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- Cement-based materials (2)
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- Agent-based modelling; ecosystem services; landscape modelling; land use; biodiversity (1)
- Alkali-activated fly ash (1)
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- Analysis (1)
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- Bacillus anthracis; Bacillus thuringiensis; microbial recovery; bioterrorism; (1)
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- International Conference on Durability of Concrete Structures (33)
- International Congress on Environmental Modelling and Software (26)
- International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference (2)
- The Summer Undergraduate Research Fellowship (SURF) Symposium (2)
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Articles 1 - 30 of 64
Full-Text Articles in Entire DC Network
The Influence Of Lightweight Aggregate On Internal Curing And Its Impact On Autogenous Shrinkage Of High-Performance Concrete, Neil J. Hartman, Timothy J. Barrett, Jason Weiss
The Influence Of Lightweight Aggregate On Internal Curing And Its Impact On Autogenous Shrinkage Of High-Performance Concrete, Neil J. Hartman, Timothy J. Barrett, Jason Weiss
The Summer Undergraduate Research Fellowship (SURF) Symposium
In bridge deck construction high performance concrete is often desirable, however in practice it is generally susceptible to early-age shrinkage cracking resulting in an overall reduction in service life. This research seeks to assess the potential for reducing early-age shrinkage in new bridge deck construction through the use of internal curing, a process in which internal reservoirs supply water to the hydrating cement paste during the early stages of cement hydration. In North America, internal curing is typically achieved by replacing a portion of the normal fine aggregate with an expanded fine lightweight aggregate (LWA). For this study, the free …
A Wind-Derived Upwelling Index For Lake Michigan, Stephen B. Davis, Rebecca Essig, Cary Troy
A Wind-Derived Upwelling Index For Lake Michigan, Stephen B. Davis, Rebecca Essig, Cary Troy
The Summer Undergraduate Research Fellowship (SURF) Symposium
Coastal upwelling is a phenomenon that occurs along coastlines throughout the world, and has been shown to be strongly correlated with large fish populations in these areas. Coastal upwelling occurs when strong coastal winds drive water transport away from the coast, causing colder, often nutrient-rich water to upwell in its place. While coastal upwellings can be detected with satellite imagery or in situ temperature measurements, these datasets are neither continuous nor long-term. A wind-derived upwelling index was created for Lake Michigan to continuously quantify upwellings over multiple decades, and to allow for further understanding of the impact of upwelling in …
Effects Of Stirrups On Bond Behavior Between Concrete And Corroded Steel Bars, Hongwei Lin, Yuxi Zhao, Ming Sun
Effects Of Stirrups On Bond Behavior Between Concrete And Corroded Steel Bars, Hongwei Lin, Yuxi Zhao, Ming Sun
International Conference on Durability of Concrete Structures
Steel corrosion leads to the deterioration of bond between concrete and steel bars. The serviceability and ultimate strength of concrete elements within RC structures are hence affected. Many researchers have studied the bond behavior of corroded steel bars. However, very few studies have investigated the effects of confinements on the degradation of bond strength. The present paper proposed a new kind of beam specimen based on which the effects of stirrups on degradation of bond were investigated. The test results proved that stirrups can effectively increase the bond strength between concrete and corroded steel bars.
