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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

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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.为改善再生骨料自身缺陷,提升再生混凝土性能,本文利用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,开展菌液浓度对再生骨料基本力学性能的影响试验;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.试验结果表明,微生物诱导碳酸盐沉淀技术能有效降低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,与普通混凝土相比,其抗压强度下降了 7.73%;仅再生骨料取代率为100%时,再生混凝土劈拉强度不及普通混凝土,当再生骨料取代率为40%时,再生混凝土劈拉强度相比于普通混凝土提升15%;除再生骨料取代率为40%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,本文以再生骨料取代率40%为最佳骨料取代率.本文研究成果可为再生混凝土在实际工程中的应用提供参考.
Mechanical properties of microbially modified recycled aggregate concrete and establishment of a constitutive model
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.In order to improve the defects of recycled aggregate and improve the performance of recycled concrete,the mineralization and deposition characteristics of basophilic aerobic Bacillus Coriolis were used to strengthen and modify recycled aggregate,and the influence of the concentration of bacterial solution on the basic mechanical properties of recycled aggregate was investigated.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 of RA,decreasing water absorption,and lowering the crushing index.The optimal bacterial liquid concentration for the modification effect is 1.265 × 108 cells/mL;At this concentration,the crushing index may be decreased from 13.0%to 10.8%and the water absorption 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 with 100%RC substitution rate is lower than that of NAC,and the split tensile strength of RAC with 40%RC substitution rate 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.Considering the mechanical properties and economic applicability of RAC,this paper takes the RA substitution rate of 40%as the best aggregate replacement rate.The research results can provide reference for the application of RAC in practical engineering.

mineralized sedimentationrecycled aggregatesreplacement raterecycled concretemechanical characteristicsconstitutive model

司政、张露、杜晓奇、李萌

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西安理工大学省部共建西北旱区生态水利国家重点实验室,陕西西安 710048

西安理工大学水利水电学院,陕西西安 710048

矿化沉积 再生骨料 取代率 再生混凝土 力学性能 本构模型

2024

实验力学
中国力学学会 中国科技大学

实验力学

CSTPCD北大核心
影响因子:0.522
ISSN:1001-4888
年,卷(期):2024.39(6)