【作者】 肖延亮；

【导师】 方坤河；

【作者基本信息】 武汉大学 ， 材料学， 2004， 硕士

【摘要】 混凝土是当今世界上用量最大的建筑材料，它在国民经济的发展中具有十分重要的地位，迫切要求其提高使用年限，减少混凝土由于修补或者重建带来的经济负担。在实验室里配制的混凝土，往往能够达到较好的耐久性，但在实际浇筑过程中，由于人工操作原因（过振、漏振等），使混凝土出现蜂窝、麻面等质量问题；或由于结构原因：钢筋密集部位而不易振捣、某些狭窄部位振捣机械难以振捣。使用普通工作性的混凝土容易产生质量问题，从而影响混凝土的耐久性。 自密实混凝土可以解决由于人为因素产生的施工质量不良的问题，并且可以解决钢筋密集部位或某些振捣机械难以达到的部位的混凝土施工问题。但自密实混凝土由于单位体积的胶凝材料使用高，加上粗骨料的含量较小，使得混凝土的体积稳定性不足。 本论文采用武汉地区的原材料及通用的工艺方法研制成功了高早强、微膨胀、自密实高强混凝土，试验成果具有一定的适用性。用正交设计法进行自密实混凝土的试配，在混凝土满足坍落度sl≥25mm，坍落扩展度50mm≤sf≤70mm要求下，以水胶比、水泥用量、砂率作为因素水平，以混凝土的1d、3d抗压强度和减水剂用量作为控制指标，选择出最优的因素水平，然后进行自密实混凝土的配制。 在配制的自密实混凝土中掺入一定量的Ⅱ级粉煤灰（FA）和UEA膨胀剂，配置出f₁≥5MPa，f₃≥20MPa的自密实混凝土。掺入FA可减小自密实混凝土单位体积产生的水化热；掺入UEA膨胀剂，使自密实混凝土产生一定量的膨胀，补偿混凝土的早期收缩产生裂缝的危险。优选的两组配合比，经对其进行抗折强度、抗渗性、膨胀性、弹性模量等试验研究。从而配制出各项性能均优异的高早强微膨胀自密实高强混凝土。更多还原

【Abstract】 Concrete is the largest architectural materials in the world nowadays. It is very impotant to the development of natinal economy. It is necessary to improve the life-span of the useage of the concrete, and to reduce the economic burdens caused by the mending or reconstruction of the concrete. The concrete confected in the labortory always takes on perferable durability. However, some quality problems such as honeycombed concrete, spot surface etc. Apear in the practical course of construction just because of the workers’ operational matters(over vibration or deficient vibration etc). And also because of some structural matters,some problems emerge.For example, the concrete where the reinforcing steel bars are very dense or the room is very narrow cannot be viberated easily. The hardened concrete can always apear quality problem if the fresh concrete workability is bad. And it will reduce the durability of hardened concrete.All the problems which are caused by workers’ matter, the denseness of steel or the narrow room can be settled by using self-compacting concrete. But the total quality of cement and the others pozzolana material in self-compacting concrete is very high, even more the coarse aggregates are less than commonness, the volume stability of self-compacting concrete is not so good.In the paper, the high early compressive strength, slight expansion, self-compacting and high compressive concrete was made successfully by using normal technolgy and raw materials in Wuhan. The result of the experiment is aplicable. We try to confect self-compacting concrete by orthogonal design tseting, and try to control the slump of the self-compacting concrete not less than 250 millimeter and the slump flow of the concrete between 500 millimeter and 700 millimeter. Looking the water/cement+ pozzolana material ratio, the cement quantity per volume and percentage of slag as the factor level, Taking the concrete compressive strength of 1 day age and 3 days age and the dosage of superplasticizer as the control target, to select the best factor level, And then contine confecting self-compacting concrete.If a certain dosages of second-grade flying-ash(FA) and UEA are mixed into the concrete when we confect self-compacting concrete, the compressive strength of 1 day must be not less than 5 MPa, and the compressive strength of 3 day must be not less than 20 MPa. And if some flying-ash is mixed into the self-compacting concrete, the heat of hydration can be reduced. And also if some UEA is mixed into the concrete, it will produce a little expansibility and compensate the early shrinkage of the concrete so as not apear crack. To select two groups of mix proportions from the nine ones and then carry out the others tests, flexural strength, penetration resistance test, expansibility test and modulus of elasticity test. We can confect the high early compressive strength, slight expansion, self-compacting, high compressive strength concrete successfully whose properties are excellent.更多还原