Use of Rhenish trass in marine concrete: A microscopic and durability perspective

[摘要] Use of Rhenish trass in (historic) lime mortars is well known. However, its application to concrete has not been investigated elaborately. In the past, trass was used as a pozzolanic addition to concrete for marine structures in the Netherlands. Recent investigations of several structures have shown that identification of trass in aged concretes by polarization-and-fluorescence microscopy isdifficult. In order to facilitate PFM studies, historic mixtures were recast. Two mixtures have been recast, viz. a mixture of 300 kg/m3 ordinary Portland cement (CEM I) and another mixture of 310 kg/m3 ground granulated blastfurnace slag cement (CEM III/B), both with an addition of 10% trass by cement mass. Concrete mixes were originally designed for a major lock, built in the 1920`s, and a quay constructed in Rotterdam harbour in the 1970`s, respectively. Difficulties of recognizing trass in aged concretes by PFM and apparent effects of trass on both microstructure of the concrete and durability arediscussed. Durability in a maritime environment has extensively been studied in the case of Rotterdam harbour. It is shown that addition of 10% of trass to CEM III/B has no effect on the durability of concrete.

[学科分类] 建筑学

[关键词] Marine concrete;trass;microscopy;resistivity;durability;field experience;ASR