Civil Engineering Commons^™

Comparing The Measured And Thermodynamically Predicted Afm Phases In A Hydrating Cement, Niall Holmes Dr., Mark Russell, Geoff Davis, Mark Tyrer

Articles

In hydrating Portland cements, more than one of the AFm family of calcium aluminates may exist. Depending on the amount of carbonate and sulfate present in the cement, the most common phase to precipitate is monosulfate, monocarbonate and/or hemicarbonate. It has been reported in the literature that hemicarbonate often appears in measurements such as XRD but not predicted to form/equilibrate in thermodynamic models. With the ongoing use of commercial cements such as CEM I and CEM II containing more and more limestone, it is important to understand which hydrate solids physically precipitate and numerically predict over time. Using 27 cement …

Employing Discrete Solid Phases To Represent C-S-H Solid Solutions In The Cemdata07 Thermodynamic Database To Model Cement Hydration Using The Phreeqc Geochemical Software, Niall Holmes Dr., Mark Tyrer, Denis Kelliher

Articles

This paper presents a cement hydration model over time using the cemdata07 thermodynamic database and a series of derived discrete solid phases (DSPs) to represent calcium silicate hydrate (C-S-H) as a binary solid solution with two end-members. C-S-H in cement is amorphous and poorly crystalline with a range of molar Ca/Si ratios from 0.6 to 1.7. It displays strongly incongruent dissolution behaviour, where the release of calcium into solution is several orders of magnitude greater than silicon. It is, therefore, important that any cement hydration model provides a credible account of this behaviour. C-S-H has been described in the cemdata07 …

Versatile And Robust Non-Iterative Coupling Algorithm For Vehicle-Structure Interaction, Arya Datta

Theses and Dissertations

The dynamic analysis of the vehicle-structure interactions can be extremely computationally expensive. A general non-iterative coupling algorithm based on the substructure approach has been presented. It retains the advantage of the substructure approach that smaller subsystems are solved instead of a large system, which is usually solved when monolithic systems are solved. However, the advantage of using this general coupling approach is that it is non-iterative in nature, instead of the substructure approach that usually uses iterative procedure. The general coupling algorithm developed has been implemented to analyze dynamic interactions between the vehicle and the structure, both in two and …

Achieving Sustainability In Urban Transit And High-Occupancy Vehicle Systems Through Emerging Technologies And Operations, Ruixiao Sun

Theses and Dissertations

It is critical to reduce road transportation emissions, as it is the major source contributing to greenhouse gas emissions (GHGs) and air pollution. However, the increasing travel demand due to the rise of population and economy makes the task challenging. Mathematically, road transportation emissions can be minimized in the manner of reducing total vehicle miles traveled (VMT) and lowering vehicle emission rate. Many strategies have been proven viable for achieving transportation sustainability. For example, the total VMT can be reduced by switching low-occupancy transportation modes (i.e., driving alone) to high-occupancy transportation modes (i.e., public transit, ridesharing). The development of alternative-fuel …

Understanding Unsteady Corner Separation Within Wing-Body Junction Flows, Paul G. Winner

Doctoral Dissertations and Master's Theses

Wing-body junction flows, formed at the interface between a wing and fuselage surface, are a complex, coupled, three-dimensional, turbulent flow field. This thesis focused on the unsteady corner separation that develops at the trailing edge of this wing-body junction under certain conditions. A NACA 0015 wing mounted on a flat plate at an angle of attack of 13°was used as the model junction flow field. The wing had an aspect ratio of 8 with a linear washout twist of 15°. The Reynolds number based on the wing chord was Re_c = 4.5 × 10⁵. Time-dependent stereoscopic particle …

Cyclic Response And Liquidfaction Behavior Of Gravelly Soils, Pitak Ruttithivaphanich

Theses and Dissertations

Cyclic response and liquefaction behavior are soil mechanisms under earthquake conditions. The study of dynamic soil response is important to evaluate soil behaviors under dynamic loading for a wide range of strains. Soil liquefaction phenomena involving a significant reduction in the strength and stiffness of saturated cohesionless soils has caused catastrophic ground failure in numerous earthquakes. Liquefaction mostly occurs in sand, but liquefaction of gravelly soil has been observed. To date, only a few studies have focused on the liquefaction of gravelly soils; hence, research data is limited. This research aims to improve the understanding of cyclic response and liquefaction …

