Deterioration of a concrete surface due to the oxidation of pyrite contained in pyritic aggregates

✍ Scribed by A. Shayan

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 853 KB
• Volume: 18
• Category: Article
• ISSN: 0008-8846
• DOI: 10.1016/0008-8846(88)90095-6

✦ Synopsis

Sevm~ blistering of a concrete floor slab has uccuned over an extensive area in a 10 year old building, resulting in unevenness of the surface and rapturing of vinyl tiles covering the floor. The blistering was found to be cansed by the oxidation of pyrite in pyritic aggregates located at the surface of the slab. Oxida~on of pyrite resulted in the f~ of sulftwic acid and femms sulfam which reacted with other mineral components of the aggcgam to form complex sulfates such as jamsite, haloaichite and small amounts of other sulfates, and mucted with the mortar stmrounding the aggregate to form gypsum. The portion of the vinyl tiles in contact with the highly acidic envirenment near the degrading aggregate became very brittle and upward movement of the soluble salts and their accumulation beneath the brittle portions caused blistering which grew end finally ruptured the tiles. Pyritic aggregates within the co.fete were not affected due to complete protection by the mortar and a general sulfate att~-k was not observed.