scholarly journals Influence of Mechanochemical Activation of Concrete Components on the Properties of Vibro-Centrifugated Heavy Concrete

2021 ◽  
Vol 11 (22) ◽  
pp. 10647
Author(s):  
Evgenii M. Shcherban’ ◽  
Sergey A. Stel’makh ◽  
Alexey Beskopylny ◽  
Levon R. Mailyan ◽  
Besarion Meskhi
Keyword(s):  
Mechanochemical Activation ◽  
Chemical Activation ◽  
Energy Resource ◽  
Concrete Mixture ◽  
Double Complex ◽  
Activation Effect ◽  
Study Results ◽  
Concrete Production ◽  
Production Techniques ◽  
New Material

One of the crucial problems in current construction is energy, resource, and material efficient technologies in both industrial and civil engineering, associated with new material manufacturing and building construction. This article is devoted to developing comprehensive technology for activation effects on concrete made by various production techniques: vibration, centrifugation, and vibro-centrifugation. The possibility of a significant improvement in the microstructure of concrete and obtaining materials with increased specified characteristics, depending on its manufacturing technology, were studied during the complex activation effect exposed to this concrete and its components. Chemical activation of water and mechanical activation of cement were considered. The urgency and prospects of double, complex mechanochemical activation of concrete mixture components were substantiated. It was proven that the complex mechanochemical activation of the concrete mixture components gives a synergistic effect in obtaining concrete composition with an improved structure and improved characteristics. Furthermore, the relationship between concrete production technology and the technology of activation of its components was established. It was revealed that the most effective is the complex mechanochemical activation of vibro-centrifuged concrete, which gives an increase in strength up to 30%. The study results indicate a further direction of development associated with an increase in variatropic characteristics using both prescription and technological factors.

Measure and Analyze the Problems of Concrete Mixture Production via Six Sigma DMAIC Tools: Central Concrete Mix Plant as a Case Study

2012 ◽  
Vol 622-623 ◽  
pp. 472-477
Author(s):  
Ali A. Karakhan ◽  
Angham E. Alsaffar
Keyword(s):  
Six Sigma ◽  
Business Strategy ◽  
Concrete Mixture ◽  
Statistical Tools ◽  
Sigma Level ◽  
Defect Rate ◽  
Concrete Production ◽  
Concrete Mix ◽  
Six Sigma Methodology

The aims of this study are to measure the defect rate and analyze the problems of production of ready concrete mixture plant by using Six Sigma methodology which is a business strategy for operations improvement depending basically on the application of its sub-methodology DMAIC improvement cycle and the basic statistical tools where the process sigma level of concrete production in the case study was 2.41 σ.

Quantification of geographical proximity of sugarcane bagasse ash sources to ready-mix concrete plants for sustainable waste management and recycling

2020 ◽  
pp. 0734242X2094537 ◽  
Author(s):  
Gopinath Athira ◽  
Abdulsalam Bahurudeen ◽  
Vijaya Sukumar Vishnu
Keyword(s):  
Fly Ash ◽  
Sugarcane Bagasse ◽  
Raw Materials ◽  
Disposal Site ◽  
Partial Replacement ◽  
Geographic Proximity ◽  
Study Results ◽  
Concrete Production ◽  
Sugarcane Bagasse Ash ◽  
Ready Mix Concrete

As stated in the European Commission’s waste framework directive, the geographic proximity of wastes to the potential recovery/disposal site is of paramount importance in attaining an effective resource recycling paradigm. The global interest in achieving an end-of-waste scenario encourages the recovery of useful products/secondary raw materials from locally available waste materials. Sugarcane bagasse ash is an abundantly available waste (44,200 tonnes day–1) from sugar plants in India which has the potential to be used as a partial replacement to cement in ready-mix concrete plants. Although pozzolanic performance of sugarcane bagasse ash and its ability in reducing the carbon emissions associated with concrete production have been reported in earlier research studies, its use in concrete is hindered due to the lack of availability and accessibility data. In this study, the geographical distribution of sugar plants and the available quantity of sugarcane bagasse ash in India have been determined. In addition, a detailed network analysis using a geographic information system was conducted to quantify the geographic proximity of bagasse ash, fly ash and slag sources to ready-mix concrete plants. The study results indicate that for most of the ready-mix concrete plants in India, the probability of having a bagasse ash source in proximity is higher than the probability of encountering slag/fly ash sources.

