Carbonation depth predictions in concrete bridges under changing climate conditions and increasing traffic loads

2018 ◽  
Vol 93 ◽  
pp. 140-154 ◽  
Author(s):  
Chao Jiang ◽  
Xianglin Gu ◽  
Qinghua Huang ◽  
Weiping Zhang
Keyword(s):  
Concrete Bridges ◽  
Carbonation Depth ◽  
Climate Conditions ◽  
Changing Climate ◽  
Traffic Loads

scholarly journals Effect of Graphene Nanoplatelet on the Carbonation Depth of Concrete under Changing Climate Conditions

2021 ◽  
Vol 11 (19) ◽  
pp. 9265
Author(s):  
Yingzi Zhang ◽  
Yanze Wang ◽  
Mingqian Yang ◽  
Huatao Wang ◽  
Guofang Chen ◽  
...  
Keyword(s):  
Control Sample ◽  
Co2 Concentration ◽  
Favorable Effect ◽  
Carbonation Depth ◽  
Graphene Nanoplatelet ◽  
Carbonation Reaction ◽  
Climate Conditions ◽  
Ordinary Concrete ◽  
Changing Climate ◽  
Carbon Dioxide Co2

Climate change has been unprecedented in the past decades or even thousands of years, which has had an adverse impact on the mechanical properties of concrete structures. Many researchers have begun to study new concrete materials. Graphene nanoplatelet (GNP) is an attractive nanomaterial that can change the crystal structure of concrete and improve durability. The aim of the present study was to investigate the effect of GNP (0.05%wt) on the carbonation depth of concrete under simulated changing climate conditions (varying temperature, relative humidity, and carbon dioxide (CO2) concentration), and compare it with ordinary concrete. When the concentration of CO2 is variable, the carbonation depth of graphene concrete is 10% to 20% lower than that of ordinary concrete. When the temperature is lower than 33 °C, the carbonation depth of graphene concrete is less than that of the control sample; however, above 33 °C, the thermal conductivity of GNP increases the carbonation reaction rate of concrete. When the humidity is a variable, the carbonation depth of graphene concrete is less than 15% to 30% of ordinary concrete, and when the humidity is higher than 78%, the difference in the carbonation depth between the ordinary concrete and the graphene concrete decreases gradually. The overall results indicated that GNP has a favorable effect on anti-carbonation performance under changing climate conditions.

scholarly journals Potential shift from a carbon sink to a source in Amazonian peatlands under a changing climate

2018 ◽  
Vol 115 (49) ◽  
pp. 12407-12412 ◽  
Author(s):  
Sirui Wang ◽  
Qianlai Zhuang ◽  
Outi Lähteenoja ◽  
Frederick C. Draper ◽  
Hinsby Cadillo-Quiroz
Keyword(s):  
21St Century ◽  
Carbon Sink ◽  
Accumulation Rate ◽  
Foreland Basin ◽  
Carbon Accumulation ◽  
Climate Conditions ◽  
Changing Climate ◽  
Soil Carbon Density ◽  
Increasing Precipitation ◽  
Aerobic And Anaerobic

Amazonian peatlands store a large amount of soil organic carbon (SOC), and its fate under a future changing climate is unknown. Here, we use a process-based peatland biogeochemistry model to quantify the carbon accumulation for peatland and nonpeatland ecosystems in the Pastaza-Marañon foreland basin (PMFB) in the Peruvian Amazon from 12,000 y before present to AD 2100. Model simulations indicate that warming accelerates peat SOC loss, while increasing precipitation accelerates peat SOC accumulation at millennial time scales. The uncertain parameters and spatial variation of climate are significant sources of uncertainty to modeled peat carbon accumulation. Under warmer and presumably wetter conditions over the 21st century, SOC accumulation rate in the PMFB slows down to 7.9 (4.3–12.2) g⋅C⋅m−2⋅y−1 from the current rate of 16.1 (9.1–23.7) g⋅C⋅m−2⋅y−1, and the region may turn into a carbon source to the atmosphere at −53.3 (−66.8 to −41.2) g⋅C⋅m−2⋅y−1 (negative indicates source), depending on the level of warming. Peatland ecosystems show a higher vulnerability than nonpeatland ecosystems, as indicated by the ratio of their soil carbon density changes (ranging from 3.9 to 5.8). This is primarily due to larger peatlands carbon stocks and more dramatic responses of their aerobic and anaerobic decompositions in comparison with nonpeatland ecosystems under future climate conditions. Peatland and nonpeatland soils in the PMFB may lose up to 0.4 (0.32–0.52) Pg⋅C by AD 2100 with the largest loss from palm swamp. The carbon-dense Amazonian peatland may switch from a current carbon sink into a source in the 21st century.

