Title: Aggregate Reaction with Cement Alkalies

Author(s): Willard H. Parsons and Herbert Insley

Publication: Journal Proceedings

Volume: 44

Issue: 4

Appears on pages(s): 625-632

Keywords: none

DOI: 10.14359/12194

Date: 4/1/1948

Abstract:
Experiments reported tend to support and amplify Hensen's hypothesis on alkali-aggregate reaction. Test specimens composed of high-alkali cement and reactive aggregate (opal) were exposed to conditions promoting the reaction resulting in cracking and expansion. Petrographic examination at frequent intervals during the course of exposure indicated that the chemical reaction results in liquefaction, swelling and migration of the reaction products. The liquefied gel produced by the reaction fills pores existing in the specimen. After the poe is filled, a reaction at the pore wall occurs to form a dense, semi-permeable membrane through which osmosis takes place, resulting in expansion and cracking.