A Proposed Mix Design for High-Volume Fly Ash-Self Compacting Concrete (HVFA-SCC)

Abstract

High-Volume Fly Ash Self-Compacting Concrete (HVFA-SCC) is an environmentally friendly concrete type that uses a high quantity of fly ash as a partial replacement of cement by at least 50%. The use of fly ash not only increases cost efficiency but also reduces the environmental impact of cement production. During the application of HVFA-SCC, an appropriate mix design is required to ensure its compressive strength and meet the criteria of Self-Compacting Concrete (SCC). This study proposes a mix design procedure for HVFA-SCC. A concrete cylinder test with varying water contents and water-powder ratios was conducted. The water contents used were 150, 175, and 200 kg/m3, the water-powder ratio utilized was 0.3-0.7, and the replacement of cement with fly ash was 50%. The ratio between the Fine Aggregate (FA) and Coarse Aggregate (CA) was determined using the packing density approach, where the ratio was selected based on the maximum packing density value. The results showed that all test specimens exhibited adequate flowability, filling ability, and segregation resistance, as per EFNARC 2005. From the results of the compressive strength test, it was observed that a higher water-to-powder ratio led to a lower compressive strength. Based on experimental data, the study proposes an equation for the relationship between the water-powder ratio and compressive strength. This equation is used to determine the waterpowder ratio according to the planned compressive strength. The proposed mix design procedure discussed in this study can be used to produce concrete with a compressive strength ranging from 18 to 47 MPa, making it a useful reference for the production of structural concrete.