scholarly journals Leaching of Carbon Reinforced Concrete—Part 1: Experimental Investigations

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4405
Author(s):  
Lia Weiler ◽  
Anya Vollpracht
Keyword(s):  
Heavy Metal ◽  
Reinforced Concrete ◽  
Laboratory Experiments ◽  
Outdoor Exposure ◽  
Experimental Investigations ◽  
Background Concentrations ◽  
Steel Reinforced Concrete ◽  
Zinc Concentrations ◽  
High Concentrations ◽  
Outdoor Behavior

The composite material ‘carbon concrete composite (C3)’ is currently capturing the building sector as an ‘innovative’ and ‘sustainable’ alternative to steel reinforced concrete. In this work, its environmental compatibility was investigated. The focus of this research was the leaching behavior of C3, especially for the application as irrigated façade elements. Laboratory and outdoor exposure tests were run to determine and assess the heavy metal and trace element emissions. In the wake of this work, the validity of laboratory experiments and the transferability to outdoor behavior were investigated. The experimental results show very low releases of environmental harmful substances from carbon concrete composite. Most heavy metal concentrations were in the range of <0.1–8 µg/L, and higher concentrations (up to 32 µg/L) were found for barium, chromium, and copper. Vanadium and zinc concentrations were in the range of 0.1–60 µg/L, boron and nickel concentrations were clearly exceeding 100 µg/L. Most of the high concentrations were found to be a result of the rainfall background concentrations. The material C3 is therefore considered to be environmentally friendly. There is no general correlation between laboratory leaching data and outdoor emissions. The results depend on the examined substance and used method. The prediction and evaluation of the leaching of building elements submitted to rain is therefore challenging. This topic is debated in the second part of this publication.

Study on Mechanical Behaviors and Calculation of Shear Strength of Steel Truss Reinforced Concrete Deep Beams

2011 ◽  
Vol 243-249 ◽  
pp. 514-520
Author(s):  
Chun Yang ◽  
Ming Ji He ◽  
Jian Cai ◽  
Yan Sheng Huang ◽  
Yi Wu
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Experimental Investigations ◽  
Deep Beam ◽  
Deep Beams ◽  
Steel Reinforced Concrete ◽  
Strut And Tie ◽  
Steel Truss ◽  
Mechanical Performances ◽  
Strut And Tie Model

Based on strut-and-tie model (STM) in deep beams, steel truss reinforced concrete (STRC) deep beam was developed. Experimental investigations of mechanical performances of STRC deep beams were carried out, and results show that STRC deep beam is of high ultimate bearing capacity, large rigidity and good ductility; Strut-and-tie force transference model is formed in STRC deep beams, and loads can be transferred in the shortest and direct way. Then Steel reinforced concrete (SRC) strut-and-tie model (SSTM) for determining the shear strength of STRC deep beams is proposed. The contribution of SRC diagonal strut, longitudinal reinforcements, stirrups and web reinforcements to the shear strength of STRC deep beams are determined with consideration of softened effects of concrete, and for safe consideration, superposition theory is employed for SRC struts. Computer programs are developed to calculate the shear strength of STRC deep beams and verified by experimental results.

An Application of Electrical Resistivity Tomography to Investigate Heavy Metals Pathways

2017 ◽  
Vol 22 (4) ◽  
pp. 315-324
Author(s):  
El Mehdi Benyassine ◽  
Ahmed Lachhab ◽  
Abdelilah Dekayir ◽  
Jean C. Parisot ◽  
Mohamed Rouai
Keyword(s):  
Heavy Metal ◽  
Electrical Resistivity ◽  
Heavy Metal Contamination ◽  
High Resistivity ◽  
Lead And Zinc ◽  
High Atlas Mountains ◽  
Zinc Concentrations ◽  
High Concentrations ◽  
Average Lead ◽  
Risk Reduction Measures

