Non-metallic Composite Reinforcement Research Articles

Strength and uniformity of composite reinforced columns

Development prospects reinforced concrete are inextricably linked with the use of both new materials and and their combinations with already proven traditional materials. Transition of construction to non-metallic composite reinforcement will help reduce operating costs for structures, located in aggressive environments and reduce the cost of living design cycle due to extended repair intervals. Yes, according to research shows reduced life cycle costs structures with composite non-metallic reinforcement can reach 53–205% over 100 years compared to a similar design with traditional steel reinforcement. At the time of this study, there was no method calculation of centrally compressed concrete elements reinforced glass composite fittings. The development of such a methodology will allow correctly assess the load-bearing capacity of compressed elements with composite reinforcement. The use of non-metallic, and mainly glass-composite, reinforcement in building structures has previously been insufficiently studied due to its relatively high cost. Currently, in our country there is a lack of research into compressed structures with glass-composite reinforcement. The need to study the operating features of such structures, as well as insufficient knowledge of the influence of glass-composite reinforcement on the strength and deformability of compressed glass-composite concrete elements determined the relevance of this study.

CARBON FOOTPRINT OF A CONCRETE TRANSPORT STRUCTURE - A DEEP TUNNEL

The research object of this scientific work is the massive concrete structures of underground low-deep transport tunnels, reinforced with steel and non-metallic composite reinforcement. Circular-section tunnels with the frame nominal diameters of 5, 10 and 15 m are considered. The subject of the research study is the assessment of the averaged carbon footprint in both types of the constructive solution throughout their entire life cycle. The presented research is due to the need to implement the European Climate Law (the European Green Agreement. At the same time the Paris Agreement (2016) recommends to stop producing and using carbon steel in construction by 2030. The ecological impact of both types of transport tunnels is expressed in the form of carbon footprint, as the equivalent of carbon dioxide emissions, which is calculated separately for each stage of their existence in accordance with the current European Codes, including the recommendations of the proprietary methodology. To determine the required sizes of the tunnels concrete frames and their reinforcement, the numerical routine (B3) experiment was carried out in PLAXIS software complex in accordance with the current regulations. Averaged according to three different diameters and generalized carbon dioxide emissions during the life cycle of the reference structure (type 1) and proposed one (type 2) of the underground transport tunnel with the length of 1 m.p. were, respectively, 15.97 t СО2 eq and 11.551 t СО2 eq, i.e. decreased by almost 1.4 times. The conducted research made it possible to analyze the carbon dioxide emissions into the atmosphere, to systematize the existing factors and impact factors of the specified building on the environment, and to determine the ways of their reduction. The possibility and expediency of using basalt-plastic reinforcement instead of steel in monolithic concrete structures, incl. transport tunnels, according to the criterion of reducing greenhouse gas emissions are proved. Keywords: carbon footprint, carbon dioxide emissions, underground transport tunnel, monolithic heavy concrete, steel and non-metallic composite reinforcement, construction life cycle, stage, information group (module).

Advanced hybrid nonmetallic composite reinforcement for concrete structures

During the last decades, fiber reinforced polymer (FRP) reinforcing bars for concrete structure has been extensively investigated and a number of FRP bars became commercially available. However, major shortcomings of the existing FRP bars are its low elastic modulus and high initial cost compared to conventional steel bars. The possibility to obtain a hybrid composite reinforcement (HCR) with increased performance based on glass and carbon fibers (GCFRP) is considered. The optimal content of carbon fibers in the amount of 6.3 − 6.5 % of the mass of the HCR was established. Further increase in the carbon fiber content gives a slight improvement in physical and technical characteristics, which is not comparable to the increase in the cost of the material. The manufacturing technology of HCR has been developed. The effect of hybridization on tensile properties of FRP bars were obtained by comparing the results of tensile test with those of non-hybrid GFRP bars. Operation regularities of HCR in the bent concrete beams are established. HCR can increase the stiffness of concrete beams by 15 % and crack resistance by 12 % in comparison with glass composite reinforcement. Dependences for predicting the HCR elasticity modulus are established. Physical and technical characteristics of HCR, including adhesion to concrete and resistance to the alkaline medium, were established. High durability of HCR for more than 50 years is experimentally shown. Experimental-industrial concrete piles, reinforced with GCFRP bars were produced and tested. For further development, new types of HCR, as well as a study of prestressed concrete structures are recommended.

