MECHANOCHEMICAL ACTIVATION OF PORTLAND CEMENT AND ITS INFLUENCE ON THE THERMOMECHANICAL CHARACTERISTICS OF CEMENT-WATER COMPOSITIONS AND SOLUTIONS BASED ON THEM
DOI:
https://doi.org/10.31650/2786-6696-2024-8-43-49Keywords:
mechanical activation, rotary high-speed mixer, activation, exothermic heating, water-binder ratio, ground quartz sand.Abstract
Issues discussed in the article related to determining the influence of mechanical activation in a rotary high-speed mixer of cement-water compositions and solutions based on them. Relevant for this study is the activation of cement in combination with the consumption of ground quartz sand (S = 250 m2/kg), the amount of which was adjusted in the range from 0 to 40 % of the cement mass. The use of this technology, along with reducing cement consumption, ensures acceleration of the processes of cement hydration and intensification of exothermic heating of the hardening composition. Mechanical activation is also reflected in the acceleration of the loss of mobility of cement-water compositions filled with ground sand. The presented experimental data made it possible to evaluate the influence of the activation times (90 and 180 sec) of the binder on the diameter of the spread of the aqueous cement-containing composition. It has been established that the main contribution (up to 90 % of the total value) to the decrease in the water-binder ratio (provided that equal-viscosity compositions are obtained) is achieved when the cement-containing composition is activated for 90 seconds. Subsequent activation of the binder (up to 180 sec) has a slight effect on the growth of the diameter of the composition spread and does not exceed 5-10 %.
The exothermia of the hardening cement-water composition determined by the thermos method indicates a significant influence of mechanical activation both on the kinetics and on the achievement of the maximum temperature of its heating. The introduction of ground sand does not change the overall picture of the effect of mechanical activation on exothermic heating, changing only the decrease in intensity and the decrease in maximum heating of the cement-water composition.
The influence of mechanical-chemical activation of Portland cement with the addition of quartz sand on the strength of a 1:1 mortar at 3 and 7 days of age was revealed. Experimental studies indicate a positive effect of binder activation on the compressive strength of the mortar. The increase in strength of samples using mechanically activated cement reached 15-25 % compared to the control.
References
[1] Runova R.F., Kosovsky Yu.L. Technology of modified mortars. Kyiv: KNUSA, 2007, 256 p.
[2] Koval S.V. Modeling and optimization of the composition and properties of modified concrete. Odessa: Astroprint, 2012, 424 p.
[3] Dvorkin L.I. and others Effective technologies of concrete and mortars with hardening of technogenic raw materials / L.Y. Dvorkin, V.V. Zhitkovsky, V.V. Marchuk, Y. Stasyuk, M.M. Violinist. Monograph. Rivne: NUVKhP, 2017, 424 p.
[4] Sanitsky M.A., Kropivnitskaya T.P., Gevyuk V.M. Fast-hardening clinker-effective cements and concretes. Monograph. Lviv: Prostir-M LLC, 2021, 206 p.
[5] Solodky S.Y. Crack resistance of concretes based on modified cements/ S.Y. Solodky// Lviv: Publication of the National Institute "Lviv Polytechnic". 2008. -144 p.
[6] Vyrovoy V.N. Composite building materials and structures. Structure, self-organization, properties / V.N. Vyrovoy, V.S. Dorofeev, V.G. Sukhanov//Odessa: Publishing house "TES", 2010. 176 p.
[7] Runova R.F. Construction materials of the new generation and technologies of their implementation in construction/ R.F. Runova, V.I. Hotz, M.A. Sanytskyi et al./ K: UVPK "Ex Ob", 2008. 360p.
[8] Barabasch I.V., Babiy I.M., Streltsov K.O. Intensive individual technology and its impact on the properties of cement -Water compositions, solutions and concretes on their base // Modern structure and architecture, Issue N2. Odessa State Academy of Civil Engineering and Architecture, 2022. P. 44-51.
[9] Shpirko M.V., Dubov T.M. Study of the effect of electromagnetic activation of a concentrated cement suspension on the properties of cement stone and concrete / Bulletin of PDABA, 2020, N2 (263-264). pp. 102-107.
[10] Gots V.I. Concrete and mortars Kyiv: UVPK Eks Ob, 2003. 468 p.
[11] Fedorkin S.I. Mechanical activation of secondary raw materials in the production of building materials. /Simferopol: Tavria, 1997. 180 p.
[12] Dvorkin L.I., Dvorkin O.L., Garnitsky Yu.V. Modified ash-containing dry construction mixtures for stone and adhesive mortars. NOOOOT. Smooth. 2013. 325 p.
[13] Heinicke G. Tribochemistry. Per. from German, 1987. 584 p.
[14] Charnetsky L. The future of concrete / L. Charnetsky, V. Kurdovsky // IX International. science and practice conference: Zaporizhzhia, 2007. – pp. 13–21.
[15] Rusyn B.G. High-performance concretes based on Portland cement modified with ultradisperse mineral additives: author. thesis for obtaining sciences. Art. Ph.D. for special 05.23.05/ NU "Lviv Polytechnic". Lviv. 2014. 21 p.
[16] Aktivation des Betonanmachwasser. / A. Kudyahow, G. Semyonova, Y. Sarkisow [etc.] // Tagungbericht, Band 2. Weimar, Deutschland, 1997. S.20501 – 20507.
[17] Bratchun V. I., Zaichenko L. G. Optimization of factors of electromagnetic activation of concrete mixtures / Bulletin of OGASA: Odessa, 2005. Vol. No. 20. pp. 40-46.
[18] Sanchez F., Sobolev K. Nanotechnology in concrete - a review / Construction and Building Materials, 2010. V. 24. P. 2060-2071.
[19] Kondratyeva N.V. Nanotechnologies in the production of construction materials / N.V. Kondratieva / Construction of Ukraine, 2012. No. 6. pp. 2-9.
[20] Maslov A.G. Development of an installation for vibromechanical processing of building mixtures / A.G. Maslov, Yu.S. Salenko, E.V. Stukota // Bulletin of the Kharkov National. highway un-ta. Vol. 57, 2012. P.59-62.
[21] Vyrovov V.N. et al. Mechanical activation in concrete technology. OGASA. 2014.148 p.
[22] Usherov-Marshak A.V., Kabus A.V. Functional-kinetic analysis of the influence of additives on the hardening of cements / Inorganic materials, 2016. Volume 52, N4. pp. 479-484.
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