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Articles 241 - 270 of 419

Full-Text Articles in Civil and Environmental Engineering

Frictional Resistance Of Geotextiles, Md. Khairul Alam Dec 1991

Frictional Resistance Of Geotextiles, Md. Khairul Alam

Theses

The pullout resistance of geotextiles was examined using pullout tests. A suitable wooden box with large (2 ft x 2 ft x 4 ft) dimensions was used to avoid the effect of boundary and to simulate field conditions. Two types of failure patterns were observed. For shallow embedment (<3 ft), geotextile produced a movement of the surrounding mass of sand in the shape of an inverted cone due to interlocking friction between geotextile and sand particles. The cone angle decreases with increase in depth of embedment. For embedment equal to or greater than 3 ft., no sand cone developed and the failure occurred along the interface of geotextile and sand. For 1 ft. surcharge, the increase in the pullout resistance due to combined horizontal and vertical embedment was about 30 %.


Stability And Durability Of Large Aggregate Asphalt Concrete, Rais A. Khan Dec 1991

Stability And Durability Of Large Aggregate Asphalt Concrete, Rais A. Khan

Theses

There are many factors which affect the properties of asphalt concrete and one of these is a maximum aggregate size used in the mix. In this study of the effect of maximum aggregate size on Marshall stability, flow and durability of asphalt aggregate mixtures is investigated.

Two different mixes having gradations with maximum aggregate sizes of 3/4 and 1-1/2 inches were considered. The optimum asphalt content for mix having 3/4 inch maximum aggregate size, was determined by the standard Marshall procedure. The optimum asphalt content for the mix having 1-1/2 inch maximum aggregate size, was estimated based on thickness of …


Strength And Fragility Of Concrete, Kang-Qun Shao Dec 1991

Strength And Fragility Of Concrete, Kang-Qun Shao

Theses

It is known that both strength and fragility are two of the most important properties in concrete. In this research, theories of Chemistry, Physical Chemistry of Surfaces, Thermodynamics and Fracture Mechanics are used to study the relationships between the macromechanical behavior of concrete and the microstructure in concrete. The objectives of this research are therefore to find some effective ways to explain theoretically why the concrete is so brittle (fragile) and how to increase its strength or to decrease its fragility. Based on the present studies, an equation is formulated to calculate the coefficient of the fragility (or brittleness) of …


The Strength Of Cement Bentonite In Containment Structures, Liong Tin So Dec 1991

The Strength Of Cement Bentonite In Containment Structures, Liong Tin So

Theses

In recent years the use of cutoff or slurry walls has increased in the containment of hazardous waste. Several materials have been utilized for backfill in slurry walls. Two important properties of the material are shear strength and permeability. Previously, sodium bentonite had been used. However, it was discovered that variable pH would cause an increase in permeability. Studies have shown calcium bentonite have a constant permeability with varied pH (Oweis and Khera, 1990). This study was undertaken to determine strength of calcium bentonite as affected by cement and slag.

Triaxial shear tests and unconfined compression tests were done on …


Disc Size Scale-Up In Rotating Biological Contactor System, Chi-Sheng Chang Oct 1991

Disc Size Scale-Up In Rotating Biological Contactor System, Chi-Sheng Chang

Theses

Disc size scale-up of prototype and small-scale RBC plants are successfully developed by applying the 114 data sets obtained from 12 RBC plants to the evaluation of percent sBOD remaining. These data analyses are performed by the least square method, therefore, the scale-up factors of the prototype and the small-scale are determined at different hydraulic loading. Furthermore, the relationship between scale-up factor and the disc diameter are established under the given flow rate, the number of stages, and the number of discs. A group of Curves are obtained and can be utilized for the full-scale RBC plant preliminary design. The …


Stability Of Hot Mix Asphalt With Petroleum Contaminated Soils, De-Rong Lobo Huang Sep 1991

Stability Of Hot Mix Asphalt With Petroleum Contaminated Soils, De-Rong Lobo Huang

Theses

One of the most effective ways of reducing petroleum contaminated soil is to use it in the production of hot mix asphalt. Both asphalt cement and petroleum contaminates have similar chemical properties. Therefore, The contaminates will be locked within the asphalt matrix without potential leaching.