Effect of Non-Metallic Composite Reinforcement on Load-Bearing Capacity

It is known that non-metallic composite reinforcement was invented in the 60's of the last century, and already then, a large number of scientists began to investigate its physical and mechanical characteristics. Despite its rather old age, this reinforcement has not been sufficiently studied for its work in building structures. Fiberglass composite reinforcement (Arvit) is a high quality construction material with many advantages: 4-5 times less weight compared to metal of the same diameter; it does not rust or oxidize; tensile strength is 2 times higher than metal reinforcement; it does not conduct electricity; high resistance to temperature changes from -70 to +200 ° C; easy to transport. The distinctive features of work of fiberglass composite reinforcement in bending spacer elements are still insufficiently studied, which in design and production practices leads to the non-use of such reinforcement in the construction of elements of buildings and structures. The experimental results of the test specimens are presented in the article. In first test specimen, longitudinal working reinforcement was made of two metal rods Ø8 class A400S, in second - two fiberglass rods Ø8 AKS 600.

НЕЛІНІЙНА ДЕФОРМАЦІЙНО-СИЛОВА МОДЕЛЬ БЕТОННОГО СТЕРЖНЯ З НЕМЕТАЛЕВОЮ КОМПОЗИТНОЮ АРМАТУРОЮ У ЗАГАЛЬНОМУ ВИПАДКУ НАПРУЖЕНОГО СТАНУ

The article discusses a nonlinear deformation-force model of a concrete bar structure with a non-metallic composite reinforcement (NKA-FRP) in the general case of a stressed state, when all four internal force factors from an external load (namely, bending and twisting moments, transverse and longitudinal forces). A sufficiently deep and meaningful analysis of well-known studies on the selected topic is given. It has been established that the proposed nonlinear deformation-force model of a bar structure with FRP in the general case of a stressed state can be practically useful due to the possibility of its application in the design or reinforcement of beams, girders, columns and elements of rosette trusses of rectangular cross-section, which are operated under aggressive environmental conditions. This model can also be used to check the bearing capacity of existing FRP concrete bar structures, which operate not only under the influence of an aggressive environment, but also under conditions of a complex stress-strain state. In the course of the research, an algorithm was developed for determining the bearing capacity of the design section of a concrete rod with FRP under its complex stress state. General physical relations for the design section are given in the form of a stiffness matrix. The algorithm for calculating a concrete bar with FRP consists of a block for inputting the initial data, the main part, auxiliary subroutines for checking the conditions for increasing the load vector and depletion of the bearing capacity, as well as a block for printing the calculation results. At each stage of a simple static stepwise increasing load, the calculation is carried out by performing a certain number of iterations until the accuracy of determining all components of the deformation vector satisfies a certain predetermined value. The features and patterns of changes in normal and tangential stresses, generalized linear and angular deformations, as well as the equations of equilibrium of a concrete bar with FRP, which operates under the influence of an aggressive environment under conditions of a complex stress state, are also considered.

