scholarly journals Mobile attachment for automated crack milling

2021 ◽  
Vol 1 ◽  
pp. 21-22
Author(s):  
Birte Froebus ◽  
Sascha Gentes ◽  
Christoph Unverzagt
Keyword(s):  
Reinforced Concrete ◽  
New Combination ◽  
Automation System ◽  
Ministry Of Education ◽  
Nuclear Facilities ◽  
Research Project ◽  
New Development ◽  
Strenuous Work ◽  
Anchor Plates ◽  
Concrete Matrix

Abstract. In the dismantling of nuclear facilities, the decontamination and remote-controlled crushing of reinforced concrete is a central point. The main objective is to selectively remove the contaminated material in order to feed the remaining material, which in relation to the overall system or overall mass, represents the predominant part of the normal recycling cycle. For the surface decontamination of the upper millimeters, several methods are available that are constantly being optimized and further developed. However, there is a great need for research in the demolition and selective deep removal of reinforced concrete, e.g. in the case of cracks or eruptions into which contamination could penetrate, or the removal of metallic fixtures. The production of freely measurable surface geometries is a constant objective (Edelmann et al., 2018). The German “Defined removal of highly reinforced concrete” (DefAhS) research project was funded by the German Federal Ministry of Education and Research (BMBF) from October 2013 to the end of March 2018. In the course of the project, a new combination tool consisting of indexable inserts and impact lamellas was developed. With this method it is possible to remove highly reinforced concrete in one operation. The following property right could be granted: “Device for removing building material” (DE102015114122B3). Within the research project, concrete, reinforcement and fixtures (dowels, rails, anchor plates, pipe penetrations) could be successfully cut. It could also be shown that it is possible to remove several layers of steel reinforcement within a concrete matrix. The “Mobile attachment for automated crack milling” (MAARISS) research project has been running since November 2020. The hybrid milling technology developed in DefAhS is intended to form the basis for the milling drum used in MAARISS. The aim in MAARISS is, among other things, a new development of the extraction system directly on the removal unit and an automation system for use in a nuclear facility. Cracks are to be automatically milled over in order to enable subsequent clearance measurement by the staff on site. The physically very strenuous work of crack uncovering should be reduced to just one operator in a safe environment. The construction of a scaffold should be completely dispensed with and existing transport technology (forklift or lifting platform) should be used.

Adding an expansive agent to increase the toughness of steel fibre reinforced concrete

2019 ◽  
Vol 26 (4) ◽  
pp. 197-208
Author(s):  
Leo Gu Li ◽  
Albert Kwok Hung Kwan
Keyword(s):  
Reinforced Concrete ◽  
Steel Fibre ◽  
The Other ◽  
Fibre Reinforced Concrete ◽  
Test Results ◽  
Compressive Properties ◽  
Shrinkage Cracking ◽  
Steel Fibre Reinforced Concrete ◽  
Expansive Agent ◽  
Concrete Matrix

Previous research studies have indicated that using fibres to improve crack resistance and applying expansive agent (EA) to compensate shrinkage are both effective methods to mitigate shrinkage cracking of concrete, and the additions of both fibres and EA can enhance the other performance attributes of concrete. In this study, an EA was added to fibre reinforced concrete (FRC) to produce concrete mixes with various water/binder (W/B) ratios, steel fibre (SF) contents and EA contents for testing of their workability and compressive properties. The test results showed that adding EA would slightly increase the superplasticiser (SP) demand and decrease the compressive strength, Young’s modulus and Poisson’s ratio, but significantly improve the toughness and specific toughness of the steel FRC produced. Such improvement in toughness may be attributed to the pre-stress of the concrete matrix and the confinement effect of the SFs due to the expansion of the concrete and the restraint of the SFs against such expansion.

Improved Early-Age Cohesive Stress Response from Hybrid Blends of Micro and Macro Fibers

2021 ◽  
Vol 1046 ◽  
pp. 1-7
Author(s):  
Manjunath V. Bhogone ◽  
Kolluru V.L. Subramaniam
Keyword(s):  
Reinforced Concrete ◽  
Stress Response ◽  
Volume Fraction ◽  
Polypropylene Fiber ◽  
Fiber Reinforced Concrete ◽  
Early Age ◽  
Fiber Reinforced ◽  
Cohesive Stress ◽  
Concrete Matrix ◽  
Polypropylene Fiber Reinforced Concrete

The fracture response of macro polypropylene fiber reinforced concrete (PPFRC) and hybrid blend of macro and micro polypropylene fiber reinforced concrete (HyFRC) are evaluated at 1, 3, 7 and 28 days. There is an improvement in the early-age fracture response of HyFRC compared to PPFRC. The changing cohesive stress-crack separation relationship produced by ageing of the concrete matrix is determined from the fracture test responses. An improved early-age cohesive stress response is obtained from the hybrid blend containing micro and macro fibers. The hybrid fiber blend also has a higher tensile strength at early age when compared to an identical volume fraction of macro polypropylene fibers.

