Portland cement concrete (PCC) has been the most widely used concrete in the construction industry. However, PCC has a short service life under some aggressive environments, leading to the need of costly repairs. The purpose of this research was to implement local materials to produce a modified sulfur concrete (MSC) with better performance in industrial applications. Several modified sulfur concrete mixtures were prepared using natural aggregates from the northern region of Colombia, and sulfur cement by combination of sulfur with a modifier, with the objective of achieving the best performance based on mechanical strength and chemical resistance. To achieve this purpose, an experimental program based on a k-factorial design was used to determine the optimal mix design based on the results of the compressive strength. The mixture presenting the best results was then examined further with standardized tests to determine its physical, mechanical, and chemical properties (compressive strength, abrasion resistance, bulk density, absorption, and chemical resistance). Final results showed that the sulfur concrete mixture is very resistant to chemical attack and an outstanding substitute for PCC. The results indicated that there is no significant loss in weight and no relevant variation in compressive strength after the specimens were immersed in sulfuric acid and sulfate solutions. In addition, similar results were obtained for the slabs located in chemicals plants whose conditions were assessed during a 60-day period of exposure.

The polarization behavior of commercial galvanic point anodes for corrosion protection of reinforcing steel in patch repairs applications was investigated. Concrete specimens were used to analyze the polarization history of the embedded sacrificial anodes under galvanostatic load and in yard slabs as a function of anode service aging. The results were used to develop a characteristic time-dependent potential-current function (PF) of each anode type. Typically, the performance function showed relatively little anodic polarization from an open-circuit potential at low current levels, followed by an abrupt increase in potential as the current approached an apparent limiting value. Aging of the anodes was manifested by significantly steeper PF as time and total charge delivered increased. Modest to poor steel polarization levels were achieved when coupled with point anodes in yard slabs tests. There was marked performance function variability among replicate units of one anode type. The results are used for cathodic prevention performance modeling in a companion (Part 2) paper.

This paper addresses projecting the performance of point anodes for patch repair applications as a function of service parameters and anode aging. Input data from a concurrent experimental test program are presented as well. Modeling of a generic patch configuration was implemented with a one-dimensional approximation. The model calculated the throwing distance that could be achieved by a given number of anodes per unit perimeter of the patch, concrete thickness, concrete resistivity, amount of steel, and amount of polarization needed for cathodic prevention. The model projections and aging information suggest that anode performance in likely application scenarios may seriously degrade after only a few years of operation, even if a relatively optimistic 100 mV corrosion prevention criterion were assumed. The effect of adopting less conservative criteria proposed in the literature is presented as well and the need for supporting information is discussed.

Reinforced concrete structures are the backbone of the transportation infrastructure. Their structural safety and functional performance are critical to sustaining a globalized economy. Corrosion of steel reinforcement is typically triggered by chloride contamination and carbonation, becoming a primary factor in reinforced concrete deterioration. This paper presents a durability assessment of a tunnel structure located in a tropical marine environment. The condition assessment included visual examination, crack survey, cover depth measurements, half‐cell potential mapping, and concrete coring. The chloride profiles showed that the tunnel walls are subjected to chloride attack from both surfaces, an unusual finding in the literature. A stochastic approach is implemented to estimate the probability of corrosion initiation for chlorides and carbonation, including an innovative model for two‐sided chloride diffusion. The results indicate that two‐sided chloride exposure significantly reduces the corrosion initiation time.

Temperature changes affect current delivery and electrochemical assessment of galvanic anode–steel in concrete systems. Interfacial corrosion processes are thermally activated and, hence, temperature dependent. In addition, concrete resistivity varies with temperature, with consequent change in any resistive polarization component that may be present. This work presents advances in the approach to temperature correction procedures. Galvanic current, electrode potentials, and resistivity measurements were determined as a function of concrete temperature in outdoor reinforced concrete slabs where sacrificial point anodes were connected to the steel. Measured values were successfully standardized to an equivalent resistivity/current at a predefined reference temperature, through the application of a master temperature correction equation based on a differential formulation that derived correction parameters from short-term fluctuations and filtered long-term aging trends. A refined steel cathodic polarization characterization was introduced and demonstrated by accounting for the effect of electrode potential, as an added term to the nominal activation energy of the cathodic reaction.

This paper addresses the first phase in developing a numerical model for polarization distribution prediction of the rebar- anode system in concrete reinforced slabs with residual chloride contamination, where sacrificial point anodes were embedded in the concrete patch repair area. The modeling approach was developed to characterize the performance of this system under two application scenarios: one with part of the rebar assembly in the active condition and the other with an all-passive assembly. The model results and experimental finding in > 1 year old concrete slabs are compared. Results could be used for determine the anode operating potentials that may be achieved with a specific anode placement spacing for highway applications.