Physico-Mechanical Characterization Of Prototype Earth Block Material For Constitutive Modeling, Erika Lorena Rengifo-López

Theses and Dissertations

The comprehensive understanding and experimental characterization of the overall compressive behavior of earth masonry block materials, such as compressed and stabilized earth blocks (CSEBs), are essential for developing analytical and numerical tools to predict the mechanical response and designing earth masonry structures. Furthermore, advancing the understanding of the extent of the influence of testing parameters on the material's response, such as specimen geometry, is a critical step towards standardization.

CSEBs are produced by compressing a mixture of soil, water, and a stabilizer (e.g., Portland cement). The heterogeneity of the material accrues from the variety of soil particle morphology and potential …

Non-Proprietary Ultra-High Performance Concrete (Uhpc) With Application For Retrofitting Deteriorating Infrastructure, Harshdutta I. Pandya

Theses and Dissertations

This research describes a study on the stiffness degradation of reinforced concrete beams due to corrosion of reinforcement and the effect of subsequent retrofitting. A total of eleven beams were tested under cyclic loading history, where the amplitude on subsequent cycles is increased until the beam fails. The two corroded-repaired beams were repaired with a non-proprietary UHPC applied to the tension and compression surfaces, respectively. The results indicated substantial stiffness degradation of the corroded beam that was not retrofitted. The control beam passed the ACI 437 acceptance criteria (Ipr = 0.22, IR = 100.1, IDL = -0.036). The corroded beam …

Minimizing Surface Run-Off, Improving Underground Water Recharging, And On-Site Rain Harvesting In The Kathmandu Valley, Ambika P. Adhikari, Keshav Bhattarai

Himalayan Research Papers Archive

Nepal's political institutions and administrative units were thoroughly restructured in 2015 with the promulgation of the new Constitution. Several rural areas were combined to meet the definition of urban threshold criteria to classify rural areas into urban categories. Accordingly, over 3,900 local political and administrative units were amalgamated into 753 units, of which, 293 units are classified as urban. Within these newly defined urban areas, many natural environments have been converted into impervious surfaces such as paved roads, sidewalks, and building roofs. These impervious surfaces have drastically increased the amount of surface run-offs-often termed as "urban floods"--under increasing precipitation caused …

Modelling The Hydrating Behaviour Of Fly-Ash In Blended Cements Using Thermodynamics, Nikki Shaji, Niall Holmes Dr., Mark Tyrer

Conference papers

This paper presents a new method to thermodynamically model the hydration behaviour of fly-ash (FA) blended cements by deriving individual phase descriptions depending on the proportion of FA in the blended cement. The predicted hydrated phase assemblage, pore solution chemistries and pH over 1,000 days of hydration and with increasing FA proportions are presented. The thermodynamic data for the FA phases are derived using oxide proportions and mineral compositions are copied directly into the PHREEQC input file. The FA phases take account of all minerals to give a more accurate description of its behaviour during hydration. The calcium aluminosilicate hydrate …

Maximum Grid Spacing Effect On Peak Pressure Computation Using Inflow Turbulence Generators, Zahra Mansouri, Rathinam Panneer Selvam, Arindam Gan Chowdhury

Civil Engineering Faculty Publications and Presentations

The peak pressures are computed using computational fluid dynamics (CFD) with the synthetic inflow turbulence generator and compared with 1:6 scale Texas Tech University (TTU) wind tunnel measurements. The inflow turbulence is calculated using the Consistent Discrete Random Flow Generation Method (CDRFG) method. The maximum and minimum frequencies from the field or experimental measurements as input to the inflow turbulence generator without considering the largest grid spacing used in the CFD model leads to high pressure error. For one case, more than 100% error in peak pressure results is observed. In addition, spurious pressures are observed at the building location …

Numerical Simulation On The Fire Performance Of Reinforced Concrete Flat Slab, David Tipton

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Impact Of Operational And Restoration Interdependencies On Cost And Disruptive Effect In Multilayered Infrastructure Networks, Brigham A. Moore, Steven J. Schuldt, Ramana V. Grandhi, David R. Jacques

