INFLUENCE OF PULVERIZED FLY ASH ON THE PROPERTIES OF SELF-COMPACTING FIBER REINFORCED CONCRETE

(Abdullah Mohsen Zeyad and Abdalla Mostafa Saba)

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Abstract

Self-compacting concrete (SCC) has high flowability and high resistance to segregation and bleeding. These characteristics facilitate the mixing, casting, and finishing of SCC without using compacting ‎or vibrating machines. Adding mineral admixtures, such as pulverized fly ash‎ (PFA), of polypropylene fibers (PFs) and superplasticizers improves SCC properties by preventing segregation and bleeding and by increasing rheological parameters. SCC requires high flowability under the influence of self-weight to fill completely all mold parts for full compaction. This investigation discusses the results of experimental tests on the properties of SCC and self-compacting fiber reinforced concrete (SCCF) ‎mixtures with the inclusion of PFs 0.22% and containing PFA at replacement rates of 0%, 20%, 40%, and 60 % cement mass. The compressive, flexural, and split tensile strengths of the prepared concrete samples were investigated at ages of 7, 14, 28, and 90 days. The workability of fresh concrete mixtures was also studied through segregation, bleeding, slump flow, slump flow T50, L-box V-funnel T5, and V-funnel tests. Results showed that the more favorable properties of fresh SCCs were obtained when PFA was added at replacement rates of 20% and 40% cement mass. In addition, the inclusion of PFs at a volumetric ratio of 0.22% decreased segregation and bleeding and improved the flexural and tensile strengths of SCCFs. Key Words Cement substitutes, Concrete flowability, Concrete workability, Hardened concrete, High-‎volume replacement, Pozzolanic materials.‎‎
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