Application of sugar cane bagasse ash as filler in ultra-high performance concrete

Abstract

Ultra-high-performance concrete (UHPC) has become a research hotspot in the field of cementitious materials because of its excellent mechanical properties and good durability. However, the high production cost of UHPC limits its development and application. Quartz powder (QP) is an important component of UHPC. However, the production of QP will not only lead to the depletion of quartz resources but also to problems of high cost and environmental pollution. In recent years, sugar cane bagasse ash (SCBA), which is mainly composed of silicon dioxide, has been studied as an auxiliary cementitious material due to its pozzolanic characteristic. However, the pozzolanic activity of some SCBA is not high, and the silicon dioxide mainly exists in the form of quartz. In this study, SCBA was used as an active filler to replace 20%, 40%, 60%, and 80% QP to prepare a new type of green UHPC. Results showed that the flexural strength and compressive strength of UHPC increased by 18% and 12%, respectively, when SCBA replaced 60% of QP under standard curing conditions. Hydration heat, X-ray diffraction (XRD), thermogravimetric (TG) analysis, and mercury injection (MIP) were used to study the mechanistic of UHPC. In the present study, we identified SCBA as a filler can improve the strength of the matrix, compared with QP, by pozzolanic reaction and internal curing. Using SCBA as a filler to replace QP in UHPC can broaden the application area of SCBA and reduce the production cost and negative environmental impact of UHPC.