Influence of matrix properties on alkali silica reaction rates

Matrices with different cracking and confinement characteristics are utilized to isolate the important parameters that influence gel initiation and alkali silica reaction rate. The paper is divided into two parts. In Part I, the matrix exhibits crack growth resistance behavior which induces compressive stresses on the alkali silica gel and in addition prevents the alkali silica gel from leaving the reaction site, which slows down the alkali silica reaction rate and modifies the gel composition. In Part II the matrices are designed to provide little confinement and hence allow the alkali silica gel to expand almost freely. However, the matrices in Part II differ in their ability to allow the alkali silica gel to escape the reaction site. The results reveal that lack of confinement accelerates early gel formation whereas the lack of escape of alkali silica gel products away from the reaction site reduces the alkali silica reaction rate.