Mae Concrit Awyredig Awtoclafiedig Cyfnerth (RAAC) yn ddeunydd a ddefnyddiwyd wrth adeiladu nifer o adeiladau rhwng y 1960au a'r 1990au. Cadarnhawyd ei fod yn bresennol mewn ystod o eiddo sector cyhoeddus ledled y Deyrnas Unedig, gan gynnwys mewn ysgolion ac ysbytai.
Reinforced Autoclaved Aerated Concrete (RAAC) is a material used in construction in many buildings between the 1960s and 1990s. Its presence has been confirmed in a range of public sector properties across the United Kingdom including schools and hospitals.