scholarly journals Deterioration of modern concrete structures and asphalt pavements by respiratory action and trace quantities of organic matter

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0249761
Author(s):  
Akihiro Moriyoshi ◽  
Eiji Shibata ◽  
Masahito Natsuhara ◽  
Kiyoshi Sakai ◽  
Takashi Kondo ◽  
...  
Keyword(s):  
Organic Matter ◽  
Evaluation Method ◽  
Fine Particles ◽  
Concrete Structures ◽  
Asphalt Pavements ◽  
Concrete Pavements ◽  
Snow Melting ◽  
Concrete Damage ◽  
Amine Compounds ◽  
Peeling Off

In concrete structures (concrete), damage from cracks, deterioration, amorphization, and delamination occur in some structures, causing disaggregation (concrete changed to very fine particles) and hollowing out of the concrete. In concrete pavements, damage from large amounts of pop-out of aggregate occurs from the surface of the concrete pavement 4–5 hours after spraying of snow melting agent on the surface of the pavement. The damage from disaggregation, blistering, cracks, and peeling-off of a surface course have also been observed in asphalt runways and highways. The damage from disaggregation, cracks and pop-out of aggregate in asphalt pavements and concrete structures have long been seen as strange and unexpected and have defied explanation. As a result of examinations in various experiments, it was concluded that all of the unexplained kinds of damage of both asphalt pavements and concrete structures were caused by Trace Quantities of Organic Matter (TQOM), Air Entrained (AE) water reducing agent in air and/or cement, and surfactant in snow melting agent. The emission sources of TQOM and these organic substances were also identified by chemical analysis for these unexpected and unexplained phenomena. The TQOM includes phthalate compounds (phthalates in the following), amine compounds, phosphate compounds, snow melting agent and Sodium Polyoxyethylene Nonyl phenyl Ether Sulfate (SPNES). SPNES is a surfactant in windshield washer fluid for automobiles. We found that the water content and content of organic matter in damaged asphalt pavements and concrete structures are also important indicators for the damage. Further, a new evaluation method for amorphization was proposed in this study and it appears suitable for evaluating the safety of concrete structures along roads which were exposed to TQOM in severely air-polluted environments.

scholarly journals Effect of soil coarseness on soil base cations and available micronutrients in a semi-arid sandy grassland

Solid Earth ◽  
2016 ◽  
Vol 7 (2) ◽  
pp. 549-556 ◽  
Author(s):  
Linyou Lü ◽  
Ruzhen Wang ◽  
Heyong Liu ◽  
Jinfei Yin ◽  
Jiangtao Xiao ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Ph ◽  
Fine Particles ◽  
Base Cations ◽  
Main Process ◽  
Soil Base ◽  
Exchangeable Ca ◽  
Semi Arid ◽  
Sandy Grassland

Abstract. Soil coarseness is the main process decreasing soil organic matter and threatening the productivity of sandy grasslands. Previous studies demonstrated negative effect of soil coarseness on soil carbon storage, but less is known about how soil base cations (exchangeable Ca, Mg, K, and Na) and available micronutrients (available Fe, Mn, Cu, and Zn) response to soil coarseness. In a semi-arid grassland of Northern China, a field experiment was initiated in 2011 to mimic the effect of soil coarseness on soil base cations and available micronutrients by mixing soil with different mass proportions of sand: 0 % coarse elements (C0), 10 % (C10), 30 % (C30), 50 % (C50), and 70 % (C70). Soil coarseness significantly increased soil pH in three soil depths of 0–10, 10–20 and 20–40 cm with the highest pH values detected in C50 and C70 treatments. Soil fine particles (smaller than 0.25 mm) significantly decreased with the degree of soil coarseness. Exchangeable Ca and Mg concentrations significantly decreased with soil coarseness degree by up to 29.8 % (in C70) and 47.5 % (in C70), respectively, across three soil depths. Soil available Fe, Mn, and Cu significantly decreased with soil coarseness degree by 62.5, 45.4, and 44.4 %, respectively. As affected by soil coarseness, the increase of soil pH, decrease of soil fine particles (including clay), and decline in soil organic matter were the main driving factors for the decrease of exchangeable base cations (except K) and available micronutrients (except Zn) through soil profile. Developed under soil coarseness, the loss and redistribution of base cations and available micronutrients along soil depths might pose a threat to ecosystem productivity of this sandy grassland.

