of ph against exposure time of LCI, Tiger TMT and Pulkit of 16mm diameter reinforcement in fresh water Figure 15 Plot of ph against exposure time of LCI, Tiger TMT and Pulkit of 16mm diameter reinforcement in fresh water Sodium Chloride (NaCl) Figures show the variation in the ph value of the three (3) brands of reinforcements for the three (3) diameters used in this research when immersed in 1.0 mole Sodium Chloride. It was observed that Tiger TMT again has the highest p value, which means that it displays higher resistance to corrosion, followed again by LCI. Pulkit has the lowest ph value. The lesser the ph value the more acidic the solution and it aggressiveness to corrode the sample. Figure 16 Plot of ph against exposure time of LCI, Tiger TMT and Pulkit of 12mm diameter reinforcement in 1M NaCl solution editor@iaeme.com

10 Experimental Study of Potential Difference, PH Values, and Weight Loss Effects on Selected Reinforcement, Case Study: Lagos State, Nigeria Figure 17 Plot of ph against exposure time of LCI, Tiger TMT and Pulkit of 16mm diameter reinforcement in 1M NaCl solution Figure 18 Plot of ph against exposure time of LCI, Tiger TMT and Pulkit of 20mm diameter reinforcement in 1M NaCl solution Potassium Chloride Figures show the variation in the ph values of the three (3) brands of reinforcements for the three (3) diameters used when immersed in 1.0 molar Potassium Chloride. It was observed that LCI has the highest ph value, which also means that LCI display higher resistance to corrosion, followed again by Tiger while Pulkit has the lowest ph value and which makes the solution more acidic. Figure 19 Plot of ph against exposure time of LCI, Tiger TMT and Pulkit of 12mm diameter reinforcement in 1M KCl solution

11 Olukanni David, Ige Babatunde Mutiu, Bamigboye Gideon and Bamidele Durodola Figure 20 Plot of ph against exposure time of LCI, Tiger TMT and Pulkit of 16mm diameter reinforcement in 1M KCl solution Figure 21 Plot of ph against exposure time of LCI, Tiger TMT and Pulkit of 16mm diameter reinforcement in 1M KCl solution Lagoon Figures show the variation in ph values of the three brands of reinforcement for the three diameters used in this research when immersed Lagoon. It is seen that Tiger TMT has the highest ph value followed again by LCI, while Pulkit has the lowest ph value. The lesser the ph value the more acidic the solution and the more the sample is vulnerable to corrosion. Figure 22 Plot of ph against exposure time of LCI, Tiger TMT and Pulkit of 12mm diameter reinforcement in 1M KCl solution

12 Experimental Study of Potential Difference, PH Values, and Weight Loss Effects on Selected Reinforcement, Case Study: Lagos State, Nigeria Figure 23 Plot of ph against exposure time of LCI, Tiger TMT and Pulkit of 16mm diameter reinforcement in 1M KCl solution Figure 24 Plot of ph against exposure time of LCI, Tiger TMT and Pulkit of 20mm diameter reinforcement in 1M KCl solution Figures show the graphical representation of ph against exposure time in different environments and it show that pulkit has the lowest ph value while Tiger TMT has the highest ph value among the three (3) specimens of the three (3) types of reinforcement diameters and in the four-host environment used in this research. The lower the ph value, the more tendency is the sample specimens to corrode and vice versa. Tiger TMT has the highest value of ph both in Fresh water, NaCl 1.0M, and in Lagoon, while LCI has the highest ph in KCl 1.0M. So, in summary Tiger s ability to corrode is less compared to others 4. CONCLUSION From the study it was shown that Tiger TMT has the least negative electro potential. Therefore, Tiger (TMT) ability to resist corrosion is high as compared to others. Also, it was observed that LCI has the least negative Pd which means LCI resist corrosion more in NaCl. Also, from the study it was concluded that Pulkit has lowest ph value while Tiger has the highest and the lower the PH value the tendency is the specimens to corrode and vice versa. Considering their electro potential and ph results outcome. To work in an environment that has potential chloride solution composition LCI is endorsed while Tiger TMT is suggested for construction in environments like fresh water and Lagoon environment that has some level of salt solution editor@iaeme.com

