Comparative analysis of methods for assessing the rheological efficiency of complex modifiers in cement systems

Introduction. In practice, standard technical characteristics (such as cone slump, mixture spread diameter, etc.) are used as indicators of the efficiency of plasticizing additives. However, these characteristics make it difficult to judge the rheological properties of cement systems. This paper is devoted to analyzing the correlation between mobility indicators and rheological characteristics, as well as the regulation of rheological parameters of cement mixtures considering electro-surface phenomena.

Materials and methods. Fine fillers (quartz, marble) with different electro-surface properties (Ssp = 300 and 600 m2/kg) were used. The binder was CEM I 42.5 N produced by CJSC “Oskoltsement”; chemical additives included the superplasticizer Polyplast SP-1 and the superplasticizer Sunbo 2021. Rheological characteristics of the dispersions were determined using a Rheotest RN 4.1 rotational viscometer, and mobility was assessed with a mini-cone. Surface microanalysis was conducted using a TESCAN MIRA 3 LM scanning electron microscope. Specific surface area was measured with a PSKh-10a device, and the electrokinetic potential of particle surfaces was measured using a Zetasizer Nano ZS.

Results. It was shown that the greatest thinning effect was observed in suspensions where the predominant surface charge of mineral filler particles was opposite to the charge of the functional group of anionic plasticizing additives, and vice versa. It was revealed that the type of mineral filler had a stronger impact on mobility indicators than on rheological characteristics. A correlation between plastic viscosity and mobility (spread diameter) was established. Based on the analysis of the obtained rheological data and mobility, flow regions of cement dispersions were identified.

Conclusions. The use of fine powders positively influences the flowability of cement dispersions, with marble filler being more effective than quartz. In the region of moderate dispersion thinning (spread diameter = 60–170 mm), the cone spread is consistent with the rheological properties of cement systems. Practical application of the research results presented in this paper will enhance the efficiency of superplasticizers and superplasticizers and simplify the assessment of the rheological flow regime of dispersions.

1. Tolypina N., Tolypin D. Influence of mineral fillers on the liquishing of cement systems with the help of surfactants. Bulletin of Belgorod State Technological University named after V.G. Shukhov. 2022; 9:26-33. DOI: 10.34031/2071-7318-2022-7-9-26-33. EDN ENFGLL. (rus.).

2. Rakhimbaev Sh.M., Tolypina N.M., Khakhaleva E.N. Interrelation between plastic viscosity of cement systems and their rethehnological characteristics. The Russian Automobile and Highway Industry Journal. 2018; 15(2):(60):276-282. EDN XSDGCL. (rus.).

3. Lesovik V.S., Elistratkin M.Yu., Salnikova A.S., Kazlitina O.V. On the issue of improving the efficiency of high-strength self-compacting concretes. Regional Architecture and Engineering. 2021; 1(46):20-27. EDN DIRJUN. (rus.).

4. Ledenev A., Kozodaev S., Percev V., Bara-nov E., Zagoruyko T., Vnukov D. Mechanisms of act of various kinds of organic mineral additives in cement system. Bulletin of Belgorod State Technological University named after V.G. Shukhov. 2021; 9:8-19. DOI: 10.34031/2071-7318-2021-6-9-8-19. EDN UFSCDT. (rus.).

5. Ghosal M., Chakraborty A.K. Superplasticizer compatibility with cement properties — a study. Materials Today: Proceedings. 2022; 56:568-573. DOI: 10.1016/j.matpr.2022.02.386

6. Shakhova L.D. On the compatibility of cements with plasticizing additives. Journal Cement and its Applications. 2024; 4:48-55. EDN DTZPCT. (rus.).

7. Ortiz-Álvarez N., Lizarazo-Marriaga J., Bran-dão P.F.B., Santos-Panqueva Y., Carrillo J. Rheological properties of cement-based materials using a biopolymer viscosity modifying admixture (BVMA) under different dispersion conditions. Cement and Concrete Composites. 2021; 124:104224. DOI: 10.1016/j.cemconcomp.2021.104224

8. Du J., Meng W., Khayat K.H., Bao Y., Guo P., Lyu Z. et al. New development of ultra-high-performance concrete (UHPC). Composites Part B: Engineering. 2021; 224:109220. DOI: 10.1016/j.compositesb.2021.109220

9. Pertsev V.T., Ledenev A.A. Development of effective complex organomineral additives for regulating the rheological properties of concrete mixtures : monograph. Voronezh, VSUACE, 2012; 135. EDN QNQCST. (rus.).

10. Chen J., Qiao M., Gao N., Wu J., Shan G., Zhu B. et al. Acrylate based post-acting polymers as no-vel viscosity modifying admixtures for concrete. Construction and Building Materials. 2021; 312:125414. DOI: 10.1016/j.conbuildmat.2021.125414

11. Ferraz D.F., Martho A.C.R., Burns E.G., de Oli-veira Romano R.C., Pileggi R.G. Effect of prehydration of Portland cement on the superplasticizer consumption and the impact on the rheological properties and chemical reaction. Revista IBRACON de Estruturas e Materiais. 2023; 16(2). DOI: 10.1590/s1983-41952023000-200010

12. Zhang Q., Chen J., Zhu J., Yang Y., Zhou D., Wang T. et al. Advances in organic rheology-modifiers (chemical admixtures) and their effects on the rheological properties of cement-based materials. Materials. 2022; 15(24):8730. DOI: 10.3390/ma15248730

13. Rakhimbaev Sh.M., Logvinenko A.A. Rheological properties of materials for transport infrastructural construction. News of Higher Educational Institutions. Construction. 2014; 5(665):26-33. EDN SQTAGF. (rus.).

14. Khayat K.H., Meng W., Vallurupalli K., Teng L. Rheological properties of ultra-high-performance concrete — an overview. Cement and Concrete Research. 2019; 124:105828. DOI: 10.1016/j.cemconres.2019.105828

15. Qiao M., Chen J., Gao N., Shan G., Wu J., Zhu B. et al. Effects of adsorption group and molecular weight of viscosity-modifying admixtures on the properties of cement paste. Journal of Materials in Civil Engineering. 2022; 34(7). DOI: 10.1061/(ASCE)MT.1943-5533.0004296

16. Ji X., Pan T., Zhao W., Liu J., Sha J., Han F. Interaction of superplasticizers with C3A: Understanding the superplasticizer compatibility with cement. Journal of Materials in Civil Engineering. 2023; 35(9). DOI: 10.1061/JMCEE7.MTENG-15185

17. Shrihari S., Seshagiri Rao M.V., Srinivasa Reddy V., Manasa A. Compatibility assessment of commercial cements with superplasticizers. E3S Web of Conferences. 2020; 184:01079. DOI: 10.1051/e3sconf/20201-8401079

18. Lesovik V.S., Sheremet A.A., Chulkova I.L., Zhuravleva A.E. Geonics (Geomimetics) and search for optimal solutions in building materials science. The Russian Automobile and Highway Industry Journal. 2021; 18(1):(77):120-134. DOI: 10.26518/2071-7296-2021-18-1-120-134. EDN HMWWZK. (rus.).

19. Lesovik V.S., Fomina E.V. The new paradigm of designing construction composites to protect the human environment. Vestnik MGSU [Monthly Journal on Construction and Architecture]. 2019; 14(10):1241-1257. DOI: 10.22227/1997-0935.2019.10.1241-1257. EDN NPNPBT. (rus.).

20. He D., Lu Z., Liang X., Liu R., Sun G. A study to improve the compatibility of PCE with cement paste containing clay. Materials Letters. 2022; 308:131111. DOI: 10.1016/j.matlet.2021.131111