Engineering Commons^™

Durability And Fatigue Behavior Of Cip Concrete Connections For Accelerated Bridge Construction, Peng Zhu

Doctoral Dissertations

Continuous longitudinal and transverse U-bar joint connections between flanges of the decked bulb-Ts (DBTs) or between precast panels for accelerated bridge construction are investigated. The procedure for selecting durable closure pour (CP) materials for the connections is discussed firstly. The accelerated construction is quantified as two categories: overnight cure and 7-day cure of CP materials. Candidate materials are selected first based on literature review as well as tests of compressive strength and flow and workability. Then, performance criteria for selecting durable CP materials for both categories are developed based on durability tests of selected candidate materials. These durability tests include …

Development Of Internally Cured Concrete For Increased Service Life, John Schlitter, Ryan Henkensiefken, Javier Castro, Kambiz Raoufi, Jason Weiss, Tommy Nantung

JTRP Technical Reports

Higher strength, lower water to cement ratio (w/c) concrete has been advocated over the last two decades due to its increased strength and reduced permeability. The lower w/c of these concretes makes them susceptible to autogenous shrinkage. This autogenous shrinkage can be significant and can be a contributing factor to early age cracking. Internal curing was investigated as a potential method to improve the durability of concrete pavements and bridge decks. Prewetted lightweight aggregate was used to supply water to the hydrating cement paste. This additional water can counteract the hindered strength development, suspended hydration, autogenous shrinkage, and early age …

Reuse The Bed Ash From Circulating Fluidized Bed Combustion On Mortar Mixture, Hui-Mi Hsu, An Cheng, Sao-Jeng Chao

Journal of Marine Science and Technology

This paper investigates mortars consisting of various circulating fluidized bed combustion (CFBC) bed ash contents. The CFBC bed ash used in this study was obtained from Taiwan’s petroleum industry. This study presents experimental results on the flowability, compressive strength, drying shrinkage, scanning electronic microscopy (SEM) and mercury intrusion porosimetry (MIP) of mortar samples containing CFBC bed ash. The initial surface absorption tests (ISAT) and rapid chloride penetration test (RCPT) of mortar were used to measure water absorption and the ability to resist chloride ion characteristics for different mortar samples containing CFBC bed ash. CFBC bed ash is X-ray amorphous and …

Developments In Intelligent Monitoring Of Concrete Structures, T. M. Chrisp, G. Starrs, W. J. Mccarter, E. H. Owens, S. V. Nanukuttan, Niall Holmes, L. Basheer

Conference papers

Deterioration in concrete comprises an initiation period and a propagation period. The initiation period is characterised by changes that occur within the concrete in response to the exposure environment and continues until a stage is reached when damage begins to propagate. The propagation period begins at a point in time defined when a particular event occurs (e.g. loss of steel passivity due to chloride ingress) and continues until a specified limit state is reached. The initiation and propagation stages of a deterioration process result from a complex interaction of physical, chemical and electrochemical phenomena. Prediction of the field performance of …

Factors Affecting Asphalt Pavement Density And The Effect On Long Term Pavement Performance, Jonathan Fisher, Clark Graves, Phillip Blankenship, Salman Hakimzadeh-Khoee, R. Michael Anderson

Kentucky Transportation Center Research Report

The Kentucky Transportation Center, the Asphalt Institute, and the Kentucky Transportation Cabinet worked together in order to identify factors that affect asphalt pavement density, and to then evaluate their effect on long term pavement performance.

By determining which variables are most influential to pavement performance (i.e. roller pattern, temperature when rolled, etc.), and then monitoring the attention given to those variables, Kentucky would be able to increase the service life of asphalt roadways by at least 25%, therefore saving as much as $30 million annually on a resurfacing budget of $129.2 million (2007), while still maintaining the current roadway level …

On The Use Of Polyurethane Matrix Carbon Fiber Composites For Strengthening Concrete Structures, Zachary Haber

Electronic Theses and Dissertations

Fiber-reinforced polymer (FRP) composite materials have effectively been used in numerous reinforced concrete civil infrastructure strengthening projects. Although a significant body of knowledge has been established for epoxy matrix carbon FRPs and epoxy adhesives, there is still a need to investigate other matrices and adhesive types. One such matrix/adhesive type yet to be heavily researched for infrastructure application is polyurethane. This thesis investigates use of polyurethane matrix carbon fiber composites for strengthening reinforced concrete civil infrastructure. Investigations on mirco- and macro-mechanical composite performance, strengthened member flexural performance, and bond durability under environmental conditioning will be presented. Results indicate that polyurethane …

Production Of High Strength Concrete Incorporating An Agricultural Waste- Rice Husk Ash, Hilmi Mahmud

Hilmi Mahmud

Rice husk which is an agricultural waste, constitutes about one-fifth of the 500 million tonnes of rice produced annually worldwide. Normally, the residue is disposed off by burning at the mill sites and the resultant rice husk ash (RHA) is dumped on a waste land. This generates environmental, pollution and land dereliction problems. Under controlled burning and if sufficiently ground, the highly reactive ash that is produced can be used as a supplementary cementing material or in the production of high strength concrete (HSC). This paper shows that it is relatively easy to produce high strength Grade 80 concrete incorporating …

Developments In Monitoring Techniques For Durability Assessment Of Cover-Zone Concrete, W.J. Mccarter, T. M. Chrisp, G. Starrs, Niall Holmes, L. Basheer, M. Basheer, S. V. Nanukuttan

Conference papers

This paper outlines developments in the use of an embedded multi-electrode sensor to study the response of the cover-zone (surface 50mm) to the changing ambient environment. The sensor enables the measurement of the spatial and temporal distribution of the electrical properties of concrete and temperature within the cover-zone thereby allowing an integrated assessment of cover-zone concrete performance. Both laboratory and field results are presented to highlight the information that can be obtained from embedded sensors. When exposed to the natural environment, the temperature dependence of the electrical response is highlighted and standardization protocols are developed to account for this effect. …