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

控制使用 ECC 和 GFRP 材料的结构中因收缩和温度影响而导致的开裂和泄漏

• 批准号: 538053-2019
• 负责人: Lachemi, Mohamed
• 金额: $ 1.82万
• 依托单位: Ryerson University
• 依托单位国家: 加拿大
• 项目类别: Engage Grants Program
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=680396
• 关键词: Control; cracking; leakage; due; shrinkage

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.

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。这种影响会引起使用性问题，这在诸如液体连续结构和核电站等生命线设施的结构设计中具有特别重要的意义。钢筋混凝土结构裂缝宽度的预测和控制是多年来的研究课题。然而，对于底部约束墙裂缝控制的配筋设计，目前还缺乏共识。对于由ECC和GFRP等先进材料制成的结构，更需要进行此类研究。本研究旨在通过几个实验和分析案例研究来调查这一问题。三个大规模的钢筋混凝土墙标本与不同的材料和混合成分将被铸造，适当固化，并进行测试，以确定不同类型的材料如何影响开裂模式，裂缝开口，以及收缩和热效应产生的应变分布。有两个主要问题要解决，通过这项研究：1）的宽度和模式的ECC和FRP加固墙的温度和收缩裂缝相比，通常使用的普通混凝土墙在今天的实践中，2）由于热效应产生的裂缝两个主要因素-季节性温度变化和早期的热收缩。其目标是促进混凝土技术的改进，并为工程师提供实用的设计指南。主要目的是研究潜在的改善开裂行为的基础约束墙使用新开发的材料，如ECC和GFRP承受极端天气条件下，类似于在加拿大遇到的。在这种关系中，它是建议的时间依赖性的影响，由于收缩和温度变化引起的试样由不同的材料和裂纹的发展，在他们随着时间的推移进行监测和检查。