Date of Graduation

8-2014

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering (MSCE)

Degree Level

Graduate

Department

Civil Engineering

Advisor/Mentor

W. Micah Hale

Committee Member

Ernie Heymsfield

Second Committee Member

Clinton Wood

Keywords

Alkali-aggregate reaction, Mitigation, Prevention, Surface Treatment

Abstract

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.

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