Microbial composite admixture for self-healing cracking of cement-based materials and its application

Abstract

The invention relates to a microbial composite additive used for cement-based material cracking self-repairing. The microbial composite additive is obtained via mixing of a bacteria liquid, a repairing nutritional component, and an auxiliary ingredient; wherein the bacteria liquid is obtained by inoculating basic culture medium with target bacteria strain Bacillus cohnii via a conventional method for culturing, and then collecting bacteria strain wet cells, the final concentration of the bacteria liquid is controlled to be 20000000 to 40000000 cell / ml; the repairing nutritional component comprises calcium glutamate and yeast extract; and the auxiliary ingredient comprises silica powder and an air entraining agent. Compared with the prior art, the microbial composite additive can be dispersed in cement matrix preferably, in-time and effective repairing of cracks at any parts is ensured, a large amount of maintenance money is saved, a generated repairing medium is natural calcium carbonate, durability and size stability are high, compatibility with cement is high, and environmental friendliness is excellent. At the same time normal hydration of cement is not influenced, so that integral performance of structures is not influenced.

Description

technical field [0001] The invention relates to a cement-based material self-repair additive, in particular to a microbial composite admixture for cement-based material crack self-repair and application thereof. Background technique [0002] If the microscopic cracks generated due to the inherent physical and mechanical properties of cement-based materials are not repaired in time, it is likely to induce macroscopic cracking of the concrete, resulting in a decrease in the bearing capacity and durability of the structure, and it is more likely that malignant expansion will occur and cause major safety hazards. Accidents and casualties. The traditional solution lies in overhauling and maintaining the concrete structure. However, the continuous maintenance of some large infrastructure structures is not only difficult, but also consumes a lot of manpower and money. Therefore, people began to pay attention to self-healing technology for cement-based materials. [0003] The exi...

AI Technical Summary

Problems solved by technology

Although these methods can achieve self-healing of cracks to a certain extent, they all have unavoidable defects: the amount of mineral self-healing method is limited, and the repair efficiency is low; pre-embedded microcapsules or hollow fibers will cause concrete molding difficult, and most of the adhesives contained are polymer materials, which are likely to cause environmental problems; the embedded shape memory alloy can only achieve the "line" repair of the matrix and cannot achieve "point" repair, and the shape memory alloy material often not economical

In this patent, Bacillus halodurans bacteria are used, and slag or ceramsite is used as the carrier for protection. The process is relatively complicated. Calcium lactate is used as the precursor calcium source, which has a certain impact on the repair efficiency, resulting in a low repair efficiency, which can only be achieved after 40 days. achieve fix

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