EFFECTS OF ALUMINIUM ADDITION ON INHIBITION OF CONCRETE EXPANSION RESULTED FROM ALKALI SILICA REACTION (ASR)

Abstract

Alkali-silica reaction (ASR) is one of the major causes of expansion, which ultimately leads to
failure in concrete. When reactive concrete is subjected to humidity, alkali silicate hydrate gel (ASR gel) is
formed. The swollen ASR gel exerts pressure and creates cracks in the concrete structure. This study, thus,
aimed at inhibiting concrete expansion which was caused by the ASR reaction, by creating pores. To achieve
pore formation, aluminium powder was used as an air entrainment agent. Mortar bars with aluminium content
of 0.05, 0.1, 0.15 and 0.2 weight percent of cement was tested according to the ASTM C1260: Standard Test
Method for Potential Alkali Reactivity of Aggregates. The results indicated that a larger quantity of entrained
pores was achieved at higher aluminium content. The results also showed that when tested according to the
ASTM C1260, concrete expansion was reduced as the aluminium content was increased. Microstructural
analysis revealed that the entrained pores accommodated spaces for ASR gel, resulting in the decline of
concrete expansion.