Chemistry of Alkali-Silica Reaction

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

Abstract Alkali-silica reaction (ASR) is a major cause of concrete deterioration. The overall goal of this research project is to combine chemical and mechanical approaches to substantially advance fundamental understanding of ASR and to provide a basis for development of more effective accelerated tests and for prevention of damage. The objectives are: 1) to understand the molecular and nanometer- scale structure of ASR gels and how the structure is affected by conditions of formation, 2) to understand the molecular and nanostructural processes that produce the gel, the chemical and structural controls on gel composition, and the kinetics of gel formation and subsequent transformations, 3) to understand the effects of aggregate type on the composition and structure of ASR gel and on the kinetics of gel formation, 4) to understand the chemical and structural aspects of gel that control swelling behavior, and 5) to understand the relationships between the macroscopic structural expansion of concrete undergoing ASR and the details of gel formation and swelling by developing a finite element model of concrete expansion that can be used to more effectively predict and evaluate the engineering effects of ASR. The proposed research will have intellectual impact in civil engineering, geological science, and materials science. It will provide a detailed understanding of the chemistry of an important concrete deterioration mechanism, knowledge of the molecular structure of a class of hydrous silicates, ASR gel and establish a link between molecular structure and swelling behavior. It will establish a microstructural-based model that links ASR chemistry and concrete expansion. Knowledge gained through this research will be incorporated into education in both civil engineering and geology. The project will enhance interactions between engineering and geology. And the proposed research will enhance minority education through participation Jackson State University, a historically black institution.