Mechanochemical Activation and Characterization of Low-Medium Grade Phosphorite Ore

2013 ◽  
Vol 690-693 ◽  
pp. 3529-3532
Author(s):  
Yu Xing ◽  
Hong Gao ◽  
Yuan Fang Ying ◽  
De Zheng Qu
Keyword(s):  
Mechanochemical Activation ◽  
Planetary Mill ◽  
Water Soluble ◽  
Particle Sizes ◽  
Leaching Rate ◽  
Activation Time ◽  
Activation Effect ◽  
Water Soluble P ◽  
Soluble P

The activation effect of ball-to-powder ratio and activation time on phosphorite ore that takes place in mechanochemical activation has been investigated in present paper, which is carried out in a planetary mill AGO-II. The results show that, particle sizes decreased after activation; the leaching rate of water-soluble P2O5 increased 4.6 percentage as ball-to-powder ratio rose from 8:1 to 40:1; the activated particle of samples has been highly dispersed, while the leaching rate of water-soluble P2O5 reached 10.1% after milling 15 minutes during activation, which was 4 times as high as the un-activated samples. The results show a potential utilization of low-medium grade phosphorite ore with mechanochemical activation directly.

Combining Mineral and Polymer Binder Material Science for Sustainability in Construction and Restoration

2015 ◽  
Vol 21 (4-6) ◽  
pp. 149-164 ◽  
Author(s):  
Dionys Van Gemert ◽  
Özlem Cizer
Keyword(s):  
Construction Industry ◽  
Performance Improvement ◽  
Hydraulic Properties ◽  
Chemical Activation ◽  
Sustainable Construction ◽  
Inorganic Polymers ◽  
Wide Range ◽  
Concrete Production ◽  
Construction Activity ◽  
The Impact

Abstract The study of microstructure formation in polymer-cement concrete provides opportunities to exploit synergetic actions between cement and polymer, leading to performance improvement and to a wide range of new and innovative properties and applications. Polymers can reduce the impact of construction industry on environment, by decreasing the carbon footprint of cement and concrete production. Renovation and restoration, largely figuring in the concept of sustainable construction development, thank their growing share in construction activity to the input of polymers in repair and binder materials and in rehabilitation procedures. The study of ancient binders and mortars reveals aspects of the origins of the observed long lasting durability of those ancient mortars. It also reveals the interaction mechanisms between carbonation of air hardening components and hydration of hydraulic components, which in turn helps to develop chemical activation methods (i.e. alkaline activation) to improve the hydraulic properties of pozzolans and industrial residues to develop inorganic polymers (i.e. geopolymers) for eventually full replacement of cement in binders.

Physical and Chemical Activation Effect on Activated Carbon Prepared from Local Pineapple Waste

2014 ◽  
Vol 699 ◽  
pp. 87-92 ◽  
Author(s):  
Abdul Rahim Yacob ◽  
Adlina Azmi ◽  
Mohd Khairul Asyraf Amat Mustajab
Keyword(s):  
Activated Carbon ◽  
Phosphoric Acid ◽  
Surface Area ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Bet Surface Area ◽  
Activation Effect ◽  
Pineapple Waste ◽  
Pineapple Peel ◽  
Physical And Chemical

The characteristics and quality of activated carbons prepared depending on the chemical and physical properties of the starting materials and the activation method used. In this study, activated carbon prepared using pineapple waste. Three parts of pineapple waste which comprises of peel, crown and leaf were studied. For comparison activated carbon were prepared by both physical and chemical activation respectively. Three types of chemicals were used, phosphoric acid (H3PO4), sulphuric acid (H2SO4), and potassium hydroxide (KOH). The preparation includes carbonization at 200°C and activation at the 400°C using muffle furnace. The chemical characterization of the activated carbon was carried out using Thermogravimetric analysis (TGA), Nitrogen gas adsorption analysis and Fourier transform infrared (FTIR). The highest BET surface area was achieved when the pineapple peel soaked in 20% phosphoric acid with a surface area of 1115 m2g-1. FTIR analysis indicates that the reacted pineapple waste successfully converted into activated carbons.

