PSI - Issue 42

Martina Drdlová et al. / Procedia Structural Integrity 42 (2022) 1391–1397 Drdlova et al/ Structural Integrity Procedia 00 (2022) 000 – 000

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-Vacuum mixing does not bring substantial benefits if the samples are further hydrothermally treated. The samples hydrothermally treated in the same conditions showed similar compressive strength values and only negligible increase of flexural strength, regardless of the preparation method. This can be stated for both quasistatic and high strain rate regimes. -Increase in peak stress values is achieved by hydrothermal treatment, with higher values connected with higher temperature and dwell time. -The pressure developed at the first stage of the curing period does not provide a significant benefit in the form of an increase in mechanical parameters. It may be related to the consistency of the mixture, which was soft and flowable and thus not very suitable for applying pressure. -The optimum manufacturing process for achieving maximum compressive strength at high strain rates is hydrothermal treatment, without the need to involve the more technologically complex step of vacuum mixing. The presented research is a part of the development process of high-performance ballistic resistant composites. The results will be used for design of the composite panels for protection against ballistic load in the A2-A4 level according to STANAG 2280 standard. Acknowledgements The authors wish to express their gratitude and sincere appreciation to the authority of the Ministry of the Interior of Czech Republic, project No. VI20192022129, for financial support. References Abid, M., Hou, X., Zheng, W, Hussain R.R., 2017. High temperature and residual properties of reactive powder concrete – a review. Construction and Building materials 147, 519. Ahmad, S. Zubair, A., Maslehuddin, M., 2015. Effect of key mixture parameters on flow and mechanical properties of reactive powder concrete. Construction and Building materials 99. Ahmed, S et al. 2021. Impact of using different materials, curing regimes, and mixing procedures on compressive strength of reactive powder concrete – a review. Journal of Building Engineering 44. Cao, S. et al. 2019. Effect of specimen size on dynamic compressive properties of fiber-reinforced reactive powder concrete at high strain rates. Construction and Building materials 194. Costovos, D.M., Pavlovic, M.N. 2008. Numerical investigation of concrete subjected to compressive impact loading. Part 1: A fundamental explanation for the apparent strength gain at high loading rates, Computer Structures 86. 1–2. Davies, E.D.H. and Hunter, S.C. 1963. The dynamic compression testing of solids by the method of the split Hopkinson pressure bar. Journal of mechanics and physics solids 11. 3. Drdlova, M., Popovic, M., Cechmanek, R., 2016. High strain rate compressive behavior of micro-fibre reinforced fine grained cementitious composite. Solid state phenomena 276. Drdlova, M., Gozzani, G., Prachar, V, Popovic, M. 2016. Characteristics of glass- based energy absorbers exposed to the blast load. Procedia engineering 151. Hiremath, P.N., Yaragal, S.C. 2017. Effect of different curing regimes and durations on early strength development of reactive powder concrete. Construction and Building Materials 154. Hiremath, P.N., Yaragal, S.C. 2017. Investigation on mechanical properties of reactive powder concrete under different curing regimes. Materials Today: Proceedings 4. 9. Mostofinejad, D., Nikoo, M.R., Hosseini, S.A. 2016. Determination of optimized mix design and curing conditions of reactive powder concrete (RPC). Construction and Building materials 123. Richard, P., Cheyrezy, M. 1995. Composition of reactive powder concretes. Cement and Concrete research 25. 7. Vojtisek et al, 2021, HPC cement materials prepared by mixing under reduced pressure. IOP Conference Series: Materials science and engineering 1039. Xun, H., Ronghua, Z., Yinghu, L. 2020. Influence of curing regime on properties of reactive powder concrete containing waste steel fibres. Construction and Building materials 232. Yazici, H., Deniz, E., Baradan, B. 2013. The effect of autoclave pressure, temperature and duration time on mechanical properties of reactive powder concrete. Construction and Building materials 42. Zdeb, T. 2019. Effect of vacuum mixing and curing conditions on mechanical properties and porosity of reactive powder concretes. Construction and Building Materials 209.