Investigation of the influence of granulometric composition of the aggregate and the content of the binder on the properties of refractory concrete

Depending on the additives used, refractory concretes acquire the necessary properties: fire resistance, porosity, heat resistance, maximum application temperature, etc. The influence of the granulometric composition of the mullite aggregate and the content of the binder (cement) on the properties of refractory concrete was evaluated. MLS-62 was used as a filler (the content of the determining component Al2O3 was more than 62%), and Secar 71 high-alumina cement was used as a binder. To test the samples obtained from different granulometric compositions, the mullite aggregate was sieved in fractions (–6+3) mm, –3 mm. In the developed compositions of refractory concrete, these fractions were mixed in different percentages:(–6+3)/(–3). The cement content in the compositions varied by weight: 15%, 20%, 25%. The study was carried out in the factory laboratory, where samples of refractories of all the compositions were made by vibration pressing method. The resulting samples were dried at 110 °C and fired. It was found that after drying, samples with a cement content of 25% had the highest strength indicators content of 25% was the best result in terms of strength and shrinkage. Studies of the impact of the granulometric composition of the charge on the physical properties of refractory concrete showed that the highest strength indicators were exhibited by samples of refractory concrete with a percentage of fractions in the aggregate of 40/60 and 20/80, as well as with the highest amount of cement content in the composition – 25%.After firing at 800oC and 1300oC, the strength of the samples decreases. It was shown that the reason of this phenomenon was softening, mainly associated with dehydration of the binder. The refractory concrete obtained with the use of aggregate with a fractional composition of 20/80 and a cement.

TO THE QUESTION OF CONCRETE QUALITY CONTROL

The article provides information on the results of assessing the quality of concrete internal wall panels. The requirements of various regulatory documents for the rules for accepting a batch of concrete are considered. The procedure of statistical sampling control on a quantitative basis is described. According to the statistical data of the factory laboratory of Open Joint Stock Company “ZhBK-1” (Penza) on the quality of grade 300 concrete in the manufacture of internal wall panels, the influence of the type of cement on the variability of concrete strength indicators is considered. The influence of the type of cement on the decision to accept a batch of concrete is established. Due to the higher value of the standard deviation of the quality indicators of Haldenberg cement in comparison with Sengileevsky cement, the acceptance of a batch of concrete depends on the level of product defectiveness. It is revealed that, depending on the number of samples during testing, the decision on batch acceptance, made in accordance with GOST 10180-2012 and GOST R ISO 12491-2011, may be different. It is proposed to amend GOST 10180-2012 in paragraph 4 regarding the number of samples for testing, taking into account the requirements of GOST R ISO 12491. This will contribute to a more objective decision on the acceptance of the batch. The effect of the type of cement on the reproducibility of the production process is shown.

Physico-chemical characterization of liquid waste from sugar production unit labs in Zuenoula, Côte d'Ivoire

Managing liquid waste from the laboratories of Integrated Agricultural Unit (IAU) of Zuénoula (Côte d´Ivoire) is a major concern for the decision-makers of the company, who are working to solve this problem in their sustainable development policy. This work aims at quantifying liquid waste from the agronomic laboratories and factory of IAU of Zuénoula and to assess their level of pollution. The quantities of waste produced daily are estimated at 28.5 L, 52.6 L and 2600 L respectively for waste from the agronomy laboratory, the factory laboratory and from the rinsing water from latter's glassware. The following parameters were analyzed, temperature, pH, conductivity, turbidity, total suspended solids, COD, BOD5, total nitrogen, total phosphorus, zinc, copper, lead and mercury. The results of these analyzes generally showed that waste produced did not comply with national standards. In particular, the level of lead was very high in these liquid wastes and reached 160 times the standard value. These results require a waste treatment system, which would reduce all the parameters, in particular those of the most noxious metals (lead and mercury).Keywords: Heavy metals, Pollution, Industrial unit, Ivorian standards, Wastewater.

Use of Foam Polystyrene Waste in the Conditions of a Reinforced Concrete Products Factory

The relevance of research in the factory laboratory of JSC «198 KZHI», which is part of the HC GVSU «Center», is dictated by the need to dispose of foam polystyrene waste that occurs in large quantities when producing the precast concrete. In the production of three-layer external wall panels, polystyrene heatinsulating plates of the PPS 17-R-A brand are used as an effective insulation material. The secondary use of PPS 17-R-A for its intended purpose, as a heater, is not possible. The volume of foam polystyrene produced varies from 25 to 45 m3 per month. Utilization (disposal) of foam polystyrene waste is an expensive undertaking. Its use as a filler in the production of expanded polystyrene blocks was tested in the factory’s laboratory to produce foam polystyrene concrete with specified physical and mechanical characteristics. The results of testing of expanded polystyrene concrete of classes B2.5 and B 7.5 are presented. It is shown that under the conditions of the reinforced concrete factory technology, the production of polystyrene concrete blocks is possible with the achievement of the design strength. The information presented in the article is aimed at motivating specialists who produce recast concrete to the possibility of using foam polystyrene waste for low-rise construction. Keywords: foam polystyrene, ecology, energy efficiency, foam polystyrene concrete, foam polystyrene heat insulation plates, precast concrete.

