Microstructural properties of lithium-added cement mortars subjected to alkali-silica reactions

Abstract

Little comparative research has been done on the efficiency of lithium additives to reduce the alkali-silica reaction (ASR) expansion. To reduce the ASR effects of reactive aggregate, different mortar bars were obtained by adding lithium additives (Li2SO4, LiNO3, Li2CO3, LiBr and LiF) to the mixing water by the following mass percentages of cement: 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3%. The ASR expansions of the mortar bars at 2, 7 and 14 days were identified according to ASTM C 1260-14. The morphology of the specimens subject to the ASR effect was analysed using a scanning electron microscope, and their chemical composition was analysed by electron dispersion spectroscopy. Among all specimens, the lowest level of 14-day ASR expansion was obtained in mortar bars with 3% Li2CO3 additive.