- The document investigates test methods to measure the void space of aggregates for use in particle matrix modeling of concrete. Four methods were tested - EN 1097-3, EPP 4C, New Zealand Flow Cone, and Norbetong. - The tests were performed on four types of sand with varying shapes and size distributions. Slight differences in filling procedures between tests led to considerable differences in measured void content. - Decreasing particle circularity and increasing specific surface area were found to increase void content, with circularity having a more pronounced effect. However, only a moderate increase in specific surface area did not significantly affect void ratios.