沸石粉掺合料混凝土配制及其早龄期抗裂性能研究

发布时间：2018-05-06 06:18

本文选题：沸石粉 + 混凝土　；参考：《海南大学》2014年硕士论文

【摘要】：矿物掺合料广泛应用于高性能混凝土,而收缩开裂是影响混凝土耐久性的重要因素。随着粉煤灰、硅灰和矿渣粉等的大量使用,其价格也随之增长。因此将沸石粉应用于混凝土,并研究其对混凝土的收缩与抗裂性能的影响具有一定的意义。本文依托海南省自然科学基金项目“热带海洋环境下早龄期混凝土抗裂性能研究”,开展了沸石粉掺合料混凝土的配合比设计、基本力学性能、干燥收缩试验和平板式约束试验,具体研究工作如下： (1)以水胶比、胶凝材料用量、沸石粉掺量、砂率为影响因素进行正交试验配制了C35沸石粉掺合料混凝土,并考查各影响因素的主次关系。试验结果表明：掺入沸石粉配制出C35沸石粉掺合料混凝土具有良好的工作性能,且沸石粉的最佳等量取代率为20%；水胶比对强度的影响最大,沸石粉掺量次之,胶凝材料用量第三,砂率影响最小。 (2)通过试验研究了最优配合比下沸石粉掺合料混凝土早龄期的力学性能与工作性能,并与基准混凝土作比较。试验结果表明：混凝土中掺入沸石粉后,坍落度和流动性有所减小,各龄期的抗压强度和劈拉强度均减小,但抗折强度却略微增大,而且增大了拉压比,从而能降低混凝土的脆性；考虑龄期变化的模型可以描述沸石粉掺合料混凝土各强度之间的关系。 (3)通过干燥收缩试验研究了不同掺量沸石粉掺合料混凝土的干燥收缩性能。试验结果表明：混凝土中加入沸石粉后干燥收缩值将增大,均随沸石粉掺量的增加而增大；建议采用指数式表达式来描述和预测不同掺量沸石粉掺合料混凝土的干燥收缩与龄期之间的关系。 (4)通过平板式约束试验研究了C35最佳配合比下沸石粉掺合料混凝土的早龄期抗裂性能。试验结果表明：在本文所采用的试验条件下,沸石粉掺合料混凝土的早龄期抗裂性较好,但相较于未掺沸石粉混凝土,沸石粉掺合料混凝土的初裂时间提前,且单位面积上总开裂面积增大,掺入沸石粉后混凝土的早龄期抗裂性能降低。
[Abstract]:Mineral admixtures are widely used in high performance concrete, and shrinkage cracking is an important factor affecting the durability of concrete. With the large use of fly ash, silica fume and slag powder, its price also increases. Therefore, it is significant to apply boiling stone powder to concrete and study its effect on shrinkage and crack resistance of concrete. Based on Hainan Provincial Natural Science Foundation project "study on crack resistance of early-age concrete in tropical marine environment", this paper has carried out the mix ratio design and basic mechanical properties of concrete with boiling stone admixture. Drying shrinkage test and plate restraint test, the specific research work is as follows: 1) using water / binder ratio, the amount of cementitious material, the amount of boiling stone powder and sand ratio as the influencing factors, the orthogonal test was carried out to prepare the concrete with C35 zeolite powder admixture, and the primary and secondary relationships of the influencing factors were examined. The experimental results show that the C 35 mixture concrete has good working performance, and the optimum substitution ratio of boiling stone powder is 20%, and the ratio of water to binder has the most influence on strength, followed by the content of boiling stone powder. The amount of cementitious material is the third and the sand ratio is the least. 2) the mechanical properties and working properties of boiling stone admixture concrete at early age under the optimum mix ratio are studied and compared with the reference concrete. The test results show that the slump and fluidity decrease, the compressive strength and splitting tensile strength decrease, but the flexural strength increases slightly, and the ratio of tension and compression increases. Thus, the brittleness of concrete can be reduced, and the model considering age change can describe the relationship between the strength of concrete with boiling stone admixture. The drying shrinkage of concrete with different amount of boiling stone was studied by drying shrinkage test. The experimental results show that the drying shrinkage value increases with the addition of boiling stone powder in concrete, and increases with the increase of the amount of boiling stone powder. It is suggested that the exponential expression be used to describe and predict the relationship between drying shrinkage and age of concrete mixed with different amounts of zeolite powder. (4) the early age crack resistance of boiling stone admixture concrete under the optimum mixture ratio of C35 was studied by plate confinement test. The experimental results show that under the experimental conditions adopted in this paper, the early age crack resistance of the concrete mixed with zeolite powder is better, but the initial crack time of the concrete mixed with zeolite powder is earlier than that of the concrete without boiling stone powder. The total cracking area per unit area increases, and the early age crack resistance of concrete with boiling stone powder decreases.
【学位授予单位】：海南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528

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