Title: Calcium Hydroxide Formation in Thin Cement Paste Exposed to Air

Author(s): Liv M. Haselbach and Lu Liu

Publication: Materials Journal

Volume: 107

Issue: 4

Appears on pages(s): 365-371

Keywords: calcium hydroxide content; pervious concrete; sustainability

DOI: 10.14359/51663862

Date: 7/1/2010

Abstract:
In recent years, novel concrete mixtures have been adopted to address many environmental concerns. One of these is pervious concrete, which is being used to manage stormwater runoff. With large internal surface areas exposed to air, the reactions within pervious concrete may be different from those in traditional concretes. This paper focuses on how hydration in cement pastes varies for thin samples with increased exposure to air. The traditional formation of calcium hydroxide might be altered by competition for the calcium oxide site by carbon dioxide and the lower levels of water within the paste. Thermal programmed desorption (TPD) was used to analyze cement samples under various environmental conditions. It was found that there was a substantial decrease in the formation of calcium hydroxide in the thin samples with high exposure to air as compared to similar samples with restricted exposure.