Faculty Publications

Network-based modeling and simulation of interdependent infrastructure systems has traditionally modeled 1 to 2 interdependency subtypes within a given model. Typically, different interdependency subtypes are modeled with special sets, variables, and parameters rather than integrated into the model as a standard feature. The most thorough current modeling efforts have modeled only four of the nine interdependency subtypes identified throughout academic literature. This paper presents the first model to incorporate all nine of the identified interdependency subtypes in a multiobjective mixed-integer program. The model is tested using a simulated flood event and a modified interdependent infrastructure dataset representing a medium- to …

Building Services Engineering September/October 2022

Building Services Engineering

No abstract provided.

Multimodal Imaging Of Structural Concrete Using Image Fusion And Deep Learning, Sina Mehdinia

Dissertations and Theses

Concrete structures may be exposed to a variety of loads and environments during their service life. Non-destructive testing (NDT) techniques can be helpful in evaluating the condition of a structure. Imaging provides a visual representation of the interior of concrete and its condition non-destructively. Ground penetrating radar (GPR) and ultrasonic echo array (UEA) using electromagnetic and stress waves, respectively, provide the data that can be used to reconstruct an image. In this PhD dissertation, image reconstruction and fusion algorithms, simulation, and a deep learning model were investigated with the goal to lay the foundation for enhanced imaging applications for concrete. …

Evaluation Of Material Request Order To Support Sustainable Construction, Fajar Susilowati, Nur Nahdiah Anggraeni

Makara Journal of Technology

This study was conducted on one of Indonesia’s apartment projects, in which reinforced concrete is the main structure. Based on existing project data, this project experienced a decline in the construction work’s progress, thus reducing the project’s overall progress. This decline occurred because the delivery of concrete reinforcement material was delayed. This study aimed to determine the process of material request order and its relationship with the work implementation, as well as the factors that influenced the delayed arrival of concrete reinforcement material at the project site. The method used in this study was observation and interview. Data were analyzed …

Review Of Fly-Ash As A Supplementary Cementitious Material, Nikki Shaji, Niall Holmes Dr., Mark Tyrer

Conference papers

This paper presents a review of fly-ash as a Supplementary Cementitious Material (SCM) in concrete in terms of its effects on hydration and durability. The climate change agenda has focused the cement and concrete industry on using low embodied CO2 materials and much effort has been made on incorporating industrial by-products into cement as SCMs. With worldwide cement production (circa 4 billion tonnes) currently accounting for approximately 8% of global CO2 emissions and 7% of industry energy use, the use of suitable SCMs to partially replace cement in concrete is extremely important. However, while coal-fired power stations are in the …

Correlations Between Dynamic Probe Blow Count And Undrained Shear Strength For Peat At A Well-Characterised Raised Bog In Ireland, David Mchugh, Ciaran Reilly, Juan Pablo Osorio

Articles

Peat deposits are generally heterogeneous, with large variations over small areas. Peat has an extremely high water content, high compressibility and low shear strength. This presents a major issue in studying the geomechanical behavior of peat. For this study, field and laboratory tests were conducted to establish the undrained shear strength (s_u) of peat at a cutover industrial peatland in Ireland which had been extensively characterized in the past. The new field work included TRL-type Dynamic Cone Penetrometer, Mackintosh probe and field vane shear tests. A correlation was developed between the Mackintosh probe “M-value” blow count and the …

Deriving Discrete Solid Phases From Csh-3t And Cshq End-Members To Model Cement Hydration In Phreeqc, Niall Holmes Dr., Colin Walker, Mark Tyrer, Denis Kelliher

Conference papers

This paper presents a cement hydration model over time using the CEMDATA thermodynamic database and a series of discrete solid phases (DSP) to represent calcium silicate hydrate (C-S-H) as a ternary (CSH-3T) and quaternary (CSHQ) solid solution. C-S-H in cement is amorphous and poorly crystalline with a range of molar Ca/Si ratios = 0.6-1.7 and displays strongly incongruent dissolution behaviour where the release of calcium into solution is several orders of magnitude greater than silicon. It is therefore important that any cement hydration model provides a credible account of this behaviour. C-S-H has been described in the CEMDATA thermodynamic database …