The six different petroleum contaminate soil samples from New Jersey were used in this research. Since those samples have different physical properties (such as moisture content, specific gravity, plastic limit, liquid limit, grain size distribution) and chemical properties( such as concentration of the contaminate, and type of contaminates) the maximum amount of petroleum contaminated soil …


Load-Deformation Behavior Of Reinforced Fibrous Concrete Beams, Rujun He May 1991

Load-Deformation Behavior Of Reinforced Fibrous Concrete Beams, Rujun He

Theses

This study deals with the load-deformation behavior of steel fiber reinforced concrete beams.

Theoretical development of moment-curvature and load-deformation relationships is presented in this paper. It is based on the assumption that the failure at a section occurs either when the force equilibrium equation is violated or when the concrete elements start to get crushed in the member. The complete stress-strain relationship of plain fibrous concrete in reference [2] was used in this study.

A special computer program is presented herein to carry out the theoretical studies of load-deformation behavior of simply supported beam under two-point loading. The validity of …


Automated Determination Of Air Content In Hardened Concrete, Anita R. Navalurkar May 1991

Automated Determination Of Air Content In Hardened Concrete, Anita R. Navalurkar

Theses

An automated system was developed for the microscopic determination of air content and the related parameters in hardened concrete using the principles of Image Analysis and Computer Technology. Slices taken from the concrete specimen were viewed through a microscope with 40X magnification. The magnified image of the concrete slice is digitized by an Image Analyzing Software. Methodologies were developed for analysis of the digitized image and determination of air content and the required parameters. The automated system included a motorized positioner which translated microscope stage in a frame by frame sequence so that the whole image is digitized. Several tests …


Evaluation Of Cracking Mechanism In Fiber Reinforced Concrete Subjected To Impulsive Loading, Rajendra K. Navalurkar May 1991

Evaluation Of Cracking Mechanism In Fiber Reinforced Concrete Subjected To Impulsive Loading, Rajendra K. Navalurkar

Theses

This thesis presents an experimental evaluation of J-Integral for plain and fiber reinforced concrete subjected to impact loading. A computer assisted instrumented Charpy test system was employed in applying the impact loads. Twenty two three point bend specimens with two different notch lengths were tested under impact velocity of 43.29 in/sec. Development and testing of a new fiber optic sensor, for the determination of internal Crack Tip Opening Displacements (CTOD) in concrete is described.

Evaluation of JIC values from experimental results of this study indicate that JIC can be characterized as a material constant. The Dynamic value of …


Water Treatment Plant Sludge As Sanitary Landfill Liner, Sinnadurai Sockanathan May 1991

Water Treatment Plant Sludge As Sanitary Landfill Liner, Sinnadurai Sockanathan

Theses

This study was performed to explore the possibility of using the sludge waste from the water treatment plant at Boonton New Jersey as a containment material for the sanitary landfills or as a fill material. At present natural clay is being used as a containment liner for the landfills and by using this sludge, recycling of a waste product will be achieved in an economical manner.

As a first part of this studies, efforts were made to utilize the liquid sludge having a solid content of about 3%. Attempts to dewater the liquid sludge to a workable mix by adding …


Determination Of Water-Cement Ratio In Cement Paste By Atomic Absorption Spectrometry, Jiong Zhao May 1991

Determination Of Water-Cement Ratio In Cement Paste By Atomic Absorption Spectrometry, Jiong Zhao

Theses

As one of the important characteristics of concrete, water-cement ratio controls porosity and thus strength and corrosion resistance of hardened concrete.

This paper presents a laboratory observation for determination of water-cement ratio of fresh concrete for quality control and quality assurance. The atomic absorption spectrophotometer and the flouresence spectrophtometer were used to determine the calcium concentration in cement solution of various water-cement ratio. The level of water-cement ratio investigated ranged from 0.4 to 0.55 which covers the most range of water-cement ratios in present practice. The result of lab experiments shows an immediate relation between the water-cement ratio and the …


Influence Of Fly Ash Characteristics On Compressive Strength Of Mortar, Poorna Rajeswari Ratnaweera May 1991

Influence Of Fly Ash Characteristics On Compressive Strength Of Mortar, Poorna Rajeswari Ratnaweera

Theses

Fly ash-cement mortar, constituting of fly ash, cement and sand, vary in strength characteristics from conventional cement sand mortar. Out of many parameters effecting the compressive strength characteristics of fly ash-cement mortar, four were investigated in this study. They are particle size and its distribution, weathering of fly ash, moisture content & water/cementitious ratio and mix proportioning.

