scholarly journals Experimental Evaluation of Recycled Aggregates, Washing Water and Cement Sludge Recovered from Returned Concrete

2021 ◽  
Vol 12 (1) ◽  
pp. 36
Author(s):  
Alessandra Diotti ◽  
Luca Cominoli ◽  
Giovanni Plizzari ◽  
Sabrina Sorlini
Keyword(s):  
Solid Phase ◽  
Raw Materials ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Experimental Program ◽  
Innovative Technology ◽  
Technical Standards ◽  
Washing Process ◽  
Concrete Production ◽  
Washing Water

In this paper, a new innovative technology for the treatment of returned concrete is proposed. This method is based on the application of physical–mechanical processes that allow to obtain new quality products: recycled aggregates, microfiltered water and cement sludge. Specifically, by means of a mechanical system equipped with buffer and Archimedes screws, fine (d < 5 mm) and coarse (d > 5 mm) aggregates are obtained. The water coming from the washing process is sent to a microfiltration process, where a filter membrane separates the liquid phase (microfiltered water) from the solid phase (cement sludge) and no type of potentially toxic additive is added. In this context, this paper investigates the feasibility of using all these components as new raw materials for sustainable concrete production. In particular, according to the requirements imposed by technical standards, an experimental program was developed, aimed at evaluating the physical, chemical, and mechanical properties of the analyzed materials. The results showed that both recycled aggregates, the microfiltered water and the cement sludge can be used to produce new structural concrete. In particular, it was proven that also the cement sludge, which generally represents the most critical component destined for disposal, can be reused as filler in the partial replacement of sand.

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.

scholarly journals A Study on Fresh and Hardened Properties of Concrete with Partial Replacement of Bottom Ash as a Fine Aggregate

2021 ◽  
Keyword(s):  
Industrial Waste ◽  
Raw Materials ◽  
Bottom Ash ◽  
Industrial Wastes ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Research Papers ◽  
Fine Aggregates ◽  
Concrete Production ◽  
Hardened Properties

Abstract. To overcome the shortage of natural resources for the production of concrete, many waste materials are used to replace the raw materials of concrete. In this way, bottom ash is one of the major industrial wastes which shall be used as the replacement of materials in concrete production. It shall be used to replace the materials either up to one-third. This review brings out the evaluation of the industrial waste material which can be repeatedly used as a substitution for concrete as fine aggregate. This paper reviewed the use of industrial waste i.e., bottom ash as fine aggregate in the concrete. The parameters discussed were physical, chemical, fresh, and hardened properties of the concrete with partial replacement of bottom ash. By reviewing some of the research papers, concluded that 10-15% replacement of fine aggregates is acceptable for all the properties of concrete. High utilization of natural sources -gives the pathway to produce more industrial wastes which are responsible for the development of new sustainable development.

scholarly journals Sustainability Potential Evaluation of Concrete with Steel Slag Aggregates by the LCA Method

2020 ◽  
Vol 12 (23) ◽  
pp. 9873
Author(s):  
Vojtěch Václavík ◽  
Marcela Ondová ◽  
Tomáš Dvorský ◽  
Adriana Eštoková ◽  
Martina Fabiánová ◽  
...  
Keyword(s):  
Life Cycle ◽  
Construction Industry ◽  
Raw Materials ◽  
Steel Slag ◽  
Physical And Mechanical Properties ◽  
Partial Replacement ◽  
Utilization Rate ◽  
Natural Aggregate ◽  
Concrete Production ◽  
Natural Aggregates