13 Olukanni David, Ige Babatunde Mutiu, Bamigboye Gideon and Bamidele Durodola ACKNOWLEDGMENT The authors wish to thank the Chancellor and Management of Covenant University for the platform made available for this research. REFERENCES [1] Islama, M. A. Corrosion behavoiurs of high strenght TMT steel bars for reinforcing cement concrete structure. Construction and Building Materials, 2015, pp [2] Ngene B. U., Ede A.N., Bamigboye G.O., Prashant K., and Boulent I. Environment Effect of Climate Change Pollutants Loading on Structural Steel Stresses. International Journal of Applied Engineering Research. 12, 2017, pp [3] Vidal T, Castel A, and Francosis R, (2007). Corrosion process and structure performance of a 17 years old reinforced concrete beam stored in chloride environment. Cement and concrete research, 37, 2007, pp [4] Hansson, C. M., Poursaee, A., and Jaffer, A. S. Corrosion of reinforcing bar in concrete. The Master Builder, 2012, pp [5] Ede A. N., Olofinnade O.M., Enyi-Abonta E., Bamigboye G.O. Implication of Construction Materials on Energy Efficiency of Building in Tropical Regions. International Journal of Applied Engineering Research. 12, 2017, pp [6] Novak. P, Mala R, Joska L. Influence of pre-rusting on steel corrosion in concrete. Cement and Concrete Reaserch. 31, 2001, pp [7] Andrius Kiele, Vitoldas Valkevicus, Vytautas Sasanskas, Danute Vaicuikyniene, and Reda Bistrickaite. Reinforement corrosion degree effect on adhesion with concrete. Journal of sustainable architecture and civil engineering. 2, 2014, pp [8] Zhang R, Castel A, and Francois R. Conrete cover cracking with reinforcement corrosion of RC beam during chlorine-induced corrosion process. Cement and Concrete Research. 40, 2010, [9] Ede A.N., Olofinnade O.M., Bamigboye G.O., Shittu K.K., and Ugwu, E.I. Prediction of fresh and Hardened Properties of Normal Concrete via Choice of Aggregates Sizes, Concrete Mix-ratios and Cement. International Journal of Civil Engineering and Technology. 8, 2017, pp [10] Kayyali O. A. and Yeomons S. R, (1995) Bond and slip of coated reinforcement in concrete. Construction and Building Materials, 9, 1995, pp [11] Kumar V, Ramesh Singh, and Quraishi M. A. A study on corrosion of reinforcement in concrete and effect of inhibitor on service life of RCC. Journal of Material in Environmental Science. 4, 2013, pp [12] Shi, X., Xie, N. & Fortune, K. and Gong, J. Durability of steel reinforced concrete in chloride environments: an overview. Construction and Building Materials, 30, 2012, pp [13] Ashutosh S. Trivedi, Sudhir SinghBhadauria, and Ravi Singh Sengar. Analytical study of influence of ph and weight loss on steel corrosion embedded in reinforced concrete: A review paper. International Journal of Advance Science and Technology, 91, 2016, pp [14] Ghaz Z. The Effect of Temperature on the corrosion of steel in concrete Part 1: Simulate Polarization resistance test and model development. Corrosion Science, 51, 2009, pp [15] Song, H.W. and Saraswathy, V. (2007). Corrosion Monitoring of Reinforced Concrete Structures A Review. International Journal of Electrochemical Science., 2, 2007, pp [16] Bamigboye G.O., Adedeji A.A., Olukanni D.O., Jolayemi K. J. Reliability of gravel in place of granite in concrete production. Journal of Engineering and Applied Sciences. 12, 2017, pp editor@iaeme.com