Influence Of Fly Ash On Surface Chloride Concentration Under Shallow Immersion Condition, Jun Liu, Xiaodong Wang, Feng Xing, Ningxu Han
Influence Of Fly Ash On Surface Chloride Concentration Under Shallow Immersion Condition, Jun Liu, Xiaodong Wang, Feng Xing, Ningxu Han
International Conference on Durability of Concrete Structures
In this paper, the influence of fly ash content on concrete surface chloride concentration was investigated through periodical tests of surface chloride concentration of concrete by immersing three kinds of concrete specimens in 5.0 wt.% sodium chloride solution. One kind of specimen is common concrete without fly ash, whereas the other two kinds of specimens are mixed with fly ash. The results show that the surface chloride ion concentration ranges from 0.295 to 0.777 wt.% for the immersed concrete samples in this study; in the initial stage of immersion, the concrete surface chloride ion concentration is affected by added fly …
Research On Chloride Penetration Resistance Of Phosphoaluminate Cement Concrete, Wu-Jian Long, Ning Xu Han, Da Wang Li, Feng Xing, Ya-Man Zhao
Research On Chloride Penetration Resistance Of Phosphoaluminate Cement Concrete, Wu-Jian Long, Ning Xu Han, Da Wang Li, Feng Xing, Ya-Man Zhao
International Conference on Durability of Concrete Structures
The chloride penetration resistance of phosphoaluminate cement (PAC) concrete was investigated in this study. The effects of mixture proportioning parameters, including cement content, water–cement ratio (w/c), and superplasticizer content on chloride ion penetration resistance of PAC concrete were investigated by the rapid chloride migration test (RCM). The result shows that the increase of cement content and the decrease of w/c can reduce the coefficient of chloride ion penetration of PAC concrete at a certain range. Moreover, the penetration of chloride ion can be declined effectively when polycarboxylate superplasticizer is employed. The PAC concrete exhibited better chloride penetration resistance compared with …
Effect Of Aggregate Gradation With Fuller Distribution On Properties Of Sulfoaluminate Cement Concrete, Chenchen Gong, Jie Zhang, Shoude Wang, Wen Zong, Lingchao Lu
Effect Of Aggregate Gradation With Fuller Distribution On Properties Of Sulfoaluminate Cement Concrete, Chenchen Gong, Jie Zhang, Shoude Wang, Wen Zong, Lingchao Lu
International Conference on Durability of Concrete Structures
Aggregate, the main ingredient of concrete, has a great effect on mechanical property and durability of concrete. Sulfoaluminate cement has lots of special properties such as high early-age compressive strength, fast hydration and setting rate, and hydration with slight swelling. But effect of aggregate gradation with Fuller distribution on properties of sulfoaluminate cement concrete was seldom studied. Hence, in this paper, experimental investigations on mechanical property and durability of sulfoaluminate cement concrete with aggregate gradations according to Fuller distribution were presented. Fuller distribution of aggregates was beneficial to the close packing of aggregates, and the packing density was changed by …
Study On Variable Action Value Standard For Harbor Infrastructures, Xiaoping Zhong, Qianyi Zhao, Weiliang Jin
Study On Variable Action Value Standard For Harbor Infrastructures, Xiaoping Zhong, Qianyi Zhao, Weiliang Jin
International Conference on Durability of Concrete Structures
To meet with different levels of requirements from proprietors and users and to offer a basis for variable action value to the designers, associated with the standards, this dissertation studied the value standard of load effect and environmental effect. For load effect, on the foundation of analyzing variable load effect model, we used equal exceeding probability principle to calculate the load adjustment coefficient for the cargo loading in harbor and river port under different designing service life. For environmental effect, according to the ranks of marine chloride environment in standards GB/T 50476-2008, after analyzing and comparing the research achievements on …
Nondestructive Integrated Ct-Xrd Method For Research On Hydrated Cement System, Takafumi Sugiyama, T. Hitomi, K. Kajiwara
Nondestructive Integrated Ct-Xrd Method For Research On Hydrated Cement System, Takafumi Sugiyama, T. Hitomi, K. Kajiwara
International Conference on Durability of Concrete Structures
