【作者】 陈斌；

【导师】 刘国华；

【作者基本信息】 浙江大学 ， 水工结构工程， 2005， 博士

【摘要】 混凝土结构在硬化早期产生的各类缺陷,包括裂缝、裂纹、裂隙等,是导致工程耐久性破坏的主要内在诱因之一。以最低的综合施工成本,生产出符合设计要求的混凝土,并通过有效的施工、养护等控制措施,减少乃至避免结构早期裂缝的产生,从而提高工程耐久性,降低维护成本,延长使用寿命,既能提高混凝土建、构筑物的适用性,也有利于节约能源和减少污染,具有重要的理论与现实意义。 本文首先从总体上对混凝土工程的耐久性评估,收缩变形导致的应力应变计算,以及施工、养护措施对早期裂缝的影响等问题进行理论探讨,从中找出影响早期裂缝产生的主要因素,作为配合比优化的限制性依据。在此基础上,再考虑混凝土不同龄期强度、和易性等其它要求,结合非线形多元回归、人工神经网络等预测技术,探讨采用不同方法,包括单纯形法、复形调优法、Monte-Carlo法和遗传算法等,进行配合比优化的可行性,最终建立混凝土配合比的多目标优化模型,并通过工程实例进行验证。 以上述配合比优化模型为基础,采用面向对象的程序设计语言Visual C++6.0,开发出配合比优化设计专家系统。 作为防止混凝土早期裂缝产生的特殊措施,本文对采用掺MgO补偿收缩混凝土、后张预应力法防裂技术也作了一定的研究,得出一些有用的结论。更多还原

【Abstract】 Early deficiencies of concrete building, including flaws, cracks, and fractures, have been thought one of principal intrinsic predisposing causes, which lead to structure durability inactivation. By least construct cost and effective execution&curing methods, producing concrete, which can satisfy design demand, reduce structure deficiencies and improve durability, is objective requirement of modern concrete science development. It can not only reduce building service cost, but also conservatism energy and decrease pollution.In this paper, the durability evaluation, structure stress&strain calculation leaded by shrinkage distortion, and the construct&curing effect to early deficiencies have been universally discussed at first. Then, the major factors leading to early deficiencies are extracted, as limited parameters during mix-proportion optimization. After the parameters associating with concrete strength, workability in different ages, employing forecasting techniques such as non-linear regression analysis and artificial neural network program, optimize methods such as simplex method, complex method, Monte-Carlo technique, and genetic algorithms and so on, research the feasibility of mix-proportion optimization. As outcome of all the work mentioned above, the concrete mix-proportion multi-objective optimization model has been established in the end.Base on the optimize model established above, and using programming language Visual C++ 6.0, the concrete mix-proportion optimization system has been developed.In addition, as special means preventing concrete building early deficiencies, the MgO compensating contraction concrete and post-tensioned pretressing concrete has also been researched elementarily in this paper.更多还原