Control of cracking and leakage due to shrinkage and temperature effects in structures using ECC and GFRP materials

约束温度和收缩应变是钢筋混凝土结构开裂的主要原因之一。这种影响可能会引起适用性问题，这在液体连续结构和核电站等生命线设施的结构设计中特别重要。普通混凝土钢筋混凝土结构裂缝宽度的预测和控制是多年来研究的课题。然而，对于基础约束墙体的配筋设计以控制裂缝，目前仍缺乏共识。对于由ECC和GFRP等先进材料制成的结构，这种研究的必要性更大。本研究旨在通过几个实验和分析案例研究来探讨这一问题。三个具有不同材料和混合料组成的大型加筋墙体试件将被浇注、适当养护并进行测试，以确定不同类型的材料如何影响裂缝模式、裂缝张开以及收缩和热效应产生的应变分布。通过这项研究有两个主要问题需要解决：1)与目前通常使用的普通混凝土墙相比，ECC和FRP加固墙的温度和收缩裂缝的宽度和模式；2)由两个主要因素-季节性温度变化和早期热收缩-引起的温度效应引起的裂缝。目标是为混凝土技术的改进做出贡献，并为工程师提供实用的设计指南。主要目的是研究使用ECC和GFRP等新开发的材料来抵御极端天气条件的基础约束墙的裂缝性能的潜在改善，类似于加拿大遇到的情况。在这一关系中，建议在不同材料制成的试件中诱发收缩和温度变化的时变效应，并随着时间的推移监测和检查裂缝的发展。

Restrained temperature and shrinkage strains are one of the major reasons for cracking in reinforced concrete structures. Such effect can cause serviceability problems which is of particular significance in the structural design of lifeline facilities such as liquid continuing structures and nuclear power plants. The prediction and control of crack widths in reinforced concrete structures made of normal concrete has been the subject of research for many years. However, there is still a lack of consensus on the design of reinforcement in base-restrained walls for crack control. The need for such study is even more for structures made of advanced materials such as ECC and GFRP. This study aims to investigate this matter through several experimental and analytical case studies. Three large-scale reinforced wall specimens with different materials and mix compositions will be casted, properly cured, and tested to determine how different types of material can affect the cracking pattern, the crack opening, and the strain profile produced by shrinkage and thermal effects. There are two main issues to be addressed through this study: 1) the width and pattern of temperature and shrinkage cracking in ECC and FRP-reinforced walls as compared to the customary normal concrete walls typically used in today's practice, 2) cracking due to thermal effects derived from two main factors - seasonal temperature variations and early-age thermal contraction. The goal is to contribute to the improvement of concrete technology and to provide engineers with practical design guidelines. The main objective is to study the potential improvements in cracking behavior of base-restrained walls using newly developed materials such as ECC and GFRP to withstand extreme weather conditions, similar to those encountered in Canada. In this relation, it is proposed that the time-dependent effects due to shrinkage and temperature change be induced in specimens made of different materials and the development of cracking in them be monitored and examined over time.