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| 微生物改性再生骨料混凝土力学性能与本构模型 |
| Mechanical properties of microbially modified recycled aggregate concrete and establishment of constitutive model |
| 投稿时间：2023-11-23 修订日期：2024-01-15 |
| DOI： |
| 中文关键词: 矿化沉积 再生骨料 取代率 再生混凝土 力学性能 本构模型 |
| 英文关键词:Mineralized sedimentation, Recycled Aggregates, Replacement rate, Mechanical characteristics, Constitutive model |
| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| 中文摘要: |
| 再生骨料替代天然骨料可循环回收废弃混凝土，节省能源损耗，推动建筑行业可持续发展。但再生骨料自身缺陷会降低混凝土性能，基于嗜碱好氧型科氏芽孢杆菌矿化沉积特性，二次强化改性再生骨料，探究菌液浓度对再生骨料基本力学性能的影响；对不同取代率再生混凝土力学性能进行研究，并建立改性再生混凝土单轴受压本构模型。试验结果显示，微生物诱导碳酸盐沉淀技术有效地降低了再生骨料吸水率和压碎指标，提升其表观密度，且改性效果最优的菌液浓度为1.265×108cells/ml；基于此浓度，再生骨料吸水率可由改性前的4%降至2.4%，压碎指标可由13.0%降至10.8%；当取代率低于40%时，再生混凝土抗压强度变化不大；当取代率为100%时，与普通混凝土抗压强度相比下降7.73%；仅全替代再生混凝土劈拉强度不及普通混凝土，N60-R40组再生混凝土劈拉强度相比普通混凝土提升15%；除N60-R40组外，其他再生混凝土抗折强度均低于普通混凝土。综合考虑再生混凝土的力学性能及经济适用性，以40%作为再生骨料优选取代率，研究结果可供再生混凝土的发展应用参考。 |
| 英文摘要: |
| By substituting recycled aggregates (RA) for natural aggregates (NA), it is possible to reuse leftover concrete, consume less energy, and advance the sustainable development of building materials. This paper is based on the mineralization deposition characteristics of alkaliphilic aerobic Bacillus Cohnii, modified RA, to investigate the impact of various bacterial liquid concentrations on the physical and mechanical characteristics of RA, such as water absorption, apparent density and crushing indicators. However, the defects of RA itself will degrade the mechanical characteristics of concrete; Modeling the uniaxial compression configuration of modified recycled aggregate concrete (RAC) and examine the mechanical characteristics of modified RAC under various replacement rates. The test results demonstrate the effectiveness of microbial mineralization deposition technology in enhancing the apparent density and packing density of RA, decreasing absorbency, and lowering the crushing index. The optimal bacterial liquid concentration for the modification effect is 1.265×108cells/ml; At this concentration, the crushing index may be decreased from 13.0% to 10.8% and the absorbency of RA can be decreased from 4% to 2.4% before modification; When the substitution rate of RA obtained by less than 40%, the compressive strength of recycled concrete does not vary significantly; The compressive strength of normal aggregate concrete (NAC) crease of 7.73% when the substitution rate was 100%; The split tensile strength of RAC is greater than that of NAC, and the split tensile strength of RAC with a replacement rate of 40% is 15% greater than that of NAC. This is in addition to the RA replacement rate of 100%; Except when the replacement ratio of RA is 40%, RAC has a lower flexural strength than NAC. The results can be used as a guide for the development and usage of recycled concrete since they take into account the mechanical characteristics and economic applicability of recycled concrete. 40% is chosen as the ideal substitution rate of RA. |
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