Optimising Existing Digital Workflow For Structural Engineering Organisations Through The Partnering Of Bim And Lean Processes, John Mclaughlin, Barry Mcauley

Conference Papers

Building Information Modelling (BIM) is now seen as one of the leading transformative processes within the Architectural, Engineering and Construction (AEC) sector and has the potential to assist in streamlining the structural design process. However, its practical implementation can often add another layer to the existing workflow and can result, to its detriment, in the primary objective of optimising structural workflows being hindered. This can lead to structural organisations producing 3D models in tandem with traditional drawings, a lack of human intervention regarding software interoperability, and a reluctance to move away from conventional work methods. This paper will explore how …

Modelling The Thermoelectric Properties Of Cement-Based Materials Using Finite Element Method And Effective Medium Theory, Lorenzo Stella, Conrad Johnston, Javier Troncoso, Piotr Chudzinski, Esther Orisakwee, Jorge Kohanoff, Ruchita Jani, Niall Holmes Dr., Brian Norton, Xiaoli Liu, Ming Qu, Hongxi Yin, Kazuaki Yazawa

Conference papers

Because of the thermoelectric (TE) effect (or Seebeck effect), a difference of potential is generated as a consequence of a temperature gradient across a sample. The TE effect has been mostly studied and engineered in semiconducting materials and it already finds several commercial applications. Only recently the TE effect in cement-based materials has been demonstrated and there is a growing interest in its potential. For instance, a temperature gradient across the external walls of a building can be used to generate electricity. By the inverse of the TE effect (or Peltier effect), one can also seek to control the indoor …

Critical Evaluation Of Time And Cost Of Terrestrial Laser Scanning For Construction Automated Qa Analysis, Joao Rocha, Davitt Lamon

Capstone Reports

Many governments agencies and private owners are demanding up-to-date information related to the current conditions of their facilities. Conventional QA is time-consuming and inefficient; thus, 3D terrestrial laser scanning (TLS) technology has been adopted due to the fast speed and high accuracy in acquiring data. Automated QA analysis can reduce the labour and time needed, reduce the costs, and improve the overall project efficiency. However, very few research efforts have been made to study the benefits of the automated QA analysis in a quantitative way. The process of the TLS-based geometric QA based in an automated data analysis process is …

Improving Data-Driven Infrastructure Degradation Forecast Skill With Stepwise Asset Condition Prediction Models, Kurt R. Lamm, Justin D. Delorit, Michael N. Grussing, Steven J. Schuldt

Faculty Publications

Organizations with large facility and infrastructure portfolios have used asset management databases for over ten years to collect and standardize asset condition data. Decision makers use these data to predict asset degradation and expected service life, enabling prioritized maintenance, repair, and renovation actions that reduce asset life-cycle costs and achieve organizational objectives. However, these asset condition forecasts are calculated using standardized, self-correcting distribution models that rely on poorly-fit, continuous functions. This research presents four stepwise asset condition forecast models that utilize historical asset inspection data to improve prediction accuracy: (1) Slope, (2) Weighted Slope, (3) Condition-Intelligent Weighted Slope, and (4) …

Study On Road Performance Of High Content Phosphogypsum Cement Stabilized Red Clay, Yang Dezhong, Chen Kaisheng, Li Qiang

Journal of China & Foreign Highway

In response to the waste of phosphogypsum resources and engineering characteristics of red clay, by referring to the mix ratio design method of fly ash mixtures, 18 sets of mix ratio samples were set up indoors. By conducting compaction tests, seven-day unconfined compression strength tests, water-stability tests, and CBR tests, exploratory research was conducted on the road performance of high content phosphogypsum stabilized red clay. The results indicate that the optimal water content of high content phosphogypsum stabilized red clay is lower than that of plain red clay. The seven-day unconfined compression strength is 1.8-3.7 times that of plain red …

Incorporating Geopolymer Binders To Fully Utilize Recycled Concrete Aggregates, Matthew Upshaw

