Optimization of properties of fly ash aggregates for high-strength lightweight concrete production

The optimization of properties of lightweight fly ash aggregates for suitability in high-strength lightweight fly ash concrete production was investigated using response surface methodology (RSM). Design-Expert software was used to establish the design matrix and to analyze the experimental data. The relationships between the sintering parameters (temperature, binder content and binder type) and experimentally obtained three responses (specific gravity, water absorption and crushing strength) were established. Also, the optimization capabilities in Design-Expert software were used to optimize the sintering process. Historical data design technique under RSM was performed to optimize the input parameter interactions which showed the best conditions for preparation of fly ash pellets. According to the obtained results, the developed models are statistically accurate and can be used for further analysis. The experimental values agreed with the predicted ones, thus indicating suitability of the model employed and the success of RSM in optimizing the sintering conditions.

Research highlights
► At lower and upper levels of binder content, as temperature increased, water absorption decreased.
► The desirability decreased with decrease in temperature and binder content.
► The models were quite accurate as the percentages of error were in a good agreement.