scholarly journals Source apportionment of fine organic aerosols in Beijing

2009 ◽  
Vol 9 (21) ◽  
pp. 8573-8585 ◽  
Author(s):  
Q. Wang ◽  
M. Shao ◽  
Y. Zhang ◽  
Y. Wei ◽  
M. Hu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Biomass Burning ◽  
Fine Particles ◽  
Organic Aerosols ◽  
Gas Chromatography Mass Spectrometry ◽  
Chemical Compositions ◽  
Vehicle Exhaust ◽  
Coal Burning ◽  
Alkanoic Acids

Abstract. Fine particles (PM2.5, i.e., particles with an aerodynamic diameter of ≤2.5 μm) were collected from the air in August 2005, August–September 2006, and January–February 2007, in Beijing, China. The chemical compositions of particulate organic matter in the ambient samples were quantified by gas chromatography/mass spectrometry. The dominant compounds identified in summertime were n-alkanoic acids, followed by dicarboxylic acids and sugars, while sugars became the most abundant species in winter, followed by polycyclic aromatic hydrocarbons, n-alkanes, and n-alkanoic acids. The contributions of seven emission sources (i.e., gasoline/diesel vehicles, coal burning, wood/straw burning, cooking, and vegetative detritus) to particulate organic matter in PM2.5 were estimated using a chemical mass balance receptor model. The model results present the seasonal trends of source contributions to organic aerosols. Biomass burning (straw and wood) had the highest contribution in winter, followed by coal burning, vehicle exhaust, and cooking. The contribution of cooking was the highest in summer, followed by vehicle exhaust and biomass burning, while coal smoke showed only a minor contribution to ambient organic carbon.

scholarly journals Experimental Study and Damage Effect Analysis of Concrete Structures under the Combined Loadings of Penetration and Explosion

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Hao Geng ◽  
Hao Lu ◽  
Shanzheng Sun ◽  
Songlin Yue ◽  
Chunming Song ◽  
...  
Keyword(s):  
Field Experiments ◽  
Concrete Structures ◽  
Damage Effect ◽  
Price Ratio ◽  
Combined Effects ◽  
Effect Analysis ◽  
Concrete Damage ◽  
Impact Coefficient ◽  
Damage Depth ◽  
Explosive Charges

The penetration-explosion warhead is one of the most effective weapons for use against concrete structures. In order to study the phenomena and results for concrete damage caused by the combined effects of penetration and explosion, field experiments were performed on damaged concrete targets with different penetration speeds and explosive charges. The damage to the targets was analyzed, the causes were determined, and prediction methodologies were developed. Dimensional analysis was used to fit experimental results, a formula for calculating the damage depth and volume was proposed, and the dependence of the damage depth and volume on the aspect ratio of the explosive (or charge) and the kinetic energy of bullet penetration were determined. For a given projectile size and quantity of explosives, the damage depth and volume of the concrete target increase with the increasing projectile impact coefficient, but this trend gradually decreases. This observation can also provide a reference for the optimal design of penetration-explosion warheads, exhibiting the desired performance-price ratio.

scholarly journals Influence of variability of water content in different states on electromagnetic waves parameters affecting accuracy of GPR measurements of asphalt and concrete pavements

2019 ◽  
Vol 262 ◽  
pp. 06012
Author(s):  
Małgorzata Wutke ◽  
Anna Lejzerowicz ◽  
Wioletta Jackiewicz-Rek ◽  
Andrzej Garbacz
Keyword(s):  
Dielectric Constant ◽  
Electromagnetic Wave ◽  
Water Content ◽  
Electromagnetic Waves ◽  
Atmospheric Precipitation ◽  
Propagation Speed ◽  
Asphalt Pavements ◽  
Concrete Pavements ◽  
Moisture Conditions ◽  
Accuracy And Repeatability