Дослідження неметалевої композитної базальтової арматури періодичного профілю та перспективи її застосування

Дослідження неметалевої композитної базальтової арматури періодичного профілю та перспективи її застосування

Дослідження впливу зміни співвідношення вмісту сталевої та базальтопластикової арматури на показники міцності балок із гібридним армуванням

Introduction.The current stage of development of the construction industry is associated with the introduction of new materials into practice, compared with the «traditional» (steel, concrete, wood) have certain advantages in the form of improved strength, corrosion resistance, etc. These materials include non-metallic composite reinforcement.Problems Statement. The main disadvantage of non-metallic composite reinforcement (except for carbon fiber reinforcement) is significantly lower modulus of elasticity compared to metal reinforcement. This is the reason for the occurrence of excessive deformations in concrete structures, does not ensure the fulfillment of the requirements for the second group of limiting states. One of the ways to reduce the de-formations of concrete structures, without a significant increase in the percentage of reinforcement of the section, is the use of hybrid reinforcement, when reinforcement is performed simultaneously with metal and composite reinforcement. Currently, there is a very limited amount of experimental data on the stress-strain state of structures with such reinforcement.Purpose. Research of the stress-strain state of structures with hybrid reinforcement, establishing its effectiveness and the optimal ratio of the content of metal and composite reinforcement to achieve sat-isfactory strength and stiffness of a concrete structure.Materials and Methods. The work of beams under load, reinforced with basalt-plastic reinforce-ment, metal reinforcement (control series) and with hybrid reinforcement with metal and basalt-plastic re-inforcement simultaneously was researched. To find out the effect of changes in the content of basalt-plas-tic reinforcement in relation to metal on the performance of beams with hybrid reinforcement, various series of samples of beams with different ratios of basalt-plastic and metal reinforcement.Results. On the basis of the conducted studies, the nature of the work and destruction of concrete beams with hybrid reinforcement was assessed depending on the percentage of metal and basalt-plas-tic reinforcement. The strength indicators of concrete beams with hybrid reinforcement were obtained and analyzed. The test results showed that the strength of beams with hybrid reinforcement increased in comparison with beams of the control series and was at the level of beams reinforced with basalt-plastic reinforcement. At the same time, the deflections and crack width of the beams decreased.Conclusion. The use of hybrid reinforcement makes it possible to increase the bearing capacity of concrete beams, depending on the percentage of reinforcement in the section. The determining factors for the strength of beams with hybrid reinforcement are the strength of the concrete in the compressed zone and the percentage of section reinforcement. The optimal percentage of the ratio of metal and basalt reinforcement in concrete beams with hybrid reinforcement is 60 % / 40 %.Keywords:beams with hybrid reinforcement, basaltoplastic reinforcement, steel reinforcement, strength, deformability.

DESIGN MODELS OF THE BEARING CAPACITY OF THE SUPPORT SECTIONS OF BASALT-CONCRETE BEAM STRUCTURES

Abstract. In the past decade, structures with non-metallic composite reinforcement (FRP) find more and more widespread use in construction practice, especially in buildings and structures for special purposes. Due to its high strength, resistance to chemical and physical corrosion, dielectric and diamagnetic properties, low weight and low thermal conductivity, FRP is increasingly replacing steel reinforcement. However, the wider use of concrete structures with FRP is constrained by insufficient knowledge of the features of their work, insufficient regulatory support and little experience in operating these facilities. Practice has shown the promise and economic feasibility of using FRP in road, hydraulic engineering, transport construction, in the construction of bridge spans, treatment facilities, chemical and food industry facilities, and foundations in an aggressive soil environment. At the same time, the prospects for using basalt-plastic reinforcement (BFRP) are primarily due to the low cost of the main raw material, basalt fibers, due to the presence of significant reserves of basalt in the world. The basic principles of calculation of bending structures reinforced with FRP, in all foreign standards, as well as in the domestic Manual, are the same as for elements with steel reinforcement. The design models of the bearing capacity of the bearing sections of concrete beams reinforced with BFRP are considered. The bearing capacity of inclined sections of elements with large and medium shear spans should be determined by an inclined crack using variable coefficients , taking into account the real length of a dangerous inclined crack , a significant reduction in tensile stresses in transverse reinforcement to . The bearing capacity of the support sections with small shear spans must be determined as for short cantilevers along an inclined compressed strip between the concentrated force and the support using a variable coefficient . This approach provides satisfactory convergence between the calculated and experimental values of the bearing capacity of inclined sections (coefficient of variation BFRP.