A nondestructive integrated CT-XRD method has been developed and used to study hydrated cement system. In this research, a beam line (BL) at the third-generation synchrotron radiation facility, SPring-8, in Japan, was used. First, X-ray computed tomography (CT) was employed to obtain three-dimensional (3D) images and select a region of interest (ROI) in a given plane section of the hardened cement paste. Then, X-ray diffraction analysis (XRD) was conducted on the specified region. These operations were implemented in situ without the removal of specimen from the stage inside the BL. The hardened cement paste was precracked and then leached by …
Visualization And Quantification Of Solute Diffusivity In Cracked Concrete By X-Ray Ct, Michael Henry, T. Sugiyama, I. S. Darma
Visualization And Quantification Of Solute Diffusivity In Cracked Concrete By X-Ray Ct, Michael Henry, T. Sugiyama, I. S. Darma
International Conference on Durability of Concrete Structures
This paper explores the usage of microfocus X-ray computed tomography (CT) for visualization and quantification of diffusion phenomena in cracked concrete. Mortar specimens of varying shapes (prismatic and cylindrical), crack types (artificial and splitting tensile), and binder compositions (OPC and fly ash) were prepared. Cesium carbonate (Cs2CO3) was used as a tracer in the diffusion test because it has high X-ray absorption due to its high atomic number and thus contrasts with mortar and air voids in the CT images. Image processing and analysis was carried out to visualize and quantify the diffusion behavior in 3D …
Research On Embedded Sensors For Concrete Health Monitoring Based On Ultrasonic Testing, Shifeng Huang, Mimi Li, Yuesheng Xu, Dongyu Xu, Xinchun Xie, Xin Cheng
Research On Embedded Sensors For Concrete Health Monitoring Based On Ultrasonic Testing, Shifeng Huang, Mimi Li, Yuesheng Xu, Dongyu Xu, Xinchun Xie, Xin Cheng
International Conference on Durability of Concrete Structures
In this article, embedded ultrasonic sensors were prepared using 1–3-type piezoelectric composite and piezoelectric ceramic as the piezoelectric elements, respectively. The frequency bandwidth of the novel embedded ultrasonic sensors was investigated. To obtain the relationship between the receiving ultrasonic velocity and compressive strength, as well as their response signals to crack damage, the sensors were fabricated and embedded into the cement mortar before testing. The results demonstrated that the piezoelectric composite sensor had wider frequency bandwidth than the piezoelectric ceramic sensor. The compressive strength and ultrasonic velocity had a positive linear relationship, with a correlation coefficient of 0.9216. The head …
Surface Treatment Of Cement-Based Materials With Nanosio2, Pengkun Hou, Xin Cheng, Jueshi Qian, Surendra P. Shah
Surface Treatment Of Cement-Based Materials With Nanosio2, Pengkun Hou, Xin Cheng, Jueshi Qian, Surendra P. Shah
International Conference on Durability of Concrete Structures
A dense surface structure of cement-based material is favorable for its resistance to the impacts of environment. In this work, effectiveness and mechanisms of the surface treatment of cement-based materials with nanoSiO2 of different states, that is, colloidal nanoSiO2 (CNS) and the in situ formed nanoSiO2 gel through the hydrolysis of its precursor of tetraethoxysilane (TEOS), by brushing and soaking techniques, were investigated. Results showed that both CNS and TEOS are capable of reducing the liquid and gaseous transport properties of hardened cement-based materials, although at a different extent. It revealed that the pozzolanic reactivity and the …
Application Of Nanomechanical Methods In Investigation Of C–S–H Gel/Cement Grain Interface, Jing Xu, David J. Corr, Surendra P. Shah
Application Of Nanomechanical Methods In Investigation Of C–S–H Gel/Cement Grain Interface, Jing Xu, David J. Corr, Surendra P. Shah
International Conference on Durability of Concrete Structures
Investigation on the mechanical properties of cement-based materials at micron and submicron scales is important for understanding the overall performance, particularly of high-performance concrete (HPC). Due to low water-tocement ratio of HPC, a large amount of unhydrated cement grains remain in matrix, and a significant impact of the interface between C–S–H gel and cement grains on concrete behavior could be expected. Recent progress in experimental nanomechanics opens new access to nanoengineering of cement-based composites. In this paper, nanoindentation and viscoelastic modulus mapping were used to study the interfacial properties. The interface width measured by modulus mapping was around 200 nm …
