【作者】 彭小平；

【导师】 蒲心诚； 李金玉；

【作者基本信息】 重庆大学 ， 材料学， 2002， 博士

【摘要】 在综合分析影响混凝土及大坝混凝土性能因素的基础上，采用国家“九五”重点科技攻关项目之专题“混凝土新型胶凝材料的研究”的成果，即高贝利特水泥（High Belite Cement，缩写为HBC），研究开发一种新型的低热高抗裂的高性能大坝混凝土。 根据水工混凝土试验规程、设计和施工规范等要求，对高贝利特水泥混凝土的各项宏观性能（如工作性能、力学性能、热学性能、耐久性能等）与目前三峡工程使用的高性能大坝混凝土（Middle-heat cement concrete，缩写为MHC混凝土）的性能进行充分的对比试验比较，并计算、分析两种混凝土的抗裂能力。采用孔结构分析、质谱分析、透射电镜、红外光谱等高新检测技术，研究和深入探讨其微观机理。同时，模拟大坝工程内部混凝土的绝热温升变化规律，研究大坝内部混凝土的实际强度性能。 试验结果和理论分析均表明：高贝利特水泥混凝土的各项性能优良，是一种低热高抗裂的高性能大坝混凝土，更适合于大坝混凝土工程或其它大体积混凝土工程的应用。现摘要论述如下： 1.经过近二百年的研究、应用，水泥及混凝土材料的发展实现了几次质的飞跃，其各项性能得到了大幅度的改善，应用范围越来越广。混凝土及大坝混凝土的研究表明：①混凝土的原材料优选、配合比设计、施工浇注、养护等环节是保证大坝混凝土各项性能优良的关键。②混凝土的温度裂缝是影响大坝混凝土整体性能及耐久性能的主要因素之一。 因此减少混凝土的用水量、降低水泥用量、采用水化热低的水泥等措施成为配制高性能大坝混凝土的重要技术途径。2.三峡工程大坝混凝土的研究，借鉴国内外已建大坝工程的经验，汇集了国内外水泥及混凝土学科的最新理论成果，确保工程使用混凝土的各项性能指标达到了世界先进水平。试验结果和工程检测也证明，三峡大坝混凝土是一种高性能大坝混凝土，处于世界先进水平（混凝土中的用水量仅为80～90Kg/ m3，水泥用量为100Kg/m3左右）。但温度裂缝等问题仍不可避免。 3.高贝利特水泥的研究，是中国建材院负责的国家“九五”重点科技攻关成果，顺应了水泥胶结材的发展方向。该水泥能耗低、环境污染少，同时又具有水化热低、<WP=6>后期强度高、耐久性好等优点，为配制新型的低热高性能大坝混凝土提供了可能。4.与三峡工程高性能大坝混凝土相比，采用高贝利特水泥配制的低热高抗裂的高性能大坝混凝土具有优良的性能，表现在以下几个方面。①高贝利特水泥混凝土的工作性在基准试验条件下，高贝利特水泥混凝土的初始坍落度（或VC值）与中热水泥混凝土的差不多，经时损失也相近，即其坍落度（或VC值）经过1～2h后的绝对值仍与中热水泥混凝土的相近，可见高贝利特水泥混凝土的工作性能良好。而在各自掺入适应性良好的高效减水剂和引气剂的条件下，高贝利特水泥混凝土比三峡工程使用的中热水泥混凝土有更好的工作性。②高贝利特水泥混凝土的力学性能强度性能，在配合比相同的标准养护条件下，高贝利特水泥混凝土的早期强度（7d）偏低，28d强度与中热水泥混凝土的持平，90d强度则超出中热水泥混凝土的强度。在模拟大体积混凝土绝热温升的养护条件下，高贝利特水泥混凝土的早期强度有较大的提高，后期强度得到继续增长，而中热水泥混凝土的后期强度增长不明显。试验还表明：采用与高贝利特水泥混凝土适应性良好的外加剂，可使该混凝土的用水量进一步减少，有利于混凝土的强度性能和耐久性，特别是早期强度的提高，如7d龄期时，高贝利特水泥混凝土的强度已达到中热水泥混凝土的同等水平。弹模性能，高贝利特水泥混凝土的静压弹模和抗拉弹模整体上与中热水泥混凝土的相近，而其抗拉强度和极限拉伸变形则比中热水泥混凝土的稍大。变形性能，高贝利特水泥混凝土的自身体积变形、徐变变形与中热水泥混凝土的相近，但其干缩变形早期稍大（10%左右），后期则相近。因此从整体上看，高贝利特水泥混凝土的体积变形性能与中热水泥混凝土的相近。③高贝利特水泥混凝土的耐久性能在相同的配比试验条件下，高贝利特水泥混凝土的抗冻性与中热水泥混凝土的相近，均能满足设计要求（如外部混凝土的抗冻等级≥F300次），而其抗渗性和抗硫酸盐侵蚀性能则优于中热水泥混凝土。④热学性能 高贝利特水泥混凝土早期的绝热温升比中热水泥混凝土的低4～5℃，28d龄期的绝热温升也比中热水泥混凝土的低3℃，在相当大程度上可降低大坝混凝土的温度应力，对提高大坝混凝土的抗裂能力非常有利。⑤抗裂能力从材料学科的观点，与中热水泥混凝土相比，高贝利特水泥混凝土的抗拉强度、极限拉伸变形较大，绝热温升值较小，而两者的弹性模量、体积变形性能相近，因<WP=7>此高贝水泥混凝土具有较高的抗裂性能。从混凝土的弹性抗裂能力、温度应力控制的抗裂安全系数、物理意义的抗裂系数等方面考察，初步计算均表明：在不同龄期时，高贝利特水泥混凝土的抗裂能力均大于中热水泥混凝土，进一步说明了高贝利特水泥混凝土的抗裂性能优良。5.微观研究也取得了成果。本文对高贝利特水泥、硅酸盐水泥、中热水泥胶砂的更多还原