The abandoned lead mine of Zeida is located at the center of the High Moulouya watershed between the Middle and the High Atlas Mountains of Morocco. Zeida has produced a total of 640,000 tons of concentrated lead during the 14 years of its activity (1972–1985). Three large tailings were left at the center of the mine on both sides of Moulouya River without any risk reduction measures or monitoring and there is a concern regarding heavy metal contamination of local groundwater. Samples taken from and around the tailings were found to contain average lead and zinc concentrations of 3,000 ppm and 140 ppm, respectively, primarily in the form of galena and barite. Prior studies have also found high concentrations of lead and zinc in both local wells near the town of Zeida and along the banks of Moulouya River. In this study, five electrical resistivity imaging surveys were performed to identify the risk of pollution and trace the pathways of mine-based contaminants to groundwater and to the Moulouya River. The analysis of electrical resistivity data has provided new insights showing: 1) an average tailings thickness of 15 m; 2) rounded structures with high resistivity values at the center and gradually decreasing toward their edges that are assumed to be granite, with fractures and a weathered zone; and 3) the potential pathways of heavy metal occur predominantly along these fractures and in the thick layers of the sandstone overlaying granitic bedrock.

Experimental Investigation on Behavior of Slender Steel Reinforced Concrete Columns Subjected to Eccentric Load

2012 ◽  
Vol 256-259 ◽  
pp. 697-701
Author(s):  
Zhuo Han ◽  
Shao Fei Jiang ◽  
Zhi Ping Sun ◽  
Le Zhou
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Slenderness Ratio ◽  
Concrete Strength ◽  
Axial Loading ◽  
Experimental Investigations ◽  
Eccentric Load ◽  
Composite Columns ◽  
Steel Reinforced Concrete ◽  
Steel Shape

The objectives of this research were to investigate the structural behavior of slender steel reinforced concrete (Referred to as SRC)composite columns subjected to eccentric axial loading. The test consisted of 10 slender columns, with rectangular section160×180mm, and steel shape I10 encased in concrete. The stirrup spacing was 150 mm; its diameter was 6 mm. The diameter of longitudinal reinforcing bars was 10 mm. Details of the experimental investigations including description of the test columns, failure modes and mechanisms, strain characteristics, and load-deformation responses are discussed. Effects of concrete strength, slenderness of columns, and eccentricity of axial loads on the load-carrying capacity of slender column are then presented. Based on these results, a range of slenderness ratio and eccentric ratio of slender SRC column is proposed.

Heavy-Metal Contamination by Atmospheric Fallout of Several Flin Flon Area Lakes and the Relation to Fish Populations

1977 ◽  
Vol 34 (7) ◽  
pp. 899-906 ◽  
Author(s):  
J. C. Van Loon ◽  
R. J. Beamish
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Heavy Metal Contamination ◽  
Aquatic Organisms ◽  
Toxicity Tests ◽  
Atmospheric Fallout ◽  
High Zinc ◽  
Zinc Concentrations ◽  
Flin Flon ◽  
High Concentrations

High concentrations of zinc and other heavy metals were found in lakes in the immediate vicinity of the Flin Flon smelters. In a study of 31 lakes, 7 had Zn levels above 100 μg/ℓ, 6 had levels between 50 and 100 μg/ℓ, and the remainder had concentrations < 50 μg/ℓ. The accuracy and precision of the heavy metal chemical analyses were evaluated using intercomparisons with other laboratories and a standard reference water. A linear relationship was demonstrated between log10 concentration of Zn, Cu, and SO42− and log10 distance from the smelter, suggesting atmospheric fallout as the main source of these substances in the lakes. Fishes were more tolerant of these high zinc concentrations than would be expected on the basis of the responses of fish and other aquatic organisms to similar concentrations of zinc in some laboratory toxicity tests. Key words: heavy metals, zinc, atmospheric fallout, fish toxicity, lake contamination, chemical analysis, Flin Flon, Canada

Environmental Compatibility of Carbon Reinforced Concrete: Irrigated Construction Elements

2019 ◽  
Vol 809 ◽  
pp. 314-319 ◽  
Author(s):  
Lia Weiler ◽  
Anya Vollpracht
Keyword(s):  
Heavy Metal ◽  
Composite Material ◽  
Reinforced Concrete ◽  
Composite Materials ◽  
Building Materials ◽  
Outdoor Exposure ◽  
Leaching Behavior ◽  
Environmental Compatibility ◽  
Materials Research ◽  
Harmful Substances

To foster a sustainable deployment of the innovative composite material ‘carbon concrete composite’ in the building sector, it is necessary to ensure its resource efficiency and environmental compatibility. The Institute for Building Materials Research of the RWTH Aachen University is therefore investigating the leaching behavior of this material, especially for the case of irrigated façade elements. Laboratory and outdoor exposure tests are run to determine and assess the heavy metal and trace element emissions by leaching. Feasible interconnections between laboratory and outdoor examinations can be used to develop a faster testing of future composite materials. Current results show no critical release of environmental harmful substances from carbon concrete composite.

