MATH MODELING OF CAST FINE-GRAINED CONCRETE WITH INDUSTRIAL WASTES OF COPPER PRODUCTION

Vestnik MGSU 10/2017 Volume 12
  • Kravtsov Aleksey Vladimirovich - Kostroma State Agricultural Academy (KSAA) Postgraduate student, Department of Building Technology, Management and Economy, Kostroma State Agricultural Academy (KSAA), 34 Uchebniy gorodok, Karavaevo poselok, Kostroma oblast, 156530, Russian Federation.
  • Tsybakin Sergey Valerievich - Kostroma State Agricultural Academy (KSAA) Candidate of Technical Sciences, Associate Professor, Dean of the Faculty of Architecture and Civil Engineering, Kostroma State Agricultural Academy (KSAA), 34 Uchebniy gorodok, Karavaevo poselok, Kostroma oblast, 156530, Russian Federation.
  • Kuznetsova Ekaterina Fedorovna - Kostroma State Agricultural Academy (KSAA) Candidate of Technical Sciences, Associate Professor, Department of Constrcution Technology, Management and Economy, Kostroma State Agricultural Academy (KSAA), 34 Uchebniy gorodok, Karavaevo poselok, Kostroma oblast, 156530, Russian Federation.
  • Evseeva Tatyana Michaylovna - Kostroma State Agricultural Academy (KSAA) Master's Student, Kostroma State Agricultural Academy (KSAA), 34 Uchebniy gorodok, Karavaevo poselok, Kostroma oblast, 156530, Russian Federation.

Pages 1132-1144

Subject: applying mineral microfillers on the basis of technogenic wastes of non-ferrous metallurgy in the technology of cast and self-compacting concrete. The results of experiments of scientists from Russia, Kazakhstan, Poland and India show that copper smelting granulated slag can be used when grinding construction cements as a mineral additive up to 30 % without significantly reducing activity of the cements. However, there are no results of a comprehensive study of influence of the slag on plastic concrete mixtures. Research objectives: establishment of mathematical relationship of the influence of copper slag on the compressive strength and density of concrete after 28 days of hardening in normal conditions using the method of mathematical design of experiments; statistical processing of the results and verification of adequacy of the developed model. Materials and methods: mathematical experimental design was carried out as a full 4-factor experiment using rotatable central composite design. The mathematical model is selected in the form of a polynomial of the second degree using four factors of the response function. Results: 4-factor mathematical model of concrete strength and density after curing is created, regression equation is derived for dependence of the 28-days strength function and density on concentration of the cement stone, true water-cement ratio, dosage of fine copper slag and superplasticizer on the basis of ether polycarboxylates. Statistical processing of the results of mathematical design of experiments is carried out, estimate of adequacy of the constructed mathematical model is obtained. Conclusions: it is established that introduction of copper smelting slag in the range of 30…50 % by weight of cement positively affects the strength of concrete when used together with the superplasticizer. Increasing the dosage of superplasticizer in excess of 0.16 % of the dry component leads to a decrease in the strength of cast concrete. The developed compositions of cast fine-grained concrete mixtures can be used in high-density reinforcement concrete structures with strict requirements for size of fillers and plasticity of mixture.

DOI: 10.22227/1997-0935.2017.10.1132-1144

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EFFECT OF RICE HUSK ASH ON THE PROPERTIES OF HYDROTECHNICAL CONCRETE

Vestnik MGSU 6/2018 Volume 13
  • Ngo Xuan Hung - Moscow State University of Civil Engineering (National Research University) (MGSU) Postgraduate Student, Department Technology of Binders and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Tang Van Lam - Moscow State University of Civil Engineering (National Research University) (MGSU) Postgraduate Student, Department Technology of Binders and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Bulgakov Boris Igorevich - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Associate Professor, Department of the Technology of Binders and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Aleksandrova Ol’ga Vladimirovna - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Associate Professor, Department of the Technology of Binders and Concretes, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Larsen Oksana Alexandrovna - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Associate Professor, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Ha Hoa Ky - Moscow State University of Civil Engineering (National Research University) (MGSU) Student, Department of the Construction of Unique Buildings and Structures, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Melnikova Anastasiya Igorevna - Moscow State University of Civil Engineering (National Research University) (MGSU) Student, Institute of Construction and Architecture, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.

Pages 768-777

Subject: operation of concrete and reinforced concrete hydraulic structures on river systems and in the extended coastal zone of Vietnam takes place under the influence of aggressive environments, which significantly limits their service life. Therefore, the search for ways to solve the problem of increasing the durability and terms of maintenance-free operation of such facilities is very important. Previous studies have established the possibility of increasing the operational performance of hydraulic concrete (HC) by modifying their structure with complex additives that combine the water-reducing and densification effects. The possibility of increasing the quality of hydraulic concretes by using rice husk ash (RHA) as a finely dispersed mineral additive with high pozzolanic activity was also established. Research objectives: modification of the structure of hydraulic concrete; determination of the effect of an organo-mineral modifier consisting of RHA in combination with a superplasticizer on water resistance, chloride-ion permeability and strength of hydraulic concrete. Materials and methods: portland cement of type CEM II 42.5 N was used with the addition of rice husk ashes and a superplasticizer ACE 388 “Sure Tec” BASF. Quartz sand and limestone crushed stone were used as aggregates. Composition of the concrete mixture, compressive strength of concretes, water resistance and permeability of the concrete structure for chloride ions was calculated based on methods of Russian and international standards. Results: the use of an organo-mineral modifier consisting of a water-reducing superplasticizer ACE 388 and finely dispersed rice husk ash leads to a densification of the HC structure, which increases their water resistance and decreases the permeability for chloride ions. Conclusions: it was found that the introduction of the developed organo-mineral additive into the concrete mixture leads to densification of the concrete structure, contributes not only to the growth of compression strength at the age of 28 days by 32 % for HC-10, 23 % for HC-20 and 9 % for HC-30, but also to the increase of its water resistance by one or two marks. In addition, there is a significant decrease in the permeability for chloride ions of HC samples containing 10, 20 and 30 % RHA by mass of the binder, since the average value of electric charge that have passed through the samples made of HC-10, HC-20 and HC-30 were 305, 367.5 and 382.7 K respectively against 2562 K for control samples made of non-modified concrete without RHA. (The experimental results of measuring permeability for chloride ions were obtained according to standard ASTM C1202-12). Our study has confirmed the assumption that the introduction into the concrete mix of organo-mineral modifier consisting of a polycarboxylate superplasticiser and fine ash of rice husk, up to 90 % consisting of amorphous silica, will increase the density of hydraulic concrete structure, which will increase their strength, water resistance and reduce permeability for chloride ions.

DOI: 10.22227/1997-0935.2018.6.768-777

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