Title:
Is Microcracking Really a Precursor to Delayed Ettringite Formation and Consequent Expansion?
Author(s):
Nikola Petrov and Arezki Tagnit-Hamou
Publication:
Materials Journal
Volume:
101
Issue:
6
Appears on pages(s):
442-447
Keywords:
concrete; durability; entrained air; ettringite; expansion; microcracks; mortar; steam curing; sulfate attack
DOI:
10.14359/13482
Date:
11/1/2004
Abstract:
Several holistic approaches for predicting the risk of expansion caused by delayed ettringite formation postulate that microcracking is the necessary precondition for this expansion. Other research results, however, showed clear differences of expansion behavior depending on the causes of microcracks. By studying the expansion of 40 and 36 heat-cured mortar and concrete mixtures, respectively, the authors have shown in this paper that microcracking caused by thermal shock does not promote expansion. On the contrary, this type of microcracking decreases the ultimate value of expansion, though it can accelerate it because microcracks facilitate the availability of water.