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31 NACE INTERNATIONAL: VOL. 55, NO. 10 MATERIALS PERFORMANCE OCTOBER 2016 Investigations Evaluations were conducted on 152 selected electric transmission tower foun- dations located along Persian Gulf coasts. A variety of parameters were measured for corrosion assessment. These parameters included effects of the environmental condi- tions, as well as the concrete's structure and properties, on the degree of damage caused by steel corrosion. During this investigation, NACE SP0308- 2008 8 guidelines were followed. After check- ing the repair history and visual inspection, data on each foundation were collected for the following parameters: • Age • Distance from sea • Height above the sea level • Concrete cover depth • Rebar diameter • Alkalinity • Chloride ion concentration • Concrete homogeneity and compres- sive strength • Soil resistivity • Corrosion potential • Corrosion current density (CD) • Concrete electrical resistivity Alkalinity (pH) and chloride ion concen- tration were determined from concrete pow- der obtained by drilling three 30-mm diam- eter holes, each 25-mm deep. Alkalinity and chloride content values were obtained by averaging the values of three tested samples. According to ASTM C1218-15, 9 water-solu- ble chloride content is used as an applicable parameter related to corrosion occurrence. The concrete homogeneity and strength were estimated using the Schmidt hammer. The values for cement content and water/ cement ratio were obtained from design documents. Since water content in the mix design is a significant parameter affecting structural durability, it was also obtained from design documents and considered in the evaluation. Soil resistivity and corrosion potential were field-measured according to ASTM G57-06 10 and ASTM C876-09, 11 respectively. The galvanostatic pulse method was used to measure corrosion CD and resistivity of the concrete (Figure 3). FIGURE 1 An important sea-crossing mast that transmits electricity to Iran's biggest island. FIGURE 2 A severely cracked electric distribution tower foundation. The average temperatures and relative e nv i r o n m e n t a l h u m i d i t y a re s i m i l a r throughout the locations investigated, so the inf luence of these parameters on the rebar corrosion was not considered. Results Table 1 shows typical results for one of th e selected foundations. Th e data for each parameter were then analyzed and processed by software developed in-house