In the paper a water content effect in various states on the variability of the electromagnetic waves parameters is discussed. This variation can affect accuracy and repeatability of asphalt and concrete pavement thickness estimation with GPR method. In case of asphalt pavements, tests were carried out using the air-coupled 1.0 GHz antenna and included three approaches: two on asphalt road and one of asphalt slabs. In the case of concrete slabs, tests were carried out using a ground-coupled 1.6 GHz antenna on two slabs: reinforced and unreinforced. A high variability of the electromagnetic wave parameters was observed depending on moisture conditions. The increase in the humidity of the medium causes a reduction in the propagation speed of the electromagnetic wave (increasing the dielectric constant of the medium), increasing of waves time propagation, decreasing of reflection amplitude and increasing of frequency attenuation, which should be considered when determining the thicknesses of the construction layers. Studies showed that not always higher air humidity, atmospheric precipitation and consequently wet surface indicate a higher dielectric constant of the medium. It can be concluded that not only the humidity and ambient temperature affect the change in the dielectric constant, but also other factors not resulting from the construction of the pavement as well as material microstructure.

Effectiveness Analysis of Subsurface Drainage Features Based on Design Adequacy

2000 ◽  
Vol 1709 (1) ◽  
pp. 69-77
Author(s):  
Timothy Robert Wyatt ◽  
Emir Jose Macari
Keyword(s):  
Design Methodology ◽  
Design Feature ◽  
Subsurface Drainage ◽  
Asphalt Pavements ◽  
Concrete Pavements ◽  
Pavement Distress ◽  
Theoretical Design ◽  
Pavement Structures ◽  
Pavement Base ◽  
Effectiveness Assessment

To prevent the deleterious effects of undrained moisture in pavement structures, it has become common to incorporate subsurface drainage features such as permeable bases and edgedrains into pavement design. A theoretical design methodology has been developed to ensure that the level of subsurface drainage is adequate for the specific pavement structure. However, recent research has called into question the effectiveness of subsurface drainage for certain types of pavement structures. Correlating the presence of moisture-related pavement distress with drainage features has revealed that drainage features do not significantly reduce faulting of doweled jointed concrete pavements, and that edgedrains may negatively impact hot-mix asphalt pavements. However, the study in which this correlation was accomplished did not attempt to assess the adequacy of the provided drainage features using the theoretical design methodology. This research presents an alternative method of effectiveness assessment based on design adequacy. The theoretical drainage capacity of a design feature, such as a pavement base or edgedrain system, is computed using the design methodology and compared with the expected inflow to that feature. The adequacy of the design is expressed as the proportion of the computed capacity to the expected service requirement. The method is applied to cases in the Long-Term Pavement Performance database. Examples are provided in which adherence to the design methodology would have indicated that the drainage features were inadequate; however, the more simplistic observational approach would reflect poorly on the effectiveness of the provided drainage features.

Durability Environment Division of Concrete Structures Based on Combination of Fuzzy and Rough Set

2011 ◽  
Vol 368-373 ◽  
pp. 617-623 ◽  
Author(s):  
Di Tao Niu ◽  
Da Ming Luo ◽  
Guo Hua Xing ◽  
Hui Ma
Keyword(s):  
Rough Set ◽  
Data Model ◽  
Evaluation Method ◽  
Rough Set Theory ◽  
Comprehensive Evaluation ◽  
Concrete Structures ◽  
Measured Data ◽  
Determination Method ◽  
Shenzhen City ◽  
Regional Factors

In this paper, fuzzy set and rough set theory were used to the research of durability environment division of concrete structures. Based on discretization of the measured data, the significance of attributes among rough sets was estimated instead of weight determination, and a relation data model about the durability effecting factors of concrete structures was established. A knowledge system was built through making attribute value into eigenvalue. During data analysis, the assessment of the regional factors was computed by analyzing the support and significance of evaluation method for the predicted object. The proposed approach overcomes the subjectivity of traditional weight determination method, After researching on durability environment divisions of concrete structures in Shenzhen city, the result shows that the proposed approach overcomes the subjectivity of traditional weight determination method, possesses much more objectivity and improved the accuracy and efficiency of comprehensive evaluation.

