Predicting the Strength of Ultrahigh-Volume Ash Concrete Containing Fly Ash and Bottom Ash as a Substitute for Fine Aggregates

Abstract

A systematic laboratory-based experimentation was carried out by replacing the fine aggregates in M35-grade concrete with varying dosages of fly ash (FA) and bottom ash (BA). Multiple linear regression (MLR) analysis was carried out to predict the compressive strength of the proposed ultrahigh-volume ash concrete at 28 and 90 days and the results of predicted versus observed strengths are discussed. ANOVA was analyzed using the Excel add-in named XLSTAT—Basic by Addinsoft. Durability studies were also carried out in terms of resistance to chloride penetration to ensure the serviceability of the developed mix designs. Finally, life-cycle assessment (LCA) was carried out and the mixes were evaluated in terms of emissions and embodied carbon. The mixes containing either only FA or a combination of both FA and BA revealed enhanced strength properties as compared to the control sample. However, the mix containing only BA failed to achieve the necessary strength requirements. Furthermore, the predicted equations for compressive strength at 28 days and 90 days exhibited a minor difference between the R2 and adjusted R2 indicating their statistical significance. The R2 of 0.858 and 0.837 observed for C28 and C90 respectively indicate that the proposed models can predict the strengths of ultrahigh-volume ash concrete with high accuracy. These equations were then validated from the findings of published literature and found to be within an acceptable degree of variance.