Development Of Improved Electrodeposition Method For Repair Of Reinforced Concrete Structures, Takahiro Nishida, Nobuaki Otsuki, Atsushi Saito
Development Of Improved Electrodeposition Method For Repair Of Reinforced Concrete Structures, Takahiro Nishida, Nobuaki Otsuki, Atsushi Saito
International Conference on Durability of Concrete Structures
Deterioration of reinforced concrete members and their repair methods have been reported in various concrete published reports. Electrodeposition method is one of these repair methods for repairing deteriorated concrete members using an electrochemical mechanism. The purposes of the electrodeposition method are to fill cracks in concrete and to coat the concrete surface by electrodeposits of chemical compounds. This can be accomplished by passing a weak direct current (1.0–3.0 A/m2 of concrete surface area) between a reinforcing steel bar (cathode) in concrete and an external electrode (anode) located in an external solution near the concrete surface. This method also accomplishes …
Saturation Of Air Entrained Voids And Its Implication On The Transport Of Ionic Species In Concrete, Yiwen Bu, Jason Weiss
Saturation Of Air Entrained Voids And Its Implication On The Transport Of Ionic Species In Concrete, Yiwen Bu, Jason Weiss
International Conference on Durability of Concrete Structures
Air entrainment is commonly used to improve the durability of concrete materials exposed to freezing and thawing. While the influence of air voids on freeze/thaw damage and salt scaling is frequently studied, the influence of entrained air voids on ionic transport has been studied less frequently. Since ionic transport in concrete materials relies on pore fluid as the medium of conduction, only saturated or partially saturated air voids participate in the transport processes. This paper discusses the conditions under which air voids could become saturated. Specifically, the saturation condition of entrained air voids in laboratory tests and in service is …
Numerical Simulation Method For Fracture Effect Of Corroded Steel Strand Under Tension, Fumin Li, Yaxu Qu, Yu Zhao, Rong Lu
Numerical Simulation Method For Fracture Effect Of Corroded Steel Strand Under Tension, Fumin Li, Yaxu Qu, Yu Zhao, Rong Lu
International Conference on Durability of Concrete Structures
Steel strand presents characteristic pitting corrosion in chloride environment, which leads PC structures to a serious structural failure even with light presentational corrosion. So it is necessary to analyze the fracture effect of steel strand caused by pitting corrosion. The theoretical analyses are difficult for the presence of complicated threedimension pits, so numerical method becomes a feasible choice. A numerical simulation method for fracture effect of corroded steel strand under tension by the ANSYS software is introduced in this paper, which contains mainly four issues such as fracture criterion, constitutive relation, geometrical models, and simplified mechanical models. The Mises strain …
Tensile Bond Between Substrate Concrete And Normal Repairing Mortar Under Freeze–Thaw Cycles, Ye Qian, Dawei Zhang, Tamon Ueda
Tensile Bond Between Substrate Concrete And Normal Repairing Mortar Under Freeze–Thaw Cycles, Ye Qian, Dawei Zhang, Tamon Ueda
International Conference on Durability of Concrete Structures
Concrete patch repair has long been used to repair the damaged concrete structures. In cold regions, freeze– thaw cycle is one of the major damage factors. Not only the material itself is damaged by freeze–thaw cycles, but also the adhesive interface, which is regarded as the weakest part of composite system, degrades under freeze–thaw cycles. Air entraining agent has long been used to increase the freeze–thaw resistance of concrete materials. However, the effect of air entraining agent on the adhesive interface under freeze–thaw cycles has not been explored. The degradation mechanism and failure mode of concrete repair system have not …
Effect Of Transverse Crack On Chloride Penetration Into Concrete Subjected To Drying–Wetting Cycles, Chunhua Lu, Y. Gao, R. G. Liu
Effect Of Transverse Crack On Chloride Penetration Into Concrete Subjected To Drying–Wetting Cycles, Chunhua Lu, Y. Gao, R. G. Liu
International Conference on Durability of Concrete Structures