The Future of the Natural Resources Sector in Russia

2016 ◽  
pp. 1817-1840
Author(s):  
N.S. Kasimov ◽  
N.N. Alekseeva ◽  
A.A. Chulok ◽  
A.V. Sokolov
Keyword(s):  
Environmental Management ◽  
Natural Resources ◽  
Research University ◽  
Competitive Advantages ◽  
Ministry Of Education ◽  
Research Project ◽  
Expert Opinions ◽  
Potential Market ◽  
Challenges And Opportunities ◽  
Potential Applications

Environmental management, technologies, products and services are commonly expected to provide significant economic opportunities for companies and countries. This is mainly due to increasing awareness among politicians, academics and the wider population on the importance of environmental aspects in daily life. Consequently demand for environmentally friendly solutions is expected to grow continuously in the next decade. The present study is part of a broader research project which examines the long-term science and technology (S&T) agenda in Russia up to 2030. The project's results were approved by the Prime Minister of Russia in early January 2014. Researchers from the National Research University Higher School of Economics carried out the research project at the request of the Russian Ministry of Education and Science between 2011 and 2013. The research comprised six interrelated spheres: ICT; biotechnology, medicine and public health; new materials and nanotechnologies; environmental management; transport and space systems; and energy efficiency and energy conservation. For each sphere, the project explored in-depth the global emergent challenges and opportunities, the risks, and their degree of influence on Russia. The authors analysed the most important potential market niches, products and services that are capable of radically shaping world markets and highlighted their competitive advantages. Within the framework of these priority science areas authors emphasised several spheres of particular potential value and compared the level of research carried out in Russia and the leading countries. The current chapter also covers the analyses the natural resources sector made within a project aimed at integration of national and sectoral S&T Foresight studies funded by the Russian Ministry of Education and Science. Findings show that the potential applications for environmental products and services are manifold. The study is based on a thorough analysis of expert opinions and their assessment of future applications and the development of demand for these applications. However the authors note that the expert opinions included in the assessment of prospective products, services and markets, despite being based on rigorous assessment, still reflect expectations. Their opinions incorporate a degree of uncertainty especially with regard to how and when (or whether) the markets, technologies, products and services will develop in the expected ways.

Numerical Analysis of Nuclear Facility Reinforced Concrete Wall and Roof Slab Behavior Under Close-in Explosions

2020 ◽  
Author(s):  
Li Rongpeng ◽  
Li Yumin ◽  
Sui Chunguang ◽  
Jiang Di
Keyword(s):  
Numerical Simulation ◽  
Reinforced Concrete ◽  
Simulation Method ◽  
Concrete Slabs ◽  
Nuclear Facilities ◽  
Concrete Wall ◽  
Empirical Formulas ◽  
Air Overpressure ◽  
Reinforced Concrete Slabs ◽  
Reinforced Concrete Wall

Abstract With the change of anti-terrorism situation, civil unmanned aerial vehicles carrying small equivalent of explosives may cause damage to the reinforced concrete wall or roof of nuclear facilities at close range. Existing research has mostly focused on the overall damage caused by large equivalent explosives at medium and long distances. In this paper, the air overpressure peak curve and behavior of reinforced concrete slabs under small equivalent TNT close-in explosion conditions are calculated by numerical simulation methods and compared with empirical formulas and experimental results in the literature to verify. Furthermore, the numerical simulation method was used to evaluate the resistance of 300mm thick reinforced concrete slabs to close-in impacts of different mass TNT at a standoff distance of 0.4m.

A Review of Stee-Polypropylene Hybrid Fiber Reinforced Concrete

2012 ◽  
Vol 238 ◽  
pp. 26-32 ◽  
Author(s):  
Xiao Ke Li ◽  
Li Sun ◽  
Y.Y. Zhou ◽  
Shun Bo Zhao
Keyword(s):  
Reinforced Concrete ◽  
Fresh Concrete ◽  
Strengthening Mechanism ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Mix Proportion ◽  
Macro Scale ◽  
Working Performance ◽  
Concrete Matrix

The steel-polypropylene hybrid fiber reinforced concrete can take full advantages of macro-scale crack resistance and toughening effect on the concrete matrix of steel and polypropylene fibers. The shortcomings of concrete are improved and there is a wide prospect application in engineering. This paper summarizes the enhancement theories of hybrid fiber reinforced concrete to explain its strengthening mechanism. The research status is reviewed including mix proportion design, working performance of fresh concrete, mechanical behaviors, durability (impermeability, shrinkage and others), and engineering applications etc. Some further researches are forecasted. It would be very useful to apply and popularize steel-polypropylene hybrid fiber reinforced concrete.

New Research Project for Evaluating Seismic Linkage Around the Nankai Trough —Integration of Observation, Simulation, and Disaster Mitigation—

2009 ◽  
Vol 4 (2) ◽  
pp. 61-66 ◽  
Author(s):  
Yoshiyuki Kaneda ◽  
◽  
Kazuo Hirahara ◽  
Takashi Furumura ◽  
◽  
...  
Keyword(s):  
Strong Motion ◽  
Disaster Mitigation ◽  
Ministry Of Education ◽  
Research Project ◽  
National Budget ◽  
Megathrust Earthquakes ◽  
Sports Science ◽  
Close Cooperation ◽  
New Research ◽  
Education Culture

Maga thrust earthquakes have occurred with an interval of 100-200 years around the Nanki trough southwestern Japan. The estimated economical damage of next mega thrust earthquakes is equivalent to the national budget. Therefore, progresses of seismological researches and new proposals of disaster mitigation for next mega thrust earthquakes are urgent and important issues for Japan. So, from 2009, the new research project of MEXT (Ministry of Education, Culture, Sports, Science and Technology) is starting as a five years project. This project is composed of two subprojects including researches of observations simulations and disaster mitigations. In observational researches, we will carry out seismic surveys, seismic tomography and monitoring researches. Simulation researches are including the theme such as developments of crustal deformation databases, advanced simulation methods, seismic linkage studies and recurrence cycle simulations. In disaster mitigation researches, there are prediction researches of strong motion and tsunami hazards and proposals of future risk managements. These researches are progressing in close cooperation with each other. Finally, results from this project will be integrated to improve the recurrence simulation model and advanced proposal of disaster mitigation. The collaboration and integration of scientific researches, engineering researches and social sciences of next megathrust earthquakes will lead to the practical disaster mitigation.

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