Microstructural Changes Due to Alkali-Silica Reaction during Standard Mortar Test

Materials

Jun-Ho Shin²  Leslie J. Struble²  R. James Kirkpatrick¹ 

[1] Department of Geology, University of Illinois, Urbana, IL 61801, USADepartment of Civil and Environmental Engineering, University of Illinois, Urbana, IL 61801, USA;

关键词: alkali-silica reaction;    backscattered electron imaging;    silica glass;    ASTM C1260;    microcracking;    microstructure;   

DOI  :  10.3390/ma8125450

来源: mdpi

【 摘 要 】

The microstructural development of mortar bars with silica glass aggregate undergoing alkali-silica reaction (ASR) under the conditions of American Society for Testing and Materials (ASTM) Standard Test C1260 was analyzed using scanning electron microscopy and qualitative X-ray microanalysis. Cracking in the aggregate, the hydrated paste, and the paste-aggregate interface was important in the development of the microstructure. Cracks were characterized according to their location, their relationship to other cracks, and whether they are filled with ASR gel. Expansion of the bars was approximately 1% at 12 days and 2% at 53 days. They fell apart by 63 days. The bars contained two zones, an inner region that was undergoing ASR and an outer and much more highly damaged zone that extended further inward over time. Evidence of ASR was present even during the period when specimens were immersed in water, prior to immersion in NaOH solution.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.