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Improving Bridge Concrete Overlay Performance, Gregory Vieira
Improving Bridge Concrete Overlay Performance, Gregory Vieira
Theses and Dissertations
Low slump concrete overlays have been widely utilized in the midwestern United States, including Wisconsin, to mitigate bridge deck deterioration and extend service life. However, concerns regarding their performance have necessitated investigations into optimal mix designs, placement procedures, and curing practices. This study focuses on assessing the cracking potential of seven overlay mixtures, including: Current Wisconsin Grade E concrete with Type I and IL cement, latex modified concrete, fly-ash modified Grade E concrete, Grade E with reduced cement content, and fiber reinforced concrete. The various concrete mixtures were tested for compressive strength, slump, and air content. Seven 8ft x 8ft …
Assessments Of Concrete Internal Damage Caused By Freeze-Thaw Cycles And Mechanical Loading, Zeqian Li
Assessments Of Concrete Internal Damage Caused By Freeze-Thaw Cycles And Mechanical Loading, Zeqian Li
Theses and Dissertations
Concrete in bridge decks in Northern States, such as Wisconsin, is subjected to both freeze-thaw cycles and mechanical stresses. Standard testing methods are available to evaluate the deterioration of concrete, including ASTM C215 (Dynamic Modulus test), ASTM C1202 (Rapid Chloride Ion Penetrability test), and ASTM WK37880 (ESR test) are available. In addition, ASTM C642 (water absorption test) helps quantification of permeable voids in concrete. These tests have been used to evaluate undamaged concrete or concrete samples after freeze-thaw cycles.
The concrete samples in this study have been subjected to compressive stresses (0.4f_c^') and freeze-thaw cycles (100 to 300 cycles) to …
Smart Carbon Nanotube/Fiber And Pva Fiber-Reinforced Composites For Stress Sensing And Chloride Ion Detection, Joshua A. Hoheneder
Smart Carbon Nanotube/Fiber And Pva Fiber-Reinforced Composites For Stress Sensing And Chloride Ion Detection, Joshua A. Hoheneder
Theses and Dissertations
Fiber reinforced composites (FRC) with polyvinyl alcohol (PVA) fibers and carbon nanofibers (CNF) had an excellent flexural strength in excess of 18.5 MPa compared to reference samples of 15.8 MPa. It was found that the developed, depending on applied stress and exposure to chloride solutions, composites exhibit some electrical conductivity, from 4.20x10^-4 (ohm*m)^-1 to. 4.13x10^-4 (ohm*m)^-1. These dependences can be characterized by piezioresistive and chemoresistive coefficients demonstrating that the material possesses self-sensing capabilities. The sensitivity to stain and chloride solutions can be enhanced by incorporating small amounts of carbon nanofibers (CNF) or carbon nanotube (CNT) into composite structure. Conducted research …