In today’s market, it is imperative to be knowledgeable and have an edge over the competition. ACI members have it…they are engaged, informed, and stay up to date by taking advantage of benefits that ACI membership provides them.
Read more about membership
Become an ACI Member
Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design, construction, and materials, who share a commitment to pursuing the best use of concrete.
ACI World Headquarters
38800 Country Club Dr.
Farmington Hills, MI
ACI Middle East Regional Office
Second Floor, Office # 02.01/07
The Offices 02 Building, One Central
Dubai World Trade Center Complex
Phone: +971.4.516.3208 & 3209
Feedback via Email
Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Title: Mechanisms of Alkali-Aggregate Reaction
Author(s): Robert G. Pike, Donald Hubbard, and Herbert Insley
Publication: Journal Proceedings
Appears on pages(s): 13-34
Keywords: no keywords
Abstract:An interferometer procedure was used to determine the attack on character-istic active and nonreactive aggregates over an extended pH range, in solutions of NaOH, Ca (OH),, NaOH + Ca (OH), and in aqueous extracts of high-and low-alkali cements. Curves are given showing the hygroscopicity of high- and low-alkali cement pastes and powders and the same cements with added reactive and nonreactive aggregates. Curves are given showing ex-pansion of the mortar bars containing various percentages of Pyrex glass of different grain sizes. Microscopic studies of reactive aggregates in high-alkali cements are described, and photographs show instances where the major reaction takes place inside the opal grain rather than at the outside of the particle. This effect is rationalized in terms of the uneven distribution of the migratable ions. An expansion of 300 percent is demonstrated when opal reacts with soda to form a sodium silicate hydrate complex. It is believed that this expansion is the major cause of alkali-aggregate distress in concrete.
Click here to become an online Journal subscriber