- Author
- Bentz, D. P. | Irassar, E. F. | Bucher, B. E. | Weiss, W. J.
- Title
- Limestone Fillers Conserve Cement. Part 2. Durability Issues and the Effects of Limestone Fineness on Mixtures.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD Universidad Nacional del Centro de la Provincia de Buenos Aires, Olavarria, Argentia Purdue Univ., West Lafayette, IN
- Journal
- Concrete International, Vol. 31, No. 12, 35-39, December 2009
- Keywords
- limestone | cements | durability | water | particle size | deformation | compressive strength | mortar | powders | equations | ions | diffusion
- Identifiers
- autogeneous deformation; compressive strength results for mortar cubes; transport mechanisms and durability
- Abstract
- Part 1 of this article used Powers' model to demonstrate the viability of increased limestone filler replacement levels in lower water-cementitious material ratio (w/cm) concretes. Commonly cited potential negative impacts of increased limestone replacement levels typically center on two durability issues: increased susceptibility to carbonation and the potential for thaumasite formation. One might conjecture that both of these would be dramatically reduced in the denser, lower water-cement ratio (w/c) concretes where increased limestone replacement levels may be most applicable. For the case of thaumasite formation, a recent review article highlights that damage is indeed controlled when a low effective w/c is employed. The topic of limestone fineness is also addressed by contrasting the performance of limestone substitutions of different median particle sizes. The topic of fineness becomes paramount when one considers differences between interground limestone and limestone that's added after the cement is ground. In the former case, the interground limestone powder will likely be finer than the interground cement clinker due to it being the softer of the two materials, while in the latter case, the limestone powder can be finer, as fine as, or coarser than the base cement, depending on the selection of the limestone powder itself.