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基于高分子质量生物胶的自密实混凝土流变性能优化
作者：陈诚1，苏延文2，曾永平2，徐文3
（1.江苏苏博特新材料股份有限公司，江苏 南京 211103；
2.中铁二院工程集团有限责任公司，四川 成都 610031；3.东南大学 材料科学与工程学院，江苏 南京 211189）
摘要：运用赫切尔-巴尔克模型试验研究了不同种类与掺量流变改性剂对水泥浆体流变性能的影响，在此基础上，综合采用坍落扩展度、V漏斗通过时间、浮浆百分比等方法表征了掺入流变改性剂的自密实混凝土工作性能。结果表明：对比常用的纤维素醚与温伦胶，掺入高分子质量生物胶可有效调节水泥浆体的屈服应力与表观黏度，掺量敏感性较低，且使浆体假塑性与触变性分别提高了20%~40%和50%以上，特别适用于中低胶凝材料用量自密实混凝土，显著优化其填充性、间隙通过性及抗离析性。这可能与高分子质量生物胶溶于水形成凝胶，使得整个溶液体系产生了一种大范围的“桥式”网状效应有关。
关键词：流变改性剂；屈服应力；假塑性；触变性；自密实混凝土
中图分类号：TU528.042 文献标识码：A 文章编号：1001-702X（2020）10-0014-005
Rheology optimization of self-compacting concrete based on a high molecular weight biological gum
CHEN Cheng1，SU Yanwen2，ZENG Yongping2，XU Wen3
（1.Jiangsu Sobute New Materials Co. Ltd.，Nanjing 211103，China；
2.China Railway Eryuan Engineering Group Co. Ltd.，Chengdu 610031，China；
3.School of Materials Science and Engineering，Southeast University，Nanjing 211189，China）
Abstract：An experimental investigation was carried out to evaluate the effect of Rheology Modifying Admixtures（RMAs） with different type and dosage on the rheology of cement paste based on Herschel-Bulkley model. On this basis，the slump flow，V-funnel time，segregation rate and so on were measured to characterize the workability of fresh self-compacting concrete（SCC）. The results indicate that the application of a high molecular weight biological gum（HBP） has regulated the yield value and apparent viscosity of cement paste effectively and it has lower mixing amount sensitivity compared to the frequently-used cellulose ether and welan gum. Simultaneously the cement paste with HBP has improved its pseudoplasticity（shear thinning behavior） 20%~40% and thixotropy more than 50%. Therefore，the HBP has been particularly useful for preparing SCC with medium and low cementing material and significantly optimized the filling ability，passing ability，and resistance to segregation of SCC. This may be related to a wide range of "bridge" network effect in the whole solution system caused by the HBP dissolving in water and forming gel.
Key words：rheology modifying admixture，yield stress，pseudoplasticity，thixotropy，self-compacting concrete