In this paper, several transversely cracked RC beams, self-anchored in a three-point bending mode, were prepared and subjected to NaCl solution drying–wetting cycles. Based on two experimental results obtained after 15 and 30 cycles, respectively, the profiles of free chloride concentration at different sections of sound and cracked concretes were presented and analyzed. The depth of surface convection zone in cracked concretes subject to chloride drying–wetting cycles is about 10–20 mm, which may increase gradually with the increasing of crack width. Then, it can be found that the speed of chloride penetration in concrete will be increased by cracks. Based …
Numerical Simulation Of The Early Age Three-Dimensional Microstructure Development Of Cement Pastes, Yunsheng Zhang, Zhiyong Liu, Wei Sun
Numerical Simulation Of The Early Age Three-Dimensional Microstructure Development Of Cement Pastes, Yunsheng Zhang, Zhiyong Liu, Wei Sun
International Conference on Durability of Concrete Structures
The formation process of microstructure in cement pastes was first simulated with a numerical model CEMHYD3D. The influence of water-to-cement ratio and particles size on heat release and degree of hydration were then investigated. In addition, the mass of CH and C–S–H phases simulated have been verified by measuring values by thermogravimetry–differential scanning calorimetry (TG-DSC) and X-ray diffraction (XRD)-Rietveld analysis. The evolutions of solids phase percolation and capillary pores de-percolation were also identified by means of a three-dimensional (3D) numerical model. The results show that the simulated values are in good agreement with the available experimental data, indicating a good …
Review Of Microbially Induced Corrosion And Comments On Needs Related To Testing Procedures, Mitchell House, W. J. Weiss
Review Of Microbially Induced Corrosion And Comments On Needs Related To Testing Procedures, Mitchell House, W. J. Weiss
International Conference on Durability of Concrete Structures
Concrete is the most widely used material for the construction of the wastewater collection, storage, and treatment infrastructure. The chemical and physical characteristics of hydrated Portland cement may make it susceptible to degradation under highly acidic conditions. As a result, some concrete wastewater infrastructure may be susceptible to a multistage degradation process known as microbially induced corrosion (MIC). MIC begins with the production of aqueous hydrogen sulfide (H2S(aq)) by anaerobic sulfate-reducing bacteria present below the waterline. H2S(aq) partitions to the gas phase where it is oxidized to sulfuric acid by the aerobic sulfur-oxidizing bacteria Thiobacillus that resides on concrete surfaces …
Flexural Behavior Of Rc Beams Under Combined Effects Of Acid–Salt Mist And Carbon Dioxide, Wu Yuan-Zhou, Lv Heng-Lin, Fang Zhong-Nian
Flexural Behavior Of Rc Beams Under Combined Effects Of Acid–Salt Mist And Carbon Dioxide, Wu Yuan-Zhou, Lv Heng-Lin, Fang Zhong-Nian
International Conference on Durability of Concrete Structures
The coupling effects of hydrochloric acid mist, carbon dioxide, and salt mist rich in Cl– and SO42– on the degradation of reinforcement concrete (RC) beams were researched with the simulation of colliery ground environment (CGE) and experimental investigation. The results indicated that carbonation of concrete and corrosion of rebar increased slowly as the maximum width of crack became <0.5 mm. Meanwhile, the flexural carrying capacity of the deteriorated beam decreased slightly, while the concrete strength got a small increase first and a large decrease of more than 20% quickly. As the width of crack exceeded 0.5 mm, each target changed rapidly except the carbonation depth. Because of the interaction of deteriorated concrete and corroded rebar, the crack width, and flexural behavior of the beams have discrete correlation with the corrosion of rebar. The failure mode of beams changed from the crushing of compression concrete to the yielding of rebar.
Effect Of Blast Furnace Slag Powder And Fly Ash On Durability Of Concrete Mixed With Seawater, Nobuaki Otsuki, Takahiro Nishida, Chang Yi, Tomohiro Nagata, Hiroki Ohara
Effect Of Blast Furnace Slag Powder And Fly Ash On Durability Of Concrete Mixed With Seawater, Nobuaki Otsuki, Takahiro Nishida, Chang Yi, Tomohiro Nagata, Hiroki Ohara
International Conference on Durability of Concrete Structures
According to the report of the United Nations, it is said that two-third of world population would be influenced by water shortage before 2050. To use fresh water effectively, the usage of seawater in concrete industry seems imperative. However, the usage of seawater as concrete material is prohibited in almost all the standards or specifications around the world. In this article, the usage of seawater as a material of concrete based on the results of experimental works and deterioration prediction was discussed. Especially, the effects of by-products such as blast furnace slag or fly ash on the durability of concrete …