LSU Doctoral Dissertations

This study aims to develop a geopolymer concrete binder that will yield desirable strength and durability characteristics when applied to recycled aggregate concrete. In order to achieve this, a geopolymer binder consisting of a metakaolin-silica fume aluminosilicate source material blend activated by potassium-based alkaline solutions is developed and used in place of ordinary Portland cement (OPC) with four different levels of recycled aggregate replacement ratios. The properties of these concretes were analyzed and compared with the properties of OPC concretes produced with the same replacement ratio levels. The results showed that the geopolymer recycled aggregate concrete (GRAC) achieved greater than …

Experimental Performance Evaluation Of A Convective Thermoelectric Building Envelope For Building Heating And Cooling, Xiaoli Liu, Kazuaki Yazawa, Ming Qu, Orkan Kurtulus, Brian Norton, Niall Holmes Dr., Ruchita Jani, Jorge Kohanoff, Lorenzo Stella, Conrad Johnston, Hongxi Yin

Articles

The thermoelectric building envelope (TBE) integrates thermoelectric materials with the building envelope for active space heating and cooling. The advantage of TBE heating and cooling includes its significantly low-profile design and no refrigerant use. Although there are existing studies evaluating TBE performance, they were based on limited operating conditions. The study aims to experimentally evaluate the heating and cooling performance of a TBE prototype under various operating conditions. The TBE prototype was installed between two psychrometric chambers, which simulated indoor and outdoor conditions. The prototype was tested at an indoor temperature of around 22.35–23.58 degrees C and outdoor temperatures from …

Evaluation Of Flood Damage On Cross Laminated Timber Wall Configurations, Mustafa Nezih Kaya

Theses and Dissertations

Greenhouse gas emissions are one of the critical factors that affect climate change, increasing flooding risk and threatening human life. The use of traditional construction materials is responsible for a higher percentage of global greenhouse gas emissions when compared to the use of sustainable materials in the construction industry. The substitution of current building materials with sustainable materials is essential to reduce greenhouse gas emissions and positively influence climate change when the current construction demand in the world is considered. Wood is one of the primary environmentally friendly construction materials in regard to high carbon storage and low carbon emissions. …

Mechanical Responses Of Soil-Geosynthetic Composite (Sgc) Mass Under Failure Load, Meen-Wah Gui, Truc Phan, Thang Pham

Civil Engineering Faculty Publications

There is an increasing awareness on the major benefits of using soil-geosynthetic composite (SGC) to achieve and maintain the stability of earth-filled embankment. Unlike the mechanically stabilized earth wall, the mechanism of the composite mass is still not fully understood. For examples, current analyses have been limited to an SGC mass with a reinforcement spacing Sv of 0.2 m only; the combined effect of reinforcement and backfill properties is rarely studied; the equation for the estimation of the load-carrying capacity of the SGC mass has only been validated for backfill with maximum particle size dmax between 10 mm and 33 …

Effect Of Varying Amounts Of Sandstone On The Performance Of Asphalt Mixtures In Arkansas, David Murphy

Graduate Theses and Dissertations

There are many different species and subspecies of aggregate used across the state of Arkansas, and the rest the country. However, it cannot be presumed that the amount and type of these aggregates will be compatible with the commonly used asphalt binder of an area; this can lead to performance issues and premature pavement damage. It has been suspected in Arkansas that an excessive amount of sandstone in asphalt mixtures may be a culprit of some of these premature pavement damage issues, especially regarding the moisture susceptibility of a pavement. This study aimed to analyze the performance effects of using …

Development Of Deep Shear Wave Velocity Profiles And An Approach To Generate Site Signature Consistent Pseudo Shear Wave Velocity Profiles In The Mississippi Embayment, Ashraf Kamal Himel

Graduate Theses and Dissertations

This dissertation details the development of a surface wave method (SWM) technique to generate deep shear wave velocity profiles (VS profiles), applying this technique at 24 sites across the Mississippi embayment and developing an approach to generate pseudo site signature consistent VS profiles from velocity functions and fundamental frequency. In the presented SWM technique, active and passive source surface wave measurements are inverted along with fundamental frequency to develop a site signature consistent VS profile. Multiple transformation methods, including MSPAC, HRFK and FK are used to resolve experimental dispersion data from surface wave measurements. SWM VS profile at the Central …