High-volume use of limestone in ultra-high performance fiber-reinforced concrete for reducing cement content and autogenous shrinkage

Abstract

Abstract In spite of superior mechanical performance, ultra-high performance fiber-reinforced concrete (UHPFRC) is one of the most inefficient construction materials in terms of Portland cement usage. In this study, low-cement UHPFRC is proposed using high-volume limestone powder as a binder. Under ambient curing conditions, ultra-high strength (150–180 MPa) at 91 days was achieved with cement amount of 400–600 kg/m3. Efficient cement consumption of the concrete was quantitatively evaluated based on cement consumption index (CCI). In addition, autogenous shrinkages of UHPFRCs were effectively mitigated owing to the filler effect of limestone powder and the cement dilution effect which increases the water-to-cement ratio. Although this type of concrete incorporates quartz powder as physical filler, cement hydration was further accelerated with increasing limestone powder content. Accelerated cement hydration owing to the limestone powder shortens not only the dormant period but also the duration of the early stage during which risk of cracking is exceptionally high because of rapid shrinkage and low mechanical property. The production strategy suggested herein can practically contribute to reducing demand for Portland cement, along with advantages in dimensional stability.