Abstract
In this research, self-healing due to further hydration of unhydrated cement particles is taken as an example for investigating the effects of capsules on the self-healing efficiency and mechanical properties of cementitious materials. The efficiency of supply of water by using capsules as a function of capsule dosages and sizes was determined numerically. By knowing the amount of water supplied via capsules, the efficiency of self-healing due to further hydration of unhydrated cement was quantified. In addition, the impact of capsules on mechanical properties was investigated numerically. The amount of released water increases with the dosage of capsules at different slops as the size of capsules varies. Concerning the best efficiency of self-healing, the optimizing size of capsules is 6.5 mm for capsule dosages of 3%, 5%, and 7%, respectively. Both elastic modulus and tensile strength of cementitious materials decrease with the increase of capsule. The decreasing tendency of tensile strength is larger than that of elastic modulus. However, it was found that the increase of positive effect (the capacity of inducing self-healing) of capsules is larger than that of negative effects (decreasing mechanical properties) when the dosage of capsules increases.
Highlights
Cracking, caused by shrinkage and external loadings, is inherent in reinforced concrete structures
It has been reported that the availability of water is essential for autogenous self-healing and selfhealing based on mineral admixtures and bacteria [9, 10]
By knowing the amount of water supplied via capsules, the efficiency of self-healing due to further hydration of unhydrated cement can be quantified by modeling
Summary
Cracking, caused by shrinkage and external loadings, is inherent in reinforced concrete structures. Capsules storing various adhesive agents are being manufactured in laboratory for self-healing of cracks in cementitious materials [11,12,13]. Bacteria are applied as selfhealing agent in concrete structures [17, 20,21,22,23,24] Even without these aforementioned healing agents, cementitious materials have the ability of self-healing, that is, autogenous selfhealing [7, 25,26,27,28]. It has been reported that the availability of water is essential for autogenous self-healing and selfhealing based on mineral admixtures and bacteria [9, 10]. The impacts of capsules on mechanical properties of cementitious materials as a function of capsule dosages are still unclear either
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