Long-term Performance of Fiber Grid Reinforced Asphalt Pavements Overlaid on Old Concrete Pavements

2017 ◽  
Vol 19 (3) ◽  
pp. 31-43
Author(s):  
Ju Myeong Lee ◽  
Seung Beom Baek ◽  
Kang Hoon Lee ◽  
Jo Soon Kim ◽  
Jin Hoon Jeong
Keyword(s):  
Asphalt Pavements ◽  
Concrete Pavements ◽  
Long Term Performance ◽  
Term Performance

Concrete Damage Parameter and its Size Effect

2007 ◽  
Vol 348-349 ◽  
pp. 369-372
Author(s):  
Xiang Dong Wang ◽  
Wei Xuan Zhu ◽  
Ai Min Deng ◽  
Dong Zhou ◽  
Dao Yuan Xu
Keyword(s):  
Growth Rate ◽  
Size Effect ◽  
Concrete Structures ◽  
Damage Parameter ◽  
Mass Concrete ◽  
Initial Damage ◽  
Standard Specimens ◽  
Concrete Damage ◽  
Design And Construction

Damage parameter of concrete is widely used in design and construction of concrete structures. An experimentation method has been designed, which can simulate the initial damage by mixed initiator into concrete. Damage parameter can be obtained in laboratory with standard specimens. But practical structure is very large. It is not rational to use this parameter in practical structures. So size effect on damage parameter is studied. It is concluded that initial damage and summit damage grow with the increase of structure size, but the growth rate becomes gentle with size increasing. When the size is larger than 500 mm×500 mm, the growth rate is less than 15‰, so the results obtained from specimen in 500 mm×500 mm can be used for mass concrete structures.

scholarly journals CARACTERÍSTICAS GEOQUÍMICAS DE LOS SEDIMENTOS SUPERFICIALES DE LA LAGUNA LA RESTINGA, ISLA DE MARGARITA, VENEZUELA.

2016 ◽  
Author(s):  
Juan Velásquez ◽  
Arístide Márquez ◽  
Ivis Fermín ◽  
Fabiola López ◽  
Deudedit Hernández ◽  
...  
Keyword(s):  
Organic Matter ◽  
Calcium Carbonate ◽  
Organic Carbon ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Fine Particles ◽  
Sandy Loam ◽  
Aliphatic Hydrocarbons ◽  
Main Body ◽  
Total Organic Matter

This research aims to evaluate some chemical parameters of surface sediments of La Restinga coastal lagoon, located in Margarita Island, Nueva Esparta State, Venezuela. Using classical methodology for geochemical studies, grain size and texture of sediment percentage of organic carbon and total organic matter, as well as calcium carbonate were analyzed. Additionally, the concentrations of total nitrogen, total phosphorus and aliphatic hydrocarbons were determined. The results showed that in La Restinga lagoon sedimentary sandy texture dominate above sandy-loam and sandy-clay. The percentages of total organic carbon, total organic matter and calcium carbonate respectively varied as follows: 1.70-25.53%, 11.10-82.10% and 2.93-44.01%. Concentrations of 282.10-1571.80 mg kg-1 in total nitrogen, 419.50-2033.70 mg kg-1 in total phosphorus and 5.65-63.18 mg kg-1 for aliphatic hydrocarbons were determined. The total organic matter in the lagoon La Restinga is distributed based on the fine particles of sediment and the presence of mangroves, in turn calcium carbonate, was associated mainly to contributions from organisms with calcareous shell. The low values of the ratio NT/PT (under 5) suggest limitation of nitrogen in the ecosystem, and natural or anthropogenic enrichment of phosphorus in the sediment. The levels found of certain aliphatic hydrocarbons, are not considered as contamination levels as established by CARIPOL (1980), except in the eastern end of the main body of the lagoon. According to the points made in this study, we can infer that La Restinga Lagoon showed symptoms of degradation product of human intervention in the ecosystem.

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