Resumen
This study was conducted on concrete using sewage sludge ash (SSA) with the aim to establish an efficient use of SSA as a cement replacement material. Concrete specimens with three degrees of strength were made from two different SSAs and exposed in temperate plain and cold mountain regions for a prolonged period of time to investigate the long-term properties of SSA concrete. After 17 years of exposure, the properties of the specimens were examined. SSA concrete basically maintained its strength after 17 years of exposure. No significant drop in the relative dynamic modulus of elasticity was detected in SSA concrete left in a cold mountain region, despite the fact that it would be exposed to a considerable number of freeze-and-thaw cycles. It was also confirmed that the SSA concrete exhibited high resistance against carbonation. A small amount of Katoite formed in the hardened cement/SSA mixture, probably due to the high content of Al2O3 in SSA. No abnormal formation of ettringite was observed.