Class F fly ashes from three different sources were used in this study. The particle size distribution and moisture content of fly ashes were investigated by standard ASTM methods. The unconfined compressive strength of mortar was obtained by testing 2"x2"x2" test cubes conforming …


Solidification/Stabilization Of Chromium Contaminated Soil Using Cement And Fly Ash, Arunkumar Sripathi May 1991

Solidification/Stabilization Of Chromium Contaminated Soil Using Cement And Fly Ash, Arunkumar Sripathi

Theses

Chromium, when present in the soil, can cause serious health hazards. Toxicity depends upon the concentration in the soil. Chromium in soil has become a major problem in some sites and a method must be developed so that it can be treated or disposed of in a safe manner.

In this research experiments are conducted to check whether the chromium contaminated soil can be solidified and landfilled in a safe way. To have a control over the amount of chromium present in the soil, pure soil (free from chromium contamination) was used and chromium was added in different proportion.

Another …


Centrifugal Modeling Of Leaking Underground Storage Tanks, Kuo-Neng George Chang Jan 1991

Centrifugal Modeling Of Leaking Underground Storage Tanks, Kuo-Neng George Chang

Theses

There are between 2 to 3.5 million Underground Storage Tanks (UST) located through this nation. Most of these tanks store gasoline and fuel oil. Many tanks in fact are or will soon be leaking, thus making them one of the major sources of groundwater contamination in USA. The fate and transport of chemicals from the leaking USTs is estimated from mathematical models. A major difficulty in these modeling efforts has been a crucial lack of information concerning the constitutive relationships governing multiphase contaminant movement.

Centrifugal modeling is an alternative to mathematical modeling, which may give an insight to the problem …


A Pc Based Computer Model With A Postprocessor For The Movement Of Groundwater, Joseph Byra Dec 1990

A Pc Based Computer Model With A Postprocessor For The Movement Of Groundwater, Joseph Byra

Theses

Currently available computer programs that model groundwater flow are inherently limited in their capabilities, in one way or another. Additionally, many of these computer programs are relatively inaccessible to the general user because they operate off of mainframe computers and sophisticated plotters. As a result, a simple to use computer program called 2DFLOW has been modified so it can be run on a personal IBM compatible computer. It models steady-state fluid flow through saturated porous media. In addition, a postprocessor called 2DPLOT has been developed. The postprocessor generates the equipotential contours and the flux vectors that describe the physics of …


The Dewaterability Of Anaerobically-Digested Sludges, Hui-Ching Lee Dec 1990

The Dewaterability Of Anaerobically-Digested Sludges, Hui-Ching Lee

Theses

Vacuum filtration is the most common method used for sludge dewatering. Filtering or dewatering was operated to reduce the moisture content of the sludge after anaerobic digestion treatment.

The main purpose of this study is to determine the effect of the operating conditions of anaerobic digestion system on specific resistance in sludge filtration. The anaerobic sludges used for the present study were produced from the conventional single stage system and the multiple-stage system. From the experimental results, presently obtained that it is possible to compare the advantage and disadvantage of the two different digestion systems.

In addition, the effectiveness of …


Temperature Scale-Up On Rotating Biological Contactor Nitrification System, Kuanchun Lee Dec 1990

Temperature Scale-Up On Rotating Biological Contactor Nitrification System, Kuanchun Lee

Theses

The relationship between RBC scale-up factor (SUF) and wastewater temperature is successfully developed by using Dr. Wu's mathematical model as a basis and 114 sets of data from the operation of 8 full-scale and 5 pilot-scale RBC plants served for NH3-N removal. The SUF obtained from this study is put into practice to present the scale-up of hydraulic loading for basic full-scale RBC plant design when the pilot study results are known and the design efficiency is fixed. An additional study is made to investigate two different RBC products manufactured by Autotrol Inc. and Lyco Inc. in terms of the …


A Critical Analysis On Cogeneration Policy, R. Tjahjokartiko Gondokusumo Aug 1990

A Critical Analysis On Cogeneration Policy, R. Tjahjokartiko Gondokusumo

Theses

It could be difficult to understand electricity problems without knowing its history; how a combine of legal, administration, and financial means effects electricity in the development. The recent public law on energy-related issues traceable by this study is the Renewable Energy and Energy Efficiency Technology Competitiveness Act of 1989.

