Microbially induced calcium carbonate precipitation (MICP) presents a sustainable, environmentally friendly solution for repairing cracks in cement-based materials, such as mortar and concrete. This self-healing approach mechanism enables the matrix to autonomously close its own cracks over time. In this study, specimens (50 mm in diameter and 25 mm in height) were exposed to submersion and a wet–dry cycle environment. The solution considered a nutrient-rich suspension with calcium lactate, urea, calcium nitrate, and Bacillus subtilis or Sporosarcina pasteurii in a biomineralization approach. The self-healing efficiency was assessed through optical microscopy combined with image processing, focusing on the analysis of the superficial crack closure area. S. and B. subtilis exhibited notable capabilities in effectively healing cracks, respectively, 8 mm² and 5 mm² at 35 days. Healing was particularly effective in samples placed in a submerged environment, especially with a 69 mM concentration of calcium lactate in bacterial suspensions containing B. subtilis, where 87.5% of a 4 mm² crack was closed within 21 days. In contrast, free calcium ions in the solution, resulting from anhydrous cement hydration, proved ineffective for S. pasteurii biomineralization in urea-rich environments. However, the addition of an external calcium source (calcium nitrate) significantly enhanced crack closure, emphasizing the critical role of calcium availability in optimizing MICP for bio-agents in cement-based materials. These findings highlight the potential of MICP to advance sustainable self-healing concrete technologies.

Several factors, such as chemical shrinkage or environmental attack can produce concrete cracks. Calcium hydroxide content from the environment or cement hydration can promote the self-healing phenomenon (SHP). This study evaluates the calcium hydroxide concentration influence on the self-healing phenomenon of cement-based materials. Cracked mortars with different types of cement, such as a filler, pozzolanic, and high initial strength, were exposed to four environmental conditions. Titration was the method proposed to determine the amount of calcium hydroxide content leached in the water, and the cracks closure were analyzed by optical microscopy. CPII F (Portland Cement, type II, compound with limestone) samples showed no trend to Ca(OH)2 leached, and to superficial cracking closure. Regarding CPV (Portland cement, type V, high initial strength cement) samples, their behavior showed the highest Ca(OH)2 content to all environmental exposure, and cracking closure to samples in submerged condition. Thus, a significant influence in the cracks´ closure regarding the presence of Ca2+ leached to the exposure environments, and a water source related to this behavior seems to be a primary factor to improve the SHP.

Resumo Anecessidade de inovar está diretamente relacionada ao crescimento econômico e à competitividade. Algumas barreiras são observadas no processo de implantação da inovação na construção civil, a exemplo da falta de entendimento dos benefícios da inovação no setor. Diante da importância dos agentes envolvidos na construção como facilitadores do processo de inovação, é necessário identificar suas percepções acerca do tema. No presente estudo é proposta uma ferramenta que objetiva captar a percepção da inovação pelos agentes internos da construção civil e que permite a comunicação do diagnóstico da inovação em uma empresa. A ferramenta desenvolvida está dividida em três etapas: (i) desenvolvimento da estrutura através da revisão teórica; (ii) aplicações em estudo de caso e no meio acadêmico, gerando ajustes ao questionário e ao infográfico; e (iii) desenvolvimento da versão final da ferramenta e de sugestões de ações por cada categoria). A proposta da ferramenta mostrou-se eficiente para o diagnóstico acerca da percepção dos agentes da inovação, além de trazer resultados práticos no embasamento para tomada de decisão nas empresas.