Preparation of microcapsule and its influence on self-healing property of asphalt

A kind of microcapsule was prepared, and a new type of self-healing asphalt was manufactured by mixing asphalt, microcapsule and curing agent with proper ratio. The ductility(15 degrees C and 10 degrees C), softening point and penetration of asphalt were tested both before and after adding microcapsule and curing agent into the asphalt. The results showed that the three indexes were kept in normal ranges after adding microcapsule and curing agent. However, the ductility(10 degrees C) was lower than the technical standard when the additive amount of microcapsule was 5.0wt%. Whereafter, the influence of additive amount, self-healing temperature and time on the asphalt self-healing property were all investigated by ductility self-healing tests (10 degrees C). The outcome indicated that the addition of microcapsule into the asphalt promote its self-healing properties obviously. The self-healing rate of blank asphalt in 20 degrees C and for 3 h was 20%, and when the microcapsule additive amount was 3.0wt%, the rate was improved to 40.0%. The highest self-healing rate was 52.0%. The elevation of temperature and extension of time were both beneficial for the promotion of the self-healing properties of asphalt. However, when healing temperature and healing time were improved to 30 degrees C and 7 h, the improvement of self-healing rate was not obvious.