scholarly journals Potential impacts to freshwater ecosystems caused by flow regime alteration under changing climate conditions in Taiwan

2008 ◽  
Vol 5 (6) ◽  
pp. 3005-3032 ◽  
Author(s):  
J.-P. Suen
Keyword(s):  
Climate Change ◽  
Flow Regime ◽  
River Flow ◽  
Aquatic Organisms ◽  
Freshwater Ecosystems ◽  
Climate Conditions ◽  
Regime Changes ◽  
Changing Climate ◽  
Extreme Flood ◽  
Precautionary Measures

Abstract. Observed increases in the Earth's surface temperature bring with them associated changes in precipitation and atmospheric moisture that consequentially alter river flow regimes. This paper uses the Indicators of Hydrologic Alteration approach to examine climate-induced flow regime changes that can potentially affect freshwater ecosystems. Analyses of the annual extreme water conditions at 23 gauging stations throughout Taiwan reveal large alterations in recent years; extreme flood and drought events were more frequent in the period after 1991 than from 1961–1990, and the frequency and duration of the flood and drought events also show high fluctuation. Climate change forecasts suggest that such flow regime alterations are going to continue into the foreseeable future. Aquatic organisms not only feel the effects of anthropogenic damage to river systems, but they also face on-going threats of thermal and flow regime alterations associated with climate change. This paper calls attention to the issue, so that water resources managers can take precautionary measures that reduce the cumulative effects from anthropogenic influence and changing climate conditions.

scholarly journals Identification and analysis of pathological defect appearance in superstructures of reinforced-concrete bridges in Chapare region, Bolivia

DYNA ◽  
2021 ◽  
Vol 88 (216) ◽  
pp. 15-21
Author(s):  
Joaquin Humberto Aquino Rocha ◽  
Rolando Ibarra Villanueva
Keyword(s):  
Visual Inspection ◽  
Structural Characteristics ◽  
Concrete Bridges ◽  
High Humidity ◽  
Carbonation Depth ◽  
Carbonation Process ◽  
Reinforced Concrete Bridges ◽  
Inspection And Maintenance ◽  
Core Extraction ◽  
Selection Of

The objective of this article is to identify and analyze the main pathological manifestations in bridges in the Chapare - Bolivia region, an area characterized by high humidity and constant rainfall throughout the year. The methodology consisted of the selection of five bridges that showed evident signs of deterioration, in which a visual inspection was carried out and, subsequently, different tests: sclerometer, carbonation depth, penetration of chlorides and core extraction. All the bridges present advanced states of deterioration; highlighting corrosion as the main problem, generating detachment of the concrete and risk of collapse. Although the concrete has a compression strength greater than 30 MPa, the existing carbonation process and the different problems encountered compromises it. It is necessary that the entities in charge provide inspection and maintenance programs according to the environmental and structural characteristics of each bridge.

scholarly journals Plant–Pathogen Warfare under Changing Climate Conditions

2018 ◽  
Vol 28 (10) ◽  
pp. R619-R634 ◽  
Author(s):  
André C. Velásquez ◽  
Christian Danve M. Castroverde ◽  
Sheng Yang He
Keyword(s):  
Plant Pathogen ◽  
Climate Conditions ◽  
Changing Climate
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