Study on the Properties of High‐Dosage Micro‐Steel Fiber Self‐Compacting Concrete With Combined Incorporation of Fly Ash and Slag Powder

To improve the mechanical properties of self‐compacting concrete (SCC) with single fly ash (FA) incorporation, this study used SCC with 30% Grade I FA replacing cement as the matrix and conducted experiments with ultrashort and ultrafine steel fibers (SFs) length 6 mm and diameter 0.2 mm at volume contents of 0%, 1.5%, 3%, 5%, and 6%, investigating their effects on compressive, splitting tensile, and flexural strengths. The results showed that the SFs significantly enhanced the mechanical properties of SCC, with strengths increasing with fiber content; beyond 3% fiber content, the growth of compressive and splitting tensile strengths slowed down and flexural strength growth stabilized at 5% fiber content. This study provides references for mix proportion optimization and engineering application of such SCC.