Service life evaluation system for durability of structures at the time of planning and design

在混凝土结构的使用寿命的耐久性，这应该是在其施工前的设计和规划的时间进行了一个框架。提出了一种评价混凝土结构初始性能的方法，该方法将影响混凝土结构初始性能的因素分为施工方法、构造细节和材料性能，可以定量地评价各因素对混凝土初始性能的影响程度，并能简单地评价混凝土的初始性能。通过扩展热湿分析系统，建立了一种基于时间的材料和结构性能评价方法，以处理水化、微孔收缩和水分平衡之间的相互作用。氯离子、二氧化碳和氧气的浓度被附加到模型中的控制方程中，然后多达100个参数被包括在元素模型中。另一方面，对混凝土结构耐久性各影响因素的模型进行了如下修正：钢筋锈蚀后钢筋混凝土构件结构性能，裂缝混凝土中水分迁移，低水灰比混凝土水化速率，自收缩与干缩的相互作用，石灰石粉对混凝土氯离子扩散性的影响此外，还研究了影响长期耐久性的新鲜特性。研究了表面含水率对新拌混凝土流动性的影响。研究了影响混凝土组成均匀性的粗集料颗粒在砂浆中下沉程度的因素。

A framework was achieved for the durability in the service life of concrete structures, which is supposed to be carried out at the time of the design and planning before its construction. An evaluation method for initial properties to be achieved in RC structures was developed, in which the factors affecting the properties are construction method, structural details, and material properties and it made possible to evaluate the degree of the influence from each factor quantitatively and to evaluate initial properties of concrete simply. An evaluation method for time-dependent material and structural properties was developed by expanding thermo-hygro analysis system so that the interaction among hydration, micro-pore stricture, and moisture equilibrium can be treated. The concentrations of chloride ion, carbon dioxide, and oxygen were attached to the governing equations in the model and then as much as 100 parameters became included in the element model. It made possible to estimate the time-dependent deterioration of material and structural performance of structure.In the other hand, the model for each factors in durability of concrete structures were also modified as follows : structural behavior of RC member with corroded reinforcing bar, moisture transport in concrete with cracks, hydration rate of concrete with low water to cement ratio, interaction between autogenous- and drying shrinkages, effect of limestone powder on chloride diffusivity in concrete. In addition, fresh properties affecting the long term durability were also investigated. Influence of surface moisture content on the flowability of fresh concrete was investigated. The factors affecting the degree of sinking of coarse aggregate particles into mortar were examined, which affects the uniformity of concrete s composition.