Influence of freeze-thaw cycles on properties of Integral Water Repellent Concrete

Abstract

Service life of reinforced concrete structures usually was designed on the basis of one selected deteriorating mechanism as for instance carbonation, chloride penetration, and frost action. It could be shown in the meantime by numerous authors, however, that combined actions such as chloride penetration under mechanical load or chloride penetration in combination with freeze-thaw cycles may shorten the service life of reinforced concrete structures more than individual processes acting alone. We have found that chloride penetration is accelerated significantly by freeze-thaw cycles. Frost damage not only reduces mechanical strength and elastic modulus but migration of chloride is facilitated in the damaged pore structure. Chloride penetration can be retarded by the addition of silane emulsion to the fresh concrete. In this way Integral Water Repellent Concrete (IWRC) can be produced. Migration of water and ions dissolved in water can not be prevented by integral water repellent treatment but it is slowed down. The combination of damage mechanisms and the protective measures by integral water repellent treatment have to be taken into consideration in realistic service life prediction and design.