| 摘要: |
| 为了开发适用于有压作用下混凝土结构渗漏缺陷快速封堵的材料,本文采用可再分散乳胶粉(VAE)改性快硬硫铝酸盐水泥(R.SAC),测试其早期流变性和力学性能,揭示其早期性能发展过程。结果表明：R.SAC粘度时变规律基本符合Herschel-Bulkley模型,即初始粘度维持时间约为40 min,随后粘度呈“指数型”急剧增长；加入VAE后R.SAC的初始粘度增加、突变点提前且突变后粘度增长速率显著加快,提高了封堵材料抵抗渗漏水压的能力,掺量在4%时此现象最为明显；掺量为3%~4%时可将R.SAC的早期抗折强度提高15%~21%,抗压强度则随掺量提高而降低,折压比上升表明改性R.SAC柔韧性提高； 1 d粘结强度在VAE掺量为4%时达到最大值,粘结强度较对照组提高121%；扫描电镜(SEM)分析表明改性R.SAC内部颗粒之间形成了致密的搭接结构,封堵渗漏缺陷的能力得到明显改善。 |
| 关键词: 混凝土渗漏 快硬硫铝酸盐水泥 可再分散乳胶粉 早期性能 掺量 |
| DOI： |
| 分类号: |
| 基金项目:国家重点研发计划项目(2016YFC0401609),国家自然科学基金重点项目(51739008),中央高校基本科研业务费(2018B13614) |
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| Study on early performance of rapid hardening sulphoaluminate cement-based sealing material |
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FAN Chengwen1,2, BAI Yin3, LI Ping1,2
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1. Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering，Hohai University , Nanjing 210098, China;2. College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China;3.State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China
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| Abstract: |
| In order to develop materials suitable for rapid plugging of concrete leakage defects under pressure, this paper uses vinyl acetate-ethylene copolymer (VAE) to modify rapid hardening sulphoaluminate cement (R·SAC). Employing rheometer, R·SAC’s rheologic property was revealed by testing its viscosity law which varies with time. The early performance of R·SAC-based materials was unveiled by combining the testing results of R·SAC’s mechanics property by means of anti- flexural and anti-pressure test and adhesion test on “8”-shaped model with analysis of scanning electron microscope（SEM）. The study shows that maintainable time of initial viscosity of R·SAC is about 40 minutes, whose viscosity surges with exponential rate later. With an addition of VAE, plugging material’s ability to resist leaking water pressure improved accompanied by an increase of R·SAC’s initial viscosity, an acceleration of mutational site and an remarkable leap of viscosity’s growing rate. The most obvious phenomenon above occurs by adding 4% VAE into the material. When the content of VAE ranges from 3% to 4% , the increase of R·SAC’s early anti- flexural strength varies from 15% to 21% and anti-pressure strength decreases accordingly. The increase of flexural -press ratio demonstrates that the flexibility of the modified R·SAC achieves improvement. When the content of VAE reaches 4%, 1 d bonding strength hits its maximum with a 121% bonding strength growth compared with the control group. Anaysis from SEM illustrates that dense lap structures are formed among interior granules of R·SAC and thus the material’s ability to plug leakage defects gets substantive progress. |
| Key words: concrete leakage rapid hardening sulphoaluminate cement vinyl acetate-ethylene copolymer early performance content |
