Modified self-healing cementitious materials based on epoxy and calcium nitrate microencapsulation.

AIM: This study was conducted to utilise the effective self-healing system to regain the mechanical properties of the cementitious materials containing micro-cracks.

METHODS

Storing epoxy and calcium nitrate as healing agents was performed by microencapsulation in the urea-formaldehyde shell. The microcapsules were characterised by Fourier transform infrared, thermogravimetric analysis, differential scanning calorimetric, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. Cementitious samples were prepared by mortar mixing with various amounts of microcapsules (0, 1, 3 and 6% w/w). The healing potential of microcapsules was analysed based on the recovery rate of the mechanical properties.

RESULTS

The obtained microcapsules have an outer rough surface, suitable diameter (1-100 μm) and shell thickness (0.2-0.6 µm), and remarkable thermal stability (up to 260 °C). Mechanical test results exhibit that created micro-cracks were healed completely and regained the recovery rates over 100%.

CONCLUSION

The prepared microcapsules besides enhancing thermal stability, demonstrate a high performance in microcracks sealing to improve durability of cementitious materials.