Impact strength of underground cement materials Vladimir I. Travush, Nikolay I. Karpenko, Vladimir T. Erofeev, Vasiliy D. Cherkasov, Denis V. Emelyanov and Irina V. Erofeeva MATEC Web Conf., 265 (2019) 01012 Published online: 30 January 2019 DOI: 10.1051/matecconf/201926501012