Evaluation of concrete self-healing by encapsulated sodium metasilicate in perlite and expanded clay

Investigating the behavior of self-healing cementitious composites is necessary to know alternatives that can be applied in structures increasing their life service. Therefore, this study evaluated concrete self-he aling from the use of expanded perlite (EP) and expanded clay (EC) capsules impregnated with a sodium metasilicate solution. These materials were used to substitute natural aggregates in concrete in proportions of 0 wt·%, 15 wt·% and 30 wt·% which were cured in humid or submerged environments. Cracking was induced with a flexural test and a closing with cicatrization product. was evaluated and measured visually with a software. Capillary absorption tests indicated a reduction in the porosity of samples which incorporated self-healing materials, considering it as an important property related to durability. Samples with EP achieved 100% self-healing with 15% substitution. Crack filling was achieved in cracks up to 0.43 mm wide. Samples with EC achieved 50% crack recovery under humid curing and 90% under submerged curing. It was concluded that incorporating the sodium silicate allowed improvements to fissure sealing and it is an alternative to produce self-healing concrete in Brazil. EP was more effective than EC as encapsulating material. Despite that, the EP did not impact the compressive strength due to its small size and better packing of the mixture, Also, EP presented higher healing percentage when comparing with samples containing EC. resumo: Investigar o comportamento de compósitos cimentícios autocicatrizantes é necessário para conhecer alternativas que possam ser aplicadas em estruturas aumentando a sua vida útil. Portanto, este estudo avaliou a cicatrização do concreto a partir do uso de cápsulas de perlita expandida (PE) e argila expandida (AE) impregnadas com solução de metassilicato de sódio. Esses materiais foram utilizados em substituição aos agregados naturais no concreto nas proporções de 0%, 15% e 30% em relação à massa. Os exemplares foram curados em ambientes úmidos ou submersos. A fissura foi induzida pelo teste de flexão e a cicatrização foi avaliada visualmente e medida por meio de software. Testes de absorção capilar indicaram redução da porosidade das amostras que incorporaram materiais autocurantes, sendo esta uma importante propriedade relacionada à durabilidade do conjunto. As amostras com PE alcançaram 100% de cicatrização com 15% de substituição. O preenchimento da fissura foi obtido em fissuras de até 0,43 mm de lar