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An evaluation of alkali-silica reaction (ASR) and freezing and thawing (F/T) in concrete transportation structures is presented along with mitigation methods for slowing the rate of deterioration in concrete. A combination of field and laboratory testing confirms ASR deterioration is exacerbated by exposure to F/T. Laboratory testing indicates an aggregate previously deemed inert to ASR, caused ASR deterioration in several concrete pavement and transportation structures. Existing standard test methods deem this aggregate safe for use in concrete. A modified test method shows the concrete can deteriorate rapidly when subjected to cycles of conditions promoting ASR and F/T. Several structures containing this aggregate deteriorated rapidly and severely during exposure to F/T. The interstate pavement underwent less deterioration as the incorporation of some Class C fly ash limited the development of ASR, and improved the durability to F/T. A three-year field test of various treatments applied to concrete barriers indicates silane reduces the moisture state of the concrete and slows the development of F/T and ASR deterioration as compared to untreated sections. A corresponding three-year evaluation of silane applied to concrete pavements, indicates silane slows F/T deterioration over time by reducing the moisture state of the concrete. Measuring the moisture state of concrete in the field proved difficult. Results of field and laboratory testing indicate measuring vapor pressure may prove more useful for evaluating the efficacy of treatments in reducing the moisture within concrete. The moisture state of the concrete is critical to the development of both ASR and F/T, as concretes protected from external moisture did not develop deleterious deterioration while specimens exposed to additional moisture deteriorated. This indicates limiting the ingress of external moisture is a viable method for slowing both ASR and F/T deterioration in concrete.

In 2012 it was discovered that roughly 4 miles of interstate median barrier along Interstate 540 had rapidly deteriorated. After the initial inspection, a sample was submitted for analysis, and found to contain evidence of alkali-silica reaction (ASR). A research program was implemented with the goal of determining the cause of ASR and developing a program for mitigating the ongoing deterioration. The median barrier had not deteriorated equally throughout the 4 miles, and the level of damage varied considerable throughout the length. A visual inspection of the median barrier was conducted and the median barrier was divided into sections based on visible damage. A research program was implemented to evaluate several treatment methods, with the goal of slowing or arresting the deterioration within the median barrier. Several sections of the median barrier were instrumented with devices to measure expansion and internal relative humidity. The sections were then treated and monitored to evaluate the efficacy of each treatment. The treatments were applied to sections of each damage level to evaluate the effect of damage at the time of treatment on the efficacy of the treatment. Monitoring was conducted for one year and some preliminary conclusions and recommendations were developed from the results. The aggregates used in the median barrier construction were also evaluated in laboratory testing, which included the accelerated mortar bar test and the concrete prism test. The fine aggregate and course aggregate were evaluated, and the results compared to the findings from the petrographic analysis. Additionally the cement alkalis and supplementary cementations materials (SCMs) were evaluated to determine if they were a contributing factor in the development of ASR in the median barrier. The results of laboratory testing were used to develop recommendation on the prevention of ASR in concrete which contains these aggregates.