- Author
- Bilodeau, A. | Kodur, V. K. R. | Hoff, G. C.
- Title
- Optimization of the Type and Amount of Polypropylele Fibers for Preventing the Spalling of Lightweight Concrete Subjected to Hydrocarbon Fire.
- Coporate
- National Research Council of Canada, Ottawa, Ontario
- Journal
- Cement and Concrete Composites, Vol. 26, No. 2, 163-174, February 2004
- Report
- NRCC-45687,
- Keywords
- fibers | polypropylene | spalling | lightweight concrete | hydrocarbon fires | lightweight aggregates | temperature | fire tests | compressive strength
- Identifiers
- High Strength Concrete (HSC); water-to-cement ratio (W/C); proportions of the concrete mixtures and properties of the fresh concrete
- Abstract
- This paper presents the results from an experimental study on the optimum amount of polypropylene fibers to be used in lightweight high-strength concrete to prevent spalling when exposed to hydrocarbon fire, taking into consideration the characteristics of the lightweight aggregate, the water-to-cement ratio (W/C) of the mixtures, and the length and thickness of the fibers. Twelve different concrete mixtures were made. One block, 610x425x770 mm in size, was cast from each mixture and tested for fire resistance under hydrocarbon fire exposure. The temperature in the blocks during the test was recorded. After the test, the condition of the blocks was evaluated, and cores were taken for determining the residual compressive strength of the concrete. Results from the study show that close to 3.5 kg of the 20-mm polypropylene fibers per cubic meter of concrete is required to prevent the spalling of a low W/C lightweight concrete made with a silica fume-blended cement when subjected to hydrocarbon fire but that only 1.5 kg of the finer 12.5-mm fibers per cubic meter is sufficient. The amount of 20-mm fibers required to prevent spalling for a higher W/C of 0.42 is significantly less: of the order of 1.5 kg per cubic meter of concrete. The susceptibility of the concrete to spalling increases with the degree of absorption of the lightweight aggregate used in concrete.