Passive fire protection of concrete structures

Author:

Khoury G. A.1

Affiliation:

1. Padua University Italy

Abstract

Passive fire protection of concrete structures is chiefly aimed at combating explosive thermal spalling, which relies on two underlying mechanisms: (a) the build-up of pore pressures and (b) the development of thermal stresses. The former could be alleviated, or eliminated, by the use of polypropylene (PP) fibres in the mix. Thermal stresses could be reduced by the use of thermally stable aggregates of low thermal expansion—not always practical when the choice of aggregates is limited at the location in question. The second, more effective, but much costlier solution is the use of thermal barriers that reduce the heat flow into the substrate concrete and hence reduce concrete temperature (and the resulting pore pressures and thermal stresses). Thermal barriers, therefore, address both underlying mechanisms of explosive thermal spalling. Criteria for determining the thickness of thermal barriers are currently based on specified maximum temperatures at the barrier/concrete interface. This is fundamentally flawed. The current author proposes that authorities should consider instead other criteria, which would include the heating rate at the interface (because explosive spalling is more a function of heating rate than maximum temperature) as well as permeability (strength), silica fume content, initial moisture content and, if possible, aggregate type. This approach is scientifically more correct and provides a more conservative (i.e. safer) result. In new designs, a judicial cost-effective use of both thermal barriers and PP fibres is recommended.

Publisher

Thomas Telford Ltd.

Subject

Building and Construction,Civil and Structural Engineering

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3