Drying Process of Cement Mortar Composites Reinforced with Cellulosic Fibres: Experiment and Mathematical Modelling

In this paper, six novel mathematical models based on semi-empirical calculus are proposed and applied to characterise the oven-drying process of cement mortar composites reinforced with cellulosic fibres (CMCRCFs). The drying experiments were carried out on four levels of oven-drying temperatures (70, 85, 105, and 120 °C), with four different cellulosic fibres content (0, 5, 10, and 20 %). Obtained results were compared to those derived by regression analysis of six most typically used mathematical drying models (Newton, Page, Page modified1, Page modified2, Handerson Pabis, and Logarithmic) in addition to six proposed models. The regression accuracy of the drying process was evaluated by the coefficient of determination (R2), low mean square error (MSE), low root mean squared error (RMSE), and mean absolute error (MAE). Additional criteria were used to ensure more validity of the selected models. The obtained values indicate a highly accurate fit of the proposed model MR9, meaning that the proposed model can clearly interpret the experimental drying data and predict the dry state of CMCRCFs.
U ovom radu predloženo je i primijenjeno šest novih matematičkih modela temeljenih na poluempirijskom proračunu za karakterizaciju procesa sušenja u pećnici kompozita cementne žbuke ojačane celuloznim vlaknima (CMCRCF). Pokusi sušenja provedeni su pri četiri razine temperature sušenja u pećnici (70, 85, 105 i 120 °C) s četiri različita udjela celuloznih vlakana (0, 5, 10 i 20 %). Dobiveni rezultati uspoređeni su s onima dobivenim regresijskom analizom šest najčešće primjenjivanih matematičkih modela sušenja (Newton, Page, Page modified1, Page modified2, Handerson Pabis i Logarithmic) uz šest predloženih modela. Regresijska točnost procesa sušenja procijenjena je koeficijentom determinacije (R2), srednjom kvadratnom pogreškom (MSE), korijenom srednje kvadratne pogreške (RMSE) i srednjom apsolutnom pogreškom (MAE). Primijenjeni su i dodatni kriteriji da bi se osigurala veća valjanost odabranih modela. Dobivene vrijednosti pokazuju dobro slaganje predloženog modela MR9 s eksperimentalnim vrijednostima, što znači da predloženi model može jasno interpretirati eksperimentalne podatke o sušenju i predvidjeti suho stanje CMCRCF-a.