scholarly journals Effect of polymer and functional additives on the properties of bitumen and asphalt-concrete

2020 ◽  
Vol 1 (11-12) ◽  
pp. 47-49
Author(s):  
N. P. Kotenko ◽  
Yu. S. Shcherba ◽  
A. S. Evforitskiy
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Asphalt Concrete ◽  
Warm Season ◽  
Physical And Mechanical Properties ◽  
Polymeric Materials ◽  
Repair Work ◽  
Concrete Mixtures ◽  
Functional Additives ◽  
Functional Additive

The possibility of modifying the oil road bitumen of the BND 70/100 grade is investigated; it belongs to the category of viscous bitumen and is used for road works in the warm season, with an average daily temperature not lower than +5°C. The material is widely used for repair work, and for laying new roads. Copolymers of styrene with butadiene and ethylene with vinyl acetate were used as polymeric materials for polymer-bitumen binders (PBV). Their optimal concentrations were determined for obtaining PBV with increased heat resistance and elasticity. Carbon nanotubes were used as a functional additive to bitumen.. The physical and mechanical properties of modifi ed bitumen and asphalt concrete mixtures based on them are given. It was shown that the introduction of even a small amount of nanotubes into asphalt concrete leads to an increased shear stability and strength at diff erent temperatures from 0 to 50°C.

scholarly journals Fabrication and Characterization of Polylactic Acid Electrospun Scaffolds Modified with Multi-Walled Carbon Nanotubes and Hydroxyapatite Nanoparticles

Biomimetics ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 43
Author(s):  
Athanasios Kotrotsos ◽  
Prokopis Yiallouros ◽  
Vassilis Kostopoulos
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Polylactic Acid ◽  
Physical And Mechanical Properties ◽  
Polymeric Materials ◽  
Cost Effective ◽  
Electrospinning Process ◽  
Wide Range ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The solution electrospinning process (SEP) is a cost-effective technique in which a wide range of polymeric materials can be electrospun. Electrospun materials can also be easily modified during the solution preparation process (prior SEP). Based on this, the aim of the current work is the fabrication and nanomodification of scaffolds using SEP, and the investigation of their porosity and physical and mechanical properties. In this study, polylactic acid (PLA) was selected for scaffold fabrication, and further modified with multi-walled carbon nanotubes (MWCNTs) and hydroxyapatite (HAP) nanoparticles. After fabrication, porosity calculation and physical and mechanical characterization for all scaffold types were conducted. More precisely, the morphology of the fibers (in terms of fiber diameter), the surface properties (in terms of contact angle) and the mechanical properties under the tensile mode of the fabricated scaffolds have been investigated and further compared against pristine PLA scaffolds (without nanofillers). Finally, the scaffold with the optimal properties was proposed as the candidate material for potential future cell culturing.

Physical and Mechanical Properties of the Road Surface when Replacing the Finely Crushed Mineral Part of Asphalt Concrete with Porcelain Stoneware Production Waste

2021 ◽  
Vol 1043 ◽  
pp. 101-107
Author(s):  
Natalia Yatsenko ◽  
Alexandr Evforitsky ◽  
Natalya Kotenko
Keyword(s):  
Mechanical Properties ◽  
Asphalt Concrete ◽  
Water Resistance ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Type B ◽  
Grain Composition ◽  
The Road ◽  
Concrete Mixtures ◽  
Additional Hydrogen

The possibility of using waste porcelain stoneware - a high-strength non-porous, dense material as a finely crushed mineral part of asphalt concrete with 0-5 mm fraction has been established. The adhesive additive Bitaden content was revealed, that intensifies porcelain stoneware interaction with bitumen due to the additional hydrogen bonds formation, the particles’ contact plane activation with the action of van der Waals forces. The conditions for obtaining asphalt concrete mixtures of type B, grade 1 and G, grade 2 of the optimal grain composition with a reduced content of BND 60/90 bitumen have been developed. Physical and mechanical properties are characterized by an increase in the water resistance of asphalt concrete samples based on porcelain stoneware, compressive strength and shear resistance.

