Title: Physico-Chemical Studies of Cement Pastes, Mortars, and Concretes Exposed to Sea Water

Author(s): M. Regourd

Publication: Symposium Paper

Volume: 65

Issue:

Appears on pages(s): 63-82

Keywords: blast furnace slag; cement pastes; concrete durability; C3A; electron microscopy; marine atmospheres; mortars (material); pernieability; pozzolan cements; sea water.

DOI: 10.14359/6346

Date: 8/1/1980

Abstract:
In a marine environment the durability of permeable concrete is a function of the chemical resistance of the hydrated cement paste to sea water. Portland cements with various amounts of C3A, blast-furnace slag cements, and pozzolan cements were investigated. The test specimens were stored both in laboratory and natural sea water conditions. The sequence of chemical reactions between the hydrated components and the aggressive ions dissolved in sea water was followed by scanning electron microscopy, electron probe microanalysis and X-ray diffraction. It is concluded that as a result of diffusion of C1- and SO42- ions, degradation of Ca(OH)2 and C-S-H occurs due to the substitution of Mg2+ for Ca2+ and formation of secondary products such as CaS04.2H20, C3A.CaC12.10H20, C3A.3CaS04.32H20, and CaSiO3.CaS04.CaC03.15H20.