Preparation and Mechanical Properties of Microcapsule-Based Self-Healing Cementitious Composites

Abstract

Self-healing concrete designs can protect against deterioration and improve durability. However, there is no unified conclusion regarding the effective preparation and mechanical properties of self-healing concrete. In this paper, microcapsules are used in cement-based materials, the reasonable dosage of microcapsules is determined, and the self-healing performance of the microcapsule self-healing system under different curing agents is explored. The microcapsules and curing agent are shown to enhance the flexural and compressive strength of mortar specimens at relatively low contents. The optimal microcapsule content in terms of compressive strength is 1–3%. When the content of the microcapsule reaches 7%, the strength of the specimen decreases by approximately 30%. Sodium fluorosilicate is better-suited to the microcapsule self-healing cement-based system than the other two fluorosilicates, potassium fluorosilicate and magnesium, which have similarly poor healing performance as curing agents. Healing time also appears to significantly influence the microcapsule self-healing system; mortar specimens that healed for 28 days are significantly higher than those that healed for 7 days. This work may provide a valuable reference for the design and preparation of self-healing cementitious composite structures.

Compressive properties of self-healing microcapsule-based cementitious composites subjected to freeze-thaw cycles using acoustic emission

“…Microcapsule content refers to the percentage of microcapsule dosage and cement dosage, which are 0%, 1%, 3%, 5%, and 7% respectively in this paper. According to the previous study (Jiang et al, 2021;Wang et al, 2022c), the proportion of sodium fluosilicate is 15% of microcapsules. Since fluosilicate is insoluble in water, sodium fluosilicate is mixed with cement first, and then put into a cement mortar mixer for mixing.…”

“…In the third selection, we eliminated the microcapsules with obvious defects and tried to ensure the consistency of quality and size. For details of the specific preparation process and relevant raw materials, the previously published papers (Jiang et al, 2021;Wang et al, 2022c) can be referred to.…”

“…After mixing for 1 minute, they are loaded into the mold, vibrated, and cured. The specific preparation process can refer to (Jiang et al, 2021;Wang et al, 2022c). After the prepared samples were cured to a certain age under standard conditions, the changes of strength loss, mass loss, and electric flux of cement-based composites before and after different freeze-thaw cycles were compared to characterize the frost resistance of cement-based composites and the influence of microcapsules on the frost resistance.…”

Mechanical characterization of soft microparticles prepared by droplet microfluidics

“…Therefore, finding the optimal mechanical properties of the embedded microcapsules is important to ensure the excellent self‐healing performance of the polymer composites. Various experimental studies have considered the effect of size, 102 concentration, 103 and fill content 104 of the microcapsules. Moreover, parametric studies on the optimal combination of microcapsules and polymer matrix have also been investigated through numerical techniques.…”

Microwave-magnetic field dual-response raspberry-like microspheres for targeted and repeated self-healing from electrical damage of insulating composites

“…[20][21][22][23] In addition, the healing agent contained in the microcapsules is released passively after the rupture of the shell triggered by the external stimulation, which causes problems such as failed shell cracking, delayed release, and low healing rates. [24][25][26][27][28][29] Finally, the microcapsule shell, which serves as a container, dramatically deteriorates the insulating characteristics of the matrix. 30 In particular, when the healing agent flows out of the shell, the residual shell introduces new defects into the matrix, 14 which causes fresh electric-tree damage.…”