Polycarboxylate superplasticizers based on methacrylic acid and methoxylated polyethylene glycol with a molecular weight of 1000 were synthesized by the method of co-administration of monomers in the mixture. The suitability of using the resulting mixture of monomers for the synthesis of polycarboxylates, by the method of radical polymerization, is shown. The influence of the obtaine superplasticizers on the spreadability of cement-sand paste based on cement of 3 Belarusian manufacturers (OJSC «Krasnoselskstroymaterialy» – OJSC «Belarusian Cement Plant» – OJSC «Krichevcementnoshifer») was ivestigated. It was found that the effectiveness of plasticizing additives based on polycarboxylates depends significantly on their molecular weight and tricalcium aluminate content in cement. It has been established that for cement with a lower content of tricalcium aluminate C3A, the greatest efficiency is achieved for samples with medium mean sizes of macromolecules providing an optimal ratio of the rate of adsorption to the content in the aqueous phase. For cement with a high C3A content, a low molecular weight sample, which is adsorbed in the C3A phase, is more effective. Testing the properties of chemical additives was carried out at the Department of Chemical Technology of binders Belarusian State Technological University. The effectiveness of the plasticizing action of the synthesized samples of these chemical additives was carried out on a cement-sand mixture in the ratio of 1 to 3, using for this purpose the cement grade CEM I 42.5N.
Ключевые слова: tricalcium aluminate, molecular weight, methacrylic acid, copolymer, spreadability, intrinsic viscosity.
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СПИСОК ИСПОЛЬЗОВАННЫХ ИСТОЧНИКОВ
1. Cement industry of Belarus, electronic edition. Uniter. 2015. http://investinbelarus.by/docs/Cement.pdf
2. Ramachandran V. S., Malhotra V. M., Jolicoeur C., Spiratos N. Superplasticizers: Properties and Applications in Concrete. CANMET, Ottawa, Canada, Center for Energy and Technology. 1998. p. 404.
3. Wiliński D., Łukowski P., Rokicki G. Polymeric superplasticizers based on polycarboxylates for ready-mixed concrete: current state of the art. POLIMERY. 2016, 61. No. 7–8. pp. 474 –481. (pl)
4. Lei L., Plank J. A concept for a polycarboxylate superplasticizer possessing enhanced clay tolerance. Cement and Concrete Research. 2012. No. 42. pp. 1299 -1306.
5. Liu Ming [at all] Preparation of polycarboxylate-based superplasticizer and its effects on zeta potential and rheological property of cement paste . J. Wuhan Univ. Technol. Mater. Sci. Ed. 2015. 30. No. 5. pp. 1008-1012.
6. J. Plank , K. Pöllmann, N. Zouaoui, P.R. Andres, C. Schaefer. Synthesis and performance of methacrylic ester based polycarboxylate superplasticizers possessing hydroxy terminated poly(ethylene glycol) side chains. Cement and Concrete Research 38 (2008) 1210–1216.
7. Tan H., Qi C., Ma B., Li X., Jian S. Effect of polycarboxylate superplasticiser adsorption on fluidity of cement–clay system. Materials Research Innovations. 2015. Vol. 19. pp. 423–428.
8. Effect of Molecular Weight of Polycarboxylate Superplasticizer on Its Dispersion, Adsorption, and Hydration of a Cementitious System Qianping Ran; Jinzhi Liu; Yong Yang3; Xin Shu4, Jiangang Zhang, Yonglin Mao. J. Mater. Civ. Eng., 04015184 pp. 1–6.
9. Effect of PCs superplasticizers on the rheological properties and hydration process of slag-blended cement pastes M. Palacios, F. Puertas, P. Bowen, Y. F. Houst. J Mater. Sci. 2009. Vol. 44. pp. 2714–2723.