Long-term prediction of compressive creep development in expanded polystyrene

The results obtained in investigating the creep of expanded polystyrene (EPS) boards under compressive stress are presented. Power and exponential equations were used for describing creep compliance. It was found that the curves of creep compliance approximated by both equations adequately represent the research results, taking into account the scatter of the experimental data. Based on the calculation and empirical estimate of long-term creep of EPS under compressive stress σc=(0.25-0.45)σ10%, its creep compliance I¯c(T=10) was determined for a period of 10 years in the future. The dependence of I¯c(T=10) on the density of polystyrene boards and the value of long-term compressive stress σc was established. The expected values of creep strain ε¯c(T=10) development in expanded polystyrene boards EPS 80-EPS 250 under constant compressive stress σc=(0.25-0.45)σ10% are presented for the prediction period of 10 years. To obtain the expected creep values for any other period of time in the interval of 5⩽T⩽50 years, the values of ε¯c(T=10) should be multiplied by the empirical coefficient m¯I¯c(Ti)j.