Sustainability in the construction industry refers to all resource-efficient and environmentally responsible processes throughout the life cycle of a structure. Green buildings may incorporate reused, recycled, or recovered materials in their construction. Concrete is as an important building material. Due to the implementation of by-products and waste from various industries into its structure, concrete represents a significant sustainable material. Steel slag has great potential for its reuse in concrete production. Despite its volume changes over time, steel slag can be applied in concrete as a cement replacement (normally) or as a substitute for natural aggregates (rarely). This paper focused on an investigation of concrete with steel slag as a substitute of natural gravel aggregate. Testing physical and mechanical properties of nontraditional concrete with steel slag as a substitute for natural aggregates of 4/8 mm and 8/16 mm fractions confirmed the possibility of using slag as a partial replacement of natural aggregate. Several samples of concrete with steel slag achieved even better mechanical parameters (e.g., compressive strength, frost resistance) than samples with natural aggregate. Moreover, a life cycle assessment (LCA) was performed within the system boundaries cradle-to-gate. The LCA results showed that replacements of natural aggregates significantly affected the utilization rate of nonrenewable raw materials and reduced the overall negative impacts of concrete on the environment up to 7%. The sustainability indicators (SUI), which considered the LCA data together with the technical parameters of concrete, were set to evaluate sustainability of the analyzed concretes. Based on the SUI results, replacing only one fraction of natural gravel aggregate in concrete was a more sustainable solution than replacing both fractions at once. These results confirmed the benefits of using waste to produce sustainable materials in construction industry.

Experimental Study on the Effect of Recycled Aggregate and GGBS on Flexural Behaviour of Reinforced Concrete Beam

2016 ◽  
Vol 857 ◽  
pp. 101-106
Author(s):  
P.R. Deepa ◽  
Joy Anup
Keyword(s):  
Experimental Study ◽  
Raw Materials ◽  
Reinforced Concrete Beam ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Concrete Aggregate ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

Globally, the concrete industry consumes large quantities of natural resources, which are becoming insufficient to meet the increasing demands. Cement and aggregates are major constituents of concrete. Utilisation of waste materials in concrete instead of raw materials reduces environmental pollution. Ground-granulated blast-furnace slag (GGBS) is a by-product of steel industry. It has cementatious property. Recycled aggregates are obtained from demolishing waste. By using recycled concrete aggregate and GGBS in concrete we can reduce environmental problem to some extent. This experimental study evaluate the effective utilisation of GGBS and recycled aggregate in concrete. In this study GGBS is used as partial replacement for cement and recycled aggregate as partial replacement for coarse aggregate.

scholarly journals INNOVATIVE TECHNOLOGY OF PRODUCTION OF FERMENTED MILK DRINKS FOR NUTRITION ELDERLY PEOPLE

2020 ◽  
pp. 65-74
Author(s):  
Alla Solomon ◽  
Yurii Polievoda
Keyword(s):  
Raw Materials ◽  
The Elderly ◽  
Fermented Milk ◽  
Point Of View ◽  
The Body ◽  
Biologically Active ◽  
Partial Replacement ◽  
Innovative Technology ◽  
Biological Organization ◽  
Food Taking

At present, the problem of rational nutrition for the elderly is extremely urgent, since every fourth Ukrainian is a retiree by age. Rationally built nutrition for such people contributes to the better functioning of all important organs and systems, increases the level of the body's protective response to adverse environmental factors. Various ways to improve the product to give it a herodetic orientation are offered. According to the concept of balanced nutrition, the structure of the diet of an aging person and its energy value should be correlated with the functional state of the enzyme systems responsible for the assimilation of food, taking into account the physiological needs of the body for nutrients and energy, according to age and health, which is especially important for seniors and seniors. From the point of view of gerontology and old age hygiene, such trends in society dictate the need for accurate and deep knowledge of aging processes at all levels of biological organization, from molecular to holistic organism in order to develop a nutritional diet that promotes aging, preventing aging lifestyle. The need for rational nutrition of the elderly puts forward the task of creating an assortment of products nutritionally adequate to the specifics of their nutrition, taking into account the most common pathologies. In the production of hereditary products, the most appropriate is the partial replacement of traditional raw materials with non-traditional, the introduction of dietary and biologically-active additives, the use of secondary raw materials and non-traditional vegetable (medicinal plants, berry syrups, vegetable oils). This makes it possible to create balanced for all criteria products for the elderly, whose production takes into account all age characteristics.

scholarly journals THERMODYNAMIC LAWS OF CHROMIUM REDUCTION BY MIXTURES OF СН4 + Н2О AND СН4 + СО2

2020 ◽  
pp. 20-29
Author(s):  
Oleksandr Gryshyn ◽  
Angela Nadtochij ◽  
Nataliia Velykonska ◽  
Yevhenii Zykin
Keyword(s):  
Chromium Oxide ◽  
Reduction Potential ◽  
Solid Phase ◽  
Raw Materials ◽  
Recovery Process ◽  
Partial Replacement ◽  
Technological Basis ◽  
Phase Reduction ◽  
High Reduction ◽  
Reduction Of Oxides

