DTIC ADA534630: Use of Fly Ash in pdf

DTIC ADA534630: Use of Fly Ash in

More Book Details

Description of the Book:

Alkali-silica reaction (ASR) is one of the leading causes of concrete deterioration throughout the world, and affects both structural and non-structural elements. Despite strong research efforts since its discovery by Stanton in the late 1930s, this deteriorating reaction is still not clearly understood nor are proper preventative measures effectively applied to reduce the risk of ASR. Central to the debate is a lack of clear understanding about how supplementary cementing materials (SCMs), in particular fly ash, limit the progression of the reaction. One reason for avoiding the use of a certain fly ash in concrete is the alkali content of the particular fly ash. Because there is very little guidance and no standardized test to accurately measure the contribution of alkalies from a given ash in a real concrete mixture, many ashes are simply avoided. Development and standardization of a rapid test method to accurately predict the contribution of fly ash alkalies to the pore solution of concrete is the goal of a multi-phase project in the Civil Engineering department at Oregon State University.

The first phase of the project included performing a series of ASTM C 1567 tests (Standard Test Method for Potential Reactivity of Aggregates (Mortar-Bar Method)) utilizing various materials and replacement levels to determine the effectiveness of different fly ashes in the mitigation of ASR expansion. Also, predictive equations introduced by Malvar et al were applied to a variety of materials to determine the efficacy of different fly ashes to control alkali silica reaction based on chemical composition. In addition, pore solution evaluation was conducted using a specialized extraction device, one of only 3 of its kind in the United States. This process, carried out on 265 paste samples made of various combinations of cements, fly ashes and fly ash replacement levels, e

• Creator/s: Defense Technical Information Center
• Date: 11/12/2010
• Year: 2010
• Book Topics/Themes: DTIC Archive, , OREGON STATE UNIV CORVALLIS DEPT OF CIVIL ENGINEERING, *CONCRETE, *SILICON DIOXIDE, *CEMENTS, *ALKALI METAL COMPOUNDS, *FLY ASH, CHEMICAL REACTIONS, REPLACEMENT, CIVIL ENGINEERING, DETERIORATION, STRUCTURAL COMPONENTS, ASHES, AGGREGATES(MATERIALS), CHEMICAL COMPOSITION, THESES, TEST METHODS, TEST AND EVALUATION, PREVENTIVE MAINTENANCE

An excerpt captured from the PDF book