COMPARATIVE ANALYSIS OF RESEARCH AND CALCULATED VALUES OF BEARING CAPACITY OF REINFORCED CONCRETE AND BASALT CONCRETE BEAMS ACCORDING TO RECOMMENDATIONS OF NATIONAL DESIGN STANDARDS

Abstract. Non-metal composite reinforcement is increasingly being used in modern construction. Composite reinforcement is a great step forward over steel, due to its higher strength and corrosion resistance. An analysis of the use of these fittings was performed, which showed that the United States, Japan and China are leading countries in the use of composite fittings. The more active pace of implementation of composite reinforcement is limited by the fact that composite reinforcement does not have a common method for calculating their bearing capacity. That is why the article discusses regulatory documents on the calculation and design of structures reinforced with composite reinforcement from around the world. The article provides a comparative analysis of the calculations of the bearing capacity of prototypes – beams, reinforced with basalt-plastic reinforcement, according to the available design standards of foreign countries, which were among the first to use non-metallic composite reinforcement for reinforcing span concrete structures. The methods of calculating the bearing capacity of beam elements for concrete and non-metallic composite reinforcement according to regulatory documents are examined in detail. A comparative analysis of the actual bearing capacity of inclined sections of basalt concrete beams and its calculated values calculated according to the recommendations of the existing design standards of foreign countries is carried out. The analysis showed that the actual bearing capacity of the inclined sections of basalt concrete beams and its calculated value showed their unsatisfactory convergence. A common feature of all considered foreign design standards is the underestimation, up to several times, of the bearing capacity of inclined sections of prototypes ‒ beams reinforced with both steel and basalt-plastic reinforcement. It has been established that the methods for calculating the bearing capacity of supporting sections of spans of reinforced concrete and basalt concrete structures, presented in national design standards, are based not on the new general method, but on partially improved methods that were used in previously existing standards.

Contact element use peculiarities in the numerical model construction of the reinforcing bar force interaction with an anchoring field

The application experience of non-metallic composite materials is quite wide in foreign countries, as well as systematized and assembled into a single database. In Russia, since the necessary computing resources have become more relevant and accessible for design organizations, independent researchers, and graduate students of higher educational institutions, this question resurfaced only in the last decade. As well as benefits, non-metallic composite reinforcement has its disadvantages, which prevent it from wide usage in structures, including a relatively low elastic module, as well as the inability to bend during installation. To improve the reinforced structures with stressed reinforcement calculation and possible prestressing force loss prediction, the finite element model production has been discussed. This model would allow us to evaluate the damaging shear stresses in the reinforcement region. The bracing formation process in the scope of this model was presented in this article, with the purpose of simulation the contact layer stress-strain state between reinforcement and concrete. The calculation is performed in a linear setting. Model development of a T-section decking component reinforced with a composite reinforcement beam produced via LIRA SAPR software. Exert a force on shank ends that is equivalent to the clamping force when the prestressed reinforcement is released. The authors proposed a selection option of the junction stiffness by stem contact with the anchoring field. The stiffness is assumed to be constant along the entire length of the contact layer. Elastic coefficient variation of the contact layer was performed here. The contact layer is highlighted conditionally as a separate material. A model for three types of materials was discussed. The shear stresses patterns in the contact element region were obtained. The patterns of abutting end reinforcement bars motion are obtained. To create a span element with a pre-tensioned reinforcement, a full-scale experiment was performed, as well as reinforcement abatement. Upon abatement, the retraction was recorded. The retraction results of the shank ends were measured, the values of which are comparable to the numerical motion.