The development of a physico-chemical model of methane behavior in the processes of solid-phase reduction of chromium-containing raw materials will allow us to create the technological basis for the production of multicomponent sponge ligatures. The reduction of oxides with methane is accompanied by the deposition of soot carbon. The negative effect of carbon black, which is blocking the reaction surface, can be eliminated by adding carbon dioxide or water vapor to methane. A thermodynamic analysis of the reduction of chromium oxide with mixtures of CH4-CO2, CH4-H2O was carried out. The effect of the partial replacement of methane by carbon on the thermodynamic preferences of the process is analyzed. A physicochemical model of the behavior of the CH4 molecule in the recovery process is proposed. The thermodynamic features of reduction at various ratios of СН4 are considered: (Н2О, СО2, О2), as well as the composition of the mixture (Н2О+СО2+О2), which ensure the conditions of solid-phase reduction of oxides and the product of carbide destruction. The use of CH4 + H2O + O2 mixtures in the reduction of chromium oxide is thermodynamically less effective. The use of a mixture of СН4 + Н2О + СО2 has a very insignificant effect on the conversion of methane, and also reduces the thermodynamic preference for the reduction of Cr2O3 in comparison with СН4 + Н2О + О2 and СН4 + Н2О. However, it should be noted that in addition to CO and H2, carbon can be present in the reduction products, so the high reduction potential in this process variant (C+CO+H2) can be used to reduce oxides. The reduction of chromium oxide with mixtures of СН4 + Н2О + О2, СН4 + Н2О, and СН4 + Н2О + СО2 can be thermodynamically realized in the temperature range excluding the melting of the charge. As a result of this process, a carbide phase is formed, as well as a gas phase, which has a high reduction potential and can be used in further technological schemes. Meanwhile, it seems possible to control the carbon content in the sponge ligature by selecting the optimal composition of the source gas mixture.

Study of the Technical Capability of Sugarcane Bagasse Ash in Concrete Production

2016 ◽  
Vol 866 ◽  
pp. 53-57 ◽  
Author(s):  
Thiago da Cruz Sessa ◽  
Marcos Martinez Silvoso ◽  
Elaine Garrido Vazquez ◽  
Eduardo Linhares Qualharini ◽  
Assed Naked Haddad ◽  
...  
Keyword(s):  
Sugarcane Bagasse ◽  
Mechanical Tests ◽  
Cement Industry ◽  
Partial Replacement ◽  
Experimental Program ◽  
Concrete Production ◽  
Sugarcane Bagasse Ash ◽  
Definition Of ◽  
Mineral Mixtures

Cement industry has a great contribution to CO2 emissions in the world. In order to reduce the levels of CO2 emissions and the consequences of global warming, some researches have been developed aiming to reduce the cement volume produced through mineral mixtures. Sugarcane bagasse ash (SCBA) represents an important environmental liability of the alcohol industry in the northern state of Rio de Janeiro and its use as a partial replacement of Portland cement in concrete has shown great potential for use. This paper aims to analyze, through experimental procedures, the consistency and mechanic strength on concrete with low environmental impact, made from sugarcane bagasse ash, in substitution levels of 20% and 40%. The methodology of the experimental program, included the steps of characterizing the materials; definition of the reference concrete; molding and dosing of the reference concrete and concrete with SCBA; mechanical tests to evaluate the resistance in the reference test bodies; and analysis of the results. The method used from production and processing of the ash to the characterization of other materials in the concrete are also addressed in this study. The results indicate the feasibility of using sugarcane bagasse ashes in application of concretes in the construction industry.

scholarly journals The Flexural and Compressive Strength of Recycled Concrete

2018 ◽  
Vol 2 (1) ◽  
pp. 24-27
Author(s):  
Nouf Jassim Alsabbagh
Keyword(s):  
Compressive Strength ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Experimental Program ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Sustainable Solutions ◽  
Coarse Aggregates ◽  
Construction And Demolition Wastes

