Effect of using sugarcane leaf ash and granite dust as partial replacements for cement on characteristics of ultra-high performance concrete

A significant quantity of cement is necessary for the production of ultra-high-performance concrete (UHPC). However, some environmental issues are associated with cement production. The worldwide agricultural growth increases ash from agricultural waste (AW). Furthermore, industrial waste (IW) generated throughout the stone-cutting and processing has increased due to the growing demand for granite stone in construction. This research conducted a unique study that involved comparing the use of sugarcane leaf ash (SLA) as AW and granite dust (GD) as IW as partial substitutes for cement in the production of eco-friendly UHPC. The effect of employing SLA and GD with replacement ratios ranging from 20% to 50% on the mechanical and transport properties of UHPC was studied. In addition, this research investigated the effectiveness of partial replacement of natural fine aggregate (NFA) by recycled fine aggregate (RFA) with ratios ranging from 25% to 100% on the UHPC qualities. Moreover, the effect of elevated temperatures on the UHPC and the microstructural examination were investigated. Results demonstrated that the optimum replacement ratio of SLA or GD from cement was 20%, showing the best mechanical characteristics of the UHPC. For example, after 28 days of casting, the compressive strength increased by 12.16% and 8.44% when SLA and GD were added to the UHPC mix, respectively. Additionally, the 25% replacement ratio of RFA from NFA presented the best mechanical and transport properties of the UHPC. The mixes containing SLA positively affected the UHPC higher than those containing GD.