Calcium hydroxide influence in autogenous self-healing of cement-based materials in various environmental conditions

Silva, Deividi Maurente Gomes da; Cappellesso, Vanessa Giaretton; Garcia, Maurício Germano Lopes; Masuero, Ângela Borges; Molin, Denise Carpena Coitinho Dal

doi:10.1590/s1678-86212021000200522

Cited by 5 publications

(2 citation statements)

References 45 publications

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“…Additionally, the concentration of calcium ions in the matrix and its surroundings significantly influences the volume of products and the speed of the self-healing phenomenon. Calcium ions are derived from the silicates hydration reactions, and their amount depends on the type of cement [9,10]. The crack's thickness also deserves special attention.…”

Section: Self-healing Phenomena In Cement-based Materialsmentioning

confidence: 99%

A self-healing approach to cement-based materials with crystalline admixtures in normal and accelerated environmental conditions

et al. 2023

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Cracks in cement-based materials can be a source of significant problems in civil works, especially those exposed to the action of harmful agents and moisture. Its occurrence may be associated with various physical, chemical, or mechanical factors. Self-healing phenomenon can promote cracks repair, contributing to a useful life increase through the sealing by cracking closure. This work aimed to evaluate the self-healing phenomenon in cementitious matrices with different crystalline admixtures. Mortars were produced using high initial strength cement, quartz sand, three types of crystalline additives, and 0.4 as w/c ratio. Compressive strength tests were performed at 3 days (crack opening age), 28 days, and 45 days. The environmental conditions were wet/dry cycles in controlled and accelerated climate chambers. Ultrasonic pulse and optical microscopy with image editing techniques were used to evaluate the self-healing phenomenon. The results indicate that the samples in accelerated chamber (CAR) presented the highest mechanical strength at 45 days, and the most significant crack closure to samples with Z crystalline admixture. The ultrasonic wave propagation speed analysis showed that crystalline admixtures-based samples (X, Y and Z) had the highest matrix densification. Additionally, special attention should be given to the samples preparing steps and images editing to identify the healed area for the techniques being used.

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Section: Self-healing Phenomena In Cement-based Materialsmentioning

confidence: 99%

A self-healing approach to cement-based materials with crystalline admixtures in normal and accelerated environmental conditions

et al. 2023

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“…Calcium carbonate precipitation could be increased from the reaction of carbon dioxide produced from bacterial respiration with the calcium hydroxide (CH) in the cementitious matrix to form calcium carbonate crystals ( 11 – 13 ). CH produced from cement hydration promotes the self-healing of cement-based materials ( 14 ).…”

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confidence: 99%

Optimization of the Self-Healing Efficiency of Bacterial Concrete Using Impregnation of Three Different Precursors into Lightweight Aggregate

Omar

Mousa

Hassan

et al. 2022

Transportation Research Record: Journal of the Transportation R

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Implementation of self-healing concrete technologies is a promising approach to enhance the durability of the transportation infrastructure. Among these technologies, bacterial concrete has the potential to seal microcracks through microbial-induced calcite precipitation (MICP). To ensure the viability of this technology, bacterial protection is essential given concrete’s harsh environment. Additionally, the success of this technology depends on the presence of an adequate mineral precursor compound and nutrient for the bacteria. As such, the main objective of this study was to optimize the healing efficiency of bacterial concrete in subtropical climates through the vacuum impregnation of bacteria into a lightweight aggregate (LWA). To achieve this objective, mortar samples were prepared while incorporating different combinations of precursors (magnesium acetate, calcium lactate, and sodium lactate) and alkali-resistant healing agent Bacillus pseudofirmus bacteria (with and without). In addition, a control sample was prepared without bacteria or precursors for comparative purposes. For each sample, three mortar cubes and three mortar beams were cast and used to evaluate the compressive strength, crack healing efficiency, and flexural strength recovery. Additionally, the morphology of healing products was observed in bacteria-containing samples under scanning electron microscopy with energy x-ray dispersive spectroscopy using a scanning electron microscope (SEM) with EDAX Pegasus energy dispersive spectroscopy (EDS). Results showed that self-healing bacterial concrete could be optimized (without significant reduction in mechanical properties) if Bacillus pseudofirmus bacteria at a concentration of 108 cells/ml and sodium lactate precursor at a concentration of 75 mM/l were impregnated into lightweight aggregate.

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Modification of recycled aggregate and conservation and application of recycled aggregate concrete: A review

Wu,

Sun,

Cao

2024

Construction and Building Materials

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Calcium hydroxide influence in autogenous self-healing of cement-based materials in various environmental conditions

Cited by 5 publications

References 45 publications

A self-healing approach to cement-based materials with crystalline admixtures in normal and accelerated environmental conditions

A self-healing approach to cement-based materials with crystalline admixtures in normal and accelerated environmental conditions

Optimization of the Self-Healing Efficiency of Bacterial Concrete Using Impregnation of Three Different Precursors into Lightweight Aggregate

Modification of recycled aggregate and conservation and application of recycled aggregate concrete: A review

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