Where should additional cores be taken when a core measurement from pavement is deficient by more than 25 mm?

The correct approach when a core measurement from pavement is found to be deficient by more than 25 mm is to take additional cores at no less than 5 meter intervals in each direction. This strategy is effective because it allows engineers to thoroughly assess the extent of the deficiency and understand the variability in pavement thickness around the problematic area. By systematically sampling in multiple directions, it provides a more comprehensive picture of the pavement conditions, which can influence decisions regarding repairs or further testing.

Taking cores too far apart may overlook critical areas of deficiency or lead to a misleading assessment of the pavement's overall condition. Conversely, taking cores at random locations might not adequately capture the continuous nature of the issue or provide enough data to draw reliable conclusions about the structural integrity of the pavement. By maintaining a close interval of 5 meters, the strategy ensures that an adequate amount of data is collected to accurately evaluate the situation.