LONG-RUN EFFECT OF ALKALI-SILICA REACTIONS ON THE STRUCTURAL INTEGRITY OF A MULTI-STORY REINFORCED CONCRETE BUILDING

The paper investigates the long-run effect of alkali-silica reaction (ASR) on the integrity of a multi-story reinforced concrete building. Alkali-silica reaction is one of the major causes of damage to the concrete. It is produced by the formation of expansive calcium silicate hydrate (C-S-H) compounds as a result of the reaction between alkaline cement paste and non-crystalline silica in the aggregates. The expansive resultant causes outward pressure on the microstructure of the concrete. Because concrete is brittle, especially in tension, the outward pressure leads to its eventual fracture and failure. In general moisture has been found a critical element in initiating ASR. The cement alkaline content and the percentage of siliceous compounds in the aggregates are two other deciding factors which determine the potential for ASR. Although, the reaction phenomenon itself has been vastly explored in the literature, its eventual effect on the structure is not as equally well studied. This paper investigates the evidence and progress status of alkali-silica reaction (ASR) in a thirty-year-old half-built reinforced concrete building. The methodology to inspect the development of ASR in the structure is presented. Then, the effect of ASR on the structural integrity of the building is assessed using direct loading test.