复合掺合料性能的研究

发布时间：2018-05-02 09:31

本文选题：复合矿物掺合料 + 活性指数　；参考：《吉林建筑大学》2013年硕士论文

【摘要】：首先本文从理论上分析了当前采用等质量取代水泥检测复合矿物掺合料活性指数做法的不合理之处,即不同复合矿物掺合料因表观密度变化幅度较大,掺入相同质量矿物掺合料时胶浆体积却大不相同,故不能客观的评定出复合矿物掺合料的活性指数,进而影响复合矿物掺合料相关规范的制定,因此提出了等体积替代水泥法评定复合掺合料活性指数方法。经过大量的试验研究证实等体积替代水泥法测得的复合掺合料的活性指数标准差远小于等质量代替法测得的活性指数标准差。从而验证了等体积替代水泥法评定复合掺合料活性指数较等质量替代水泥法更稳定、更具科学合理性,并进一步试验验证了复合掺合料等体积替代为水泥体积50%时,测定复合掺合料活性指数是可取的。在本试验条件下再次证实了,掺合料复掺的综合性能高于单掺的性能,粉煤灰与矿渣复掺能产生“超叠加效应”,虽然掺入复合掺合料会降低胶凝材料早期强度,但能提高胶凝材料的后期强度,而且还可以减少试件的干燥收缩率。其次本文还对比了用简单混合和粉磨激发法制备的复合掺合料拌制的混凝土性能,如混凝土的工作性能、力学性能及抗冻、抗渗和体积收缩等。试验结果表明在粉煤灰与磨细矿渣掺合比例为2：1时,并掺入少量石膏和硫酸钠等外加剂进行粉磨激发水泥及复合掺合料20分钟,在复合掺合料取代40%水泥的情况下制备的混凝土,检测混凝土28天龄期的力学性能及耐久性指标远超过简单混合法制得的混凝土。实测粉磨激发试件抗压强度为32.9 MPa,而简单混合法试件抗压强度为29.5MPa,普通空白样混凝土试件抗压强度为30.7 MPa；在60d龄期时,粉磨激发试件强度达到了43.8MPa,超出了简单混合法试件强度14%以上。所以由试验可知,粉磨激发法制备的复合掺合料替代40%水泥不但能降低混凝土的施工成本,而且还能有效的提高混凝土中后期的抗压强度、抗冻、抗渗及抗收缩等性能。最后还用扫描电子显微镜对上述方法制得的水泥胶砂试件进行了微观结构观察,由微观结构可以证明,加入复合掺合料能大大增加水泥石的密实度,降低孔隙率,改善混凝土的显微结构。
[Abstract]:First of all, this paper theoretically analyzes the irrationality of using equal mass instead of cement to detect the activity index of mineral admixtures, that is, the apparent density of different mineral admixtures varies greatly. However, the volume of slurry varies greatly when the mineral admixture of the same quality is added, so the activity index of the compound mineral admixture can not be evaluated objectively, which will affect the formulation of the relevant specifications of the mineral admixture. Therefore, a method of evaluating the activity index of composite admixture by equal volume replacement cement is proposed. Through a lot of experimental studies, it is proved that the standard deviation of the active index of the composite admixture measured by the equal volume substitution cement method is much smaller than the standard deviation of the active index measured by the equal mass substitution method. It is verified that the evaluation of the activity index of the composite admixture by the equal volume substitution cement method is more stable and more scientific than that by the same quality replacement cement method, and it is further verified that the equal volume replacement of the composite admixture is 50 times the cement volume. It is advisable to determine the activity index of the compound admixture. Under the experimental conditions, it is proved that the comprehensive properties of the admixtures are higher than those of the single admixture, and the supersuperposition effect is produced by the co-mixing of fly ash and slag, although the early strength of the cementitious material can be reduced by the addition of the compound admixture. But it can improve the later strength of the cementing material and reduce the drying shrinkage of the specimen. Secondly, the properties of concrete prepared by simple mixing and grinding excitation method are compared, such as the working performance, mechanical properties, frost resistance, impermeability and volume shrinkage of concrete. The test results show that when the ratio of fly ash and fine grinding slag is 2:1, and a few admixtures such as gypsum and sodium sulfate are added, cement and compound admixture can be excited by grinding for 20 minutes. The concrete prepared by replacing 40% cement with compound admixture is used to test the mechanical properties and durability of concrete at 28 days of age, which is far more than that obtained by simple mixing method. The compressive strength of the specimen excited by grinding is 32.9 MPA, that of the simple mixed method is 29.5 MPA, the compressive strength of the ordinary blank concrete specimen is 30.7 MPA, and that of the normal blank concrete specimen is 30.7 MPA. The strength of the specimen excited by grinding is 43.8 MPA, which is more than 14% higher than that of the simple mixed method. Therefore, it can be seen from the test that the composite admixture prepared by grinding and excitation method can not only reduce the construction cost of concrete, but also can effectively improve the compressive strength, frost resistance, impermeability and shrinkage resistance of concrete. Finally, the microstructure of the cement sand made by the above method is observed by scanning electron microscope. It can be proved from the microstructure that the compactness of cement stone can be greatly increased and the porosity can be reduced by adding compound admixture. Improve the microstructure of concrete.
【学位授予单位】：吉林建筑大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528.041

【参考文献】