Establishment of a prediction model for the compressive strength of alkali-activated fly ash and ground granulated blast furnace slag

To accurately calculate and predict the final compressive strength of alkali-activated fly ash and ground granulated blast-furnace slag composite cementitious materials(AAFGMs), this study investigates the temporal variation regularity of compressive strength for alkali-activated fly ash and ground granulated blast-furnace slag mortar specimens(AAFGM), identifies the curing age required for the full development of AAFGM compressive strength, and systematically analyzes the effects regularity of GGBFS content, activator modulus, and activator dosage on the compressive strength of AAFGM, ultimately establishing a predictive model for the compressive strength of AAFGM. The results indicate that, regardless of the GGBFS content, the compressive strength of AAFGMs reaches its final development within 60 days. Based on the influence regularity that the compressive strength of AAFGMs at 60 days increases initially with the activator dosage and then stabilizes, a two-stage predictive model for compressive strength is established. The compressive strength increases linearly at low activator dosages and stabilizes once a certain critical dosage is reached. The performance of the predictive model is closely related to the growth rate and activator critical dosage. The predictive model demonstrates a high degree of fit, with an R² value exceeding 0.9, and the error between predicted and experimental values is less than 10 %. This model exhibits high accuracy and reliability, enabling precise predictions of the final compressive strength.