Compressive strength of geopolymers produced by ordinary Portland cement: Application of genetic programming for design

In the present study, compressive strength results of geopolymers produced by ordinary Portland cement (OPC) as aluminosilicate source has been modeled by gene expression programming. Six main factors including NaOH concentration, water glass to NaOH weight ratio, alkali activator to cement weight ratio, oven curing temperature, oven curing time and water curing regime each at four levels were considered for designing. A total of 32 experiments were conducted according to the L32 array proposed by the method. The gene expression programming models were constructed by 10 input parameters including NaOH concentration, water glass to NaOH weight ratio, alkali activator to cement weight ratio, oven curing Temperature, oven curing time, water curing regime, water glass content, NaOH content, Portland cement content and test trial number. The value for the output layer was the compressive strength. According to the input parameters in the models, the constructed networks were trained and tested. The results indicate that gene expression programming model is a powerful tool for predicting the compressive strength of the geopolymers in the considered range.