Application of non-metallic composite reinforcement for contact line supports

The technology for pre-stressing and anchoring of the composite rebar was developed. It makes possible to reinforce concrete products and produce the contact line supports of high quality, which possesses advantages in comparison with the steel reinforced concrete. The prototypes of supporting structures with the use of the composite BFRP reinforcement were developed. They were tested for strength, rigidity and crack resistance. In the course of testing, the value of a pole deflection in the plane of the application of the control load was determined. Poles with composite reinforcement (with vibratory load and after vibratory load) and steel reinforced poles were tested and compared. Results obtained show that the vibratory load had no significant impact on the properties of supports reinforced with pre-stressed composite rebars and confirm the practical possibility to use them. In the future, it is necessary to develop the working drawings for the replacement of the steel reinforcement by a composite polymer rebar and the technical requirements for supports of the contact lines of Russian Railways as well as the technical regulations for their design and manufacturing.

Design of concrete canoe reinforced with composite reinforcement

To participate in international competitions on concrete canoe among students at the Department of concrete and masonry structures KNUBA has been designed and manufactured concrete canoe reinforced composite reinforcement. The design of the canoe was modeled and calculated in the PC «LIRA-SAPR».The problem of this article is to determine the optimal thickness of the walls of the canoe, the composition of basalt fiber and the scheme of reinforcement of the canoe to ensure its strength and crack resistance, as well as sufficient buoyancy. To achieve the minimum weight of the canoe it is customary to use non-metal reinforcement.The dimensions of the wooden canoe were accepted for the concrete canoe project. In terms of canoeing has a lenticular shape. The total canoe length is 4,3 m and maximum width is 900 mm. The minimum height of the board is 400 mm. According to the accepted manufacturing technology, the walls and canoe bottom have a three-layer construction, consisting of an inner and outer layer of basalt fiber concrete 3… 5 mm thick and an inner layer of expanded polystyrene foam 10 mm thick. To strengthen the most intense zones in the outer layer of basalt fiber reinforced carbon mesh. In the transverse direction, transverse ribs (frames) made of expanded polystyrene 20 mm thick and 20… 30 mm high are arranged. Along the upper sides of the sides, along the keel rib and along the frames, basalt reinforcement with a diameter of 6 mm (2 rods) was installed.To calculate the canoe, its calculation model was developed in the LIRA-CAD PC. The canoe model is made in the form of a shell made of flat triangular finite elements. Linear elements were also added to model the basalt reinforcement. Linear and flat elements are rigidly connected at the nodes.According to the manufacturer, the modulus of elasticity of the rod reinforcement is 70∙103 MPa, and the temporary tear resistance - 1100 MPa, density -1,9 g/m3. The basalt fiber was adopted with a thickness of 20 mkm and a length of 50 mm.Two-component waterproofing solution SILTEK V-33/E-33 was used as the concrete matrix. The amount of basalt fiber was 3%. To determine the characteristics of basalt fiber concrete test cubes with an edge of 75 mm and samples-"eight" were made. As a result of the test, the tensile strength of basalt fiber was compressed at 8.4 MPa and the axial tensile strength was 1.8 MPa.The obtained design characteristics were used to introduce finite element stiffnesses.Canoe loading was applied on its own weight, the weight of two 80 kg paddles and hydrostatic water pressure.As a result of the calculation, mosaics of stresses were obtained. They showed the most intense zones, which were reinforced with carbon mesh.After experimental and numerical studies, we came to the conclusion that non-metallic composite reinforcement can be used in the construction of light structural elements. Such structures are absolutely not susceptible to corrosion. In the future, it is necessary to investigate structural elements that are used in the aquatic environment, such as pontoons, platforms for waterfront homes and more.

Comparative Analysis Of Bending Concrete Elements Reinforced With Steel And Fiber-Glass Reinforcement

The main advantages and disadvantages of using non-metallic composite reinforcement as a reinforcing element of bending concrete structures without pre-stressing are considered. The characteristics of composite and steel reinforcement are compared. Numerical comparative analysis of strength and deformation characteristics of bending concrete elements with plastic and steel reinforcement is performed. It is established that to ensure the strength of the normal sections of the bending elements, the consumption of non-metallic reinforcement is up to 40% higher than that of steel reinforcement. Results of calculations on deformations according to which rigidity of the bending designs reinforced with steel reinforcement is 15-20% higher, than for reinforced with non-metallic reinforcement are presented. The conclusion is substantiated that the use of non-metallic composite reinforcement in non-stressed bendable concrete structures is impractical. Recommendations on the possible use of plastic reinforcement in building structures are presented, as well as directions and prospects for further research are outlined.