scholarly journals The impact of infrastructure on driver behavior on pedestrian crossings – case studies in two Mazovian cities

2020 ◽  
Vol 2020 (33) ◽  
pp. 97-117
Author(s):  
Maciej Sulmicki
Keyword(s):  
Driver Behavior ◽  
Field Studies ◽  
National Study ◽  
Traffic Lights ◽  
The Road ◽  
Traffic Calming ◽  
Study Results ◽  
New Material ◽  
Road Width ◽  
The Impact

In 2019 field studies were conducted in order to check how various aspects of pedestrian and cycle crossing infrastructure influence driver behavior. The overall goal was to verify the adequacy of the road safety-related provisions of the main strategic and planning documents of the Mazovia Region. The crossings analyzed in Warsaw and Radom were chosen so as to take into account all the types of traffic calming mentioned in the Spatial Development Plan of Mazovia as serving to improve safety on pedestrian crossings. Other aspects taken into account included road width, type of intersection and presence/type of traffic lights. The field studies focused on the behavior of drivers towards pedestrians and cyclists, including behavior which determines how quickly a driver can react to a non-motorized person appearing. The crossings were observed from a distance, so that the presence of the observer wouldn’t influence the participants’ behavior. Each crossing was observed and recorded for at least thirty minutes in order to identify how often a driver: stops before a crossing, drives across in front of or behind a non-motorized person, stops on the crossing or drives fast across it. In selected places, another recorded aspect was whether the driver looks around before driving across the crossing. However, such detailed observation was not possible in the majority of places due to high traffic and/or inadequate visibility of the interiors of cars. The field studies in Radom were conducted by Sebastian Pawłowski and Łukasz Zaborowski of the Radom branch of the Mazovian Office for Regional Planning. The study results indicate that dangerous driver behavior is influenced by: the width of the road on the crossing, bicycle crossings and right-of-way provisions, physical traffic calming measures and traffic lights. Measures which were found to be ineffective include hatched road markings signaling a part of the road which is not to be driven across and red lights with a green arrow allowing for a conditional right-turn after stopping, which were in fact treated as green right-turn lights. The study confirmed the accuracy of the measures indicated in the strategic and spatial planning documents of the Mazovia Region, as well as the need for them to be implemented more often. An analysis of the field study results allowed for the identification of the impact of individual road crossing parameters on drivers’ behavior, thus providing new material in reference to earlier local studies and a 2018 Polish national study. A Polish version of this article will also be published in a later issue of this periodical.

scholarly journals Development of Concrete Mixture Design Process Using MCDM Approach for Sustainable Concrete Quality Management

2020 ◽  
Vol 12 (19) ◽  
pp. 8110
Author(s):  
Mohd. Ahmed ◽  
Javed Mallick ◽  
Saeed AlQadhi ◽  
Nabil Ben Kahla
Keyword(s):  
Quality Management ◽  
Design Process ◽  
Design Procedure ◽  
Mixture Design ◽  
Design Methods ◽  
Concrete Mixture ◽  
Sustainable Concrete ◽  
Concrete Production ◽  
Concrete Mix ◽  
Concrete Quality

The development of a concrete mixture design process for high-quality concrete production with sustainable values is a complex process because of the multiple required properties at the green/hardened state of concrete and the interdependency of concrete mixture parameters. A new multicriteria decision making (MCDM) technique based on Technique of Order Preference Similarity to the Ideal Solution (TOPSIS) methodology is applied to a fuzzy setting for the selection of concrete mix factors and concrete mixture design methods with the aim towards sustainable concrete quality management. Three objective properties for sustainable quality concrete are adopted as criteria in the proposed MCDM model. The seven most dominant concrete mixture parameters with consideration to sustainable concrete quality issues, i.e., environmental (density, durability) and socioeconomic criteria (cost, optimum mixture ingredients ratios), are proposed as sub-criteria. Three mixture design techniques that have potentiality to include sustainable aspects in their design procedure, two advanced and one conventional concrete mixture design method, are taken as alternatives in the MCDM model. The proposed selection support framework may be utilized in updating concrete design methods for sustainability and in deciding the most dominant concrete mix factors that can provide sustainable quality management in concrete production as well as in concrete construction. The concrete mix factors found to be most influential to produce sustainable concrete quality include the water/cement ratio and density. The outcomes of the proposed MCDM model of fuzzy TOPSIS are consistent with the published literature and theory. The DOE method was found to be more suitable in sustainable concrete quality management considering its applicable objective quality properties and concrete mix factors.