The Behavior of FRA Concrete with High Replacement Ratio

2018 ◽  
Vol 760 ◽  
pp. 204-209 ◽  
Author(s):  
Magdaléna Šefflová
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Absorption Capacity ◽  
Recycled Aggregate ◽  
Partial Replacement ◽  
Hardened Concrete ◽  
Replacement Ratio ◽  
Natural Sand ◽  
Concrete Mixtures

This study deals with determination of the properties of the fine recycled aggregate (FRA) concrete with partial replacement of natural sand in concrete mixtures. The FRA was obtained from concrete waste and crushed on fraction 0 – 4 mm by laboratory jaw crusher. The geometrical and physical properties of natural sand and the FRA were tested. The main goal of this study is evaluation of the basic physical and mechanical properties of the concrete with partial natural sand replacement by the FRA such as workability, water absorption capacity, compressive strength and flexural strength. A total four concrete mixtures were prepared. The first concrete mixture was prepared only with natural sand, did not include the FRA. In other concrete mixtures, natural sand was replaced by the FRA in various replacement ratios (40 %, 50 %, and 60 %). All concrete mixtures were designated with the same parameters for clear comparison. The workability of fresh concrete mixtures and physical and mechanical properties of hardened concrete were tested.

scholarly journals Application of Phosphogypsum in Road Construction

2021 ◽  
Vol 20 (6) ◽  
pp. 493-498
Author(s):  
Ya. N. Kovalev ◽  
V. N. Yaglov ◽  
T. A. Chistova ◽  
V. V. Girinsky
Keyword(s):  
Asphalt Concrete ◽  
Building Materials ◽  
Road Construction ◽  
Operating Costs ◽  
Capital Investments ◽  
Cultivated Land ◽  
Repair Work ◽  
Concrete Mixtures ◽  
Irreparable Harm ◽  
The Republic

Abstract. Currently the Republic of Belarus is solving the problem of processing a by-product – phosphogypsum, formed in the process of phosphorric acid production. The issue of utilization of phosphogypsum is becoming more and more relevant, and there are several reasons for this: transportation of phosphogypsum to dumps and its storage require large capital investments and operating costs; when creating phosphogypsum dumps, it is necessary to alienate large areas, sometimes even cultivated land; storage of this material in dumps, even with the neutralization of soluble impurities and with the observance of dump operational rules causes irreparable harm to the environment. There are known studies of scientists on the use of phosphogypsum for road construction as a binder for strengthening soils, foundations and repair work. The paper presents the results of experiments on obtaining road-building materials from this waste without converting it into a binder. Based on the research, a technology for the preparation of asphalt concrete mixtures with the use of mineral powder in the form of phosphogypsum dihydrate has been developed.

scholarly journals Self-Compacting Concrete and Concreting Technology for Foundation Block Using 9000 Cubic Meters of Concrete

2021 ◽  
Vol 20 (4) ◽  
pp. 329-337
Author(s):  
E. I. Batyanovskiy ◽  
A. I. Bondarovich ◽  
N. N. Kalinovskaya ◽  
P. V. Ryabchikov
Keyword(s):  
Mechanical Properties ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Test Methods ◽  
Third Party ◽  
Hardened Concrete ◽  
Self Compacting Concrete ◽  
Foundation Slab ◽  
Concrete Mixtures ◽  
Structure Height

. The paper presents the results of the development and implementation of the technology of self-compacting heavy structural concrete and the technology of concreting with its use of the largest foundation slab in Belarus (concrete volume ~9100 m3) of a high-rise building at the facility “Construction of a multifunctional complex in Minsk within the boundaries of Filimonova Street – Avenue Nezavisimosty – Makayonka Street”. The results of research are shown, which ensured the production of self-compacting concrete of class C35/45 with water resistance up to W20 (with the required W12 according to the project) from concrete mixtures of the maximum cone expansion of the PK6 (RK6) grade for three zones of the foundation slab different in degree of reinforcement: lower, middle and upper, with a total structure height of 3.5 m and plan dimensions ~(83´34) m. The technology of continuous (seamless) concreting has been developed and implemented, which made it possible to lay ~9100 m3 of concrete into the structure without defects within 42 hours of continuous operation, and a system of technological measures that prevented temperature cracking in concrete. The homogeneity of the physical and mechanical properties of concrete, confirmed by control tests, is ensured due to the uniform supply of the concrete mixture (from six  concrete pumps at the same time) in layers 200–300 mm high with a distance between the supply points of about 5–6 m and the vertical arrangement of the “trunks” of the concrete pipes during delivery of concrete to each point, as well as the fact that the time for feeding the next volume of concrete was significantly less than the setting time of the previously laid concrete (with a total concreting speed £0.1 m/h). Standardized and original test methods for concrete mixtures, hardening kinetics and properties of hardened concrete have been used during the development, research and implementation of the project. Control tests of physical and mechanical properties and characteristics of concrete, carried out at BNTU together with authorized  organizations controlling the progress of construction, as well as in independent (third-party) organizations, have confirmed their compliance with the design requirements.

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