TECHNOLOGY OF MANUFACTURING COMPOSITE VALVES OF A PERIODIC PROFILE

The widespread use of composites was restrained, mainly due to the lack of industrial technology that would allow mass production of products with a complex configuration with the required dimensional accuracy.The issues of creating a technology for the production of glass and basalt plastic reinforcement of a periodic profile for the reinforcement of cement concrete and the determination of the chemical resistance of composite reinforcement are considered.The technology was based on the formation of a reinforcing bar by pulling method - a technology that combines the broaching of pre-impregnated with a binder of continuous reinforcing fiber with its winding threads of glass, basalt or carbon fiber in a single technological non-filter process. The technology for producing a rebar by the method of non-filtering rolltrusion is a practically waste-free and high-performance process due to its continuity. The principal differences of the proposed reinforcement is the presence throughout the entire length of the main (power) cylindrical composite rod and standing anchoring - a spirally deformed layer on the surface of the reinforcing rod of the same composite, but with a smaller percentage of reinforcing filler.It has been established that composite reinforcement can be used for the reinforcement of concrete exposed to acidic and alkaline corrosive media, including concrete, used for the construction of sewage treatment plants.The research results form the basis for the development of guidelines for the design and manufacture of concrete structures with non-metallic composite reinforcement based on basalt and glass roving.

Peculiarities of calculation and design of slabs on elastic cushion reinforced with non-metallic composite reinforcement

Fiber-glass composite reinforcement becomes increasingly popular in different spheres of industry and public economy. Unique technology of the reinforcement production allows receiving the high-quality construction material which complies with modern requirements of liability, quality and safety. Pavlivska Square in Kharkiv may serve as an example of efficient application of non-metallic composite reinforcement for the reinforcement of slabs on elastic cushion during the construction of which the composite grids SKS-100/100 manufactured by Ekipage Technological Group were used as the reinforcement units. Pavement slab reinforcement scheme (including the working draft) was elaborated by the specialists of the Building Constructions Department of O.M. Beketov National University of Urban Economy. The arrangement of the pavement slab of Pavlivska Square was conducted within the short period of time. Due to this, for the purpose of mounting the two-layer reinforcing cage of the slab, the workers of Ekipage Technological Group elaborated a new mounting method which allows the essential reduction of the performance time.

АНАЛИЗ ПРИМЕНЕНИЯ ПОЛИМЕРКОМПОЗИТНОЙ АРМАТУРЫ В АРМОБЕТОННЫХ КОНСТРУКЦИЯХ

The article reviewed the experience with the application of non-metallic composite polymer reinforcement in reinforced concrete structures. It is revealed, that in Russia composite polymer reinforcement is a relatively new building material, large-scale production and implementation of which begins to be just now. The analysis showed that the perception of usefulness of composite polymer reinforcement only in prestressed reinforced concrete constructions is incorrect positioning on the field of application. In bringing together the interests of researchers, design institutes, manufacturers and consumers composite polymer reinforcement importance of Association of organizations for the production and application of non-metallic reinforcement and products «Non-metallic composite reinforcement».

Experimental and numerical investigation of concrete structures with metal and non-metal reinforcement at impulse loadings

Manufacturing durable and high-strength concrete structures has always been a relevant objective. Therefore special attention has been paid to non-metallic composite reinforcement. This paper considers experimental and numerical studies of nature of fracture and crack formation in concrete beams with rod composite reinforcement. Fiber glass rods, 6 mm in diameter, have been used as composite reinforcement. Concrete elements have been tested under dynamic load using special pile driver. The obtained results include patterns of fracture and crack formation, maximum load value and maximum element deflection. Comparative analysis of numerical and experimental studies has been held.