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Full-Text Articles in Engineering
Monitoring Damage Occurrence, Post-Peak Crack Propagation And Air Permeability In Concrete Using The Brazilian Indirect Tension Test, Angel M. Padilla
Monitoring Damage Occurrence, Post-Peak Crack Propagation And Air Permeability In Concrete Using The Brazilian Indirect Tension Test, Angel M. Padilla
Civil Engineering ETDs
This research aims to investigate the relationship between stress, damage, crack propagation, and permeability evolution in concrete. A novel experimental test method is presented that enables monitoring post-peak cracking behavior of concrete using the Brazilian tension test by slowing crack propagation while concurrently measuring permeability and monitoring damage propagation using acoustic emission techniques. The modified Brazilian test method utilizes spring supports in parallel to the test specimen to off-load the test specimen incrementally to slow down the post-peak crack propagation. A vacuum flow system is attached to the rear side of the concrete during loading to measure apparent air permeability …
The Development Of A Novel Experiment On Confined, Flattened Brazilian Disks To Correlate Damage And Permeability In Brittle Geo-Materials, Samuel H. Boyce
The Development Of A Novel Experiment On Confined, Flattened Brazilian Disks To Correlate Damage And Permeability In Brittle Geo-Materials, Samuel H. Boyce
Civil Engineering ETDs
This research develops a novel experiment using flattened Brazilian disks under confining pressure with concurrent permeability measurements and acoustic emission monitoring. The purpose of this work is to correlate damage and permeability in brittle geo-materials. Two series of tests are performed on concrete and one series on tuff, under a range of confining stresses between 2.76 and 13.79 MPa. Tests were continued beyond peak stress conditions, capturing data in the post-peak region. The acoustic emission data (cumulative energy and counts) are used to identify damage thresholds and track the progression of microscopic damage. This quantified damage is then correlated to …
Effects Of Coefficient Of Thermal Expansion On Unbonded Concrete Overlay Design And Performance, Gauhar Sabih
Effects Of Coefficient Of Thermal Expansion On Unbonded Concrete Overlay Design And Performance, Gauhar Sabih
Civil Engineering ETDs
With the deterioration of highway pavements across the country, more emphasis is being laid on the rehabilitation of existing pavements. Unbonded concrete overlay (UBCO) is a cost-effective technique used to rehabilitate damaged concrete pavements. The design and performance of UBCO rely on various properties of concrete, of which coefficient of thermal expansion (CTE) is an important one. Concrete CTE has a direct impact on the design and performance of rigid pavements and overlays. CTE regulates the magnitude of curling and related stresses that impact the performance of overlays with regards to cracking, faulting and pavement roughness. Previous research revealed that …
Modeling And Simulation Of Damage In The Brazilian Indirect Tension Test Using The Finite-Discrete Element Method, Jeremiah C. Leyba
Modeling And Simulation Of Damage In The Brazilian Indirect Tension Test Using The Finite-Discrete Element Method, Jeremiah C. Leyba
Civil Engineering ETDs
The Brazilian indirect tension test is used to investigate possible correlations between progressive damage and associated permeability changes. The test offers ease of replicability with a damage behavior known to lead to fracture openings as a tool for interpreting the indirect tensile strength of concrete and rocks. This behavior can lend insight into the nature of tensile damage and fracture progression in association with changes in permeability. The nature of these brittle materials is known to exhibit rapid failures in the Brazilian indirect tension test and require a method to retard the progression of damage for the possibility of acquiring …
Understanding Asphalt Concrete Aging Using Nanoindentation, Hasan M. Faisal
Understanding Asphalt Concrete Aging Using Nanoindentation, Hasan M. Faisal
Civil Engineering ETDs
Asphalt concrete (AC) is created by mixing liquid asphalt binder with solid aggregates. When asphalt binder is mixed with aggregates, it creates a thin film (about 7-16 microns thick) around the aggregate surface. Fine aggregate (smaller than 0.075 mm size) get entrapped within the binder film or mixed with the binder, and create a phase called mastic. Both asphalt film and mastic play significant roles in aging of asphalt pavement. To this day, tests were performed mainly on the bulk liquid asphalt, but not on the film or mastic. In this study, for the first time, nanoindentation tests were done …
Applying Modern Technology In The Preservation Of Historic Concrete Picnic Tables, Michele M. Anderson
Applying Modern Technology In The Preservation Of Historic Concrete Picnic Tables, Michele M. Anderson
Civil Engineering ETDs
Preserving historical concrete structures recognizes the work and skills of past generations and allows the communities surrounding these pieces of history the opportunity to enjoy the character and purpose of their construction. Restoration of concrete picnic tables, constructed in the 1930s by the Civilian Conservation Corps, required researching materials and methods of construction during the original construction period. Eight decades of environmental and weather cycles did not decay the historic structures. Acts of vandalism destroyed the purpose of the tables and benches. Restoration of the historic picnic tables required extensive literature review for the materials and methods used during the …
State-Based Peridynamic Particle Method, Siavash Nikravesh Kazeroni
State-Based Peridynamic Particle Method, Siavash Nikravesh Kazeroni
Civil Engineering ETDs
In this study, a novel discrete Peridynamics framework called the “State-Based Peridynamic Particle Model (SPPM)” is introduced. In this approach, a solid body is simulated by neither solving differential equations nor integral equations; instead, the simulation is accomplished by directly solving discrete systems of equations using finite summations. SPPM is formulated for a random distribution of particles, hence, it can be considered as a meshfree method. The assumptions of continuity and homogeneity are not necessary for this approach. The SPPM is a generalization of the “State-Based Peridynamic Lattice Model (SPLM)”. In the SPLM formulation, for sake of simplicity and computational …
The Effects Of An Epoxy (Epocast 546) Upon The Tensile And Compressive Properties Of Portland Cement Concrete, Alvy C. Jackson
The Effects Of An Epoxy (Epocast 546) Upon The Tensile And Compressive Properties Of Portland Cement Concrete, Alvy C. Jackson
Civil Engineering ETDs
Although the behavioral pattern of plain concrete in compression is fairly consistent, its tensile properties leave much to be desired. The laboratory investigation described here was an attempt to increase the tensile property of plain concrete by adding an epoxy resin compound to the mixture. The investigation included tests for both compressive and tensile strengths of the mixtures that were considered. The compressive strength tests were included to determine what effect, if any, the attempt to increase the tensile property had on compressive strength.