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KEY WORDS:
chemical industry, wastes, cements, ecology
ABSTRACT:
The chemical industry is one of the industries that is the material and technical basis for the chemicalization of the entire national economy, which transforms all varieties of natural mineral and organic raw materials into a wide range of various products. At the same time, the chemical industry is one of the largest sources of the modern world environmental problem associated with environmental pollution by wastes and by-products. Scientific studies and practical adoption experience have established the efficiency of chemical industry wastes as a valuable secondary raw material in the production of mineral binders and building materials based on them, the possibilities of which are not being realized enough.FOR CITATION: Rakhimov R.Z. Chemical Industry, Ecology and Mineral Binders // Technique and technology of silicates. 2022.Vol. 29. No2. Pp 10 4 – 111.
KEY WORDS:
gypsum, gypsum binders, hydrophobic chemicals, biocides
ABSTRACT:
Low-melting glasses in the ZnO-B2O3-SiO2 system of eutectic composition doped with transition metal ions (Сo2+, Mn2+, Ni2+, Cu2+) have been obtained. When studying the IR spectrum in the range of 400 - 2000 cm-1, the main structural groups of zinc borosilicate glass were established: [SiO4], [ВО3], [ВО4] and [ZnO4]. The study of the spectra of doped glasses in the visible range (200 - 1100 nm) showed the presence of intense absorption bands, on the basis of which the coordination of transition metal ions was determined: tetrahedral - for Сo2+, Mn2+; octahedral - for Ni2+, Cu2+ ions.KEY WORDS:
metakaolin, compressive strength, polypropylene fiber, reinforced concrete
ABSTRACT:
This paper studies the effect of high-reactivity metacaolin on the properties of polypropylene fiber reinforced concrete. Compressive strength, splitting tensile strength, flexural strength and impact resistance test were investigated. The content of high-reactivity metakaolin (HRM) was 5%, 10%, 15% and 20% with 0.5%, 1%, 1.5% and 2% of polypropylene fibers by concrete volume. The results show that the reference sample of concrete with 2% of polypropylene fibers perform a significant increase in compressive, tensile and flexural strength compared to the reference samples by 29.6%, 30.7%. and 17.9% respectively after 28 days. The results also show that the introduction of 15 wt.% of metacaolin as a partial replacement of cement with 0.5% polypropylene fibers showed a slight improvement in compressive strength, but the tensile strength and flexural strength increased significantly. The maximum flexural and tensile strength of modified concrete reinforced with polypropylene fibers is 6.4 MPa and 4.93 MPa, respectively, which is 17.64% and 15.18% higher than the reference strength of concrete.FOR CITATION: Abbasova S.I. The effect of metacaolin on the properties of polypropylene fiber reinforced concrete // Technique and technology of silicates. 2022. Vol. 29. No2. Pp 127 – 137.
KEY WORDS:
cement, alkali, marl, limestone, dolomite
ABSTRACT:
The development of mineral binders, taking into account the increasing requirements for the sustainable development of the construction industry, requires the development of new varieties of binders based on available and widespread mineral raw materials and the expansion of their raw material base. This paper presents the results of studies of the influence of formulation and technological parameters on the properties of alkali-activated cements based on clay-carbonate raw materials - marl, limestone, dolomite. The optimal parameters for obtaining non-clinker alkali-activated cements with compressive strength up to 43.9 MPa have been determined.KEY WORDS:
antifreeze additive, water and frost resistance of concrete, delamination, polycarboxylates.
ABSTRACT:
In the far north regions during continuous concreting in winter it is necessary to use complex antifreeze additives. They prevent freezing of the concrete mixture and eliminate the negative effect after thawing during subsequent hardening. The use of complex antifreeze additives consisting of polycarboxylate esters, polyatomic alcohol derivatives and carboxylic acid salts has been showed. It has been established that complex anti-freeze additive significantly reduces the water content of concrete mixtures and prevents their segregation. The positive effect of complex antifreeze additives on the performance of concrete mixtures, as well as the strength, water resistance and frost resistance of concrete is shown. It was found that the strength of concrete at the age of 3 days reaches 70% of the designed, and at the age of 28 days exceeds it by 110%. The use of complex antifreeze additives in design of concrete compositions for monolithic concreting at negative temperatures proves the expediency of the application.ABSTRACT:
The issues of production of high-performance composite materials with improved physical-mechanical and construction-technical properties using the waste products of industrial enterprises are becoming more and more actual. The paper considers the formation of the structure of porous slag silicate wood chip concrete material and studies the contact zone of slag silicate porous composite with wood chips in wood chip concrete materials. With the help of XRF, TGA and SEM analysis methods the nature of neoplasms arising during hardening of slag silicate porous composite has been established. It was shown that on the surface of the wood there is the formation of neoplasms of similar nature as in the slag silicate stone itself, namely: low-basic hydrosilicates and hydroaluminosilicates of different composition, this greatly increases the water resistance of the wood chip concrete material. During tests to measure water absorption of wood chips obtained directly from slag silicate porous wood chip concrete, it was found to decrease to 68%.KEY WORDS:
superplasticizer, zetta potential, steric effect, gypsum-based complex binder
ABSTRACT:
Reducing water demand and increasing the mobility of cement systems is an urgent problem that scientists and practitioners are working to resolve. This study presents the results of comparative studies of the effectiveness of various types of polycarboxylate plasticizers with different steric effects on reducing water demand and increasing strength, both in compression and in bending at constant solution mobility for a gypsum-based complex binder. It has been established that with late liquefaction it is advisable to use a superplasticizer with a higher zetta potential. With a rapid drop in the mobility of the solution over time, it is necessary to consider the possibility of using a superplasticizer with a low zetta potential. It is shown that the use of superplasticizers with an optimized ratio of the steric effect and zeta potential in systems based on a complex binder makes it possible to obtain higher strength both in compression and in bending.KEY WORDS:
specialty cements, expanding cements, sulphated clinkers, corrosion resistant cements, aluminate cements, ultrafast (superfast) setting cements
ABSTRACT:
Modern capital construction is based on new technologies and methods of its implementation. The use of concrete and reinforced concrete structures in modern construction requires close attention to the properties of Portland cement stone, which shrinks during hardening and drying. The shrinkage of cement stone causes tensile stresses that exceed the tensile strength of concrete, resulting in cracks. It is necessary to develop special effective cements that increase the technical level in the construction industry. This important problem can be solved by developing the compositions and technologies of expanding cements. At present, a large number of special cements with different mechanism of action, compositions and properties are known. In modern building materials science, the main problem of obtaining effective building materials is the modification of known cements to improve their properties and expand their scope. The objective of the study is to consider various types of special cements: expanding, aluminous, ultra-fast-hardening, corrosion-resistant. The methodological basis is the analysis of literature data on the problem of obtaining and using cements based on sulfated clinkers, which provide a solution to important technical problems that arise during the construction of various structures. Result of the study: it was found that these cements provide a rapid set of strength, high density of mortars and concretes, and corrosion protection from aggressive media. Depending on the conditions of use and requirements for the properties of cement, it is possible to regulate the compositions and technology of sulfated clinkers and composite cements based on them.