Title: Assessing Residual Expansion of Alkali-Silica Reaction- Affected Structures
Author(s): Noura Sinno, Matthew Piersanti, and Medhat H. Shehata
Publication: Materials Journal
Appears on pages(s): 139-148
Keywords: alkali-silica reaction (ASR); damage rating index (DRI); extracted cores; field exposure; recycled concrete aggregate; residual expansion; soaking cores in alkaline solutions
This paper presents tests that can be used collectively to provide a qualitative assessment of residual expansion in structures affected by alkali-silica reaction (ASR). The tests are applied to bridge barriers suffering different levels of ASR deterioration. These include testing extracted cores under different lab conditions, monitoring concrete elements under field condition, damage rating index (DRI) on cores, and measuring alkali levels in the affected concrete. Expansion of barriers with low deterioration level was double that of highly deteriorated barriers at 4.5 years. Similar results were reached through testing cores under laboratory conditions at 38°C (100°F) and 100% relative humidity, although the DRI showed the same increase in damage in both cores after testing. Testing cores under laboratory conditions until expansion ceases helps in predicting the minimum residual expansion. Soaking cores in alkaline solutions of different concentrations and finding the level required to trigger expansion helps in assessing the risk of future expansion.