Effect Of Drying Rate On Shrinkage Of Alkali-Activated Slag Cements, Hailong Ye, Christopher Cartwright, Farshad Rajabipour, Aleksandra Radlińska
Effect Of Drying Rate On Shrinkage Of Alkali-Activated Slag Cements, Hailong Ye, Christopher Cartwright, Farshad Rajabipour, Aleksandra Radlińska
International Conference on Durability of Concrete Structures
The volumetric instability of alkali-activated slag (AAS) binders has raised concerns and impeded the acceptance of this Portland cement-free material. The objective of this article is to characterize the influence of drying rate on drying shrinkage behavior of AAS mortars to better understand the mechanisms responsible for its large shrinkage deformation. A series of four AAS mortar mixtures with varying activator composition, as well as a reference Portland cement mortar, was cast and dried at different relative humidities, that is, 30, 50, 70, and 85% RH. Drying took place inside nitrogen-purged environmental chambers for the purpose of eliminating the contribution …
Surface And Uniaxial Electrical Measurements On Layered Cementitious Composites Having Cylindrical And Prismatic Geometries, Robert Spragg, Scott Z. Jones, Chiara Villani, Kenneth A. Snyder, Dale P. Bentz, Amire Poursaee, Jason Weiss
Surface And Uniaxial Electrical Measurements On Layered Cementitious Composites Having Cylindrical And Prismatic Geometries, Robert Spragg, Scott Z. Jones, Chiara Villani, Kenneth A. Snyder, Dale P. Bentz, Amire Poursaee, Jason Weiss
International Conference on Durability of Concrete Structures
Electrical measurements are becoming a common method to assess the transport properties of concrete. For a saturated homogenous system, the surface resistance and the uniaxial resistance measurements provide equivalent measures of resistivity once geometry is appropriately taken into account. However, cementitious systems are not always homogenous. This article compares bulk and surface resistance measurements in cementitious materials intentionally composed of layered materials (i.e., layers with different resistivities). For this study, layered systems were composed of paste and mortar layers, representing the heterogeneity that can exist in the surface layers of field applications as a result of differences in moisture content, …
Behavior Of Cfrp Plate In Simulated Iccp System Of Concrete Structures, Jihua Zhu, Miaochang Zhu, Ningxu Han, Feng Xing, Wei Liu, Luca Bertolini
Behavior Of Cfrp Plate In Simulated Iccp System Of Concrete Structures, Jihua Zhu, Miaochang Zhu, Ningxu Han, Feng Xing, Wei Liu, Luca Bertolini
International Conference on Durability of Concrete Structures
An innovative effort was made to utilize carbon fiber reinforced polymer (CFRP) plate as an anode in impressed current cathodic protection (ICCP) of reinforced concrete structure. The feasibility was explored by bonding CFRP strips to concrete and then applying protection current through CFRP strips to steel rebar in concrete. Service life and performance of CFRP plate were investigated in simulated ICCP systems with various configurations. Steel potential results confirmed that the steel rebar in concrete maintained at a satisfactory level with the applied protection current. It is shown that CFRP strips can be successfully used in various solutions as an …
Revised Model Of Chloride Diffusion In Concrete Bridge By Considering Complex Action Of Load And Chloride Binding Capacity, Yiqiang Xiang, Dongmei Guo
Revised Model Of Chloride Diffusion In Concrete Bridge By Considering Complex Action Of Load And Chloride Binding Capacity, Yiqiang Xiang, Dongmei Guo
International Conference on Durability of Concrete Structures
Coastal concrete bridges will suffer from deterioration of RC structural performance and resistance attenuation because of the chloride penetration and other environment factors. This article discusses current different chloride diffusion models and puts forward the revised model of chloride diffusion in concrete bridge by considering the complex action of load influence and chloride-binding capacity. Comparison of numerical predicted values and relative experimental tests show the presented chloride diffusion model to be more accurate. It provides a theoretical basis for the performance assessment and accurate prediction of the remaining life of highway concrete bridges.
