Sealing of cracks in cement using microencapsulated sodium silicate
By P. Giannaros, A. Kanellopoulos, Abir Al-Tabbaa. 2016
167 citations recorded by the source corpus.
Cement-based materials possess an inherent autogenous self-healing capability allowing them to seal, and potentially heal, microcracks. This can be improved through the addition of microencapsulated healing agents for autonomic self-healing. The fundamental principle of this self-healing mechanism is that when cracks propagate in the cementitious matrix, they rupture the dispersed capsules and their content (cargo material) is released into the crack volume. Various healing agents have been explored in the literature for their efficacy to recover mechanical and durability properties in cementitious materials. In these materials, the healing agents are most commonly encapsulated in macrocontainers (e.g. glass tubes or capsules) and placed into the material. In this work, microencapsulated sodium silicate in both liquid and solid form was added to cement specimens. Sodium silicate reacts with the calcium hydroxide in hydrated cement paste to form calcium-silicate-hydrate gel that fills cracks. The effect of microcapsule addition on rheological and mechanical properties of cement is reported. It is observed that the microcapsule addition inhibits compressive strength development in cement and this is observed through a plateau in strength between 28 and 56 days. The improvement in crack-sealing for microcapsule-containing specimens is quantified through sorptivity measurements over a 28 day healing period. After just seven days, the addition of 4% microcapsules resulted in a reduction in sorptivity of up to 45% when compared to specimens without any microcapsule addition. A qualitative description of the reaction between the cargo material and the cementitious matrix is also provided using x-ray diffraction analysis.
Subfields: Environmental Engineering, Organic Chemistry, Polymers and Plastics
View Paper: https://www.semanticscholar.org/paper/757d70155ad1e32ea3db5329dcba86a4b90c1562
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Citations in the corpus
- The effect of varying volume fraction of microcapsules on fresh, mechanical and self-healing properties of mortars (2016, result): “This has also been found to be the case for lower volume fraction of the same type, but larger, microcapsules [46].”
- Alkali-Activated Materials and Geopolymer: a Review of Common Precursors and Activators Addressing Circular Economy (2021, background): “Table 7 Different concentration of potassium hydroxide with its prospective Si/Al, K/Al, and K/Si ratios (data from [149])”