SWEDISH RECOMMENDATIONS FOR PREVENTING FIRE SPALLING IN CONCRETE STRUCTURES FOR CIVIL ENGINEERING PURPOSES

摘要

Explosive spalling may occur in moist, impermeable concrete structures exposed to fire.rnPresent knowledge implies that conventional concrete usually does not spall whereas highrnperformance concrete (HPC) and self-compacting concrete (SCC) usually do since theyrnnormally are impermeable. An increased use of HPC and SCC demands more research in thisrnarea and recommendations to prevent explosive spalling. In 2003, the Swedish ConcreternAssociation established a committee to develop guidelines for preventing explosive spallingrnin concrete structures exposed to fire. In May 2004, the committee published the firstrnpreliminary guidelines. From 2004, the committee has carefully followed the progress of twornlarge experimental research programs on concrete exposed to fire. The test results werernavailable in 2008, and the committee has used them to develop the guidelines. The guidelinesrncontain both a chart indicating when polypropylene fibres or other measures are needed inrnorder to prevent spalling and a table expressing the amount of fibres needed for differentrncases. Furthermore, the recommendations cover a description of the phenomenon, a summaryrnof factors influencing spalling based on Swedish and international test results, mechanical andrndurability properties of concrete containing polypropylene fibres, a description of testrnmethods, practical considerations based on Swedish experience gathered, e.g., in the CityrnTunnel project in Malm?, and a list of research needs.