Mix Design for High-Strength Lightweight Concrete Using Fly Ash Cenospheres

This paper presents a proposed method of mix design for high-strength lightweight concrete using fly ash cenospheres (FAC-HSLWC) with the required density and compressive strength. The basic steps of this design method include optimizing the binder composition based on the calculation of the maximum packing density of the mixture, selecting suitable binder paste content (through the binder/aggregate ratio-B/A), and the ratio water/binder (W/B) to achieve the required workability and compressive strength; calculating the ratio of cenospheres to replace sand (ratio of cenospheres/aggregate-FAC/A) to achieve the required density of concrete. To develop this method, a series of trial mixes of FAC-HSLWC with different ratios of B/A, W/B, FAC/A were experimented to establish the parameters for the proposed design method. The validation results confirm that the unit weight and compressive strength are relatively close to the calculation results based on the design method. The proposed design method can be used effectively to calculate the optimum mix proportion of FAC-HSLWC.