Transportation Research Record: Journal of the Transportation Research Board, October 2009, in press
  Performance of carbon nanofibers/cementitious composites with a high-range water-reducer
  Gay, C; Sanchez, F
  The effect of a polycarboxylate-based high-range water-reducer (HRWR) on the incorporation of carbon nanofibers (CNFs) in cement composites was evaluated. The use of the HRWR proved successful in disaggregating the CNFs in solution and did improve the dispersion of CNFs in the cement paste at the individual fiber level. However, an inhomogeneous distribution of the fibers within the composites was observed. Addition of 0.2% CNFs per weight of cement resulted in an increase in the splitting tensile strength of 22% in Portland cement composites and 26% in composites that additionally contained silica fume. Migration of the CNFs in the bleed water was observed depending upon the water-to-binder (w/b) ratio used, creating a porous layer of agglomerated CNFs intermixed with cement paste at the upper surface of the composite.