A defect despite passed freeze-thaw test?
Spalling above intact near-surface aggregate particles?
Depending on the exposure class, commonly applied concrete codes and standards specify the characteristics for raw materials and limit values for the concrete mix, assuming that the concrete will be sufficiently durable if these specifications are adhered to. The relevant standards do not include provisions on the concrete’s appearance or the prevention of isolated imperfections.
Some of the codes and guidelines, such as ZTV-Ing, ZTV-W, ZTV-Beton or the DIN EN 13198 standard governing massive treads or rules for paving flags, require CDF tests to verify the products’ freeze/thaw resistance...