The mathematical modelling of corrosion in hot dip galvanized steel reinforced concrete

2011 ◽  
Vol 2 (1) ◽  
pp. 1-12
Author(s):  
A. Hegyi ◽  
H. Vermeşan ◽  
V. Rus
Keyword(s):  
Mathematical Model ◽  
Reinforced Concrete ◽  
Numerical Model ◽  
Equation System ◽  
Galvanized Steel ◽  
Steel Reinforced Concrete ◽  
Numeric Model ◽  
Physical And Mathematical Models ◽  
Physical Phenomena ◽  
The Mathematical Model

Abstract In this paper we wish to present the numerical model elaborated in order to simulate some physical phenomena that influence the general deterioration of steel, whether hot dip galvanized or not, in reinforced concrete. We describe the physical and mathematical models, establishing the corresponding equation system, the initial and boundary conditions. We have also presented the numeric model associated to the mathematical model and the numeric methods of discretization and solution of the differential equations system that describes the mathematical model.

Applications of Bentonite to Soil Decontamination

2018 ◽  
Vol 69 (7) ◽  
pp. 1695-1698
Author(s):  
Marin Rusanescu ◽  
Carmen Otilia Rusanescu ◽  
Gheorghe Voicu ◽  
Mihaela Begea
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Laboratory Experiments ◽  
Experimental Studies ◽  
Heavy Metal Concentration ◽  
Polluted Soil ◽  
Raw Material ◽  
Soil Decontamination ◽  
Metal Retention ◽  
Removal Of Heavy Metals

A calcium bentonite from Orasu Nou deposit (Satu Mare Romania) was used as raw material. We have conducted laboratory experiments to determine the influence of bentonite on the degree of heavy metal retention. It has been observed that the rate of retention increases as the heavy metal concentration decreases. Experimental studies have been carried out on metal retention ( Zn) in bentonite. In this paper, we realized laboratory experiments for determining the influence of metal (Zn) on the growth and development of two types of plants (Pelargonium domesticum and Kalanchoe) and the effect of bentonite on the absorption of pollutants. These flowers were planted in unpolluted soil, in heavy metal polluted soil and in heavy metal polluted soil to which bentonite was added to observe the positive effect of bentonite. It has been noticed that the flowers planted in unpolluted soil and polluted with heavy metals to which bentonite has been added, the flowers have flourished, the leaves are still green and the plants whose soils have been polluted with heavy metals began to dry after 6 days, three weeks have yellowish leaves and flowers have dried. Experiments have demonstrated the essential role of bentonite for the removal of heavy metals polluted soil.

Chemical and Biological Changes in Nelson Lake, Ontario Following Experimental Elevation of Lake pH

1977 ◽  
Vol 12 (1) ◽  
pp. 213-232 ◽  
Author(s):  
N.D. Yan ◽  
W.A. Scheider ◽  
P.J. Dillon
Keyword(s):  
Heavy Metal ◽  
Lake Ontario ◽  
Background Concentrations ◽  
Precambrian Shield ◽  
Metal Levels ◽  
Zooplankton Communities ◽  
Shield Lakes

Abstract Intensive studies of Nelson Lake, a Sudbury area lake of intermediate pH ~5.7), were begun in 1975. The chemistry of the lake was typical of that of most PreCambrian Shield lakes except that low alkalinities and high sulphate concentrations were observed along with elevated heavy metal levels. After raising the pH of Nelson Lake to 6.4 by addition of Ca(OH)2 and CaCO3, the metals were reduced to background concentrations. Phytoplankton and Zooplankton communities, which at pH of 5.7 were typical of PreCambrian lakes, were not affected by the experimental elevation of lake pH.

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