Durability of H-class cement and blast furnace slag-based cementitious composites

The usage of residual slag generated in the steel making process has been highlighted both as an ecological and/or economical alternative for the production of innovative cement and/or special cement composites. However, the effect of granulated blast furnace slag (GBFS) on the durability of cement still requires experimental research. This paper discusses the durability of H-class cement considered suitable for cementing oil wells, which was mixed with blast furnace slag and activated with NaOH alkali. This research has been conducting in accordance to the methods established under Mexican standards for assessing the technical suitability in developing an alternative cementitious product. The characterization of the products thus obtained was carried out through chemical analyses, compressive resistance and sulfate attack testing. The microstructure of obtained composites was also analyzed by scanning electron microscopy. Results show a limited durability of the cementitious composites, revealing a decrease in their mechanical resistance to compression as the percentage of slag increases, as well as a poor performance when exposed to sulfates media. As the slag percentage in H-class cement was increased a certain reduction on the expansion level of the composite was observed.