Characterisation and simulation of highly dispersed carbon nanofibre-reinforced cement materials

In this work, carbon nanofibres (CNFs) were incorporated into ordinary Portland cement matrices. The mechanical behaviour of these composites and the effect of CNFs on cement hydration and microstructure of cement paste were compared with a plain cement sample by means of mercury intrusion porosimetry, X-ray diffraction, thermal analysis and scanning electron microscopy. The random distribution of CNFs in cement matrices was simulated by three-dimensional Monte Carlo method. The results showed that the added 0·1 wt% CNFs increased the maximum flexural, compressive strength, toughness and impermeability performance of blended cement compared with the samples. The incorporation of CNFs into cement paste accelerated the rate of the hydration reaction and increased the amount of hydration products. The use of CNFs also improved pore parameters, and the pore size distribution of these composites shifted towards smaller pore size scope. In addition, scanning electron micrographs showed that good interaction between CNFs and the cement matrix occurs, with CNFs acting as fillers, resulting in a denser microstructure.