LABORATORY METHODS OF RESEARCH OF ADHESIVE SYSTEMS

1UKRAINIAN MEDICAL STOMATOLOGICAL ACADEMY, POLTAVA, UKRAINE 2 ABSTRACT The aim of out research was to determine the effectiveness of the sealing property of adhesive systems V and VII generations by studying the depth of curing, water absorption and water solubility of their samples. Materials and methods: The study was performed according to ISO / TS 11405: 2015 at the Central Factory Laboratory of JSC “CTOMA”, Kharkiv, Ukraine, Certificate of Attestation No. 100-062 / 2015 dated 03/04/2015. For the study we used specially prepared laboratory samples which were made in the form of plates from adhesive system “DC Adhesive NF” (Dental Central) of V generation “Single bond Universal” (3M ESPE) of VII generation. А monitor and analyze the results obtained used micrometer MK-25, №4694, №03 / 5321 from 08/18/17; caliper SC-1, No. 267447, No. 03/5322 from 08/18/17; scales AP 210, №112144137, №87027 / 9 from 24.11.2017 Results: According to the results of the investigation the following results were obtained: 1) the average curing depth of V and VII generation of adhesive systems was 4.08mm and 3.51mm respectively at the rate of 2mm; 2) average water absorption: 45.97 μg/mm3 and 30.89 μg/mm3 for V and VII generations respectively; 3) the average water solubility was 6.94 μg / mm3 and 4.17 μg / mm3, respectively. Conclusions: According to the results of our laboratory studies, it can be concluded that adhesive systems of V and VII generations can be used for restoration of lesions of tooth hard tissued. Along with this, it can be recommended to use V generation adhesives in closed defects where direct polymerization should be performed and oral fluid access is minimal. Adhesive sysyems of VII generation can be recommended in such cases as: opened restorations, pregingival areas of teeth, cases where a permanent contact of restorations with oral fluid be found along with the cases of autonomic application of adhesive system.

Experimental investigation of secondary use of punched metal plate fasteners in timber structures

In this article, the possibility of secondary use of punched metal plate fasteners for timber structures is experimentally investigated. The secondary used metal plate fasteners are experimentally tested in both positions, parallel and perpendicular to the timber grain. For this purpose, the tension-to-tension test setup is used. Laboratory experiments of the secondary used metal plate fasteners are performed in parallel with the corresponding connection with the same size new metal plate fastener. All specimens for laboratory experiments are prefabricated at the factory. Laboratory experiments are done with an aim to investigate both, the reduction of the load bearing capacity and the stiffness, when metal plate fasteners are secondary used. In this article, the main design principles of joints with metal plate fasteners according to the Eurocode 5, are also discussed. The comparison between the strength and stiffness of the firstly and secondary used joints is provided. The comparison between the experimental and theoretical strength and stiffness calculation results according to the Eurocode 5 is provided too. The received results show high potential for the future research in secondary used punched metal fasteners, as the reduction of the strength and stiffness is around 20 percent, comparing with the first time used fasteners.

Rational redistribution of waste of resources. Manufacturing of equipment for cutting machine

Almost all metal at OJSC «Byelorussian Steel Works» – management company of holding «Belarusian Metallurgical Company» includes today a mandatory physical-mechanical tests which allow to estimate the parameters of the raw materials, to know the reasons for loss of strength and determine operational characteristics. In the Central Factory Laboratory (CFL), laboratory of physical and mechanical tests (LPMT) for the preparation of samples of reinforcement equipment is used of knives in the cutting machine SIMA GEL-30 for cutting rebar from the mill 320 rolling shop № 1 with a diameter from 6 to 24 mm. In the drop-hummer shop annually discards off for scrap waste up to 50 knives. Hydraulic shears of drop-hummer shop used knives set of production of OJSC «Kobrin tool plant «SITOMO», made of steel grade 30ХСНВФА, according to the TU14-1-4461. The staff of the Central laboratory LFMI proposed to use waste knives drop-hummer shop for the manufacture of knives for the chopping of the machine SIMA GEL-30. On the basis of the conducted researches the technological scheme was developed for production of knives for the chopping of the machine SIMA GEL-30 cold cutting of reinforcing bar mill 320 the rolling shop № 1.

DEVELOPMENT OF KETCHUPS RECIPES WITH TILT VISCOSITY

The article provides a comparative assessment of the requirements for the quality of ketchup in Russia and the United States. Differences in requirements relate to many indicators, including consistency. It is shown that the viscosity of ketchups is achieved in two ways: by the introduction of a certain amount of thickeners, or the development of recipes based on a special tomato paste made using the Hot Break technology. The task of the study was to determine the viscous characteristics of ketchups of different names, to select equipment for determining the viscosity of products in the factory laboratory conditions and to formulate prescriptions with specified parameters.