Influence Of Micro And Macro Cracks Due To Sustained Loading On Chloride-Induced Corrosion Of Reinforced Concrete Beams, Junjie Wang, Sreejith V. Nanukuttan, P. A. Muhammed Basheer, Yun Bai
Influence Of Micro And Macro Cracks Due To Sustained Loading On Chloride-Induced Corrosion Of Reinforced Concrete Beams, Junjie Wang, Sreejith V. Nanukuttan, P. A. Muhammed Basheer, Yun Bai
International Conference on Durability of Concrete Structures
Chloride-induced corrosion of steel is one of the most commonly found problems affecting the durability of reinforced concrete structures in both marine environment and where de-icing salt is used in winter. As the significance of micro-cracks on chloride induced corrosion is not well documented, 24 reinforced concrete beams (4 different mixes - one containing Portland cement and another containing 35% ground granulated blastfurnace slag at 0.45 and 0.65 water-binder ratios) were subjected to three levels of sustained lateral loading (0%, 50% and 100% of the load that can induce 0.1 mm wide cracks on the tension surface of beam - …
Comparative Study Of Alkali-Activated Fly Ash Manufactured Under Pulsed Microwave Curing And Thermal Oven Curing, Shi Shi, Yun Bai, H. Li, D. L. Xu, P. A. Muhammed Basheer
Comparative Study Of Alkali-Activated Fly Ash Manufactured Under Pulsed Microwave Curing And Thermal Oven Curing, Shi Shi, Yun Bai, H. Li, D. L. Xu, P. A. Muhammed Basheer
International Conference on Durability of Concrete Structures
This paper compares the alkali-activated fly ash (AAFA) manufactured with thermal oven curing and pulsed microwave curing methods. Fly ash activated by 8M NaOH solution at a liquid to solid ratio of 0.3 was cured by thermal oven at 85°C and domestic microwave oven, respectively. Apart from compressive strength test, the temperature profiles of AAFA samples were captured by thermal camera. Reaction products of AAFA were characterised with XRD, FTIR and TG/DTG, while the microstructure of AAFA was analysed by MIP and SEM. The results showed that with much shorter curing duration, the compressive strength of AAFA samples under microwave …
Characterizing The Pore Structure Of Carbonated Natural Wollastonite, Chiara Villani, Robert Spragg, Raikhan Tokpatayeva, Jan Olek, W. Jason Weiss
Characterizing The Pore Structure Of Carbonated Natural Wollastonite, Chiara Villani, Robert Spragg, Raikhan Tokpatayeva, Jan Olek, W. Jason Weiss
International Conference on Durability of Concrete Structures
This paper focuses on examining the pore structure of a cementitious paste made with a calcium silicate (wollastonite) that reacts with carbon dioxide and water to form a hardened solid. The pore structure of the hardened solid has been characterized using vapor sorption and desorption, low-temperature differential scanning calorimetry (LT-DSC), and scanning electron microscopy (SEM). The total porosity was also measured using mass measurement in oven-dry and vacuum-saturated conditions. Evidence exists that support the hypothesis that the solid has two main pore sizes: large macropores (>10 nm) appear to form between the initial calcium silicate particles and small micropores …
An Application Of Geographical And Statistical Linked Data To Ecology: The Brazilian Cerrado Ontology Network And Qualitative Reasoning Models, Adriano Souza, Oscar Corcho, Paulo Salles, Luis Vilches-Blázquez
An Application Of Geographical And Statistical Linked Data To Ecology: The Brazilian Cerrado Ontology Network And Qualitative Reasoning Models, Adriano Souza, Oscar Corcho, Paulo Salles, Luis Vilches-Blázquez
International Congress on Environmental Modelling and Software
This work aims to link data about wood plant communities obtained from scientific studies about the Brazilian Cerrado biome, meteorological and environmental data, geographical information (maps) and Qualitative Reasoning (QR) conceptual models. An ontology network was developed in order to integrate data from different sources. Data Cube, AEMET, GeoSPARQL, and Time ontologies and QR formalism were used as general ontologies. In addition, two domain ontologies--Cerrado Concepts and Wood Plant Dynamics Ontology (Ccon) and Fire Ontology (Fire)--were developed to represent scientific knowledge about vegetation ecology focused on vegetation dynamics under different burning regimens. Datasets provided by Brazilian geovernment agencies and those …
An R Package For Implementing Multiple Evapotranspiration Formulations, Danlu Guo, Seth Westra, Holger R. Maier
An R Package For Implementing Multiple Evapotranspiration Formulations, Danlu Guo, Seth Westra, Holger R. Maier
International Congress on Environmental Modelling and Software
The use of multiple evapotranspiration (ET) models is critical for exploring the ambiguity in the representations of ET processes. Although ensemble ET models are increasingly used to address this ambiguity, practical issues include: 1) the diversity of process representations, which require different input data and constants; 2) the diversity of nomenclature, terminology and units used in the literature; and 3) the complexity of some formulations, requiring significant time for coding and leading to potential user errors. We describe an R package that estimates both actual and potential ET from 17 well-known formulations. Results are presented as summary text and plots, …