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[:]

[:ru]Нг С.[:en]Ng, S.[:] [:ru]доктор, кафедра бетона, Институт строительства и инфраструктуры SINTEF, Трондхейм, Норвегия[:en]Dr., Department of Concrete, SINTEF Building and Infrastructure, Trondheim, Norway[:]

Alitinform №1 (33) 2014 г. 48-57 p.

Abstract

Chemical admixtures are already widely used in concrete technology, but “future challenges” are twofold: 1) to solve remaining problems; 2) to adapt to the forthcoming changes in concrete technology. The major change in concrete technology is to further decrease the clinker content in blended cements or the cement content in concrete mixes, maybe all the way to cement-free binders like geopolymers. Evidently this will require more effective hardening accelerators to counteract inherent lower early strength if productivity should be maintained with early formwork removal. Another aspect is faster carbonation rates for concrete with less cement and how this can be dealt with using admixtures.
Chemical admixtures for concrete are divided into three major categories in this paper: rheology regulators (e. g. plasticizers, viscosifiers), hydration regulators (i. e. accelerators and retarders) and durability improvers (e. g. air entraining agents, corrosion inhibitors). Each category is treated separately and commented in detail. Chemical admixtures are chemicals usually dosed below 5 % of cement mass, and mineral additives (usually dosed above 5 %) are not included.

Key words:

accelerators; admixtures; durability; rheology; retarders; sustainability