31317766weatheringPT2026-03-30 20:25:34UF31317767weatheredNDBT31304837surface or structural changesPTNT31341517alveolar weatheringPTNT31341530accelerated weatheringPTNT31341533freeze-thaw cyclePTNT31341536salt weatheringPTNT31341538sulfationPTNT31341541sugaringPTNT31304842carbonationPT