Effects of nitinol on the ductile performance of ultra high ductility fibre reinforced cementitious composite

The effects of nitinol on the ductile performance of fibre reinforced cementitious composites were investigated in this study. Nitinol fibres with two different diameters of 1 mm and 0.5 mm and nitinol powder of diameter 70 nm were used as micro-reinforcement and reactive powders respectively. The test results showed that nitinol powder accelerates the hydration of cement and promotes the nucleation of TiO2 onto C-S-H leading to increased flexural and compressive strength. The nitinol fibre cementitious composite achieved ductilities of 7.3 % and 7.8 % with 1 mm and 0.5 mm nitinol fibres respectively at 28 days of curing. However, the nitinol fibres reinforced cementitious composites were unable to sustain ductilities after 90-days of curing losing nearly half of their ductile potency. On the other hand, nitinol powder achieved ductilities of 2.8 % and 5.6 % at 28 and 90 days of curing, respectively. Nitinol powder showed a potential as a ductile cementitious composite without the use of fibres.

Automated summary

Nitinol fibres and nitinol powder exhibit different effects in cementitious composites, with the powder accelerating cement hydration and promoting strength, while the fibres increase flexural and compressive strength. However, nitinol fibre-reinforced composites lose ductility significantly after 90 days, while nitinol powder shows good long-term ductility performance.