【Abstract】 On the basis of comprehensive analyzing the factors affecting the properties of ordinary and dam concrete, with applying the achievements of the subproject "Study on New Cementitious Material" of the key science and technology project in the national ninth five-year plan, that is the High Belite Cement (HBC), a new low-heat and high performance dam concrete, called as High Belite Cement Concrete (HBCC), has been developed.According to the requirements of testing regulation, design and construction specifications for hydraulic engineering concrete, the macro properties such as workability, mechanical and thermal properties and durability of HBCC were tested and compared with those of high performance dam concrete for the Three Gorges Project, the Medium-Heat Cement Concrete (MHCC). The crack resistance of both concretes was calculated and analyzed, also the micro-properties of HBCC were studied using the pore-structure analysis, MS, TEM and IRS. Meanwhile, the strength performance of HBCC inside the dam was studied by simulating the adiabatic temperature rise of dam concrete.Test results and theoretical analysis show that the properties of HBCC are excellent; it is a new high performance concrete with low heat and high crack resistance and suitable for use in large dam and other large volume concrete projects.A discussion was carried out as follows:1. In a course of 200 year study and application, the cement and concrete materials experienced several steps of progress and the properties of concrete were improved greatly. The range of application for the concrete becomes wider and wider. The study on ordinary and dam concretes shows, that:1) The optimization of material selecting, mix proportion, concrete casting and curing are the key points for gaining the high performance of dam concrete.2) The temperature crack of concrete is one of the main factors affecting the integral performance and durability of dam concrete. Therefore, reduction of water and cement contents in concrete and use of low-heat cement etc are important ways to produce high performance concrete.2. Based on the success in research on cement and concrete with referring to<WP=9>the experience in construction of dam both at home and abroad, a study was carried out on the dam concrete for the Three Gorges Project to ensure the properties of concrete for the project to be on the world advanced level.Test results and engineering inspection show that the dam concrete for the Three Gorges Project is a high performance one and on a world advanced level. The water content and cement content are 80-90kg/m3 and 100kg/ m3 respectively. However there still is a problem with temperature crack.3. The study on the High Belite Cement is an achievement of the key science and technology project in the national ninth five-year plan performed by the China Building Materials Research Institute, conforming to the trend of development of the cement materials. This cement has a lot of advantages such as low energy consumption, less environmental pollution, low heat of hydration, high strength at later age and high durability. This makes the production of a new low-heat and high performance dam concrete possible.4. Compared with the high performance dam concrete for the Three Gorges Project, the low-heat and high performance dam concrete with High Belite Cement has excellent properties as follows:1) WorkabilityUnder the normal test conditions, the initial slump of High Belite Cement Concrete (HBCC) or VC value is similar to that of medium-heat cement concrete (MHCC) as well as the slump loss with time. That is, its absolute value of slump after 1-2 h. is close to that of MHCC, which illustrates the good workability of HBCC.On the condition of adding suitable super plasticizer and air entraining agent, the workability of HBCC is better than that of MHCC used for the Three Gorges Project.2) Mechanical propertiesStrength. Under the standard curing condition and with the same mix proportion, the strength of HBCC at early age (7 da更多还原