In short, cogeneration was proposed to utility (as public property) from industry (as private property) under PURPA (of which National Energy Act is the legislative history). Thus, it should be clear that the problems of cogeneration is not pro or contra issues. It is a national issue. Then, a cogeneration planner …


Construction Cost Estimating In Project Management, Kalpit N. Patel May 1990

Construction Cost Estimating In Project Management, Kalpit N. Patel

Theses

The primary objective of Cost Estimating is to support the timely generation of bid or alternative estimates. Cost Estimating also supports management analysis of estimate accuracy, reasonableness and project risk through the generation of summary reports and analysis. Estimates also provide a base of information during construction for such items as scope changes to the contract, variations in costs of the project cost, total project cost, feedback for scheduling etc.

Contruction cost estimating is the process of identifying and compiling the many items of cost that will enter into a construction project. This is a procedure that requires very detailed …


Experimental Evaluation Of Process Zone Deformation In Concrete, Cherng-Maou Meng May 1990

Experimental Evaluation Of Process Zone Deformation In Concrete, Cherng-Maou Meng

Theses

Concrete structures are often subjected to a variety of loading conditions. Under ultimate load design, concrete structures can resist these loads without evident deformation. However, under service, tension cracks will develop and depending on their location, they may impair load carrying capacity.

It is generally believed that microcrack development is preceeded by formation of a relatively long microcracked region. A large number of studies have indicated that due to formation of this process zone (microcracked zone), Linear Elastic Fracture Mechanics (LEFM) principles are not applicable to concrete. However, a number of nonlinear models can be developed if the length of …


Prestressed Concrete Columns Under Bending And Axial Load, Ajit Chiplunkar May 1990

Prestressed Concrete Columns Under Bending And Axial Load, Ajit Chiplunkar

Theses

A general analysis and design equation for slender and nonslender prestressed concrete columns subjected to uniaxial or biaxial moments combined with axial load is proposed. The proposed equation is an extension to the one developed by Hsu for reinforced concrete columns. The analytical results of the ultimate loads of eccentrically loaded slender prestressed columns are compared with the experimental results reported by Brown and Hall and Aroni respectively. The comparative study shows that the proposed equation of interaction diagram is in good agreement with the actual tests.

The ultimate loads of biaxially loaded short columns are also compared with the …


Shear Behavior Of Steel Fiber Reinforced Concrete Beams Under Monotonic And Cyclic Loads, June Suh May 1990

Shear Behavior Of Steel Fiber Reinforced Concrete Beams Under Monotonic And Cyclic Loads, June Suh

Theses

Up to now relatively few tests have been reported on shear behavior in fiber reinforced concrete beams. Even less experiments have been carried out under fatigue loading. In the present experiment, the reinforced concrete beams with 1 percent and 2 percent steel fiber volume fraction are investigated. Conventional stirrups are included in number of beams at certain intervals. Beams are loaded under monotonic and cyclic loads. The strength of beams are determined and the behavior of beams under each loading are observed in order to determine some advantages of adding steel fibers to reinforced concrete beams.

It has been found …


Study Of Essential Factors Affecting The Efficiency Of Sludge Digestion, I-Chang Tsao May 1990

Study Of Essential Factors Affecting The Efficiency Of Sludge Digestion, I-Chang Tsao

Theses

The sludge produced by wastewater treatment plant has some major characteristics such as high COD ( 52093 mg/1 - 79683 mg/1) and VS ( 19247 mg/1 - 44178 mg/1). The present laboratory investigation has indicated that successful treatment and purification of the subject of sludge is possible using multiple-stage anaerobic digestion system.

The multiple-stage system is capable of degrading 40-55% of COD and 50 to 60% of VS. The conventional digestion system degrades 30-45% of COD and 40-50% of VS. After treated by conventional system and multiple-stage system, the concentration of COD and VS are still high (21200 mg/1 - …


Effects Of Fly Ash And Kiln Dust On The Compressive Strength Of Cement Mortar, Yitao Yu May 1990

Effects Of Fly Ash And Kiln Dust On The Compressive Strength Of Cement Mortar, Yitao Yu

Theses

Fly ash generated from coal-burning power plants has been an increasing problem to the utility company in terms of storage and disposal in compliance with the environmental regulations. Presently, fly ash has been widely used in the concrete mix. Research shows that fly ash can improve many properties of fresh and harden concrete. Landfill is another significant usage of fly ash. Usually, fly ash is stored in dry and weathered conditions. The properties of fly ashes from different sources and in different storage conditions are different.

