The article analyses the reactivity level of aggregates from Lithuanian quarries and their effect on the alkali corrosion in mortars. The reactivity of aggregates was assessed according to Rilem Recommended Test Method: AAR-2. The hardened cement paste and cracked aggregate contact zones were tested by means of optical microscopy. Two gravel aggregates and one sand aggregate from Lithuanian quarries were selected for testing. The tests revealed that according to AAR 2 methodology fine and coarse aggregates from Lithuanian quarries shall be allocated to Group II, i.e. reactive aggregates. The expansion after 14 days exceeds 0.1 % in the case of fine aggregate, the average expansion after 14 days is 0.13 %, and in the case of coarse aggregates the average expansion ranges from 0.11 % to 0.12 %.
 M. Haugen, “The advantages of using microscopic analyses as part of the assessment of alkali aggregate reactivity”, Workshop proceeding from a Nordic-Baltic Mini-seminar “Alkali aggregate reactions (AAR) in concrete”, Riga, Latvia, 21–22 November 2013, no. 11, pp. 17–25, 2013.
 T. C. Esteves, R. Rajamma, D. Soares, A. S. Silva, V. M. Ferreira, and J. A. Labrincha, “Use of biomass fly ash for mitigation of alkali-silica reaction of cement mortars,” Construction and Building Materials, vol. 26, no. 1, pp. 687–693, Jan. 2012. https://doi.org/10.1016/j.conbuildmat.2011.06.075
 A. Leemann, G. Le Saout, F. Winnefeld, D. Rentsch, and B. Lothenbach, “Alkali-Silica Reaction: the Influence of Calcium on Silica Dissolution and the Formation of Reaction Products,” Journal of the American Ceramic Society, vol. 94, no. 4, pp. 1243–1249, Nov. 2010. https://doi.org/10.1111/j.1551-2916.2010.04202.x
 P. Hagelia, I. Fernandes, “On the Aar Susceptibility of Granitic and Quartzitic Aggregates in View of Petrographic Characteristics and Accelerated Testing”, 14th International Conference on Alkali-Aggregate Reactions in Concrete, Austin, Texas, USA: pp. 10, 2012.
 B. Fournier, M. A. Bérubé, K. J. Folliard, M. Thomas, “Report on the Diagnosis, Prognosis, and Mitigation of Alkali-Silica Reaction (ASR) in Transportation Structures”, U.S. Department of Transpotation. The Federal Highway Administration, 2010. Technical Report No. FHWA-HIF-09-004.
 Z. Owsiak, J. Zapała-Sławeta, and P. Czapik, “Diagnosis of concrete structures distress due to alkali-aggregate reaction,” Bulletin of the Polish Academy of Sciences Technical Sciences, vol. 63, no. 1, Jan. 2015. https://doi.org/10.1515/bpasts-2015-0003
 G. Skripkiūnas, M. Vaičienė, A. Kičaitė, A. Gumuliauskas, “Analysis of damages area in concrete caused by AAR”, Workshop proceeding from a Nordic-Baltic Mini-seminar “Alkali aggregate reactions (AAR) in concrete”, Riga, Latvia, 21–22 November 2013, no. 11, pp. 55–65, 2013.
 C. Anaç, R. Esposito, O. Çopuroğlu, E. Schlangen, M. A. N. Hendriks, “A tool for concrete performance assessment for ASR affected structures: An outlook”, 14th International Conference on Alkali-Aggregate Reaction in Concrete, ICAAR, Austin, Texas, USA, 2012.
 S. Góralczyk, “Alkali – carbonate reaction of aggregates”, Gospodarka Surowcami Mineralnymi, t. 28, pp. 47–62, 2012.
 K. J. Leśnicki, J.-Y. Kim, K. E. Kurtis, and L. J. Jacobs, “Characterization of ASR damage in concrete using nonlinear impact resonance acoustic spectroscopy technique,” NDT & E International, vol. 44, no. 8, pp. 721–727, Dec. 2011. https://doi.org/10.1016/j.ndteint.2011.07.010
 K. Kupwade-Patil, E. Allouche, “Effect of Alkali Silica Reaction (ASR) in Geopolymer Concrete”, World of Coal Ash (WOCA) Conference, May 9–12 2011, Denver, CO, USA, 2011.
 U.S. Department of Transpotation, “Federal Highway Administration. Alkali-Aggregate Reactivity (Aar) Workshops for Engineers and Practitioners. Reference Manual”, 2013.
 United Kingdom Quality Ash Association, “Calculating the Alkali Content of concrete containing fly ash (PFA) for minimising the risk of Alkali Silica Reaction (ASR)”, Technical Data sheet. 1.7, 2012.
 Concrete Openings, “Stress Relief for Big Dams. Wire Sawing Relieves Concrete Stress Caused by AAR”, reprinted from Concrete Openings, vol. 21, no. 4, Dec. 2012.
 C. Comi, B. Kirchmayr, and R. Pignatelli, “Two-phase damage modeling of concrete affected by alkali–silica reaction under variable temperature and humidity conditions,” International Journal of Solids and Structures, vol. 49, no. 23–24, pp. 3367–3380, Nov. 2012. https://doi.org/10.1016/j.ijsolstr.2012.07.015
 E. R. Latifee, S. Akther, K. Hasnat, “A Critical Review of the Test Methods for Evaluating the ASR Potential of Aggregates”, Proceedings of 10th Global Engineering, Science and Technology Conference, 2–3 January 2015, BIAM Foundation, Dhaka, Bangladesh, 2015. ISBN: 978-1-922069-69-6.
 M. D. A. Thomas, B. Fournier, K. J. Folliard, Y. A. Resendez, “Alkali-Silica Reactivity Field Identification Handbook”, U.S. Department of Transpotation, 2011. Technical Report No. FHWA-HIF-12-022.
 J. Lindgård, P. J. Nixon, I. Borchers, B. Schouenborg, B. J. Wigum, M. Haugen, and U. Åkesson, “The EU ‘PARTNER’ Project — European standard tests to prevent alkali reactions in aggregates: Final results and recommendations,” Cement and Concrete Research, vol. 40, no. 4, pp. 611–635, Apr. 2010. https://doi.org/10.1016/j.cemconres.2009.09.004
 V. Jensen, “Reclassification of Alkali Aggregate Reaction”, 14th International Conference on Alkali-Aggregate Reactions in Concrete, Austin, Texas, USA, pp. 10, 2012.