【作者】 蔡云；

【导师】 陈友治；

【作者基本信息】 武汉理工大学 ， 材料学， 2008， 硕士

【摘要】 钢管混凝土是将素混凝土灌入钢管而形成的一种组合材料。与传统的钢筋混凝土结构相比,它具有承载力高、重量轻、塑性韧性好、施工方便及节省水泥木材等诸多优点。近年来这种新型结构正愈来愈受到人们的重视,在国内外已得到了较深入的研究及广泛的推广应用。与普通钢管混凝土相比,钢管高强膨胀混凝土被认为是较为理想的钢管混凝土。这种材料的特点是核心高强混凝土中掺加了膨胀组分,建立了前期主动紧箍力,使钢管与核心混凝土在受荷载作用之前就产生紧箍力,从而弥补了普通钢管混凝土紧箍力出现太迟的缺陷,改善了这种材料的工作性能。本文的主要研究内容如下:对菱镁矿采取轻烧制度,分别在700℃、900℃和1100℃下煅烧保温1小时,测定其活性,通过水泥净浆试验,研究氧化镁膨胀剂的膨胀性能,并对掺氧化镁膨胀剂和钙矾石膨胀剂的水泥净浆及砂浆的膨胀性能进行实验研究,分析对比实验结果。归纳总结国内外水泥混凝土安定性检测方法,研究在一种合理的压蒸制度下,氧化镁掺量、粉煤灰掺量对氧化镁混凝土的压蒸膨胀行为及混凝土性能的影响,实验确定符合安定性要求的氧化镁混凝土中氧化镁的掺量。设计配制C50钢管混凝土,使其具有高强、微膨胀、自密实的特点及良好工作性能。分析混凝土收缩变形特性并引入混凝土收缩计算模型。引入模型对氧化镁混凝土膨胀变形模拟计算,对比实验所测实际应变数据,验证模型的准确性。研究结果表明:氧化镁膨胀剂的膨胀性能与煅烧工艺制度有较大关系,煅烧温度越高氧化镁的延迟膨胀性也越明显;合理压蒸制度的压蒸法可以较好的评定外掺氧化镁混凝土的安定性,采用在200℃下保温6小时的压蒸法确定本课题中微膨胀混凝土氧化镁掺量不超过8%;通过优化配合比设计,C50氧化镁微膨胀混凝土的最佳配合比为:水灰比0.32,砂率0.38,单位用水量160kg,胶凝材料500kg,粉煤灰15%,氧化镁膨胀剂掺6%,在此配比下的氧化镁混凝土具有良好的工作性能及后期性能。更多还原

【Abstract】 The concrete-filled steel tube is one kind of combination material which uses the plain concrete pour into the steel tube. Compares with the traditional reinforced concrete structure ’It has many merits such as: The supporting capacity to be high, the weight is light, plastic toughness is good, the construction facilitates and saves the cement lumber and so on. In recent years this kind of new structure was being valued people’s more and more, in domestic and foreign obtained the thorough research and the widespread promoted application.Compares with the general’s steel tube concretes that the steel tube high-strength expansion concretes were considered as more ideal steel tube-confined concrete. This material’s characteristic was in the core high-strength concrete mixing components of the expansion, has established the earlier period initiatives tight band strength. Causes the steel tube and the core concrete before receiving the load function has the tight band strength, which would in turn make up for the general confining of concrete-filled steel tube defects that the tight band strength appeared too late to improve the performance of such materials. The main contents are summarized as follow:Magnesite take the light burning system, in 700℃, 900℃and 1100℃under the calcine keeps warm for 1 hour, determination of its activity, through the cement paste test, magnesia expansive agent on the expansion of performance, and magnesia expansive agent and ettringite expanders cement grout and mortar performance of the expansion of research, analysis and comparison of results.The induction summarizes the domestic and foreign cement concrete stability examination method, study in one kind of reasonable pressure steams under the system, the amount of magnesia and fly ash to steam the expansion behavior and the concretes performance influence to the magnesia concretes, the experiment confirmed that conforms to the stable request magnesia concretes the magnesia to mix the quantity.The design compounds the C50 steel tube concretes, enables it to have excel, high-strength, micro- expansion, self-compacting and the characteristics of good work performance.Analysis the concrete shrinkage distortion characteristic and introduces the concrete shrinkage computation model. The model building to the magnesia concretes inflation distortion analog computation; the opposite experiment measures the actual strain data, the confirmation model accuracy.The experimental results are shown following: The expansive properties of magnesia is greatly affected by calcinations temperature, The calcinations temperature is higher its activeness to be lower, the magnesia detention expansibility is also more obvious; Reasonable pressure steam pressure steam system of law can be used to be good evaluation to magnesia concrete mixed with the stability, Uses in 200℃under keeps warm 6 hour pressure to steam the law to determine in this study the micro- expansion concretes magnesia to mix the quantity not to surpass 8%; Through optimized preparation design, C50 magnesia micro-expansion concrete for the best mix: water-cement ratio of 0.32, 0.38 of sand, water units 160 kg, cementing material 500 kg, fly ash 15%, 6% of magnesia expansive agent, and it’s have the good operating performance and the later period performance under this preparation ’s magnesia concrete.更多还原