CONCRETE

[:ru]Юстнес Х.[:en]Justnes, H.[:] [:ru]профессор, главный научный сотрудник, кафедра бетона, Институт строительства и инфраструктуры SINTEF, Трондхейм, Норвегия[:en]Prof., Chief Scientist, Department of Concrete, SINTEF Building and Infrastructure, Trondheim, Norway[:]

Alitinform №4-5 (16) 2010 г. 38-45 p.

Abstract

Industrial quality calcium nitrate can be utilized as concrete admixture in many ways. Examples are given for applications as 1) Set accelerator, 2) Counteraction of retardation by plasticizers while maintaining rheology, 3) Long term strength enhancer, 4) Anti-freeze admixture or winter concreting admixture and 5) Inhibitor against chloride induced corrosion of steel.

The first two points may be achieved by small dosages (in the range 0.2-1% dry admixture by mass of cement), point 3 and 4 at moderate dosages (1-3%), while the last point require dosages in the higher end (3-4%).

Calcium nitrate as a set accelerator, and side effects of that, is well proven in practice over many years, while the corrosion inhibitor effect was only discovered in the later years. Unlike more well known inhibitors like calcium nitrite, calcium nitrate is harmless for the environment and more cost-effective.

Key words:

Calcium Nitrate, Accelerator, Winter Concreting, Corrosion Inhibitor