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

Photocatalytic Cementitious Composites containing Mesoporous Titanium Dioxide Nanoparticles

The advanced method to produce nanoparticles of anatase mesoporous TiO₂ with high specific surface 300 m²/g has been developed. It was shown that titanium nanodioxide can be used in cement and gypsum composites as a highly efficient photocatalyst in the conversion processes of nitric oxide and volatile organic substances. Influence of radiation intensity, relative humidity, and concentration of contaminant and its stream speed on photocatalysis was studied. It was determined that efficiency of the composites with synthesized samples is 1,5–1,7 times higher than that of the commercial sample of the titanium nanodioxide

New high performance nanoadditives for photocatalytic concrete: synthesis and study

Nanotechnologies open up broad prospects for the creation of nanocatalysts, which are being more and more used in solving many problems associated with the protection of environment. Their behavior is directly related to the unique physical and chemical properties that are provided by quantum size effects, as well as the large specific surface area. It is known that the presence of photo catalysts in the construction segment of nanomaterials is becoming more prominent. One of the most significant achievements of the last years are photo catalytic active cement composites, including cements and concretes produced with the use of nanoparticles of titanium dioxide TiO₂ sensibilized through a nanotechnology . Currently they are widely used in practice to produce selfcleaning structures and to make clean an air of megacities. Further research in the field of development of new high-performance photo catalysts based on TiO₂ nanoparticles seems to be very relevant, because such R&D could significantly improve the technical characteristics of photo catalytic cements and concrete. In this paper an improved method to produce photo catalysts has been proposed. New synthesized products are based on TiO₂ nanoparticles applied on different inert carriers, including nanosilica. It was showed that these products can be used as a high performance photo catalyst in cement and cement-gypsum composites suitable for the onversion processes of nitric oxide and volatile organic substances, and air purification. It was determined that performance of the cementitious composites containing synthesized samples is 1,5…3,0 times higher than that for the commercial sample of the nanotitanium dioxide. The use of mechanical mixture of nanotitanium dioxide and inert supports is less effective and subjected to the «dilution law», in general

NANOMATERIALS AND NANOTECHNOLOGIES IN THE PRESENT-DAY CONCRETE TECHNOLOGY

Advancements in the field of nanotechnologies have converted the concrete into a high-tech material; its structure may be "tailored" to specific functional criteria, including strength, durability, and reduced environmental impacts. This feature will help keep the concrete as the main structural material in the foreseeable future. Nanotechnologies are still on the way from the pool of basic sciences to industrial enterprises. Today full-scale practical application of nanotechnologies in the construction industry is extremely limited for the reason of high costs of their implementation. However, the strongest potential of nanotechnologies is concentrated in the improvement of the properties of conventional materials and processes. Recent progress of nanotechnologies prompts us that many of the problems that are now considered as fantastic will be successfully resolved in the coming decade. Portland cement is one of the most widely used materials; it has a huge though underexplored potential. A better understanding and precise identification of the engineering properties of the complex structure of cement materials in the nanoscale science will give way to a new generation of concrete

INDUSTRIAL TECHNOLOGICAL RESEARCH «DEVELOPMENT OF RUSSIAN MARKET OF NANOTECHNOLOGICAL PRODUCTS IN CONSTRUCTION UNTIL 2020». PART 2. ANALYSIS OF THE WORLD MARKET

Some results of the industrial research «Development of Russian market of nanotechnological products in construction until 2020» have been published. Authors invite all interested specialists and specialized organization to take part in the broad public discussion

NDUSTRIAL TECHNOLOGICAL RESEARCH «DEVELOPMENT OF RUSSIAN MARKET OF NANOTECHNOLOGICAL PRODUCTS IN CONSTRUCTION UNTIL 2020». PART 1. A STATEMENT OF THE TASK AND AN APPROACH TO REALIZE THE PROJECT

Some results of the industrial research «Development of Russian market of nanotechnological products in construction until 2020» have been published. Authors invite all interested specialists and specialized organization to take part in the broad public discussion

INDUSTRIAL TECHNOLOGICAL RESEARCH «DEVELOPMENT OF RUSSIAN MARKET OF NANOTECHNOLOGICAL PRODUCTS IN CONSTRUCTION UNTIL 2020». PART 3. ANALYSIS OF THE RUSSIAN MARKET

The previous publications [1, 2] dealt with the analysis of the main indicators to the world market of nanotechnological construction materials. Today this market is estimated at 12 milliard of dollars, and its rapid growth is expected soon. The present paper analyses the Russian market