Preparation method and application of biological calcium carbonate uniformly reinforced recycled aggregate

A bio-calcium carbonate and recycled aggregate technology, which is applied in the field of recycled aggregates for building materials, can solve the problems of uneven distribution of mineralized sedimentary calcium carbonate, weak bonding on the surface of recycled aggregates, and impact on the performance of recycled aggregates. Achieve the effect of sustainable development, uniform reinforcement of recycled aggregate, good promotion prospects and application value

Active Publication Date: 2022-07-22
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the problems of uneven distribution of calcium carbonate on the surface of recycled aggregates, insufficient density of some sedimentary layers, and weak bonding with the surface of recycled aggregates in the microbial-induced mineralization strengthening recycled aggregate technology, the impact The performance of microbial mineralization treatment of recycled aggregates is limited, which limits the application of this technology

Method used

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  • Preparation method and application of biological calcium carbonate uniformly reinforced recycled aggregate
  • Preparation method and application of biological calcium carbonate uniformly reinforced recycled aggregate
  • Preparation method and application of biological calcium carbonate uniformly reinforced recycled aggregate

Examples

Experimental program
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Effect test

Embodiment 1

[0039] (1) Pour the pre-mineralized treatment liquid into the container containing the regenerated aggregate, until the pre-treated mineralized treatment liquid completely soaks the regenerated aggregate, and then the container is placed at room temperature for 24 hours;

[0040] In this step, the concentrations of urea and calcium nitrate in the pre-mineralization treatment solution are both 1 mol / L.

[0041] (2) The regenerated aggregate is taken out from the mineralization treatment solution, naturally dried for 1 hour, transferred to the sodium alginate solution containing Bacillus pasteurii and stirred for 30 seconds, and the stirring speed is 60 rpm;

[0042] In this step, the sodium alginate solution containing Bacillus pasteuri is prepared by centrifuging and resuspending the cultured bacterial solution, adding it to the sodium alginate aqueous solution, mixing and stirring, and the bacterial concentration in the solution is 10 9 CFU / ml, the mass concentration of sodiu...

Embodiment 2

[0047] (1) Pour the pre-mineralized treatment liquid into the container containing the regenerated aggregate, until the pre-treated mineralized treatment liquid completely soaks the regenerated aggregate, and then the container is placed at room temperature for 24 hours;

[0048] In this step, the concentrations of urea and calcium nitrate in the pre-mineralization treatment solution are both 1.5 mol / L.

[0049] (2) the regenerated aggregate is taken out from the mineralization treatment solution, naturally dried for 1 hour, transferred to the sodium alginate solution containing bacillus pasteuri and stirred for 60 seconds, and the stirring speed is 60 rmp;

[0050] In this step, the sodium alginate solution containing Bacillus pasteuri is prepared by centrifuging and resuspending the cultured bacterial solution, adding it to the sodium alginate aqueous solution, mixing and stirring, and the bacterial concentration in the solution is 10 9 CFU / ml, the mass concentration of sodi...

Embodiment 3

[0055] (1) Pour the pre-mineralized treatment liquid into the container containing the regenerated aggregate, until the pre-treated mineralized treatment liquid completely soaks the regenerated aggregate, and then the container is placed at room temperature for 24 hours;

[0056] In this step, the concentrations of urea and calcium nitrate in the pre-mineralization treatment solution are both 1 mol / L.

[0057] (2) the regenerated aggregate is taken out from the mineralization treatment solution, naturally dried for 1 hour, transferred to the sodium alginate solution containing bacillus pasteuri and stirred for 90 seconds, and the stirring speed is 40 rmp;

[0058] In this step, the sodium alginate solution containing Bacillus pasteuri is prepared by centrifuging and resuspending the cultured bacterial solution, adding it to the sodium alginate aqueous solution, mixing and stirring, and the bacterial concentration in the solution is 10 9 CFU / ml, the mass concentration of sodium...

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Abstract

The invention provides a preparation method of a biological calcium carbonate uniformly reinforced recycled aggregate. The preparation method comprises the following steps: (1) pretreating the recycled aggregate; (2) uniformly fixing carbonate mineralizing bacteria on the whole surface of the recycled aggregate; (3) depositing biological calcium carbonate on the whole surface of the recycled aggregate; and (4) drying. A network structure formed after the thickening agent and calcium ions are chelated is used for effectively wrapping bacteria, carbonate mineralizing bacteria are uniformly fixed on the whole surface of the recycled aggregate, and biological calcium carbonate is formed by taking the mineralizing bacteria as nucleation sites, so that in-situ deposition of the biological calcium carbonate on the surface of the recycled aggregate is realized; the distribution uniformity of the biological calcium carbonate on the surface of the recycled aggregate is improved, and the water absorption rate and the crushing value of the recycled aggregate are further reduced, so that the utilization rate of the recycled aggregate in the concrete is improved, the sustainable development of the concrete is realized, and the large-scale application of the recycled aggregate in the concrete field is promoted.

Description

technical field [0001] The invention relates to the technical field of recycled aggregates for building materials, in particular to a preparation method and application of biological calcium carbonate uniformly reinforced recycled aggregates. Background technique [0002] Faced with the problems of construction waste polluting the environment and shortage of natural sand and gravel resources, construction waste can be crushed into recycled aggregates for secondary use, such as the preparation of recycled concrete. However, the old mortar layer on the surface of recycled aggregate contains many pores and micro-cracks, which leads to the shortcomings of high porosity, high water absorption and high pressure crushing value of recycled aggregate, and its performance is much lower than that of natural aggregate. [0003] At present, the environmentally friendly microbial-induced calcium carbonate technology has been applied to the research on the strengthening of recycled aggrega...

Claims

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Application Information

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IPC IPC(8): C04B20/10C04B18/16
CPCC04B20/107C04B18/16Y02W30/91
Inventor 王剑云张芮谢德智
Owner XI AN JIAOTONG UNIV
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