In this research, the compressive strength of mortar containing cement replacement of Deep Hollow, …


A Study Of Methane Gas Production On Anaerobic Digestion System, Seng-Fung Su May 1990

A Study Of Methane Gas Production On Anaerobic Digestion System, Seng-Fung Su

Theses

The anaerobic sludge digestion process is not a recent development. At least 100 years ago in France,Louis H. Mouras designed and constructed fermenters to liquefy the sludge obtained from domestic wastes.

Since the turn of the century, the anaerobic fermentation process has been used extensively in the treatment of waste-water solids.

The necessity of preventing pollution of water resource, as a consequence of the rapid increase in human waste, demands adequate treatment of liquid wastes from domestic and industrial sources. For this purpose, the anaerobic digestion process can play an important role as a method for stabilizing and eliminating wastes …


Demulsification And Separation Of Oil In A Water/Particulate System, Fong-Jung Tai May 1990

Demulsification And Separation Of Oil In A Water/Particulate System, Fong-Jung Tai

Theses

The wastewater generated from installation factories contains high suspended solids ( SS ) and oil. Effective removal of oil and clay particles in washrack wastewater can be achieved by using organic polymer TFL-398 alone or in conjunction with alum. The dissolved/emulsified oil concentration and suspended solids are used to represent the degree of oil demulsification and clay particles destabilization, respectively.

To improve the efficiency of oil demulsification and reduce the chemical consumption, pretreatment of the influent wastewater is essentially necessary. pH adjustment to 11-12 generally reduces chemical requirement. Total oil concentration was reduced significantly at pH = 11.7 without any …


Calcium Bentonite In Containment Structures, Ramnarayan K. Tirumala May 1990

Calcium Bentonite In Containment Structures, Ramnarayan K. Tirumala

Theses

Experiments were conducted on calcium bentonite from different sources to determine its suitability as a material for slurry wall. The emphasis was placed on cement-bentonite types of materials. A few tests were conducted on specimens consisting of soil-bentonite materials. Permeability, swelling potential, and immersion tests were conducted. Specimens were initially permeated with water to determine which variety of bentonite was most suitable and later with chemicals. In cement bentonite specimens, the effect of addition of blast furnace slag, fly ash, and sand were also studied. Addition of slag cement lowered the permeability value by an order of magnitude, and with …


Behavior Of Slender High Strength Reinforced Columns Under Biaxially Eccentric Loading, Pei-Shiun Wu May 1990

Behavior Of Slender High Strength Reinforced Columns Under Biaxially Eccentric Loading, Pei-Shiun Wu

Theses

The advantage of using high strength concrete is to reduce column sizes and to increase stiffness. At present there are not any available design aids and the code provisions that provide adequate guidelines for the design of slender columns in high strength concrete.

A total of four 3 in. by 3 in. dimension, 4 ft. length high strength concrete specimens were casted, cured and tested till failures in a vertical pinned-ended configuration.The experimental results were compared with the analysis using Hsu failure surface equation.

Moment, curvature and load deflection cures were obtained successfully from the present experimental tests. These curves …


Behavior Of Slender High Strength Steel Fiber Reinforced Concrete Columns Under Combined Biaxial Bending And Axial Compression, Tzuoh-Jaw Wu May 1990

Behavior Of Slender High Strength Steel Fiber Reinforced Concrete Columns Under Combined Biaxial Bending And Axial Compression, Tzuoh-Jaw Wu

Theses

A total of four slender high strength steel fiber ( 20 vol. hooked ends 1 in and 2 in ) reinforced concrete columns were casted, cured and tested to failure under biaxially eccentric load us—KT MTS testing system. The experimental load-deflection behavior exhibits not only the ascending branch but also the descending branch of the load and deformation curves.

The experimental ultimate load capacity was analyzed by the equation of Failure Surface Method developed by Hsu. recently, the result shows that the analysis method is able to predict the ultimate load value for biaxially loaded slender concrete columns.

For biaxially …


Investigation Of Mixed-Made Fracture In Concrete, Stylianos C. Aniftos May 1990

Investigation Of Mixed-Made Fracture In Concrete, Stylianos C. Aniftos

Theses

This study is aimed at evaluating the failure characteristics of concrete in the notched beam configuration. In general, for Mode I failure tension is commonly encountered. However, in the area of high shear stress, it remains to be a question whether shear or Mode II failure exists. Researches carried out in the past decade confirmed the existance of both Mode I and Mode II failure. It is the objective of this investigation to clarify this failure characteristics using FRANC an interactive fracture mechanics software.

The investigation carried out in this study used the experimental results of Bazant and Pfeiffer (3) …