Limitations in natural resources have drawn the necessity to develop sustainable solutions for the future of the concrete industry. Kuwait has joined the world’s effort to encourage recycling by reducing the amounts of construction and demolition wastes sent to landfills, through the usage of recycled aggregates in Portland Cement concrete mixes. In this research, an experimental program was designed to test the effect of substituting virgin coarse aggregates with recycled aggregates obtained from demolished concrete. Four different concrete mixes were designed at a strength of 30MPa, with different partial replacement percentages of 100%, 50%, and 0%. All mixes were tested for workability. Samples were cast from each mix and tested for the flexural strength as well as the compressive strength; all results were compared to a control mix. Results demonstrated that in spite of the slight effect noted on both flexural and compressive strength, good quality concrete can still be achieved.

Properties of Lightweight Bubbles Aggregate (LBA) for the Replacement of Coarse Aggregates in Concrete

2014 ◽  
Vol 803 ◽  
pp. 11-15
Author(s):  
Norlia Mohamad Ibrahim ◽  
Leong Qi Wen ◽  
Roshazita Che Amat ◽  
Taksiah Abdul Majid ◽  
Nur Liza Rahim ◽  
...  
Keyword(s):  
Specific Gravity ◽  
Portland Cement ◽  
Water Absorption ◽  
Bulk Density ◽  
Ordinary Portland Cement ◽  
Raw Materials ◽  
Construction Materials ◽  
Cement Composite ◽  
Partial Replacement ◽  
Concrete Production

The depletion of natural resources in the production of coarse aggregate are very crucial. Construction materials are solely depends on natural granite in the making of cement composite. Therefore , there is an urgency need to develop new alternatives material that can replace the usage of granite in concrete production. In this study, LBA have been produced to cater this problem. It is made from a mixture of bubbles from foam and ordinary portland cement. The ratio of the raw materials used is 1 part of bubbles and 2 part of ordinary Portland cement. Its manufacturing process does not involving any sintering process so it will part help to reduce energy comsuption at about 30%. The properties and characteristics of the LBA such as density, specific gravity, water absorption, strength were investigated. Results shown that the specific gravity of LBA was 1.00, water absorption was 19.44%, dry bulk density was between 730 – 800 kg/m3 and dry loose bulk density was ranged from 700 to 730 kg/m3 and the strength of aggregates is 14.00 MPa. It is found that the LBA can be used as a partial replacement of granite in the production of concrete. Keywords: LBA, concrete, density

scholarly journals Concrete Production Using Fine Glass Aggregates as Partial Replacement of Sand

2019 ◽  
Vol 7 (12) ◽  
pp. 428-439
Author(s):  
Samuel Cameli Fernandes ◽  
Laerte Melo Barros ◽  
Rodrigo Paz Barros ◽  
Pedro Felix Liotto ◽  
David Barbosa de Alencar
Keyword(s):  
Raw Materials ◽  
Production Costs ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Glass Waste ◽  
Waste Reuse ◽  
Concrete Production ◽  
Fine Glass ◽  
Natural Aggregates ◽  
Sand And Gravel

Waste reuse is considered an excellent alternative for sustainable development. For the World Commission on Environment and Development in Our Common Future, sustainability is "one that meets the needs of the present without compromising the ability of future generations to meet their needs." One way to provide a sustainable solution for glass would be the reuse of glass waste in the production of concrete. Glass residues when suitably crushed and sieved, to assume appropriate granulometry, may exhibit characteristics similar to natural aggregates. The use of glass waste when used in concrete manufacturing reduces production costs. The main objective of the research was to replace, as much as possible, in percentage, the quantity of sand and gravel aggregates by glass waste with the same granulometry, as a way to reduce costs, reduce the use of raw materials and reduce the quantity of wastes that were inadequately disposed of in landfills. Samples of glass waste were collected in the construction industry itself, in works and glassware companies that work with cutting and delivery of the product. Comparisons were made between concretes produced with natural and concrete aggregates produced with the substitution of 20%, 30%, 40% and 50% of the fine aggregate, all of which glass was used as a substitute. The comparative analyzes were the mechanical properties of compression strength and diametral compression traction at 7, 14, 21, 28 and 90 days.

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