Diversity of initial material of buckwheat and trends in its use in breeding

2018 ◽  
pp. 31-43
Author(s):  
Yu.V. Kharchenko ◽  
O.V. Tryhub
Keyword(s):  
Gene Pool ◽  
Geographical Origin ◽  
Initial Material ◽  
Technological Parameters ◽  
Grain Number ◽  
Node Number ◽  
Breeding Parameters ◽  
Study Results ◽  
New Material ◽  
Branching Point

Goal. To assess the diversity of collection material differing by eco-geographical origin for a set of economic and breeding parameters to select the most valuable accessions, to describe and evaluate them in order to form specific sets of gene pool accessions, to widely involve them in breeding both for traditional and for new purposes.Materials and Methods. The plant material was evaluated and described in compliance with "Expanded Harmonized Classifier of the genus Buckwheat (Fagopyrum Mill.)"," Classifier of the genus Fagopyrum Mill.", etc. Over 1,600 accessions have been investigated for the last 20 years. The information base of the study results contains data on 10-23parameters of accessions (yield, performance, plant architectonics elements, grain size, etc.).Result and Discussion. Based on the data, the collection gene pool was grouped by trait expression and expression of trait sets. Sources of some traits or of their combinations were offered to breeders: 29 accessions - of the grain number per plant (over 100 grains) and the node number in the stem branching point (up to 5); 49 accessions - of performance and inflorescence fertility; 110 accessions - of indices of individual seed productivity and grain number per plant; 27 accessions – of technological parameters of product (grain); 73 accessions - of even ripening; 22 accessions – of moderate shedding resistance, etc. The selected accessions are of different eco-geographical origin: from Ukraine, the Russian Federation, France, Georgia, Japan and Korea.Conclusions. The investigation of the collection material under contrast environmental conditions and selection of sources of economically and breeding-valuable characteristics makes the collection a valuable source of initial material for all breeding trends. Significant value of the collection accessions lies in their different eco-geographical origin, that is, in considerable diversity of gene complexes determining the expression level of a particular trait. Constant replenishment of the collection with new material from different parts of the world and generation of promising trends in the use of buckwheat products require constant search for new sources of valuable features, formation of trait and specific collections, trials and introduction of the gene pool in breeding and production.

Production of High Strength Pastes, Mortars, and Concretes

1984 ◽  
Vol 42 ◽  
Author(s):  
Ramon L. Carrasquillo
Keyword(s):  
High Strength Concrete ◽  
Heterogeneous Material ◽  
High Strength ◽  
Materials Selection ◽  
Cement Pastes ◽  
Relative Contribution ◽  
Concrete Production ◽  
Conventional Production ◽  
Production Techniques ◽  
Selection Of

AbstractFor concrete, a grossly heterogeneous material, guidelines for selection of materials for its production, especially high strength concrete, should consider the interactions of its different components under load. Materials selection and production techniques for achieving concretes, mortars and cement pastes with strengths in excess of 10,000 psi are discussed. Emphasis is placed on the production of concretes having a compressive strength in the range of 10,000 to 15,000 psi using readily available materials and conventional production techniques. Emphasis is placed on the practical and technical significance of the factors involved in the selection of the materials and their proportions to achieve uniform, economical, high quality concrete. Selection of the concrete ingredients and their proportions is discussed in terms of their relative contribution to the compressive and flexural strength, elastic properties and observed failure mode of the paste, mortar and concrete. Production of concretes having compressive strengths in excess of 15,000 psi using exotic materials and special production techniques is also discussed.

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