【作者】 唐笑；

【导师】 杨长辉；

【作者基本信息】 重庆大学 ， 材料学， 2003， 硕士

【摘要】 本文采用高强页岩陶粒，掺加高效减水剂配制大流动性结构轻集料混凝土，讨论了水泥用量、水灰比、砂率、矿物掺料及轻集料的级配和预湿方式对大流动性结构轻集料混凝土强度和工作性的影响；系统研究了高强陶粒在常压和压力下的吸水规律；研究了影响大流动性结构轻集料混凝土匀质性的因素，提出了解决大流动性结构轻集料混凝土分层离析的具体措施。上述分析研究得出以下结论：①高强陶粒的吸水特性不同于超轻陶粒，其常压吸水率很小，1小时吸水率为2％，吸水速度很慢，75天吸水率仅5.7％。但是在压力条件下，其吸水率有较大增长，在30MPa压力作用下，10分钟吸水率可达到11.1％。②高强陶粒在混凝土中的吸水率低于其在水中的吸水率，且高强陶粒在混凝土中的吸水率要受到混凝土水灰比的影响，水灰比越大，吸水率越大；水灰比越低，吸水率随压力和受压时间的变化越不明显。此外，陶粒在混凝土中的压力吸水率随其初始含水率的增大而减小。③要获得均匀稳定的大流动性结构轻集料混凝土，陶粒的最大粒径不宜超过20mm，水泥用量不宜超过500kg/m~3，拌和物坍落度宜小于260mm。此外，振动对大流动性轻集料混凝土的匀质性十分不利，对坍落度220mm左右的轻集料混凝土拌和物，振动时间超过10秒，就会出现明显的分层现象。在坍落度为180mm～260mm时，轻集料混凝土具有较好的免振自密实能力。④本研究条件下，通过合理选择水泥用量、水灰比、砂率、掺加高效减水剂和活性矿物掺料，可以配制出表观密度1800kg/m~3，28天抗压强度达50MPa~60MPa的大流动性结构轻集料混凝土。对轴心抗压强度、抗折强度、弹性模量和抗渗性能的检测表明，所配混凝土具有良好的物理力学性能和耐久性。更多还原

【Abstract】 This paper deals with high fluid concrete in which high strength ceramsite made from shale was used as coarse aggregate. Effects of cement content, water-cement ratio, sand percentage, mineral admixture, grading and pretreatment of lightweight aggregate on compressive strength and workability of high fluid structural lightweight aggregate concrete have been studied. The rules of water absorption of high strength lightweight aggregate under different pressure and effects on uniformity of high fluid structural lightweight aggregate concrete have been studied too. And the measures resolving separation of mixture of high fluid structural lightweight aggregate concrete are presented. It can be concluded as following:①Water absorptivity of high strength ceramsite is different from that of extra-light ceramsite. In atmospheric pressure, water absorption rate of high strength ceramsite is very small, which 1hour and 75 days water absorption rate is only 2% and 5.7% respectively. But under additional pressure, the rate increases greatly. Under pressure of 30MPa,it reaches 11.1% in 10 minute.② Water absorption rate of high strength ceramsite in concrete is lower than in water, and it is influenced by water-cement ratio, the higher w/c ratio, the bigger water absorption rate. And the lower w/c ratio in concrete is, the less obvious changes of water absorption rate by outer pressure and time are. In addition, water absorption rate of high strength lightweight aggregate in concrete under pressure decreases with its initial containing water rate increasing. ③To obtain high fluid structural lightweight aggregate concrete with good uniformity, it is necessary to limit the max grain size of lightweight aggregate to 20mm, cement content to 500kg/m~3 and slump of concrete mixture to 260mm. In addition, vibration has great effects on uniformity of high fluid structural lightweight aggregate concrete. There is obvious separation of lightweight aggregate from mortar in mixture of high fluid structural lightweight aggregate concrete with slump of 220mm when vibrated for 10 minutes. Lightweight aggregate concrete can be densified in itself when the slump is in the range of 180~260mm.④ We have been produced high fluid structural lightweight aggregate concrete which apparent density is 1800kg/m~3 and 28d compressive strength is 50~60MPa by<WP=6>using high strength lightweight aggregate, controlling cement content, w/c ratio, sand ratio correctly and adding superplasticizer and mineral admixture.The tests of axial compressive strength, flexural strength, elastic modulus and impermeability show that the concrete produced in this paper has excellent mechanical and durable properties.更多还原